staging: Move ralink-gdma to its own directory
authorGeorge Hilliard <thirtythreeforty@gmail.com>
Fri, 11 Jan 2019 00:43:36 +0000 (17:43 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 15 Jan 2019 15:28:02 +0000 (16:28 +0100)
This is in preparation to allow it and the mt7621-dma drivers to be
built separately.  They are completely independent pieces of software,
and the Kconfig specifies very different requirements.

Cc: linux-kernel@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: Neil Brown <neil@brown.name>
Signed-off-by: George Hilliard <thirtythreeforty@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/Kconfig
drivers/staging/Makefile
drivers/staging/mt7621-dma/Kconfig
drivers/staging/mt7621-dma/Makefile
drivers/staging/mt7621-dma/ralink-gdma.c [deleted file]
drivers/staging/ralink-gdma/Kconfig [new file with mode: 0644]
drivers/staging/ralink-gdma/Makefile [new file with mode: 0644]
drivers/staging/ralink-gdma/ralink-gdma.c [new file with mode: 0644]

index 4a3d6e0..46af55a 100644 (file)
@@ -112,6 +112,8 @@ source "drivers/staging/mt7621-spi/Kconfig"
 
 source "drivers/staging/mt7621-dma/Kconfig"
 
+source "drivers/staging/ralink-gdma/Kconfig"
+
 source "drivers/staging/mt7621-mmc/Kconfig"
 
 source "drivers/staging/mt7621-eth/Kconfig"
index 413890d..4d563ed 100644 (file)
@@ -46,6 +46,7 @@ obj-$(CONFIG_SOC_MT7621)      += mt7621-pci-phy/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-pinctrl/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-spi/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-dma/
+obj-$(CONFIG_SOC_MT7621)       += ralink-gdma/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-mmc/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-eth/
 obj-$(CONFIG_SOC_MT7621)       += mt7621-dts/
index 2423c40..b6e48a6 100644 (file)
@@ -1,9 +1,3 @@
-config DMA_RALINK
-       tristate "RALINK DMA support"
-       depends on RALINK && !SOC_RT288X
-       select DMA_ENGINE
-       select DMA_VIRTUAL_CHANNELS
-
 config MTK_HSDMA
        tristate "MTK HSDMA support"
        depends on RALINK && SOC_MT7621
index d3152d4..c9e3e16 100644 (file)
@@ -1,4 +1,3 @@
-obj-$(CONFIG_DMA_RALINK) += ralink-gdma.o
 obj-$(CONFIG_MTK_HSDMA) += mtk-hsdma.o
 
 ccflags-y += -I$(srctree)/drivers/dma
diff --git a/drivers/staging/mt7621-dma/ralink-gdma.c b/drivers/staging/mt7621-dma/ralink-gdma.c
deleted file mode 100644 (file)
index d78042e..0000000
+++ /dev/null
@@ -1,932 +0,0 @@
-/*
- *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
- *  GDMA4740 DMAC support
- *
- *  This program is free software; you can redistribute it and/or modify it
- *  under  the terms of the GNU General         Public License as published by the
- *  Free Software Foundation;  either version 2 of the License, or (at your
- *  option) any later version.
- *
- */
-
-#include <linux/dmaengine.h>
-#include <linux/dma-mapping.h>
-#include <linux/err.h>
-#include <linux/init.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/spinlock.h>
-#include <linux/irq.h>
-#include <linux/of_dma.h>
-#include <linux/reset.h>
-#include <linux/of_device.h>
-
-#include "virt-dma.h"
-
-#define GDMA_REG_SRC_ADDR(x)           (0x00 + (x) * 0x10)
-#define GDMA_REG_DST_ADDR(x)           (0x04 + (x) * 0x10)
-
-#define GDMA_REG_CTRL0(x)              (0x08 + (x) * 0x10)
-#define GDMA_REG_CTRL0_TX_MASK         0xffff
-#define GDMA_REG_CTRL0_TX_SHIFT                16
-#define GDMA_REG_CTRL0_CURR_MASK       0xff
-#define GDMA_REG_CTRL0_CURR_SHIFT      8
-#define        GDMA_REG_CTRL0_SRC_ADDR_FIXED   BIT(7)
-#define GDMA_REG_CTRL0_DST_ADDR_FIXED  BIT(6)
-#define GDMA_REG_CTRL0_BURST_MASK      0x7
-#define GDMA_REG_CTRL0_BURST_SHIFT     3
-#define        GDMA_REG_CTRL0_DONE_INT         BIT(2)
-#define        GDMA_REG_CTRL0_ENABLE           BIT(1)
-#define GDMA_REG_CTRL0_SW_MODE          BIT(0)
-
-#define GDMA_REG_CTRL1(x)              (0x0c + (x) * 0x10)
-#define GDMA_REG_CTRL1_SEG_MASK                0xf
-#define GDMA_REG_CTRL1_SEG_SHIFT       22
-#define GDMA_REG_CTRL1_REQ_MASK                0x3f
-#define GDMA_REG_CTRL1_SRC_REQ_SHIFT   16
-#define GDMA_REG_CTRL1_DST_REQ_SHIFT   8
-#define GDMA_REG_CTRL1_NEXT_MASK       0x1f
-#define GDMA_REG_CTRL1_NEXT_SHIFT      3
-#define GDMA_REG_CTRL1_COHERENT                BIT(2)
-#define GDMA_REG_CTRL1_FAIL            BIT(1)
-#define GDMA_REG_CTRL1_MASK            BIT(0)
-
-#define GDMA_REG_UNMASK_INT            0x200
-#define GDMA_REG_DONE_INT              0x204
-
-#define GDMA_REG_GCT                   0x220
-#define GDMA_REG_GCT_CHAN_MASK         0x3
-#define GDMA_REG_GCT_CHAN_SHIFT                3
-#define GDMA_REG_GCT_VER_MASK          0x3
-#define GDMA_REG_GCT_VER_SHIFT         1
-#define GDMA_REG_GCT_ARBIT_RR          BIT(0)
-
-#define GDMA_REG_REQSTS                        0x2a0
-#define GDMA_REG_ACKSTS                        0x2a4
-#define GDMA_REG_FINSTS                        0x2a8
-
-/* for RT305X gdma registers */
-#define GDMA_RT305X_CTRL0_REQ_MASK     0xf
-#define GDMA_RT305X_CTRL0_SRC_REQ_SHIFT        12
-#define GDMA_RT305X_CTRL0_DST_REQ_SHIFT        8
-
-#define GDMA_RT305X_CTRL1_FAIL         BIT(4)
-#define GDMA_RT305X_CTRL1_NEXT_MASK    0x7
-#define GDMA_RT305X_CTRL1_NEXT_SHIFT   1
-
-#define GDMA_RT305X_STATUS_INT         0x80
-#define GDMA_RT305X_STATUS_SIGNAL      0x84
-#define GDMA_RT305X_GCT                        0x88
-
-/* for MT7621 gdma registers */
-#define GDMA_REG_PERF_START(x)         (0x230 + (x) * 0x8)
-#define GDMA_REG_PERF_END(x)           (0x234 + (x) * 0x8)
-
-enum gdma_dma_transfer_size {
-       GDMA_TRANSFER_SIZE_4BYTE        = 0,
-       GDMA_TRANSFER_SIZE_8BYTE        = 1,
-       GDMA_TRANSFER_SIZE_16BYTE       = 2,
-       GDMA_TRANSFER_SIZE_32BYTE       = 3,
-       GDMA_TRANSFER_SIZE_64BYTE       = 4,
-};
-
-struct gdma_dma_sg {
-       dma_addr_t src_addr;
-       dma_addr_t dst_addr;
-       u32 len;
-};
-
-struct gdma_dma_desc {
-       struct virt_dma_desc vdesc;
-
-       enum dma_transfer_direction direction;
-       bool cyclic;
-
-       u32 residue;
-       unsigned int num_sgs;
-       struct gdma_dma_sg sg[];
-};
-
-struct gdma_dmaengine_chan {
-       struct virt_dma_chan vchan;
-       unsigned int id;
-       unsigned int slave_id;
-
-       dma_addr_t fifo_addr;
-       enum gdma_dma_transfer_size burst_size;
-
-       struct gdma_dma_desc *desc;
-       unsigned int next_sg;
-};
-
-struct gdma_dma_dev {
-       struct dma_device ddev;
-       struct device_dma_parameters dma_parms;
-       struct gdma_data *data;
-       void __iomem *base;
-       struct tasklet_struct task;
-       volatile unsigned long chan_issued;
-       atomic_t cnt;
-
-       struct gdma_dmaengine_chan chan[];
-};
-
-struct gdma_data {
-       int chancnt;
-       u32 done_int_reg;
-       void (*init)(struct gdma_dma_dev *dma_dev);
-       int (*start_transfer)(struct gdma_dmaengine_chan *chan);
-};
-
-static struct gdma_dma_dev *gdma_dma_chan_get_dev(
-       struct gdma_dmaengine_chan *chan)
-{
-       return container_of(chan->vchan.chan.device, struct gdma_dma_dev,
-               ddev);
-}
-
-static struct gdma_dmaengine_chan *to_gdma_dma_chan(struct dma_chan *c)
-{
-       return container_of(c, struct gdma_dmaengine_chan, vchan.chan);
-}
-
-static struct gdma_dma_desc *to_gdma_dma_desc(struct virt_dma_desc *vdesc)
-{
-       return container_of(vdesc, struct gdma_dma_desc, vdesc);
-}
-
-static inline uint32_t gdma_dma_read(struct gdma_dma_dev *dma_dev,
-                                    unsigned int reg)
-{
-       return readl(dma_dev->base + reg);
-}
-
-static inline void gdma_dma_write(struct gdma_dma_dev *dma_dev,
-                                 unsigned reg, uint32_t val)
-{
-       writel(val, dma_dev->base + reg);
-}
-
-static struct gdma_dma_desc *gdma_dma_alloc_desc(unsigned int num_sgs)
-{
-       return kzalloc(sizeof(struct gdma_dma_desc) +
-               sizeof(struct gdma_dma_sg) * num_sgs, GFP_ATOMIC);
-}
-
-static enum gdma_dma_transfer_size gdma_dma_maxburst(u32 maxburst)
-{
-       if (maxburst < 2)
-               return GDMA_TRANSFER_SIZE_4BYTE;
-       else if (maxburst < 4)
-               return GDMA_TRANSFER_SIZE_8BYTE;
-       else if (maxburst < 8)
-               return GDMA_TRANSFER_SIZE_16BYTE;
-       else if (maxburst < 16)
-               return GDMA_TRANSFER_SIZE_32BYTE;
-       else
-               return GDMA_TRANSFER_SIZE_64BYTE;
-}
-
-static int gdma_dma_config(struct dma_chan *c,
-                          struct dma_slave_config *config)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
-
-       if (config->device_fc) {
-               dev_err(dma_dev->ddev.dev, "not support flow controller\n");
-               return -EINVAL;
-       }
-
-       switch (config->direction) {
-       case DMA_MEM_TO_DEV:
-               if (config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
-                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
-                       return -EINVAL;
-               }
-               chan->slave_id = config->slave_id;
-               chan->fifo_addr = config->dst_addr;
-               chan->burst_size = gdma_dma_maxburst(config->dst_maxburst);
-               break;
-       case DMA_DEV_TO_MEM:
-               if (config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
-                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
-                       return -EINVAL;
-               }
-               chan->slave_id = config->slave_id;
-               chan->fifo_addr = config->src_addr;
-               chan->burst_size = gdma_dma_maxburst(config->src_maxburst);
-               break;
-       default:
-               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
-                       config->direction);
-               return -EINVAL;
-       }
-
-       return 0;
-}
-
-static int gdma_dma_terminate_all(struct dma_chan *c)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
-       unsigned long flags, timeout;
-       LIST_HEAD(head);
-       int i = 0;
-
-       spin_lock_irqsave(&chan->vchan.lock, flags);
-       chan->desc = NULL;
-       clear_bit(chan->id, &dma_dev->chan_issued);
-       vchan_get_all_descriptors(&chan->vchan, &head);
-       spin_unlock_irqrestore(&chan->vchan.lock, flags);
-
-       vchan_dma_desc_free_list(&chan->vchan, &head);
-
-       /* wait dma transfer complete */
-       timeout = jiffies + msecs_to_jiffies(5000);
-       while (gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id)) &
-                       GDMA_REG_CTRL0_ENABLE) {
-               if (time_after_eq(jiffies, timeout)) {
-                       dev_err(dma_dev->ddev.dev, "chan %d wait timeout\n",
-                               chan->id);
-                       /* restore to init value */
-                       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), 0);
-                       break;
-               }
-               cpu_relax();
-               i++;
-       }
-
-       if (i)
-               dev_dbg(dma_dev->ddev.dev, "terminate chan %d loops %d\n",
-                       chan->id, i);
-
-       return 0;
-}
-
-static void rt305x_dump_reg(struct gdma_dma_dev *dma_dev, int id)
-{
-       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
-                       "ctr1 %08x, intr %08x, signal %08x\n", id,
-                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
-                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_INT),
-                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_SIGNAL));
-}
-
-static int rt305x_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
-{
-       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
-       dma_addr_t src_addr, dst_addr;
-       struct gdma_dma_sg *sg;
-       uint32_t ctrl0, ctrl1;
-
-       /* verify chan is already stopped */
-       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
-       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
-               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
-                       chan->id, ctrl0);
-               rt305x_dump_reg(dma_dev, chan->id);
-               return -EINVAL;
-       }
-
-       sg = &chan->desc->sg[chan->next_sg];
-       if (chan->desc->direction == DMA_MEM_TO_DEV) {
-               src_addr = sg->src_addr;
-               dst_addr = chan->fifo_addr;
-               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED | \
-                       (8 << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
-                       (chan->slave_id << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
-       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
-               src_addr = chan->fifo_addr;
-               dst_addr = sg->dst_addr;
-               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED | \
-                       (chan->slave_id << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
-                       (8 << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
-       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
-               /*
-                * TODO: memcpy function have bugs. sometime it will copy
-                * more 8 bytes data when using dmatest verify.
-                */
-               src_addr = sg->src_addr;
-               dst_addr = sg->dst_addr;
-               ctrl0 = GDMA_REG_CTRL0_SW_MODE | \
-                       (8 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
-                       (8 << GDMA_REG_CTRL1_DST_REQ_SHIFT);
-       } else {
-               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
-                       chan->desc->direction);
-               return -EINVAL;
-       }
-
-       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
-                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
-                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
-       ctrl1 = chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
-
-       chan->next_sg++;
-       gdma_dma_write(dma_dev, GDMA_REG_SRC_ADDR(chan->id), src_addr);
-       gdma_dma_write(dma_dev, GDMA_REG_DST_ADDR(chan->id), dst_addr);
-       gdma_dma_write(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
-
-       /* make sure next_sg is update */
-       wmb();
-       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
-
-       return 0;
-}
-
-static void rt3883_dump_reg(struct gdma_dma_dev *dma_dev, int id)
-{
-       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
-                       "ctr1 %08x, unmask %08x, done %08x, " \
-                       "req %08x, ack %08x, fin %08x\n", id,
-                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
-                       gdma_dma_read(dma_dev, GDMA_REG_UNMASK_INT),
-                       gdma_dma_read(dma_dev, GDMA_REG_DONE_INT),
-                       gdma_dma_read(dma_dev, GDMA_REG_REQSTS),
-                       gdma_dma_read(dma_dev, GDMA_REG_ACKSTS),
-                       gdma_dma_read(dma_dev, GDMA_REG_FINSTS));
-}
-
-static int rt3883_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
-{
-       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
-       dma_addr_t src_addr, dst_addr;
-       struct gdma_dma_sg *sg;
-       uint32_t ctrl0, ctrl1;
-
-       /* verify chan is already stopped */
-       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
-       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
-               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
-                       chan->id, ctrl0);
-               rt3883_dump_reg(dma_dev, chan->id);
-               return -EINVAL;
-       }
-
-       sg = &chan->desc->sg[chan->next_sg];
-       if (chan->desc->direction == DMA_MEM_TO_DEV) {
-               src_addr = sg->src_addr;
-               dst_addr = chan->fifo_addr;
-               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED;
-               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
-                       (chan->slave_id << GDMA_REG_CTRL1_DST_REQ_SHIFT);
-       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
-               src_addr = chan->fifo_addr;
-               dst_addr = sg->dst_addr;
-               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED;
-               ctrl1 = (chan->slave_id << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
-                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
-                       GDMA_REG_CTRL1_COHERENT;
-       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
-               src_addr = sg->src_addr;
-               dst_addr = sg->dst_addr;
-               ctrl0 = GDMA_REG_CTRL0_SW_MODE;
-               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
-                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
-                       GDMA_REG_CTRL1_COHERENT;
-       } else {
-               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
-                       chan->desc->direction);
-               return -EINVAL;
-       }
-
-       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
-                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
-                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
-       ctrl1 |= chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
-
-       chan->next_sg++;
-       gdma_dma_write(dma_dev, GDMA_REG_SRC_ADDR(chan->id), src_addr);
-       gdma_dma_write(dma_dev, GDMA_REG_DST_ADDR(chan->id), dst_addr);
-       gdma_dma_write(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
-
-       /* make sure next_sg is update */
-       wmb();
-       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
-
-       return 0;
-}
-
-static inline int gdma_start_transfer(struct gdma_dma_dev *dma_dev,
-                                     struct gdma_dmaengine_chan *chan)
-{
-       return dma_dev->data->start_transfer(chan);
-}
-
-static int gdma_next_desc(struct gdma_dmaengine_chan *chan)
-{
-       struct virt_dma_desc *vdesc;
-
-       vdesc = vchan_next_desc(&chan->vchan);
-       if (!vdesc) {
-               chan->desc = NULL;
-               return 0;
-       }
-       chan->desc = to_gdma_dma_desc(vdesc);
-       chan->next_sg = 0;
-
-       return 1;
-}
-
-static void gdma_dma_chan_irq(struct gdma_dma_dev *dma_dev,
-                             struct gdma_dmaengine_chan *chan)
-{
-       struct gdma_dma_desc *desc;
-       unsigned long flags;
-       int chan_issued;
-
-       chan_issued = 0;
-       spin_lock_irqsave(&chan->vchan.lock, flags);
-       desc = chan->desc;
-       if (desc) {
-               if (desc->cyclic) {
-                       vchan_cyclic_callback(&desc->vdesc);
-                       if (chan->next_sg == desc->num_sgs)
-                               chan->next_sg = 0;
-                       chan_issued = 1;
-               } else {
-                       desc->residue -= desc->sg[chan->next_sg - 1].len;
-                       if (chan->next_sg == desc->num_sgs) {
-                               list_del(&desc->vdesc.node);
-                               vchan_cookie_complete(&desc->vdesc);
-                               chan_issued = gdma_next_desc(chan);
-                       } else {
-                               chan_issued = 1;
-                       }
-               }
-       } else {
-               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to complete\n",
-                       chan->id);
-       }
-       if (chan_issued)
-               set_bit(chan->id, &dma_dev->chan_issued);
-       spin_unlock_irqrestore(&chan->vchan.lock, flags);
-}
-
-static irqreturn_t gdma_dma_irq(int irq, void *devid)
-{
-       struct gdma_dma_dev *dma_dev = devid;
-       u32 done, done_reg;
-       unsigned int i;
-
-       done_reg = dma_dev->data->done_int_reg;
-       done = gdma_dma_read(dma_dev, done_reg);
-       if (unlikely(!done))
-               return IRQ_NONE;
-
-       /* clean done bits */
-       gdma_dma_write(dma_dev, done_reg, done);
-
-       i = 0;
-       while (done) {
-               if (done & 0x1) {
-                       gdma_dma_chan_irq(dma_dev, &dma_dev->chan[i]);
-                       atomic_dec(&dma_dev->cnt);
-               }
-               done >>= 1;
-               i++;
-       }
-
-       /* start only have work to do */
-       if (dma_dev->chan_issued)
-               tasklet_schedule(&dma_dev->task);
-
-       return IRQ_HANDLED;
-}
-
-static void gdma_dma_issue_pending(struct dma_chan *c)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
-       unsigned long flags;
-
-       spin_lock_irqsave(&chan->vchan.lock, flags);
-       if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
-               if (gdma_next_desc(chan)) {
-                       set_bit(chan->id, &dma_dev->chan_issued);
-                       tasklet_schedule(&dma_dev->task);
-               } else {
-                       dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n",
-                               chan->id);
-               }
-       }
-       spin_unlock_irqrestore(&chan->vchan.lock, flags);
-}
-
-static struct dma_async_tx_descriptor *gdma_dma_prep_slave_sg(
-               struct dma_chan *c, struct scatterlist *sgl,
-               unsigned int sg_len, enum dma_transfer_direction direction,
-               unsigned long flags, void *context)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_desc *desc;
-       struct scatterlist *sg;
-       unsigned int i;
-
-       desc = gdma_dma_alloc_desc(sg_len);
-       if (!desc) {
-               dev_err(c->device->dev, "alloc sg decs error\n");
-               return NULL;
-       }
-       desc->residue = 0;
-
-       for_each_sg(sgl, sg, sg_len, i) {
-               if (direction == DMA_MEM_TO_DEV) {
-                       desc->sg[i].src_addr = sg_dma_address(sg);
-               } else if (direction == DMA_DEV_TO_MEM) {
-                       desc->sg[i].dst_addr = sg_dma_address(sg);
-               } else {
-                       dev_err(c->device->dev, "direction type %d error\n",
-                               direction);
-                       goto free_desc;
-               }
-
-               if (unlikely(sg_dma_len(sg) > GDMA_REG_CTRL0_TX_MASK)) {
-                       dev_err(c->device->dev, "sg len too large %d\n",
-                               sg_dma_len(sg));
-                       goto free_desc;
-               }
-               desc->sg[i].len = sg_dma_len(sg);
-               desc->residue += sg_dma_len(sg);
-       }
-
-       desc->num_sgs = sg_len;
-       desc->direction = direction;
-       desc->cyclic = false;
-
-       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
-
-free_desc:
-       kfree(desc);
-       return NULL;
-}
-
-static struct dma_async_tx_descriptor *gdma_dma_prep_dma_memcpy(
-               struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
-               size_t len, unsigned long flags)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_desc *desc;
-       unsigned int num_periods, i;
-       size_t xfer_count;
-
-       if (len <= 0)
-               return NULL;
-
-       chan->burst_size = gdma_dma_maxburst(len >> 2);
-
-       xfer_count = GDMA_REG_CTRL0_TX_MASK;
-       num_periods = DIV_ROUND_UP(len, xfer_count);
-
-       desc = gdma_dma_alloc_desc(num_periods);
-       if (!desc) {
-               dev_err(c->device->dev, "alloc memcpy decs error\n");
-               return NULL;
-       }
-       desc->residue = len;
-
-       for (i = 0; i < num_periods; i++) {
-               desc->sg[i].src_addr = src;
-               desc->sg[i].dst_addr = dest;
-               if (len > xfer_count)
-                       desc->sg[i].len = xfer_count;
-               else
-                       desc->sg[i].len = len;
-               src += desc->sg[i].len;
-               dest += desc->sg[i].len;
-               len -= desc->sg[i].len;
-       }
-
-       desc->num_sgs = num_periods;
-       desc->direction = DMA_MEM_TO_MEM;
-       desc->cyclic = false;
-
-       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
-}
-
-static struct dma_async_tx_descriptor *gdma_dma_prep_dma_cyclic(
-       struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
-       size_t period_len, enum dma_transfer_direction direction,
-       unsigned long flags)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct gdma_dma_desc *desc;
-       unsigned int num_periods, i;
-
-       if (buf_len % period_len)
-               return NULL;
-
-       if (period_len > GDMA_REG_CTRL0_TX_MASK) {
-               dev_err(c->device->dev, "cyclic len too large %d\n",
-                       period_len);
-               return NULL;
-       }
-
-       num_periods = buf_len / period_len;
-       desc = gdma_dma_alloc_desc(num_periods);
-       if (!desc) {
-               dev_err(c->device->dev, "alloc cyclic decs error\n");
-               return NULL;
-       }
-       desc->residue = buf_len;
-
-       for (i = 0; i < num_periods; i++) {
-               if (direction == DMA_MEM_TO_DEV) {
-                       desc->sg[i].src_addr = buf_addr;
-               } else if (direction == DMA_DEV_TO_MEM) {
-                       desc->sg[i].dst_addr = buf_addr;
-               } else {
-                       dev_err(c->device->dev, "direction type %d error\n",
-                               direction);
-                       goto free_desc;
-               }
-               desc->sg[i].len = period_len;
-               buf_addr += period_len;
-       }
-
-       desc->num_sgs = num_periods;
-       desc->direction = direction;
-       desc->cyclic = true;
-
-       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
-
-free_desc:
-       kfree(desc);
-       return NULL;
-}
-
-static enum dma_status gdma_dma_tx_status(struct dma_chan *c,
-                                         dma_cookie_t cookie,
-                                         struct dma_tx_state *state)
-{
-       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
-       struct virt_dma_desc *vdesc;
-       enum dma_status status;
-       unsigned long flags;
-       struct gdma_dma_desc *desc;
-
-       status = dma_cookie_status(c, cookie, state);
-       if (status == DMA_COMPLETE || !state)
-               return status;
-
-       spin_lock_irqsave(&chan->vchan.lock, flags);
-       desc = chan->desc;
-       if (desc && (cookie == desc->vdesc.tx.cookie)) {
-               /*
-                * We never update edesc->residue in the cyclic case, so we
-                * can tell the remaining room to the end of the circular
-                * buffer.
-                */
-               if (desc->cyclic)
-                       state->residue = desc->residue -
-                               ((chan->next_sg - 1) * desc->sg[0].len);
-               else
-                       state->residue = desc->residue;
-       } else {
-               vdesc = vchan_find_desc(&chan->vchan, cookie);
-               if (vdesc)
-                       state->residue = to_gdma_dma_desc(vdesc)->residue;
-       }
-       spin_unlock_irqrestore(&chan->vchan.lock, flags);
-
-       dev_dbg(c->device->dev, "tx residue %d bytes\n", state->residue);
-
-       return status;
-}
-
-static void gdma_dma_free_chan_resources(struct dma_chan *c)
-{
-       vchan_free_chan_resources(to_virt_chan(c));
-}
-
-static void gdma_dma_desc_free(struct virt_dma_desc *vdesc)
-{
-       kfree(container_of(vdesc, struct gdma_dma_desc, vdesc));
-}
-
-static void gdma_dma_tasklet(unsigned long arg)
-{
-       struct gdma_dma_dev *dma_dev = (struct gdma_dma_dev *)arg;
-       struct gdma_dmaengine_chan *chan;
-       static unsigned int last_chan;
-       unsigned int i, chan_mask;
-
-       /* record last chan to round robin all chans */
-       i = last_chan;
-       chan_mask = dma_dev->data->chancnt - 1;
-       do {
-               /*
-                * on mt7621. when verify with dmatest with all
-                * channel is enable. we need to limit only two
-                * channel is working at the same time. otherwise the
-                * data will have problem.
-                */
-               if (atomic_read(&dma_dev->cnt) >= 2) {
-                       last_chan = i;
-                       break;
-               }
-
-               if (test_and_clear_bit(i, &dma_dev->chan_issued)) {
-                       chan = &dma_dev->chan[i];
-                       if (chan->desc) {
-                               atomic_inc(&dma_dev->cnt);
-                               gdma_start_transfer(dma_dev, chan);
-                       } else {
-                               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n", chan->id);
-                       }
-                       if (!dma_dev->chan_issued)
-                               break;
-               }
-
-               i = (i + 1) & chan_mask;
-       } while (i != last_chan);
-}
-
-static void rt305x_gdma_init(struct gdma_dma_dev *dma_dev)
-{
-       uint32_t gct;
-
-       /* all chans round robin */
-       gdma_dma_write(dma_dev, GDMA_RT305X_GCT, GDMA_REG_GCT_ARBIT_RR);
-
-       gct = gdma_dma_read(dma_dev, GDMA_RT305X_GCT);
-       dev_info(dma_dev->ddev.dev, "revision: %d, channels: %d\n",
-                (gct >> GDMA_REG_GCT_VER_SHIFT) & GDMA_REG_GCT_VER_MASK,
-                8 << ((gct >> GDMA_REG_GCT_CHAN_SHIFT) &
-                       GDMA_REG_GCT_CHAN_MASK));
-}
-
-static void rt3883_gdma_init(struct gdma_dma_dev *dma_dev)
-{
-       uint32_t gct;
-
-       /* all chans round robin */
-       gdma_dma_write(dma_dev, GDMA_REG_GCT, GDMA_REG_GCT_ARBIT_RR);
-
-       gct = gdma_dma_read(dma_dev, GDMA_REG_GCT);
-       dev_info(dma_dev->ddev.dev, "revision: %d, channels: %d\n",
-                (gct >> GDMA_REG_GCT_VER_SHIFT) & GDMA_REG_GCT_VER_MASK,
-                8 << ((gct >> GDMA_REG_GCT_CHAN_SHIFT) &
-                       GDMA_REG_GCT_CHAN_MASK));
-}
-
-static struct gdma_data rt305x_gdma_data = {
-       .chancnt = 8,
-       .done_int_reg = GDMA_RT305X_STATUS_INT,
-       .init = rt305x_gdma_init,
-       .start_transfer = rt305x_gdma_start_transfer,
-};
-
-static struct gdma_data rt3883_gdma_data = {
-       .chancnt = 16,
-       .done_int_reg = GDMA_REG_DONE_INT,
-       .init = rt3883_gdma_init,
-       .start_transfer = rt3883_gdma_start_transfer,
-};
-
-static const struct of_device_id gdma_of_match_table[] = {
-       { .compatible = "ralink,rt305x-gdma", .data = &rt305x_gdma_data },
-       { .compatible = "ralink,rt3883-gdma", .data = &rt3883_gdma_data },
-       { },
-};
-
-static int gdma_dma_probe(struct platform_device *pdev)
-{
-       const struct of_device_id *match;
-       struct gdma_dmaengine_chan *chan;
-       struct gdma_dma_dev *dma_dev;
-       struct dma_device *dd;
-       unsigned int i;
-       struct resource *res;
-       int ret;
-       int irq;
-       void __iomem *base;
-       struct gdma_data *data;
-
-       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
-       if (ret)
-               return ret;
-
-       match = of_match_device(gdma_of_match_table, &pdev->dev);
-       if (!match)
-               return -EINVAL;
-       data = (struct gdma_data *) match->data;
-
-       dma_dev = devm_kzalloc(&pdev->dev,
-                              struct_size(dma_dev, chan, data->chancnt),
-                              GFP_KERNEL);
-       if (!dma_dev) {
-               dev_err(&pdev->dev, "alloc dma device failed\n");
-               return -EINVAL;
-       }
-       dma_dev->data = data;
-
-       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-       base = devm_ioremap_resource(&pdev->dev, res);
-       if (IS_ERR(base))
-               return PTR_ERR(base);
-       dma_dev->base = base;
-       tasklet_init(&dma_dev->task, gdma_dma_tasklet, (unsigned long)dma_dev);
-
-       irq = platform_get_irq(pdev, 0);
-       if (irq < 0) {
-               dev_err(&pdev->dev, "failed to get irq\n");
-               return -EINVAL;
-       }
-       ret = devm_request_irq(&pdev->dev, irq, gdma_dma_irq,
-                              0, dev_name(&pdev->dev), dma_dev);
-       if (ret) {
-               dev_err(&pdev->dev, "failed to request irq\n");
-               return ret;
-       }
-
-       device_reset(&pdev->dev);
-
-       dd = &dma_dev->ddev;
-       dma_cap_set(DMA_MEMCPY, dd->cap_mask);
-       dma_cap_set(DMA_SLAVE, dd->cap_mask);
-       dma_cap_set(DMA_CYCLIC, dd->cap_mask);
-       dd->device_free_chan_resources = gdma_dma_free_chan_resources;
-       dd->device_prep_dma_memcpy = gdma_dma_prep_dma_memcpy;
-       dd->device_prep_slave_sg = gdma_dma_prep_slave_sg;
-       dd->device_prep_dma_cyclic = gdma_dma_prep_dma_cyclic;
-       dd->device_config = gdma_dma_config;
-       dd->device_terminate_all = gdma_dma_terminate_all;
-       dd->device_tx_status = gdma_dma_tx_status;
-       dd->device_issue_pending = gdma_dma_issue_pending;
-
-       dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
-       dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
-       dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
-       dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
-
-       dd->dev = &pdev->dev;
-       dd->dev->dma_parms = &dma_dev->dma_parms;
-       dma_set_max_seg_size(dd->dev, GDMA_REG_CTRL0_TX_MASK);
-       INIT_LIST_HEAD(&dd->channels);
-
-       for (i = 0; i < data->chancnt; i++) {
-               chan = &dma_dev->chan[i];
-               chan->id = i;
-               chan->vchan.desc_free = gdma_dma_desc_free;
-               vchan_init(&chan->vchan, dd);
-       }
-
-       /* init hardware */
-       data->init(dma_dev);
-
-       ret = dma_async_device_register(dd);
-       if (ret) {
-               dev_err(&pdev->dev, "failed to register dma device\n");
-               return ret;
-       }
-
-       ret = of_dma_controller_register(pdev->dev.of_node,
-                                        of_dma_xlate_by_chan_id, dma_dev);
-       if (ret) {
-               dev_err(&pdev->dev, "failed to register of dma controller\n");
-               goto err_unregister;
-       }
-
-       platform_set_drvdata(pdev, dma_dev);
-
-       return 0;
-
-err_unregister:
-       dma_async_device_unregister(dd);
-       return ret;
-}
-
-static int gdma_dma_remove(struct platform_device *pdev)
-{
-       struct gdma_dma_dev *dma_dev = platform_get_drvdata(pdev);
-
-       tasklet_kill(&dma_dev->task);
-       of_dma_controller_free(pdev->dev.of_node);
-       dma_async_device_unregister(&dma_dev->ddev);
-
-       return 0;
-}
-
-static struct platform_driver gdma_dma_driver = {
-       .probe = gdma_dma_probe,
-       .remove = gdma_dma_remove,
-       .driver = {
-               .name = "gdma-rt2880",
-               .of_match_table = gdma_of_match_table,
-       },
-};
-module_platform_driver(gdma_dma_driver);
-
-MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
-MODULE_DESCRIPTION("Ralink/MTK DMA driver");
-MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/ralink-gdma/Kconfig b/drivers/staging/ralink-gdma/Kconfig
new file mode 100644 (file)
index 0000000..a12b2c6
--- /dev/null
@@ -0,0 +1,6 @@
+config DMA_RALINK
+       tristate "RALINK DMA support"
+       depends on RALINK && !SOC_RT288X
+       select DMA_ENGINE
+       select DMA_VIRTUAL_CHANNELS
+
diff --git a/drivers/staging/ralink-gdma/Makefile b/drivers/staging/ralink-gdma/Makefile
new file mode 100644 (file)
index 0000000..5d917e0
--- /dev/null
@@ -0,0 +1,3 @@
+obj-$(CONFIG_DMA_RALINK) += ralink-gdma.o
+
+ccflags-y += -I$(srctree)/drivers/dma
diff --git a/drivers/staging/ralink-gdma/ralink-gdma.c b/drivers/staging/ralink-gdma/ralink-gdma.c
new file mode 100644 (file)
index 0000000..d78042e
--- /dev/null
@@ -0,0 +1,932 @@
+/*
+ *  Copyright (C) 2013, Lars-Peter Clausen <lars@metafoo.de>
+ *  GDMA4740 DMAC support
+ *
+ *  This program is free software; you can redistribute it and/or modify it
+ *  under  the terms of the GNU General         Public License as published by the
+ *  Free Software Foundation;  either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/irq.h>
+#include <linux/of_dma.h>
+#include <linux/reset.h>
+#include <linux/of_device.h>
+
+#include "virt-dma.h"
+
+#define GDMA_REG_SRC_ADDR(x)           (0x00 + (x) * 0x10)
+#define GDMA_REG_DST_ADDR(x)           (0x04 + (x) * 0x10)
+
+#define GDMA_REG_CTRL0(x)              (0x08 + (x) * 0x10)
+#define GDMA_REG_CTRL0_TX_MASK         0xffff
+#define GDMA_REG_CTRL0_TX_SHIFT                16
+#define GDMA_REG_CTRL0_CURR_MASK       0xff
+#define GDMA_REG_CTRL0_CURR_SHIFT      8
+#define        GDMA_REG_CTRL0_SRC_ADDR_FIXED   BIT(7)
+#define GDMA_REG_CTRL0_DST_ADDR_FIXED  BIT(6)
+#define GDMA_REG_CTRL0_BURST_MASK      0x7
+#define GDMA_REG_CTRL0_BURST_SHIFT     3
+#define        GDMA_REG_CTRL0_DONE_INT         BIT(2)
+#define        GDMA_REG_CTRL0_ENABLE           BIT(1)
+#define GDMA_REG_CTRL0_SW_MODE          BIT(0)
+
+#define GDMA_REG_CTRL1(x)              (0x0c + (x) * 0x10)
+#define GDMA_REG_CTRL1_SEG_MASK                0xf
+#define GDMA_REG_CTRL1_SEG_SHIFT       22
+#define GDMA_REG_CTRL1_REQ_MASK                0x3f
+#define GDMA_REG_CTRL1_SRC_REQ_SHIFT   16
+#define GDMA_REG_CTRL1_DST_REQ_SHIFT   8
+#define GDMA_REG_CTRL1_NEXT_MASK       0x1f
+#define GDMA_REG_CTRL1_NEXT_SHIFT      3
+#define GDMA_REG_CTRL1_COHERENT                BIT(2)
+#define GDMA_REG_CTRL1_FAIL            BIT(1)
+#define GDMA_REG_CTRL1_MASK            BIT(0)
+
+#define GDMA_REG_UNMASK_INT            0x200
+#define GDMA_REG_DONE_INT              0x204
+
+#define GDMA_REG_GCT                   0x220
+#define GDMA_REG_GCT_CHAN_MASK         0x3
+#define GDMA_REG_GCT_CHAN_SHIFT                3
+#define GDMA_REG_GCT_VER_MASK          0x3
+#define GDMA_REG_GCT_VER_SHIFT         1
+#define GDMA_REG_GCT_ARBIT_RR          BIT(0)
+
+#define GDMA_REG_REQSTS                        0x2a0
+#define GDMA_REG_ACKSTS                        0x2a4
+#define GDMA_REG_FINSTS                        0x2a8
+
+/* for RT305X gdma registers */
+#define GDMA_RT305X_CTRL0_REQ_MASK     0xf
+#define GDMA_RT305X_CTRL0_SRC_REQ_SHIFT        12
+#define GDMA_RT305X_CTRL0_DST_REQ_SHIFT        8
+
+#define GDMA_RT305X_CTRL1_FAIL         BIT(4)
+#define GDMA_RT305X_CTRL1_NEXT_MASK    0x7
+#define GDMA_RT305X_CTRL1_NEXT_SHIFT   1
+
+#define GDMA_RT305X_STATUS_INT         0x80
+#define GDMA_RT305X_STATUS_SIGNAL      0x84
+#define GDMA_RT305X_GCT                        0x88
+
+/* for MT7621 gdma registers */
+#define GDMA_REG_PERF_START(x)         (0x230 + (x) * 0x8)
+#define GDMA_REG_PERF_END(x)           (0x234 + (x) * 0x8)
+
+enum gdma_dma_transfer_size {
+       GDMA_TRANSFER_SIZE_4BYTE        = 0,
+       GDMA_TRANSFER_SIZE_8BYTE        = 1,
+       GDMA_TRANSFER_SIZE_16BYTE       = 2,
+       GDMA_TRANSFER_SIZE_32BYTE       = 3,
+       GDMA_TRANSFER_SIZE_64BYTE       = 4,
+};
+
+struct gdma_dma_sg {
+       dma_addr_t src_addr;
+       dma_addr_t dst_addr;
+       u32 len;
+};
+
+struct gdma_dma_desc {
+       struct virt_dma_desc vdesc;
+
+       enum dma_transfer_direction direction;
+       bool cyclic;
+
+       u32 residue;
+       unsigned int num_sgs;
+       struct gdma_dma_sg sg[];
+};
+
+struct gdma_dmaengine_chan {
+       struct virt_dma_chan vchan;
+       unsigned int id;
+       unsigned int slave_id;
+
+       dma_addr_t fifo_addr;
+       enum gdma_dma_transfer_size burst_size;
+
+       struct gdma_dma_desc *desc;
+       unsigned int next_sg;
+};
+
+struct gdma_dma_dev {
+       struct dma_device ddev;
+       struct device_dma_parameters dma_parms;
+       struct gdma_data *data;
+       void __iomem *base;
+       struct tasklet_struct task;
+       volatile unsigned long chan_issued;
+       atomic_t cnt;
+
+       struct gdma_dmaengine_chan chan[];
+};
+
+struct gdma_data {
+       int chancnt;
+       u32 done_int_reg;
+       void (*init)(struct gdma_dma_dev *dma_dev);
+       int (*start_transfer)(struct gdma_dmaengine_chan *chan);
+};
+
+static struct gdma_dma_dev *gdma_dma_chan_get_dev(
+       struct gdma_dmaengine_chan *chan)
+{
+       return container_of(chan->vchan.chan.device, struct gdma_dma_dev,
+               ddev);
+}
+
+static struct gdma_dmaengine_chan *to_gdma_dma_chan(struct dma_chan *c)
+{
+       return container_of(c, struct gdma_dmaengine_chan, vchan.chan);
+}
+
+static struct gdma_dma_desc *to_gdma_dma_desc(struct virt_dma_desc *vdesc)
+{
+       return container_of(vdesc, struct gdma_dma_desc, vdesc);
+}
+
+static inline uint32_t gdma_dma_read(struct gdma_dma_dev *dma_dev,
+                                    unsigned int reg)
+{
+       return readl(dma_dev->base + reg);
+}
+
+static inline void gdma_dma_write(struct gdma_dma_dev *dma_dev,
+                                 unsigned reg, uint32_t val)
+{
+       writel(val, dma_dev->base + reg);
+}
+
+static struct gdma_dma_desc *gdma_dma_alloc_desc(unsigned int num_sgs)
+{
+       return kzalloc(sizeof(struct gdma_dma_desc) +
+               sizeof(struct gdma_dma_sg) * num_sgs, GFP_ATOMIC);
+}
+
+static enum gdma_dma_transfer_size gdma_dma_maxburst(u32 maxburst)
+{
+       if (maxburst < 2)
+               return GDMA_TRANSFER_SIZE_4BYTE;
+       else if (maxburst < 4)
+               return GDMA_TRANSFER_SIZE_8BYTE;
+       else if (maxburst < 8)
+               return GDMA_TRANSFER_SIZE_16BYTE;
+       else if (maxburst < 16)
+               return GDMA_TRANSFER_SIZE_32BYTE;
+       else
+               return GDMA_TRANSFER_SIZE_64BYTE;
+}
+
+static int gdma_dma_config(struct dma_chan *c,
+                          struct dma_slave_config *config)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+
+       if (config->device_fc) {
+               dev_err(dma_dev->ddev.dev, "not support flow controller\n");
+               return -EINVAL;
+       }
+
+       switch (config->direction) {
+       case DMA_MEM_TO_DEV:
+               if (config->dst_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
+                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
+                       return -EINVAL;
+               }
+               chan->slave_id = config->slave_id;
+               chan->fifo_addr = config->dst_addr;
+               chan->burst_size = gdma_dma_maxburst(config->dst_maxburst);
+               break;
+       case DMA_DEV_TO_MEM:
+               if (config->src_addr_width != DMA_SLAVE_BUSWIDTH_4_BYTES) {
+                       dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
+                       return -EINVAL;
+               }
+               chan->slave_id = config->slave_id;
+               chan->fifo_addr = config->src_addr;
+               chan->burst_size = gdma_dma_maxburst(config->src_maxburst);
+               break;
+       default:
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                       config->direction);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+static int gdma_dma_terminate_all(struct dma_chan *c)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+       unsigned long flags, timeout;
+       LIST_HEAD(head);
+       int i = 0;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       chan->desc = NULL;
+       clear_bit(chan->id, &dma_dev->chan_issued);
+       vchan_get_all_descriptors(&chan->vchan, &head);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       vchan_dma_desc_free_list(&chan->vchan, &head);
+
+       /* wait dma transfer complete */
+       timeout = jiffies + msecs_to_jiffies(5000);
+       while (gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id)) &
+                       GDMA_REG_CTRL0_ENABLE) {
+               if (time_after_eq(jiffies, timeout)) {
+                       dev_err(dma_dev->ddev.dev, "chan %d wait timeout\n",
+                               chan->id);
+                       /* restore to init value */
+                       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), 0);
+                       break;
+               }
+               cpu_relax();
+               i++;
+       }
+
+       if (i)
+               dev_dbg(dma_dev->ddev.dev, "terminate chan %d loops %d\n",
+                       chan->id, i);
+
+       return 0;
+}
+
+static void rt305x_dump_reg(struct gdma_dma_dev *dma_dev, int id)
+{
+       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
+                       "ctr1 %08x, intr %08x, signal %08x\n", id,
+                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
+                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_INT),
+                       gdma_dma_read(dma_dev, GDMA_RT305X_STATUS_SIGNAL));
+}
+
+static int rt305x_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
+{
+       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+       dma_addr_t src_addr, dst_addr;
+       struct gdma_dma_sg *sg;
+       uint32_t ctrl0, ctrl1;
+
+       /* verify chan is already stopped */
+       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
+       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
+               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
+                       chan->id, ctrl0);
+               rt305x_dump_reg(dma_dev, chan->id);
+               return -EINVAL;
+       }
+
+       sg = &chan->desc->sg[chan->next_sg];
+       if (chan->desc->direction == DMA_MEM_TO_DEV) {
+               src_addr = sg->src_addr;
+               dst_addr = chan->fifo_addr;
+               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED | \
+                       (8 << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
+                       (chan->slave_id << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
+               src_addr = chan->fifo_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED | \
+                       (chan->slave_id << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) | \
+                       (8 << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
+               /*
+                * TODO: memcpy function have bugs. sometime it will copy
+                * more 8 bytes data when using dmatest verify.
+                */
+               src_addr = sg->src_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SW_MODE | \
+                       (8 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (8 << GDMA_REG_CTRL1_DST_REQ_SHIFT);
+       } else {
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                       chan->desc->direction);
+               return -EINVAL;
+       }
+
+       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
+                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
+                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
+       ctrl1 = chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
+
+       chan->next_sg++;
+       gdma_dma_write(dma_dev, GDMA_REG_SRC_ADDR(chan->id), src_addr);
+       gdma_dma_write(dma_dev, GDMA_REG_DST_ADDR(chan->id), dst_addr);
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
+
+       /* make sure next_sg is update */
+       wmb();
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
+
+       return 0;
+}
+
+static void rt3883_dump_reg(struct gdma_dma_dev *dma_dev, int id)
+{
+       dev_dbg(dma_dev->ddev.dev, "chan %d, src %08x, dst %08x, ctr0 %08x, " \
+                       "ctr1 %08x, unmask %08x, done %08x, " \
+                       "req %08x, ack %08x, fin %08x\n", id,
+                       gdma_dma_read(dma_dev, GDMA_REG_SRC_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_DST_ADDR(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL0(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_CTRL1(id)),
+                       gdma_dma_read(dma_dev, GDMA_REG_UNMASK_INT),
+                       gdma_dma_read(dma_dev, GDMA_REG_DONE_INT),
+                       gdma_dma_read(dma_dev, GDMA_REG_REQSTS),
+                       gdma_dma_read(dma_dev, GDMA_REG_ACKSTS),
+                       gdma_dma_read(dma_dev, GDMA_REG_FINSTS));
+}
+
+static int rt3883_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
+{
+       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+       dma_addr_t src_addr, dst_addr;
+       struct gdma_dma_sg *sg;
+       uint32_t ctrl0, ctrl1;
+
+       /* verify chan is already stopped */
+       ctrl0 = gdma_dma_read(dma_dev, GDMA_REG_CTRL0(chan->id));
+       if (unlikely(ctrl0 & GDMA_REG_CTRL0_ENABLE)) {
+               dev_err(dma_dev->ddev.dev, "chan %d is start(%08x).\n",
+                       chan->id, ctrl0);
+               rt3883_dump_reg(dma_dev, chan->id);
+               return -EINVAL;
+       }
+
+       sg = &chan->desc->sg[chan->next_sg];
+       if (chan->desc->direction == DMA_MEM_TO_DEV) {
+               src_addr = sg->src_addr;
+               dst_addr = chan->fifo_addr;
+               ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED;
+               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (chan->slave_id << GDMA_REG_CTRL1_DST_REQ_SHIFT);
+       } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
+               src_addr = chan->fifo_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED;
+               ctrl1 = (chan->slave_id << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
+                       GDMA_REG_CTRL1_COHERENT;
+       } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
+               src_addr = sg->src_addr;
+               dst_addr = sg->dst_addr;
+               ctrl0 = GDMA_REG_CTRL0_SW_MODE;
+               ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) | \
+                       (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) | \
+                       GDMA_REG_CTRL1_COHERENT;
+       } else {
+               dev_err(dma_dev->ddev.dev, "direction type %d error\n",
+                       chan->desc->direction);
+               return -EINVAL;
+       }
+
+       ctrl0 |= (sg->len << GDMA_REG_CTRL0_TX_SHIFT) | \
+                (chan->burst_size << GDMA_REG_CTRL0_BURST_SHIFT) | \
+                GDMA_REG_CTRL0_DONE_INT | GDMA_REG_CTRL0_ENABLE;
+       ctrl1 |= chan->id << GDMA_REG_CTRL1_NEXT_SHIFT;
+
+       chan->next_sg++;
+       gdma_dma_write(dma_dev, GDMA_REG_SRC_ADDR(chan->id), src_addr);
+       gdma_dma_write(dma_dev, GDMA_REG_DST_ADDR(chan->id), dst_addr);
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL1(chan->id), ctrl1);
+
+       /* make sure next_sg is update */
+       wmb();
+       gdma_dma_write(dma_dev, GDMA_REG_CTRL0(chan->id), ctrl0);
+
+       return 0;
+}
+
+static inline int gdma_start_transfer(struct gdma_dma_dev *dma_dev,
+                                     struct gdma_dmaengine_chan *chan)
+{
+       return dma_dev->data->start_transfer(chan);
+}
+
+static int gdma_next_desc(struct gdma_dmaengine_chan *chan)
+{
+       struct virt_dma_desc *vdesc;
+
+       vdesc = vchan_next_desc(&chan->vchan);
+       if (!vdesc) {
+               chan->desc = NULL;
+               return 0;
+       }
+       chan->desc = to_gdma_dma_desc(vdesc);
+       chan->next_sg = 0;
+
+       return 1;
+}
+
+static void gdma_dma_chan_irq(struct gdma_dma_dev *dma_dev,
+                             struct gdma_dmaengine_chan *chan)
+{
+       struct gdma_dma_desc *desc;
+       unsigned long flags;
+       int chan_issued;
+
+       chan_issued = 0;
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       desc = chan->desc;
+       if (desc) {
+               if (desc->cyclic) {
+                       vchan_cyclic_callback(&desc->vdesc);
+                       if (chan->next_sg == desc->num_sgs)
+                               chan->next_sg = 0;
+                       chan_issued = 1;
+               } else {
+                       desc->residue -= desc->sg[chan->next_sg - 1].len;
+                       if (chan->next_sg == desc->num_sgs) {
+                               list_del(&desc->vdesc.node);
+                               vchan_cookie_complete(&desc->vdesc);
+                               chan_issued = gdma_next_desc(chan);
+                       } else {
+                               chan_issued = 1;
+                       }
+               }
+       } else {
+               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to complete\n",
+                       chan->id);
+       }
+       if (chan_issued)
+               set_bit(chan->id, &dma_dev->chan_issued);
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static irqreturn_t gdma_dma_irq(int irq, void *devid)
+{
+       struct gdma_dma_dev *dma_dev = devid;
+       u32 done, done_reg;
+       unsigned int i;
+
+       done_reg = dma_dev->data->done_int_reg;
+       done = gdma_dma_read(dma_dev, done_reg);
+       if (unlikely(!done))
+               return IRQ_NONE;
+
+       /* clean done bits */
+       gdma_dma_write(dma_dev, done_reg, done);
+
+       i = 0;
+       while (done) {
+               if (done & 0x1) {
+                       gdma_dma_chan_irq(dma_dev, &dma_dev->chan[i]);
+                       atomic_dec(&dma_dev->cnt);
+               }
+               done >>= 1;
+               i++;
+       }
+
+       /* start only have work to do */
+       if (dma_dev->chan_issued)
+               tasklet_schedule(&dma_dev->task);
+
+       return IRQ_HANDLED;
+}
+
+static void gdma_dma_issue_pending(struct dma_chan *c)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_dev *dma_dev = gdma_dma_chan_get_dev(chan);
+       unsigned long flags;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       if (vchan_issue_pending(&chan->vchan) && !chan->desc) {
+               if (gdma_next_desc(chan)) {
+                       set_bit(chan->id, &dma_dev->chan_issued);
+                       tasklet_schedule(&dma_dev->task);
+               } else {
+                       dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n",
+                               chan->id);
+               }
+       }
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+}
+
+static struct dma_async_tx_descriptor *gdma_dma_prep_slave_sg(
+               struct dma_chan *c, struct scatterlist *sgl,
+               unsigned int sg_len, enum dma_transfer_direction direction,
+               unsigned long flags, void *context)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_desc *desc;
+       struct scatterlist *sg;
+       unsigned int i;
+
+       desc = gdma_dma_alloc_desc(sg_len);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc sg decs error\n");
+               return NULL;
+       }
+       desc->residue = 0;
+
+       for_each_sg(sgl, sg, sg_len, i) {
+               if (direction == DMA_MEM_TO_DEV) {
+                       desc->sg[i].src_addr = sg_dma_address(sg);
+               } else if (direction == DMA_DEV_TO_MEM) {
+                       desc->sg[i].dst_addr = sg_dma_address(sg);
+               } else {
+                       dev_err(c->device->dev, "direction type %d error\n",
+                               direction);
+                       goto free_desc;
+               }
+
+               if (unlikely(sg_dma_len(sg) > GDMA_REG_CTRL0_TX_MASK)) {
+                       dev_err(c->device->dev, "sg len too large %d\n",
+                               sg_dma_len(sg));
+                       goto free_desc;
+               }
+               desc->sg[i].len = sg_dma_len(sg);
+               desc->residue += sg_dma_len(sg);
+       }
+
+       desc->num_sgs = sg_len;
+       desc->direction = direction;
+       desc->cyclic = false;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+free_desc:
+       kfree(desc);
+       return NULL;
+}
+
+static struct dma_async_tx_descriptor *gdma_dma_prep_dma_memcpy(
+               struct dma_chan *c, dma_addr_t dest, dma_addr_t src,
+               size_t len, unsigned long flags)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_desc *desc;
+       unsigned int num_periods, i;
+       size_t xfer_count;
+
+       if (len <= 0)
+               return NULL;
+
+       chan->burst_size = gdma_dma_maxburst(len >> 2);
+
+       xfer_count = GDMA_REG_CTRL0_TX_MASK;
+       num_periods = DIV_ROUND_UP(len, xfer_count);
+
+       desc = gdma_dma_alloc_desc(num_periods);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc memcpy decs error\n");
+               return NULL;
+       }
+       desc->residue = len;
+
+       for (i = 0; i < num_periods; i++) {
+               desc->sg[i].src_addr = src;
+               desc->sg[i].dst_addr = dest;
+               if (len > xfer_count)
+                       desc->sg[i].len = xfer_count;
+               else
+                       desc->sg[i].len = len;
+               src += desc->sg[i].len;
+               dest += desc->sg[i].len;
+               len -= desc->sg[i].len;
+       }
+
+       desc->num_sgs = num_periods;
+       desc->direction = DMA_MEM_TO_MEM;
+       desc->cyclic = false;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+}
+
+static struct dma_async_tx_descriptor *gdma_dma_prep_dma_cyclic(
+       struct dma_chan *c, dma_addr_t buf_addr, size_t buf_len,
+       size_t period_len, enum dma_transfer_direction direction,
+       unsigned long flags)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct gdma_dma_desc *desc;
+       unsigned int num_periods, i;
+
+       if (buf_len % period_len)
+               return NULL;
+
+       if (period_len > GDMA_REG_CTRL0_TX_MASK) {
+               dev_err(c->device->dev, "cyclic len too large %d\n",
+                       period_len);
+               return NULL;
+       }
+
+       num_periods = buf_len / period_len;
+       desc = gdma_dma_alloc_desc(num_periods);
+       if (!desc) {
+               dev_err(c->device->dev, "alloc cyclic decs error\n");
+               return NULL;
+       }
+       desc->residue = buf_len;
+
+       for (i = 0; i < num_periods; i++) {
+               if (direction == DMA_MEM_TO_DEV) {
+                       desc->sg[i].src_addr = buf_addr;
+               } else if (direction == DMA_DEV_TO_MEM) {
+                       desc->sg[i].dst_addr = buf_addr;
+               } else {
+                       dev_err(c->device->dev, "direction type %d error\n",
+                               direction);
+                       goto free_desc;
+               }
+               desc->sg[i].len = period_len;
+               buf_addr += period_len;
+       }
+
+       desc->num_sgs = num_periods;
+       desc->direction = direction;
+       desc->cyclic = true;
+
+       return vchan_tx_prep(&chan->vchan, &desc->vdesc, flags);
+
+free_desc:
+       kfree(desc);
+       return NULL;
+}
+
+static enum dma_status gdma_dma_tx_status(struct dma_chan *c,
+                                         dma_cookie_t cookie,
+                                         struct dma_tx_state *state)
+{
+       struct gdma_dmaengine_chan *chan = to_gdma_dma_chan(c);
+       struct virt_dma_desc *vdesc;
+       enum dma_status status;
+       unsigned long flags;
+       struct gdma_dma_desc *desc;
+
+       status = dma_cookie_status(c, cookie, state);
+       if (status == DMA_COMPLETE || !state)
+               return status;
+
+       spin_lock_irqsave(&chan->vchan.lock, flags);
+       desc = chan->desc;
+       if (desc && (cookie == desc->vdesc.tx.cookie)) {
+               /*
+                * We never update edesc->residue in the cyclic case, so we
+                * can tell the remaining room to the end of the circular
+                * buffer.
+                */
+               if (desc->cyclic)
+                       state->residue = desc->residue -
+                               ((chan->next_sg - 1) * desc->sg[0].len);
+               else
+                       state->residue = desc->residue;
+       } else {
+               vdesc = vchan_find_desc(&chan->vchan, cookie);
+               if (vdesc)
+                       state->residue = to_gdma_dma_desc(vdesc)->residue;
+       }
+       spin_unlock_irqrestore(&chan->vchan.lock, flags);
+
+       dev_dbg(c->device->dev, "tx residue %d bytes\n", state->residue);
+
+       return status;
+}
+
+static void gdma_dma_free_chan_resources(struct dma_chan *c)
+{
+       vchan_free_chan_resources(to_virt_chan(c));
+}
+
+static void gdma_dma_desc_free(struct virt_dma_desc *vdesc)
+{
+       kfree(container_of(vdesc, struct gdma_dma_desc, vdesc));
+}
+
+static void gdma_dma_tasklet(unsigned long arg)
+{
+       struct gdma_dma_dev *dma_dev = (struct gdma_dma_dev *)arg;
+       struct gdma_dmaengine_chan *chan;
+       static unsigned int last_chan;
+       unsigned int i, chan_mask;
+
+       /* record last chan to round robin all chans */
+       i = last_chan;
+       chan_mask = dma_dev->data->chancnt - 1;
+       do {
+               /*
+                * on mt7621. when verify with dmatest with all
+                * channel is enable. we need to limit only two
+                * channel is working at the same time. otherwise the
+                * data will have problem.
+                */
+               if (atomic_read(&dma_dev->cnt) >= 2) {
+                       last_chan = i;
+                       break;
+               }
+
+               if (test_and_clear_bit(i, &dma_dev->chan_issued)) {
+                       chan = &dma_dev->chan[i];
+                       if (chan->desc) {
+                               atomic_inc(&dma_dev->cnt);
+                               gdma_start_transfer(dma_dev, chan);
+                       } else {
+                               dev_dbg(dma_dev->ddev.dev, "chan %d no desc to issue\n", chan->id);
+                       }
+                       if (!dma_dev->chan_issued)
+                               break;
+               }
+
+               i = (i + 1) & chan_mask;
+       } while (i != last_chan);
+}
+
+static void rt305x_gdma_init(struct gdma_dma_dev *dma_dev)
+{
+       uint32_t gct;
+
+       /* all chans round robin */
+       gdma_dma_write(dma_dev, GDMA_RT305X_GCT, GDMA_REG_GCT_ARBIT_RR);
+
+       gct = gdma_dma_read(dma_dev, GDMA_RT305X_GCT);
+       dev_info(dma_dev->ddev.dev, "revision: %d, channels: %d\n",
+                (gct >> GDMA_REG_GCT_VER_SHIFT) & GDMA_REG_GCT_VER_MASK,
+                8 << ((gct >> GDMA_REG_GCT_CHAN_SHIFT) &
+                       GDMA_REG_GCT_CHAN_MASK));
+}
+
+static void rt3883_gdma_init(struct gdma_dma_dev *dma_dev)
+{
+       uint32_t gct;
+
+       /* all chans round robin */
+       gdma_dma_write(dma_dev, GDMA_REG_GCT, GDMA_REG_GCT_ARBIT_RR);
+
+       gct = gdma_dma_read(dma_dev, GDMA_REG_GCT);
+       dev_info(dma_dev->ddev.dev, "revision: %d, channels: %d\n",
+                (gct >> GDMA_REG_GCT_VER_SHIFT) & GDMA_REG_GCT_VER_MASK,
+                8 << ((gct >> GDMA_REG_GCT_CHAN_SHIFT) &
+                       GDMA_REG_GCT_CHAN_MASK));
+}
+
+static struct gdma_data rt305x_gdma_data = {
+       .chancnt = 8,
+       .done_int_reg = GDMA_RT305X_STATUS_INT,
+       .init = rt305x_gdma_init,
+       .start_transfer = rt305x_gdma_start_transfer,
+};
+
+static struct gdma_data rt3883_gdma_data = {
+       .chancnt = 16,
+       .done_int_reg = GDMA_REG_DONE_INT,
+       .init = rt3883_gdma_init,
+       .start_transfer = rt3883_gdma_start_transfer,
+};
+
+static const struct of_device_id gdma_of_match_table[] = {
+       { .compatible = "ralink,rt305x-gdma", .data = &rt305x_gdma_data },
+       { .compatible = "ralink,rt3883-gdma", .data = &rt3883_gdma_data },
+       { },
+};
+
+static int gdma_dma_probe(struct platform_device *pdev)
+{
+       const struct of_device_id *match;
+       struct gdma_dmaengine_chan *chan;
+       struct gdma_dma_dev *dma_dev;
+       struct dma_device *dd;
+       unsigned int i;
+       struct resource *res;
+       int ret;
+       int irq;
+       void __iomem *base;
+       struct gdma_data *data;
+
+       ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+       if (ret)
+               return ret;
+
+       match = of_match_device(gdma_of_match_table, &pdev->dev);
+       if (!match)
+               return -EINVAL;
+       data = (struct gdma_data *) match->data;
+
+       dma_dev = devm_kzalloc(&pdev->dev,
+                              struct_size(dma_dev, chan, data->chancnt),
+                              GFP_KERNEL);
+       if (!dma_dev) {
+               dev_err(&pdev->dev, "alloc dma device failed\n");
+               return -EINVAL;
+       }
+       dma_dev->data = data;
+
+       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(&pdev->dev, res);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+       dma_dev->base = base;
+       tasklet_init(&dma_dev->task, gdma_dma_tasklet, (unsigned long)dma_dev);
+
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0) {
+               dev_err(&pdev->dev, "failed to get irq\n");
+               return -EINVAL;
+       }
+       ret = devm_request_irq(&pdev->dev, irq, gdma_dma_irq,
+                              0, dev_name(&pdev->dev), dma_dev);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to request irq\n");
+               return ret;
+       }
+
+       device_reset(&pdev->dev);
+
+       dd = &dma_dev->ddev;
+       dma_cap_set(DMA_MEMCPY, dd->cap_mask);
+       dma_cap_set(DMA_SLAVE, dd->cap_mask);
+       dma_cap_set(DMA_CYCLIC, dd->cap_mask);
+       dd->device_free_chan_resources = gdma_dma_free_chan_resources;
+       dd->device_prep_dma_memcpy = gdma_dma_prep_dma_memcpy;
+       dd->device_prep_slave_sg = gdma_dma_prep_slave_sg;
+       dd->device_prep_dma_cyclic = gdma_dma_prep_dma_cyclic;
+       dd->device_config = gdma_dma_config;
+       dd->device_terminate_all = gdma_dma_terminate_all;
+       dd->device_tx_status = gdma_dma_tx_status;
+       dd->device_issue_pending = gdma_dma_issue_pending;
+
+       dd->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+       dd->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
+       dd->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);
+       dd->residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+
+       dd->dev = &pdev->dev;
+       dd->dev->dma_parms = &dma_dev->dma_parms;
+       dma_set_max_seg_size(dd->dev, GDMA_REG_CTRL0_TX_MASK);
+       INIT_LIST_HEAD(&dd->channels);
+
+       for (i = 0; i < data->chancnt; i++) {
+               chan = &dma_dev->chan[i];
+               chan->id = i;
+               chan->vchan.desc_free = gdma_dma_desc_free;
+               vchan_init(&chan->vchan, dd);
+       }
+
+       /* init hardware */
+       data->init(dma_dev);
+
+       ret = dma_async_device_register(dd);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register dma device\n");
+               return ret;
+       }
+
+       ret = of_dma_controller_register(pdev->dev.of_node,
+                                        of_dma_xlate_by_chan_id, dma_dev);
+       if (ret) {
+               dev_err(&pdev->dev, "failed to register of dma controller\n");
+               goto err_unregister;
+       }
+
+       platform_set_drvdata(pdev, dma_dev);
+
+       return 0;
+
+err_unregister:
+       dma_async_device_unregister(dd);
+       return ret;
+}
+
+static int gdma_dma_remove(struct platform_device *pdev)
+{
+       struct gdma_dma_dev *dma_dev = platform_get_drvdata(pdev);
+
+       tasklet_kill(&dma_dev->task);
+       of_dma_controller_free(pdev->dev.of_node);
+       dma_async_device_unregister(&dma_dev->ddev);
+
+       return 0;
+}
+
+static struct platform_driver gdma_dma_driver = {
+       .probe = gdma_dma_probe,
+       .remove = gdma_dma_remove,
+       .driver = {
+               .name = "gdma-rt2880",
+               .of_match_table = gdma_of_match_table,
+       },
+};
+module_platform_driver(gdma_dma_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Ralink/MTK DMA driver");
+MODULE_LICENSE("GPL v2");