MLK-17312-1 usb: cdns3: gadget: prepare setup packet buffer before receiving it

At current setup packet handling flow, the setup packet buffer
is only prepared after the controller receives the setup packet,
then stores it at its internal buffer, and trigger DESCMIS interrupt
(Transfer descriptor missing) to prepare TRB for it.

The shortcoming of this design is there is an extra DESCMIS interrupt,
and consume more time on enumeration process. As an improvement,
we parepare setup buffer beforehand, it is prepared at below situations:
- After bus reset has finished.
- For non-data stage setup transfers, prepare it before sending ACK for
status stage.
- For data stage setup transfers, prepare it after data stage but
before sending ACK for status stage.

Acked-by: Jun Li <jun.li@nxp.com>
Signed-off-by: Peter Chen <peter.chen@nxp.com>

diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
index 135fa5a..ea8ae51 100644 (file)
--- a/drivers/usb/cdns3/gadget.c
+++ b/drivers/usb/cdns3/gadget.c
@@ -100,6 +100,7 @@ static int usb_ss_gadget_udc_stop(struct usb_gadget *gadget);
 static int usb_ss_init_ep(struct usb_ss_dev *usb_ss);
 static int usb_ss_init_ep0(struct usb_ss_dev *usb_ss);
 static void __cdns3_gadget_start(struct usb_ss_dev *usb_ss);
+static void cdns_prepare_setup_packet(struct usb_ss_dev *usb_ss);
 
 static struct usb_endpoint_descriptor cdns3_gadget_ep0_desc = {
        .bLength        = USB_DT_ENDPOINT_SIZE,
@@ -270,6 +271,8 @@ static void cdns_ep0_config(struct usb_ss_dev *usb_ss)
        gadget_writel(usb_ss, &usb_ss->regs->ep_sts_en,
                EP_STS_EN__SETUPEN__MASK |
                EP_STS_EN__TRBERREN__MASK);
+
+       cdns_prepare_setup_packet(usb_ss);
 }
 
 /**
@@ -398,6 +401,12 @@ static int cdns_get_setup_ret(struct usb_ss_dev *usb_ss,
        return ret;
 }
 
+static void cdns_prepare_setup_packet(struct usb_ss_dev *usb_ss)
+{
+       usb_ss->ep0_data_dir = 0;
+       cdns_ep0_run_transfer(usb_ss, usb_ss->setup_dma, 8, 0);
+}
+
 /**
  * cdns_req_ep0_set_address - Handling of SET_ADDRESS standard USB request
  * @usb_ss: extended gadget object
@@ -435,6 +444,8 @@ static int cdns_req_ep0_set_address(struct usb_ss_dev *usb_ss,
        usb_gadget_set_state(&usb_ss->gadget,
                (addr ? USB_STATE_ADDRESS : USB_STATE_DEFAULT));
 
+       cdns_prepare_setup_packet(usb_ss);
+
        gadget_writel(usb_ss, &usb_ss->regs->ep_cmd,
                EP_CMD__ERDY__MASK | EP_CMD__REQ_CMPL__MASK);
        return 0;
@@ -1013,9 +1024,6 @@ static void cdns_check_ep0_interrupt_proceed(struct usb_ss_dev *usb_ss, int dir)
                        || (ep_sts_reg & EP_STS__ISP__MASK)) {
                gadget_writel(usb_ss,
                        &usb_ss->regs->ep_sts, EP_STS__IOC__MASK);
-               gadget_writel(usb_ss,
-                       &usb_ss->regs->ep_cmd, EP_CMD__REQ_CMPL__MASK);
-
                if (usb_ss->actual_ep0_request) {
                        usb_gadget_unmap_request_by_dev(usb_ss->sysdev,
                                        usb_ss->actual_ep0_request,
@@ -1037,6 +1045,10 @@ static void cdns_check_ep0_interrupt_proceed(struct usb_ss_dev *usb_ss, int dir)
                                        usb_ss->actual_ep0_request);
                        spin_lock(&usb_ss->lock);
                }
+               cdns_prepare_setup_packet(usb_ss);
+               gadget_writel(usb_ss,
+                       &usb_ss->regs->ep_cmd, EP_CMD__REQ_CMPL__MASK);
+
        }
 }
 
@@ -1318,6 +1330,7 @@ static int usb_ss_gadget_ep0_queue(struct usb_ep *ep,
 
                        gadget_writel(usb_ss, &usb_ss->regs->usb_conf,
                        USB_CONF__CFGSET__MASK); /* SET CONFIGURATION */
+                       cdns_prepare_setup_packet(usb_ss);
                        gadget_writel(usb_ss, &usb_ss->regs->ep_cmd,
                                EP_CMD__ERDY__MASK | EP_CMD__REQ_CMPL__MASK);
                        /* wait until configuration set */