From e1d3e89f26f19cb1d309ab16264dffdd57280906 Mon Sep 17 00:00:00 2001 From: Sascha Hauer Date: Fri, 20 Jun 2014 15:08:16 +0800 Subject: [PATCH] mmc: Allow setting slot index via devicetree alias As with gpio, uart and others, allow specifying the name_idx via the aliases-node in the devicetree. On embedded devices, there is often a combination of removable (e.g. SD card) and non-removable mmc devices (e.g. eMMC). Therefore the name_idx might change depending on - host of removable device - removable card present or not This makes it difficult to hard code the root device, if it is on the non-removable device. E.g. if SD card is present eMMC will be mmcblk1, if SD card is not present at boot, eMMC will be mmcblk0. If the aliases-node is not found, the driver will act as before. The original patch is from here: https://www.mail-archive.com/linux-mmc@vger.kernel.org/msg26472.html The patch requires additional alias_id fix or it won't work. Because according to function definition the max_idx parameter of idx_alloc is exclusive, so need add 1 or it will be unable to find the proper idx within an invalid range. Signed-off-by: Sascha Hauer Signed-off-by: Dong Aisheng (cherry picked from commit 35928d6c6a76a24a16edfa636f4c08293614a1e0) --- drivers/mmc/card/block.c | 8 +++++++- drivers/mmc/core/core.c | 38 ++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/host.c | 24 ++++++++++++++++++++++-- include/linux/mmc/core.h | 3 +++ 4 files changed, 70 insertions(+), 3 deletions(-) diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index c0300c492864..e1c271942e53 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -2228,7 +2228,13 @@ again: return ERR_PTR(-ENOMEM); spin_lock(&mmc_blk_lock); - ret = ida_get_new(&mmc_blk_ida, &devidx); + devidx = mmc_get_reserved_index(card->host); + if (devidx >= 0) + devidx = ida_simple_get(&mmc_blk_ida, devidx, devidx, + GFP_NOWAIT); + if (devidx < 0) + ret = ida_get_new_above(&mmc_blk_ida, + mmc_first_nonreserved_index(), &devidx); spin_unlock(&mmc_blk_lock); if (ret == -EAGAIN) diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 2553d903a82b..4c6dc3702e50 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -16,6 +16,7 @@ #include #include #include +#include #include #include #include @@ -3026,10 +3027,47 @@ void mmc_init_context_info(struct mmc_host *host) init_waitqueue_head(&host->context_info.wait); } +static int __mmc_max_reserved_idx = -1; + +/** + * mmc_first_nonreserved_index() - get the first index that is not reserved + */ +int mmc_first_nonreserved_index(void) +{ + return __mmc_max_reserved_idx + 1; +} + +/** + * mmc_get_reserved_index() - get the index reserved for this host + * + * Return: The index reserved for this host or negative error value if + * no index is reserved for this host + */ +int mmc_get_reserved_index(struct mmc_host *host) +{ + return of_alias_get_id(host->parent->of_node, "mmc"); +} + +static void mmc_of_reserve_idx(void) +{ + int max; + + max = of_alias_max_index("mmc"); + if (max < 0) + return; + + __mmc_max_reserved_idx = max; + + pr_debug("MMC: reserving %d slots for of aliases\n", + __mmc_max_reserved_idx + 1); +} + static int __init mmc_init(void) { int ret; + mmc_of_reserve_idx(); + ret = mmc_register_bus(); if (ret) return ret; diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 848b3453517e..d3c149db2ce8 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -333,6 +333,8 @@ int mmc_of_parse(struct mmc_host *host) EXPORT_SYMBOL(mmc_of_parse); +int mmc_max_reserved_idx(void); + /** * mmc_alloc_host - initialise the per-host structure. * @extra: sizeof private data structure @@ -344,6 +346,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) { int err; struct mmc_host *host; + int alias_id, min_idx, max_idx; host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL); if (!host) @@ -351,6 +354,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) /* scanning will be enabled when we're ready */ host->rescan_disable = 1; + host->parent = dev; again: if (!ida_pre_get(&mmc_host_ida, GFP_KERNEL)) { @@ -359,7 +363,24 @@ again: } spin_lock(&mmc_host_lock); - err = ida_get_new(&mmc_host_ida, &host->index); + + alias_id = mmc_get_reserved_index(host); + if (alias_id >= 0) { + min_idx = alias_id; + max_idx = alias_id + 1; + } else { + min_idx = mmc_first_nonreserved_index(); + max_idx = 0; + } + + err = ida_get_new_above(&mmc_host_ida, min_idx, &host->index); + if (!err) { + if (host->index > max_idx) { + ida_remove(&mmc_host_ida, host->index); + err = -ENOSPC; + } + } + spin_unlock(&mmc_host_lock); if (err == -EAGAIN) { @@ -371,7 +392,6 @@ again: dev_set_name(&host->class_dev, "mmc%d", host->index); - host->parent = dev; host->class_dev.parent = dev; host->class_dev.class = &mmc_host_class; device_initialize(&host->class_dev); diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h index 2b953eb8ceae..aa3edb7c5192 100644 --- a/include/linux/mmc/core.h +++ b/include/linux/mmc/core.h @@ -205,6 +205,9 @@ extern int mmc_flush_cache(struct mmc_card *); extern int mmc_detect_card_removed(struct mmc_host *host); +int mmc_first_nonreserved_index(void); +int mmc_get_reserved_index(struct mmc_host *host); + /** * mmc_claim_host - exclusively claim a host * @host: mmc host to claim -- 2.17.1