From 1450734ec61cda7bbb77afc8cb412b9d64c62d9a Mon Sep 17 00:00:00 2001 From: Kevin Liu Date: Thu, 28 Feb 2013 15:29:29 +0800 Subject: mmc: core: enhance card removal judgement for slow removal Function _mmc_detect_card_removed will be called to know whether the card is still present when host->bus_ops->detect is called. In current code, the return value of this function generally only depend on the result of sending cmd13 to card, which may not safe for card with detection support like slot gpio detection. Because the communication status between host and card may out of sync with the detect status if remove the card slowly or hands shake during the process. The direct reason is the async between card detect switch and card/slot pad contaction in hardware, which is defined by spec. The spec define card insert/remove sequence as below (both standard size SD card and MicroSD card have the same sequence): "Part 1 Standard Size SD Card Mechanical Addendum Ver4.00 Final, Appendix C: Card Detection Switch" (Take normally open type as example) a)SD card insertion sequence: The card detection switch should be turned on after all SD card contact pads are connected to the host connector contact pads. b)SD removal sequence: The card detection switch should be turned off when the SD card is just going to be removed and before any SD card contact pad is disconnected from the host connector contact pad. Below is the sequence when this issue occur (Take slot gpio detection as example and remove the card slowly during the process): 1. gpio level changed and card detect interrupt triggered. 2. mmc_rescan was launched. 3. the card pads were still contacted with the slot pads because of slow removal. So _mmc_detect_card_removed and mmc_rescan think card was still present (cmd13 succeed). 4. card pads were discontacted from the card slot pads. So the card was actually removed finally but the card removal event has been missed by system. The interval length between step 1 and step 4 depends on the card removal speed. If it's longer than the detect work schedule delay which is 200ms, this issue will likely happen. This patch add the card detect status check in function _mmc_detect_card_removed if cmd13 check succeed and host->ops->get_cd provided. If get_cd detect no card present then schedule another detect work 200ms later. Signed-off-by: Kevin Liu Tested-by: Johan Rudholm Reviewed-by: Philip Rakity Acked-by: Ulf Hansson Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 08a3cf2a7610..3bf1c462eded 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2289,6 +2289,19 @@ int _mmc_detect_card_removed(struct mmc_host *host) return 1; ret = host->bus_ops->alive(host); + + /* + * Card detect status and alive check may be out of sync if card is + * removed slowly, when card detect switch changes while card/slot + * pads are still contacted in hardware (refer to "SD Card Mechanical + * Addendum, Appendix C: Card Detection Switch"). So reschedule a + * detect work 200ms later for this case. + */ + if (!ret && host->ops->get_cd && !host->ops->get_cd(host)) { + mmc_detect_change(host, msecs_to_jiffies(200)); + pr_debug("%s: card removed too slowly\n", mmc_hostname(host)); + } + if (ret) { mmc_card_set_removed(host->card); pr_debug("%s: card remove detected\n", mmc_hostname(host)); -- cgit v1.2.3 From 3500ed90b26a9935b943b5e2e4cd3226600d6b58 Mon Sep 17 00:00:00 2001 From: Sergey Yanovich Date: Thu, 14 Mar 2013 05:23:13 +0400 Subject: mmc: core: wait while adding MMC host to ensure root mounts successfully MMC hosts are added asynchronously. We need to wait until detect returns to avoid failed root filesystem mounts. VFS: Cannot open root device "mmcblk0p1" or unknown-block(0,0): error -6 Please append a correct "root=" boot option; here are the available partitions: mmc0: host does not support reading read-only switch. assuming write-enable. 1f00 256 mtdblock0 (driver?) 1f01 256 mtdblock1 (driver?) 1f02 2560 mtdblock2 mmc0: new SDHC card at address b368 (driver?) 1f03 29696 mtdblock3 (driver?) 1f04 16384 mtdblock4 mmcblk0: mmc0:b368 USD 3.72 GiB (driver?) mmcblk0: p1 b300 3910656 mmcblk0 driver: mmcblk b301 3906560 mmcblk0p1 00000000-01 Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) Signed-off-by: Sergey Yanovich Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bf1c462eded..ad7decc3340a 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2418,6 +2418,7 @@ void mmc_start_host(struct mmc_host *host) host->rescan_disable = 0; mmc_power_up(host); mmc_detect_change(host, 0); + mmc_flush_scheduled_work(); } void mmc_stop_host(struct mmc_host *host) -- cgit v1.2.3 From f9a94e0a3f18ae4c0245d4a16d0ee20e93fd7bad Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 4 Apr 2013 16:41:05 +0300 Subject: Revert "mmc: core: wait while adding MMC host to ensure root mounts successfully" This reverts commit 3500ed90b26a9935b943b5e2e4cd3226600d6b58. The reverted patch caused a significant performance regression when booting with the root file system on eMMC. Before the patch: [ 1.625623] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. After the patch: [ 1.935851] VFS: Mounted root (ext4 filesystem) readonly on device 179:2. That was an addition of 310 ms which is a 19% performance degradation. Signed-off-by: Adrian Hunter Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index ad7decc3340a..3bf1c462eded 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2418,7 +2418,6 @@ void mmc_start_host(struct mmc_host *host) host->rescan_disable = 0; mmc_power_up(host); mmc_detect_change(host, 0); - mmc_flush_scheduled_work(); } void mmc_stop_host(struct mmc_host *host) -- cgit v1.2.3 From 0d3e3350d5871c53464be4c92d57198744247005 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 4 Apr 2013 16:41:06 +0300 Subject: mmc: core: fix performance regression initializing MMC host controllers Commit fa5501890d8974301042e0202d342a6cbe8609f4 introduced a performance regression by adding mmc_power_up() to mmc_start_host(). mmc_power_up() is not necessary to host controller initialization, it is part of card initialization and is performed anyway asynchronously. This patch allows a driver to leave the power up in asynchronous code (as it was before). On my current target platform this reduces driver initialization from: [ 1.313220] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 102008 usecs to this: [ 1.217209] initcall sdhci_acpi_driver_init+0x0/0x12 returned 0 after 8331 usecs Signed-off-by: Adrian Hunter Acked-by: Ulf Hansson Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 3 ++- drivers/mmc/host/sdhci-acpi.c | 2 ++ include/linux/mmc/host.h | 1 + 3 files changed, 5 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index 3bf1c462eded..c1893c9c3c31 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2416,7 +2416,8 @@ void mmc_start_host(struct mmc_host *host) { host->f_init = max(freqs[0], host->f_min); host->rescan_disable = 0; - mmc_power_up(host); + if (!(host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP)) + mmc_power_up(host); mmc_detect_change(host, 0); } diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c index 2592dddbd965..7bcf74b1a5cd 100644 --- a/drivers/mmc/host/sdhci-acpi.c +++ b/drivers/mmc/host/sdhci-acpi.c @@ -195,6 +195,8 @@ static int sdhci_acpi_probe(struct platform_device *pdev) host->mmc->pm_caps |= c->slot->pm_caps; } + host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; + err = sdhci_add_host(host); if (err) goto err_free; diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index 17d714801e94..8873e8349597 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -280,6 +280,7 @@ struct mmc_host { #define MMC_CAP2_PACKED_WR (1 << 13) /* Allow packed write */ #define MMC_CAP2_PACKED_CMD (MMC_CAP2_PACKED_RD | \ MMC_CAP2_PACKED_WR) +#define MMC_CAP2_NO_PRESCAN_POWERUP (1 << 14) /* Don't power up before scan */ mmc_pm_flag_t pm_caps; /* supported pm features */ -- cgit v1.2.3 From a08b17be8b984a7c51cd5a480cd977363df353f9 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Mon, 15 Apr 2013 11:27:25 -0400 Subject: mmc: core: fix init controller performance regression, updated patch Add MMC_CAP2_NO_PRESCAN_POWERUP to sdhci-pci.c also, use mmc_power_off() for MMC_CAP2_NO_PRESCAN_POWERUP. Signed-off-by: Adrian Hunter [cjb: previously applied v1 of this patch instead of v4] Signed-off-by: Chris Ball --- drivers/mmc/core/core.c | 4 +++- drivers/mmc/host/sdhci-pci.c | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) (limited to 'drivers/mmc/core/core.c') diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index c1893c9c3c31..65f9ca7a56ad 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -2416,7 +2416,9 @@ void mmc_start_host(struct mmc_host *host) { host->f_init = max(freqs[0], host->f_min); host->rescan_disable = 0; - if (!(host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP)) + if (host->caps2 & MMC_CAP2_NO_PRESCAN_POWERUP) + mmc_power_off(host); + else mmc_power_up(host); mmc_detect_change(host, 0); } diff --git a/drivers/mmc/host/sdhci-pci.c b/drivers/mmc/host/sdhci-pci.c index c1f037266bdf..0012d3fdc999 100644 --- a/drivers/mmc/host/sdhci-pci.c +++ b/drivers/mmc/host/sdhci-pci.c @@ -1280,6 +1280,7 @@ static struct sdhci_pci_slot *sdhci_pci_probe_slot( host->mmc->pm_caps = MMC_PM_KEEP_POWER | MMC_PM_WAKE_SDIO_IRQ; host->mmc->slotno = slotno; + host->mmc->caps2 |= MMC_CAP2_NO_PRESCAN_POWERUP; ret = sdhci_add_host(host); if (ret) -- cgit v1.2.3