[RFC PATCH v2 6/6] mmc: core: add manual resume capability

Ulf Hansson ulf.hansson at linaro.org
Fri Jun 27 19:40:50 EST 2014



On 27 juni 2014 04:23:42 CEST, Vincent Yang <vincent.yang.fujitsu at gmail.com> wrote:
>2014-06-26 17:42 GMT+08:00 Ulf Hansson <ulf.hansson at linaro.org>:
>>
>>
>> On 26 juni 2014 08:23:32 CEST, Vincent Yang
><vincent.yang.fujitsu at gmail.com> wrote:
>>>This patch adds manual resume for some embedded platforms with rootfs
>>>stored in SD card. It references CONFIG_MMC_BLOCK_DEFERRED_RESUME in
>>>kernel 3.10. It lets host controller driver to manually handle resume
>>>by itself.
>>>
>>>[symptom]
>>>This issue is found on mb86s7x platforms with rootfs stored in SD
>card.
>>>It failed to resume form STR suspend mode because SD card cannot be
>>>ready
>>>in time. It take longer time (e.g., 600ms) to be ready for access.
>>>The error log looks like below:
>>>
>>>root at localhost:~# echo mem > /sys/power/state
>>>[   30.441974] SUSPEND
>>>
>>>SCB Firmware : Category 01 Version 02.03 Rev. 00_
>>>    Config   : (no configuration)
>>>root at localhost:~# [   30.702976] Buffer I/O error on device
>mmcblk1p2,
>>>logical block 31349
>>>[   30.709678] Buffer I/O error on device mmcblk1p2, logical block
>>>168073
>>>[   30.716220] Buffer I/O error on device mmcblk1p2, logical block
>>>168074
>>>[   30.722759] Buffer I/O error on device mmcblk1p2, logical block
>>>168075
>>>[   30.729456] Buffer I/O error on device mmcblk1p2, logical block
>>>31349
>>>[   30.735916] Buffer I/O error on device mmcblk1p2, logical block
>>>31350
>>>[   30.742370] Buffer I/O error on device mmcblk1p2, logical block
>>>31351
>>>[   30.749025] Buffer I/O error on device mmcblk1p2, logical block
>>>168075
>>>[   30.755657] Buffer I/O error on device mmcblk1p2, logical block
>>>31351
>>>[   30.763130] Aborting journal on device mmcblk1p2-8.
>>>[   30.768060] JBD2: Error -5 detected when updating journal
>superblock
>>>for mmcblk1p2-8.
>>>[   30.776085] EXT4-fs error (device mmcblk1p2):
>>>ext4_journal_check_start:56: Detected aborted journal
>>>[   30.785259] EXT4-fs (mmcblk1p2): Remounting filesystem read-only
>>>[   31.370716] EXT4-fs error (device mmcblk1p2):
>ext4_find_entry:1309:
>>>inode #2490369: comm udevd: reading directory lblock 0
>>>[   31.382485] EXT4-fs error (device mmcblk1p2):
>ext4_find_entry:1309:
>>>inode #1048577: comm udevd: reading directory lblock 0
>>>
>>>[analysis]
>>>In system resume path, mmc_sd_resume() is failed with error code -123
>>>because at that time SD card is still not ready on mb86s7x platforms.
>>
>> So why does it fail? It shouldn't!
>>
>> I get the impression that you are solving this in the wrong way.
>
>Hi Uffe,
>On mb86s7x EVB, power for SD card is completely removed when entering
>STR suspend mode (i.e., echo mem > /sys/power/state). When system
>starts to resume, it turns on the power for SD card again. However, It
>take
>longer time (e.g., 600ms) to get the power ready.
>This is why mmc_sd_resume() failed with error code -123. At that time
>point,
>power for SD card is not ready yet.
>
>At first we fixed it by a simple method of using
>SDHCI_QUIRK_DELAY_AFTER_POWER:
>
>diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>index 169e17d..ed28896 100644
>--- a/drivers/mmc/host/sdhci.c
>+++ b/drivers/mmc/host/sdhci.c
>@@ -1283,7 +1283,7 @@ static void sdhci_set_power(struct sdhci_host
>*host, unsigned char mode,
>                 * they can apply clock after applying power
>                 */
>                if (host->quirks & SDHCI_QUIRK_DELAY_AFTER_POWER)
>-                       mdelay(10);
>+                       mdelay(600);
>        }

If you can't model the power to the card through a regulator, this is what you need to do.

>
>        if (host->vmmc) {
>
>However, we found it blocks the system resume path. It can slow down
>system resume and also booting.
>Therefore, we would like to resume SD card manually and asynchronously
>by host controller driver itself. Thus system resume path is not
>blocked.

That is accomplished by using MMC_CAP_RUNTIME_RESUME.

Kind regards
Uffe


>Thanks a lot for your review!
>
>
>Best regards,
>Vincent Yang
>
>>
>> Kind regards
>> Uffe
>>
>>>
>>>[solution]
>>>In order to not blocking system resume path, this patch just sets a
>>>flag
>>>MMC_BUSRESUME_MANUAL_RESUME when this error happened, and then host
>>>controller
>>>driver can understand it by this flag. Then host controller driver
>have
>>>to
>>>resume SD card manually and asynchronously.
>>>
>>>Signed-off-by: Vincent Yang <Vincent.Yang at tw.fujitsu.com>
>>>---
>>> drivers/mmc/core/core.c          |  4 ++
>>> drivers/mmc/core/sd.c            |  4 ++
>>>drivers/mmc/host/sdhci_f_sdh30.c | 89
>>>++++++++++++++++++++++++++++++++++++++++
>>> include/linux/mmc/host.h         | 14 +++++++
>>> 4 files changed, 111 insertions(+)
>>>
>>>diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>index 764af63..51fce49 100644
>>>--- a/drivers/mmc/core/core.c
>>>+++ b/drivers/mmc/core/core.c
>>>@@ -2648,6 +2648,10 @@ int mmc_pm_notify(struct notifier_block
>>>*notify_block,
>>>       case PM_POST_RESTORE:
>>>
>>>               spin_lock_irqsave(&host->lock, flags);
>>>+              if (mmc_bus_manual_resume(host)) {
>>>+                      spin_unlock_irqrestore(&host->lock, flags);
>>>+                      break;
>>>+              }
>>>               host->rescan_disable = 0;
>>>               spin_unlock_irqrestore(&host->lock, flags);
>>>               _mmc_detect_change(host, 0, false);
>>>diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
>>>index 0c44510..859390d 100644
>>>--- a/drivers/mmc/core/sd.c
>>>+++ b/drivers/mmc/core/sd.c
>>>@@ -1133,6 +1133,10 @@ static int mmc_sd_resume(struct mmc_host
>*host)
>>>
>>>       if (!(host->caps & MMC_CAP_RUNTIME_RESUME)) {
>>>               err = _mmc_sd_resume(host);
>>>+              if ((host->caps2 & MMC_CAP2_MANUAL_RESUME) && err)
>>>+                      mmc_set_bus_resume_policy(host, 1);
>>>+              else
>>>+                      mmc_set_bus_resume_policy(host, 0);
>>>               pm_runtime_set_active(&host->card->dev);
>>>               pm_runtime_mark_last_busy(&host->card->dev);
>>>       }
>>>diff --git a/drivers/mmc/host/sdhci_f_sdh30.c
>>>b/drivers/mmc/host/sdhci_f_sdh30.c
>>>index 6fae509..67bcff2 100644
>>>--- a/drivers/mmc/host/sdhci_f_sdh30.c
>>>+++ b/drivers/mmc/host/sdhci_f_sdh30.c
>>>@@ -30,6 +30,12 @@
>>> #include "../core/core.h"
>>>
>>> #define DRIVER_NAME "f_sdh30"
>>>+#define RESUME_WAIT_COUNT     100
>>>+#define RESUME_WAIT_TIME      50
>>>+#define RESUME_WAIT_JIFFIES   msecs_to_jiffies(RESUME_DETECT_TIME)
>>>+#define RESUME_DETECT_COUNT   16
>>>+#define RESUME_DETECT_TIME    50
>>>+#define RESUME_DETECT_JIFFIES msecs_to_jiffies(RESUME_DETECT_TIME)
>>>
>>>
>>> struct f_sdhost_priv {
>>>@@ -38,8 +44,59 @@ struct f_sdhost_priv {
>>>       int gpio_select_1v8;
>>>       u32 vendor_hs200;
>>>       struct device *dev;
>>>+      unsigned int quirks;    /* Deviations from spec. */
>>>+
>>>+/* retry to detect mmc device when resume */
>>>+#define F_SDH30_QUIRK_RESUME_DETECT_RETRY             (1<<0)
>>>+
>>>+      struct workqueue_struct *resume_detect_wq;
>>>+      struct delayed_work resume_detect_work;
>>>+      unsigned int            resume_detect_count;
>>>+      unsigned int            resume_wait_count;
>>> };
>>>
>>>+static void sdhci_f_sdh30_resume_detect_work_func(struct work_struct
>>>*work)
>>>+{
>>>+      struct f_sdhost_priv *priv = container_of(work, struct
>f_sdhost_priv,
>>>+              resume_detect_work.work);
>>>+      struct sdhci_host *host = dev_get_drvdata(priv->dev);
>>>+      int err = 0;
>>>+
>>>+      if (mmc_bus_manual_resume(host->mmc)) {
>>>+              pm_runtime_disable(&host->mmc->card->dev);
>>>+              mmc_card_set_suspended(host->mmc->card);
>>>+              err = host->mmc->bus_ops->resume(host->mmc);
>>>+              if (priv->resume_detect_count-- && err)
>>>+                      queue_delayed_work(priv->resume_detect_wq,
>>>+                                         &priv->resume_detect_work,
>>>+                              RESUME_DETECT_JIFFIES);
>>>+              else
>>>+                      pr_debug("%s: resume detection done (count:%d,
>wait:%d, err:%d)\n",
>>>+                               mmc_hostname(host->mmc),
>>>+                               priv->resume_detect_count,
>>>+                               priv->resume_wait_count, err);
>>>+      } else {
>>>+              if (priv->resume_wait_count--)
>>>+                      queue_delayed_work(priv->resume_detect_wq,
>>>+                                         &priv->resume_detect_work,
>>>+                              RESUME_WAIT_JIFFIES);
>>>+              else
>>>+                      pr_debug("%s: resume done\n",
>mmc_hostname(host->mmc));
>>>+      }
>>>+}
>>>+
>>>+static void sdhci_f_sdh30_resume_detect(struct mmc_host *mmc,
>>>+                                      int detect, int wait)
>>>+{
>>>+      struct sdhci_host *host = mmc_priv(mmc);
>>>+      struct f_sdhost_priv *priv = sdhci_priv(host);
>>>+
>>>+      priv->resume_detect_count = detect;
>>>+      priv->resume_wait_count = wait;
>>>+      queue_delayed_work(priv->resume_detect_wq,
>>>+                         &priv->resume_detect_work, 0);
>>>+}
>>>+
>>> void sdhci_f_sdh30_soft_voltage_switch(struct sdhci_host *host)
>>> {
>>>       struct f_sdhost_priv *priv = sdhci_priv(host);
>>>@@ -146,6 +203,12 @@ static int sdhci_f_sdh30_probe(struct
>>>platform_device *pdev)
>>>               }
>>>       }
>>>
>>>+      if (of_find_property(pdev->dev.of_node, "resume-detect-retry",
>NULL))
>>>{
>>>+              dev_info(dev, "Applying resume detect retry quirk\n");
>>>+              priv->quirks |= F_SDH30_QUIRK_RESUME_DETECT_RETRY;
>>>+              host->mmc->caps2 |= MMC_CAP2_MANUAL_RESUME;
>>>+      }
>>>+
>>>       ret = mmc_of_parse_voltage(pdev->dev.of_node,
>&host->ocr_mask);
>>>       if (ret) {
>>>               dev_err(dev, "%s: parse voltage error\n", __func__);
>>>@@ -197,6 +260,18 @@ static int sdhci_f_sdh30_probe(struct
>>>platform_device *pdev)
>>>               }
>>>       }
>>>
>>>+      /* Init workqueue */
>>>+      if (priv->quirks & F_SDH30_QUIRK_RESUME_DETECT_RETRY) {
>>>+              priv->resume_detect_wq =
>create_workqueue("sdhci_f_sdh30");
>>>+              if (priv->resume_detect_wq == NULL) {
>>>+                      ret = -ENOMEM;
>>>+                      dev_err(dev, "Failed to create resume
>detection workqueue\n");
>>>+                      goto err_init_wq;
>>>+              }
>>>+              INIT_DELAYED_WORK(&priv->resume_detect_work,
>>>+                               
>sdhci_f_sdh30_resume_detect_work_func);
>>>+      }
>>>+
>>>       ret = sdhci_add_host(host);
>>>       if (ret) {
>>>               dev_err(dev, "%s: host add error\n", __func__);
>>>@@ -229,6 +304,9 @@ static int sdhci_f_sdh30_probe(struct
>>>platform_device *pdev)
>>>       return 0;
>>>
>>> err_add_host:
>>>+      if (priv->quirks & F_SDH30_QUIRK_RESUME_DETECT_RETRY)
>>>+              destroy_workqueue(priv->resume_detect_wq);
>>>+err_init_wq:
>>>       if (gpio_is_valid(priv->gpio_select_1v8)) {
>>>               gpio_direction_output(priv->gpio_select_1v8, 1);
>>>               gpio_free(priv->gpio_select_1v8);
>>>@@ -268,6 +346,9 @@ static int sdhci_f_sdh30_remove(struct
>>>platform_device *pdev)
>>>               gpio_free(priv->gpio_select_1v8);
>>>       }
>>>
>>>+      if (priv->quirks & F_SDH30_QUIRK_RESUME_DETECT_RETRY)
>>>+              destroy_workqueue(priv->resume_detect_wq);
>>>+
>>>       sdhci_free_host(host);
>>>       platform_set_drvdata(pdev, NULL);
>>>
>>>@@ -285,7 +366,15 @@ static int sdhci_f_sdh30_suspend(struct device
>>>*dev)
>>> static int sdhci_f_sdh30_resume(struct device *dev)
>>> {
>>>       struct sdhci_host *host = dev_get_drvdata(dev);
>>>+      struct f_sdhost_priv *priv = sdhci_priv(host);
>>>
>>>+      if (priv->quirks & F_SDH30_QUIRK_RESUME_DETECT_RETRY) {
>>>+              pr_debug("%s: start resume detect\n",
>>>+                       mmc_hostname(host->mmc));
>>>+              sdhci_f_sdh30_resume_detect(host->mmc,
>>>+                                          RESUME_DETECT_COUNT,
>>>+                                          RESUME_WAIT_COUNT);
>>>+      }
>>>       return sdhci_resume_host(host);
>>> }
>>> #endif
>>>diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>>>index 7960424..55221dd 100644
>>>--- a/include/linux/mmc/host.h
>>>+++ b/include/linux/mmc/host.h
>>>@@ -283,6 +283,7 @@ struct mmc_host {
>>> #define MMC_CAP2_HS400                (MMC_CAP2_HS400_1_8V | \
>>>                                MMC_CAP2_HS400_1_2V)
>>> #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17)
>>>+#define MMC_CAP2_MANUAL_RESUME     (1 << 18)  /* Resume manually
>when
>>>error */
>>>
>>>       mmc_pm_flag_t           pm_caps;        /* supported pm
>features */
>>>
>>>@@ -338,6 +339,9 @@ struct mmc_host {
>>>       const struct mmc_bus_ops *bus_ops;      /* current bus driver
>*/
>>>       unsigned int            bus_refs;       /* reference counter
>*/
>>>
>>>+      unsigned int            bus_resume_flags;
>>>+#define MMC_BUSRESUME_MANUAL_RESUME   (1 << 0)
>>>+
>>>       unsigned int            sdio_irqs;
>>>       struct task_struct      *sdio_irq_thread;
>>>       bool                    sdio_irq_pending;
>>>@@ -384,6 +388,16 @@ static inline void *mmc_priv(struct mmc_host
>>>*host)
>>> #define mmc_dev(x)    ((x)->parent)
>>> #define mmc_classdev(x)       (&(x)->class_dev)
>>> #define mmc_hostname(x)       (dev_name(&(x)->class_dev))
>>>+#define mmc_bus_manual_resume(host) ((host)->bus_resume_flags &     
>         \
>>>+      MMC_BUSRESUME_MANUAL_RESUME)
>>>+
>>>+static inline void mmc_set_bus_resume_policy(struct mmc_host *host,
>>>int manual)
>>>+{
>>>+      if (manual)
>>>+              host->bus_resume_flags |= MMC_BUSRESUME_MANUAL_RESUME;
>>>+      else
>>>+              host->bus_resume_flags &=
>~MMC_BUSRESUME_MANUAL_RESUME;
>>>+}
>>>
>>> int mmc_power_save_host(struct mmc_host *host);
>>> int mmc_power_restore_host(struct mmc_host *host);
>>



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