From dfa13ebbe3340e538b988f5608efd9ff2ca7fc35 Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 7 May 2015 13:10:12 +0300 Subject: [PATCH] mmc: host: Add facility to support re-tuning Currently, there is core support for tuning during initialization. There can also be a need to re-tune periodically (e.g. sdhci) or to re-tune after the host controller is powered off (e.g. after PM runtime suspend / resume) or to re-tune in response to CRC errors. The main requirements for re-tuning are: - ability to enable / disable re-tuning - ability to flag that re-tuning is needed - ability to re-tune before any request - ability to hold off re-tuning if the card is busy - ability to hold off re-tuning if re-tuning is in progress - ability to run a re-tuning timer To support those requirements 7 members are added to struct mmc_host: unsigned int can_retune:1; /* re-tuning can be used */ unsigned int doing_retune:1; /* re-tuning in progress */ unsigned int retune_now:1; /* do re-tuning at next req */ int need_retune; /* re-tuning is needed */ int hold_retune; /* hold off re-tuning */ unsigned int retune_period; /* re-tuning period in secs */ struct timer_list retune_timer; /* for periodic re-tuning */ need_retune is an integer so it can be set without needing synchronization. hold_retune is a integer to allow nesting. Various simple functions are provided to set / clear those variables. Subsequent patches take those functions into use. Signed-off-by: Adrian Hunter Signed-off-by: Ulf Hansson --- drivers/mmc/core/host.c | 68 ++++++++++++++++++++++++++++++++++++++++ drivers/mmc/core/host.h | 6 ++++ include/linux/mmc/host.h | 23 ++++++++++++++ 3 files changed, 97 insertions(+) diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 8be0df758e68..e90e02fc596a 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -301,6 +301,73 @@ static inline void mmc_host_clk_sysfs_init(struct mmc_host *host) #endif +void mmc_retune_enable(struct mmc_host *host) +{ + host->can_retune = 1; + if (host->retune_period) + mod_timer(&host->retune_timer, + jiffies + host->retune_period * HZ); +} + +void mmc_retune_disable(struct mmc_host *host) +{ + host->can_retune = 0; + del_timer_sync(&host->retune_timer); + host->retune_now = 0; + host->need_retune = 0; +} + +void mmc_retune_timer_stop(struct mmc_host *host) +{ + del_timer_sync(&host->retune_timer); +} +EXPORT_SYMBOL(mmc_retune_timer_stop); + +void mmc_retune_hold(struct mmc_host *host) +{ + if (!host->hold_retune) + host->retune_now = 1; + host->hold_retune += 1; +} + +void mmc_retune_release(struct mmc_host *host) +{ + if (host->hold_retune) + host->hold_retune -= 1; + else + WARN_ON(1); +} + +int mmc_retune(struct mmc_host *host) +{ + int err; + + if (host->retune_now) + host->retune_now = 0; + else + return 0; + + if (!host->need_retune || host->doing_retune || !host->card) + return 0; + + host->need_retune = 0; + + host->doing_retune = 1; + + err = mmc_execute_tuning(host->card); + + host->doing_retune = 0; + + return err; +} + +static void mmc_retune_timer(unsigned long data) +{ + struct mmc_host *host = (struct mmc_host *)data; + + mmc_retune_needed(host); +} + /** * mmc_of_parse() - parse host's device-tree node * @host: host whose node should be parsed. @@ -504,6 +571,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev) #ifdef CONFIG_PM host->pm_notify.notifier_call = mmc_pm_notify; #endif + setup_timer(&host->retune_timer, mmc_retune_timer, (unsigned long)host); /* * By default, hosts do not support SGIO or large requests. diff --git a/drivers/mmc/core/host.h b/drivers/mmc/core/host.h index f2ab9e578126..992bf5397633 100644 --- a/drivers/mmc/core/host.h +++ b/drivers/mmc/core/host.h @@ -15,5 +15,11 @@ int mmc_register_host_class(void); void mmc_unregister_host_class(void); +void mmc_retune_enable(struct mmc_host *host); +void mmc_retune_disable(struct mmc_host *host); +void mmc_retune_hold(struct mmc_host *host); +void mmc_retune_release(struct mmc_host *host); +int mmc_retune(struct mmc_host *host); + #endif diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index b5bedaec6223..f471193ef6d6 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -12,6 +12,7 @@ #include #include +#include #include #include #include @@ -321,10 +322,18 @@ struct mmc_host { #ifdef CONFIG_MMC_DEBUG unsigned int removed:1; /* host is being removed */ #endif + unsigned int can_retune:1; /* re-tuning can be used */ + unsigned int doing_retune:1; /* re-tuning in progress */ + unsigned int retune_now:1; /* do re-tuning at next req */ int rescan_disable; /* disable card detection */ int rescan_entered; /* used with nonremovable devices */ + int need_retune; /* re-tuning is needed */ + int hold_retune; /* hold off re-tuning */ + unsigned int retune_period; /* re-tuning period in secs */ + struct timer_list retune_timer; /* for periodic re-tuning */ + bool trigger_card_event; /* card_event necessary */ struct mmc_card *card; /* device attached to this host */ @@ -513,4 +522,18 @@ static inline bool mmc_card_hs400(struct mmc_card *card) return card->host->ios.timing == MMC_TIMING_MMC_HS400; } +void mmc_retune_timer_stop(struct mmc_host *host); + +static inline void mmc_retune_needed(struct mmc_host *host) +{ + if (host->can_retune) + host->need_retune = 1; +} + +static inline void mmc_retune_recheck(struct mmc_host *host) +{ + if (host->hold_retune <= 1) + host->retune_now = 1; +} + #endif /* LINUX_MMC_HOST_H */