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Commit dfa13ebb authored by Adrian Hunter's avatar Adrian Hunter Committed by Ulf Hansson

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: default avatarAdrian Hunter <adrian.hunter@intel.com>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent 59d22309
......@@ -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.
......
......@@ -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
......@@ -12,6 +12,7 @@
#include <linux/leds.h>
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/fault-inject.h>
......@@ -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 */
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