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 <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 8be0df7..e90e02f 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -301,6 +301,73 @@
#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 @@
#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.