This is a reworked implementation of wakelocks for the MMC core from
Android kernel, originally authored by Colin Cross and San Mehat.
The patch makes sure that whenever a MMC device is inserted/removed,
the system stays awake until it's reconfigured for the new state.
It is assumed that 1/2 second is sufficient for the system to start
the configuration action for the newly detected MMC device, which might
include e.g. mounting the hosted file system(s).
The implementation uses wakeup_sources instead of wake_locks.
Feedback on the approach is greatly appreciated, in particular for the
1/2 second extension peroid.
Cc: San Mehat <san@xxxxxxxxxx>
Cc: Colin Cross <ccross@xxxxxxxxxxx>
Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Chris Ball <cjb@xxxxxxxxxx>
Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Cc: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx>
Cc: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
Cc: Konstantin Dorfman <kdorfman@xxxxxxxxxxxxxx>
Cc: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
[<zoran.markovic@xxxxxxxxxx>: tweaked commit message, reworked to use
wakeup_source_register/unregister instead of wakeup_source_init/trash,
added the missing __pm_relax() for non-removable devices in mmc_rescan().]
Signed-off-by: Zoran Markovic <zoran.markovic@xxxxxxxxxx>
---
drivers/mmc/core/core.c | 31 +++++++++++++++++++++++++------
drivers/mmc/core/host.c | 7 +++++++
include/linux/mmc/host.h | 2 ++
3 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index c40396f..d5230c7 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -23,6 +23,7 @@
#include <linux/log2.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_runtime.h>
+#include <linux/pm_wakeup.h>
#include <linux/suspend.h>
#include <linux/fault-inject.h>
#include <linux/random.h>
@@ -1656,6 +1657,7 @@ void mmc_detect_change(struct mmc_host *host, unsigned long delay)
spin_unlock_irqrestore(&host->lock, flags);
#endif
host->detect_change = 1;
+ __pm_stay_awake(host->ws);
mmc_schedule_delayed_work(&host->detect, delay);
}
@@ -2351,13 +2353,16 @@ void mmc_rescan(struct work_struct *work)
struct mmc_host *host =
container_of(work, struct mmc_host, detect.work);
int i;
+ bool extend_wakeup = false;
if (host->rescan_disable)
return;
/* If there is a non-removable card registered, only scan once */
- if ((host->caps & MMC_CAP_NONREMOVABLE) && host->rescan_entered)
+ if ((host->caps & MMC_CAP_NONREMOVABLE) && host->rescan_entered) {
+ __pm_relax(host->ws);
return;
+ }
host->rescan_entered = 1;
mmc_bus_get(host);
@@ -2400,16 +2405,27 @@ void mmc_rescan(struct work_struct *work)
mmc_claim_host(host);
for (i = 0; i < ARRAY_SIZE(freqs); i++) {
- if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min)))
+ if (!mmc_rescan_try_freq(host, max(freqs[i], host->f_min))) {
+ /* stay awake extra time to process detected device */
+ extend_wakeup = true;
break;
+ }
if (freqs[i] <= host->f_min)
break;
}
mmc_release_host(host);
out:
- if (host->caps & MMC_CAP_NEEDS_POLL)
+ if (extend_wakeup)
+ /* extra 1/2 second should be enough, hopefully */
+ __pm_wakeup_event(host->ws, MSEC_PER_SEC/2);
+ else
+ __pm_relax(host->ws);
+
+ if (host->caps & MMC_CAP_NEEDS_POLL) {
+ __pm_stay_awake(host->ws);
mmc_schedule_delayed_work(&host->detect, HZ);
+ }
}
void mmc_start_host(struct mmc_host *host)
@@ -2433,7 +2449,8 @@ void mmc_stop_host(struct mmc_host *host)
#endif
host->rescan_disable = 1;
- cancel_delayed_work_sync(&host->detect);
+ if (cancel_delayed_work_sync(&host->detect))
+ __pm_relax(host->ws);
mmc_flush_scheduled_work();
/* clear pm flags now and let card drivers set them as needed */
@@ -2628,7 +2645,8 @@ int mmc_suspend_host(struct mmc_host *host)
{
int err = 0;
- cancel_delayed_work(&host->detect);
+ if (cancel_delayed_work(&host->detect))
+ __pm_relax(host->ws);
mmc_flush_scheduled_work();
mmc_bus_get(host);
@@ -2741,7 +2759,8 @@ int mmc_pm_notify(struct notifier_block *notify_block,
spin_lock_irqsave(&host->lock, flags);
host->rescan_disable = 1;
spin_unlock_irqrestore(&host->lock, flags);
- cancel_delayed_work_sync(&host->detect);
+ if (cancel_delayed_work_sync(&host->detect))
+ __pm_relax(host->ws);
if (!host->bus_ops || host->bus_ops->suspend)
break;
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index 2a3593d..3cbb3d7 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -452,6 +452,11 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
host->class_dev.class = &mmc_host_class;
device_initialize(&host->class_dev);
+ host->ws = wakeup_source_register(
+ kasprintf(GFP_KERNEL, "%s_detect", mmc_hostname(host)));
+ if (!host->ws)
+ goto free;
+
mmc_host_clk_init(host);
mutex_init(&host->slot.lock);
@@ -555,6 +560,8 @@ void mmc_free_host(struct mmc_host *host)
spin_lock(&mmc_host_lock);
idr_remove(&mmc_host_idr, host->index);
spin_unlock(&mmc_host_lock);
+ wakeup_source_unregister(host->ws);
+ host->ws = NULL;
put_device(&host->class_dev);
}
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index e326ae2..9dc2dd6 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -15,6 +15,7 @@
#include <linux/sched.h>
#include <linux/device.h>
#include <linux/fault-inject.h>
+#include <linux/pm_wakeup.h>
#include <linux/mmc/core.h>
#include <linux/mmc/pm.h>
@@ -329,6 +330,7 @@ struct mmc_host {
int claim_cnt; /* "claim" nesting count */
struct delayed_work detect;
+ struct wakeup_source *ws;
int detect_change; /* card detect flag */
struct mmc_slot slot;
--
1.7.9.5
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