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mmc: core: Add deferred bus resume policy.

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A card driver can now specify that the underlying bus should *not*
auto-resume with the rest of the system. This is useful for reducing resume
latency as well as saving power when the card driver is not using the
bus. In the future, we'll add support for manual suspend

Signed-off-by: San Mehat <san@google.com>
This commit is contained in:
San Mehat
2009-07-30 07:55:28 -07:00
committed by Arve Hjønnevåg
parent 57fa81bd67
commit b44e6c88fc
2 changed files with 48 additions and 0 deletions
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33
drivers/mmc/core/core.c
View File

@@ -1594,6 +1594,30 @@ static inline void mmc_bus_put(struct mmc_host *host)
spin_unlock_irqrestore(&host->lock, flags);
}
int mmc_resume_bus(struct mmc_host *host)
{
if (!mmc_bus_needs_resume(host))
return -EINVAL;
printk("%s: Starting deferred resume\n", mmc_hostname(host));
host->bus_resume_flags &= ~MMC_BUSRESUME_NEEDS_RESUME;
mmc_bus_get(host);
if (host->bus_ops && !host->bus_dead) {
mmc_power_up(host);
BUG_ON(!host->bus_ops->resume);
host->bus_ops->resume(host);
}
if (host->bus_ops->detect && !host->bus_dead)
host->bus_ops->detect(host);
mmc_bus_put(host);
printk("%s: Deferred resume completed\n", mmc_hostname(host));
return 0;
}
EXPORT_SYMBOL(mmc_resume_bus);
/*
* Assign a mmc bus handler to a host. Only one bus handler may control a
* host at any given time.
@@ -2638,6 +2662,9 @@ int mmc_suspend_host(struct mmc_host *host)
{
int err = 0;
if (mmc_bus_needs_resume(host))
return 0;
cancel_delayed_work(&host->detect);
mmc_flush_scheduled_work();
@@ -2689,6 +2716,12 @@ int mmc_resume_host(struct mmc_host *host)
int err = 0;
mmc_bus_get(host);
if (host->bus_resume_flags & MMC_BUSRESUME_MANUAL_RESUME) {
host->bus_resume_flags |= MMC_BUSRESUME_NEEDS_RESUME;
mmc_bus_put(host);
return 0;
}
if (host->bus_ops && !host->bus_dead) {
if (!mmc_card_keep_power(host)) {
mmc_power_up(host);

15
include/linux/mmc/host.h
View File

@@ -335,6 +335,10 @@ 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)
#define MMC_BUSRESUME_NEEDS_RESUME (1 << 1)
unsigned int sdio_irqs;
struct task_struct *sdio_irq_thread;
bool sdio_irq_pending;
@@ -398,6 +402,17 @@ 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_needs_resume(host) ((host)->bus_resume_flags & MMC_BUSRESUME_NEEDS_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;
}
extern int mmc_resume_bus(struct mmc_host *host);
int mmc_suspend_host(struct mmc_host *);
int mmc_resume_host(struct mmc_host *);