[PATCH 25/26] mmc: sdhci: panic write: trap nonpanic tasks

From: Irina Tirdea
Date: Tue Oct 23 2012 - 09:44:22 EST


From: Adrian Hunter <adrian.hunter@xxxxxxxxx>

Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Irina Tirdea <irina.tirdea@xxxxxxxxx>
---
drivers/mmc/host/sdhci.c | 47 +++++++++++++++++++++++++++++++++++++++++----
include/linux/mmc/sdhci.h | 1 +
2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9a24417..db12fad 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2204,8 +2204,12 @@ static void sdhci_panic_cleanup(struct mmc_host *mmc)

void sdhci_lock(struct sdhci_host *host)
{
- if (mmc_am_panic_task(host->mmc))
- return;
+ if (mmc_panic_task_active(host->mmc)) {
+ if (mmc_am_panic_task(host->mmc))
+ return;
+ while (mmc_am_nonpanic_task(host->mmc))
+ cpu_relax();
+ }
spin_lock(&host->lock);
}

@@ -2219,8 +2223,12 @@ void _sdhci_lock_irqsave(struct sdhci_host *host, unsigned long *flags_ptr)
{
unsigned long flags;

- if (mmc_am_panic_task(host->mmc))
- return;
+ if (mmc_panic_task_active(host->mmc)) {
+ if (mmc_am_panic_task(host->mmc))
+ return;
+ while (mmc_am_nonpanic_task(host->mmc))
+ cpu_relax();
+ }

spin_lock_irqsave(&host->lock, flags);
*flags_ptr = flags;
@@ -2235,6 +2243,16 @@ void sdhci_unlock_irqrestore(struct sdhci_host *host, unsigned long flags)
static void sdhci_panic_begin(struct mmc_host *mmc)
{
struct sdhci_host *host = mmc_priv(mmc);
+ int i;
+
+ /* Wait a bit for other users to go away */
+ for (i = 0; i < 10000; i++) {
+ if (spin_trylock(&host->lock)) {
+ host->locked = 1;
+ break;
+ }
+ udelay(1);
+ }

if (host->runtime_suspended)
sdhci_runtime_resume_host(host);
@@ -2250,6 +2268,10 @@ static void sdhci_panic_end(struct mmc_host *mmc)

ier = sdhci_readl(host, SDHCI_INT_ENABLE);
sdhci_writel(host, ier, SDHCI_SIGNAL_ENABLE);
+ if (host->locked) {
+ host->locked = 0;
+ spin_unlock(&host->lock);
+ }
}

static const struct mmc_panic_ops sdhci_pops = {
@@ -2368,6 +2390,9 @@ static void sdhci_timeout_timer(unsigned long data)

host = (struct sdhci_host*)data;

+ if (mmc_am_nonpanic_task(host->mmc))
+ return;
+
sdhci_lock_irqsave(host, flags);

if (host->mrq) {
@@ -2399,6 +2424,9 @@ static void sdhci_tuning_timer(unsigned long data)

host = (struct sdhci_host *)data;

+ if (mmc_am_nonpanic_task(host->mmc))
+ return;
+
sdhci_lock_irqsave(host, flags);

host->flags |= SDHCI_NEEDS_RETUNING;
@@ -2596,6 +2624,9 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
u32 intmask, unexpected = 0;
int cardint = 0, max_loops = 16;

+ if (mmc_am_nonpanic_task(host->mmc))
+ return IRQ_HANDLED;
+
sdhci_lock(host);


@@ -2713,6 +2744,8 @@ int sdhci_suspend_host(struct sdhci_host *host)
if (host->ops->platform_suspend)
host->ops->platform_suspend(host);

+ mmc_trap_nonpanic_tasks(host->mmc);
+
sdhci_disable_card_detection(host);

/* Disable tuning since we are suspending */
@@ -2745,6 +2778,8 @@ int sdhci_resume_host(struct sdhci_host *host)
{
int ret;

+ mmc_trap_nonpanic_tasks(host->mmc);
+
if (host->flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
if (host->ops->enable_dma)
host->ops->enable_dma(host);
@@ -2820,6 +2855,8 @@ int sdhci_runtime_suspend_host(struct sdhci_host *host)
unsigned long flags;
int ret = 0;

+ mmc_trap_nonpanic_tasks(host->mmc);
+
/* Disable tuning since we are suspending */
if (host->flags & SDHCI_USING_RETUNING_TIMER) {
del_timer_sync(&host->tuning_timer);
@@ -2845,6 +2882,8 @@ int sdhci_runtime_resume_host(struct sdhci_host *host)
unsigned long flags;
int ret = 0, host_flags = host->flags;

+ mmc_trap_nonpanic_tasks(host->mmc);
+
if (host_flags & (SDHCI_USE_SDMA | SDHCI_USE_ADMA)) {
if (host->ops->enable_dma)
host->ops->enable_dma(host);
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 873e41d..13cc598 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -173,6 +173,7 @@ struct sdhci_host {
struct timer_list tuning_timer; /* Timer for tuning */

#ifdef CONFIG_MMC_BLOCK_PANIC_WRITE
+ int locked; /* panic task has the lock */
void *panic_buf; /* buffer for panic requests */
size_t panic_bufsize; /* panic buffer size */
dma_addr_t panic_dma_addr; /* panic buffer dma address */
--
1.7.9.5

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