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path: root/drivers/mmc
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Diffstat (limited to 'drivers/mmc')
-rw-r--r--drivers/mmc/imxmmc.c54
1 files changed, 43 insertions, 11 deletions
diff --git a/drivers/mmc/imxmmc.c b/drivers/mmc/imxmmc.c
index ffb7f55d3467..07f36c454bd6 100644
--- a/drivers/mmc/imxmmc.c
+++ b/drivers/mmc/imxmmc.c
@@ -102,6 +102,7 @@ struct imxmci_host {
#define IMXMCI_PEND_CPU_DATA_b 5
#define IMXMCI_PEND_CARD_XCHG_b 6
#define IMXMCI_PEND_SET_INIT_b 7
+#define IMXMCI_PEND_STARTED_b 8
#define IMXMCI_PEND_IRQ_m (1 << IMXMCI_PEND_IRQ_b)
#define IMXMCI_PEND_DMA_END_m (1 << IMXMCI_PEND_DMA_END_b)
@@ -111,6 +112,7 @@ struct imxmci_host {
#define IMXMCI_PEND_CPU_DATA_m (1 << IMXMCI_PEND_CPU_DATA_b)
#define IMXMCI_PEND_CARD_XCHG_m (1 << IMXMCI_PEND_CARD_XCHG_b)
#define IMXMCI_PEND_SET_INIT_m (1 << IMXMCI_PEND_SET_INIT_b)
+#define IMXMCI_PEND_STARTED_m (1 << IMXMCI_PEND_STARTED_b)
static void imxmci_stop_clock(struct imxmci_host *host)
{
@@ -131,23 +133,52 @@ static void imxmci_stop_clock(struct imxmci_host *host)
dev_dbg(mmc_dev(host->mmc), "imxmci_stop_clock blocked, no luck\n");
}
-static void imxmci_start_clock(struct imxmci_host *host)
+static int imxmci_start_clock(struct imxmci_host *host)
{
- int i = 0;
+ unsigned int trials = 0;
+ unsigned int delay_limit = 128;
+ unsigned long flags;
+
MMC_STR_STP_CLK &= ~STR_STP_CLK_STOP_CLK;
- while(i < 0x1000) {
- if(!(i & 0x7f))
- MMC_STR_STP_CLK |= STR_STP_CLK_START_CLK;
- if(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN) {
- /* Check twice before cut */
+ clear_bit(IMXMCI_PEND_STARTED_b, &host->pending_events);
+
+ /*
+ * Command start of the clock, this usually succeeds in less
+ * then 6 delay loops, but during card detection (low clockrate)
+ * it takes up to 5000 delay loops and sometimes fails for the first time
+ */
+ MMC_STR_STP_CLK |= STR_STP_CLK_START_CLK;
+
+ do {
+ unsigned int delay = delay_limit;
+
+ while(delay--){
if(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN)
- return;
+ /* Check twice before cut */
+ if(MMC_STATUS & STATUS_CARD_BUS_CLK_RUN)
+ return 0;
+
+ if(test_bit(IMXMCI_PEND_STARTED_b, &host->pending_events))
+ return 0;
}
- i++;
- }
- dev_dbg(mmc_dev(host->mmc), "imxmci_start_clock blocked, no luck\n");
+ local_irq_save(flags);
+ /*
+ * Ensure, that request is not doubled under all possible circumstances.
+ * It is possible, that cock running state is missed, because some other
+ * IRQ or schedule delays this function execution and the clocks has
+ * been already stopped by other means (response processing, SDHC HW)
+ */
+ if(!test_bit(IMXMCI_PEND_STARTED_b, &host->pending_events))
+ MMC_STR_STP_CLK |= STR_STP_CLK_START_CLK;
+ local_irq_restore(flags);
+
+ } while(++trials<256);
+
+ dev_err(mmc_dev(host->mmc), "imxmci_start_clock blocked, no luck\n");
+
+ return -1;
}
static void imxmci_softreset(void)
@@ -622,6 +653,7 @@ static irqreturn_t imxmci_irq(int irq, void *devid, struct pt_regs *regs)
atomic_set(&host->stuck_timeout, 0);
host->status_reg = stat;
set_bit(IMXMCI_PEND_IRQ_b, &host->pending_events);
+ set_bit(IMXMCI_PEND_STARTED_b, &host->pending_events);
tasklet_schedule(&host->tasklet);
return IRQ_RETVAL(handled);;