diff options
Diffstat (limited to 'drivers/mmc/imxmmc.c')
| -rw-r--r-- | drivers/mmc/imxmmc.c | 54 |
1 files changed, 43 insertions, 11 deletions
diff --git a/drivers/mmc/imxmmc.c b/drivers/mmc/imxmmc.c index ffb7f55d346..07f36c454bd 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);; |