1 files changed, 58 insertions, 26 deletions

diff --git a/drivers/mmc/imxmmc.c b/drivers/mmc/imxmmc.c
index ffb7f55d3467..a4eb1d0e7a71 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)
@@ -187,8 +218,10 @@ static int imxmci_busy_wait_for_status(struct imxmci_host *host,
         if(!loops)
                 return 0;
 
-        dev_info(mmc_dev(host->mmc), "busy wait for %d usec in %s, STATUS = 0x%x (0x%x)\n",
-                loops, where, *pstat, stat_mask);
+        /* The busy-wait is expected there for clock <8MHz due to SDHC hardware flaws */
+        if(!(stat_mask & STATUS_END_CMD_RESP) || (host->mmc->ios.clock>=8000000))
+                dev_info(mmc_dev(host->mmc), "busy wait for %d usec in %s, STATUS = 0x%x (0x%x)\n",
+                        loops, where, *pstat, stat_mask);
         return loops;
 }
 
@@ -302,6 +335,9 @@ static void imxmci_start_cmd(struct imxmci_host *host, struct mmc_command *cmd,
         WARN_ON(host->cmd != NULL);
         host->cmd = cmd;
 
+        /* Ensure, that clock are stopped else command programming and start fails */
+        imxmci_stop_clock(host);
+
         if (cmd->flags & MMC_RSP_BUSY)
                 cmdat |= CMD_DAT_CONT_BUSY;
 
@@ -498,7 +534,7 @@ static int imxmci_data_done(struct imxmci_host *host, unsigned int stat)
 
         data_error = imxmci_finish_data(host, stat);
 
-        if (host->req->stop && (data_error == MMC_ERR_NONE)) {
+        if (host->req->stop) {
                 imxmci_stop_clock(host);
                 imxmci_start_cmd(host, host->req->stop, 0);
         } else {
@@ -522,7 +558,7 @@ static int imxmci_cpu_driven_data(struct imxmci_host *host, unsigned int *pstat)
         int trans_done = 0;
         unsigned int stat = *pstat;
 
-        if(host->actual_bus_width == MMC_BUS_WIDTH_4)
+        if(host->actual_bus_width != MMC_BUS_WIDTH_4)
                 burst_len = 16;
         else
                 burst_len = 64;
@@ -560,8 +596,7 @@ static int imxmci_cpu_driven_data(struct imxmci_host *host, unsigned int *pstat)
                         stat = MMC_STATUS;
 
                         /* Flush extra bytes from FIFO */
-                        while(flush_len >= 2){
-                                flush_len -= 2;
+                        while(flush_len && !(stat & STATUS_DATA_TRANS_DONE)){
                                 i = MMC_BUFFER_ACCESS;
                                 stat = MMC_STATUS;
                                 stat &= ~STATUS_CRC_READ_ERR; /* Stupid but required there */
@@ -622,6 +657,7 @@ 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);;
@@ -714,10 +750,6 @@ static void imxmci_tasklet_fnc(unsigned long data)
                         data_dir_mask = STATUS_DATA_TRANS_DONE;
                 }
 
-                imxmci_busy_wait_for_status(host, &stat,
-                                data_dir_mask,
-                                50, "imxmci_tasklet_fnc data");
-
                 if(stat & data_dir_mask) {
                         clear_bit(IMXMCI_PEND_DMA_END_b, &host->pending_events);
                         imxmci_data_done(host, stat);
@@ -775,10 +807,6 @@ static void imxmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
         struct imxmci_host *host = mmc_priv(mmc);
         int prescaler;
 
-        dev_dbg(mmc_dev(host->mmc), "clock %u power %u vdd %u width %u\n",
-                ios->clock, ios->power_mode, ios->vdd,
-                (ios->bus_width==MMC_BUS_WIDTH_4)?4:1);
-
         if( ios->bus_width==MMC_BUS_WIDTH_4 ) {
                 host->actual_bus_width = MMC_BUS_WIDTH_4;
                 imx_gpio_mode(PB11_PF_SD_DAT3);
@@ -837,7 +865,11 @@ static void imxmci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
                 imxmci_stop_clock(host);
                 MMC_CLK_RATE = (prescaler<<3) | clk;
-                imxmci_start_clock(host);
+                /*
+                 * Under my understanding, clock should not be started there, because it would
+                 * initiate SDHC sequencer and send last or random command into card
+                 */
+                /*imxmci_start_clock(host);*/
 
                 dev_dbg(mmc_dev(host->mmc), "MMC_CLK_RATE: 0x%08x\n", MMC_CLK_RATE);
         } else {