[ARM] 3531/1: i.MX/MX1 SD/MMC ensure, that clock are stopped before new command and cleanups

Patch from Pavel Pisa

There has been problems that for some paths that clock are not stopped
during new command programming and initiation. Result is issuing
of incorrect command to the card. Some other problems are cleaned too.
Noisy report of known ERRATUM #4 has been suppressed.

Signed-off-by: Pavel Pisa <pisa@cmp.felk.cvut.cz>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 14 insertions, 10 deletions

diff --git a/drivers/mmc/imxmmc.c b/drivers/mmc/imxmmc.c
index 79358e223f57..a4eb1d0e7a71 100644
--- a/drivers/mmc/imxmmc.c
+++ b/drivers/mmc/imxmmc.c
@@ -218,8 +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;
 }
 
@@ -333,6 +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;
 
@@ -553,7 +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;
@@ -591,8 +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 */
@@ -746,10 +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);
@@ -865,7 +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 {