MVEBUMMC : Speed up access time

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 Fix some SD type compatibility

 Changes in v3:
 - fix the HW_STATE (from linux mvsdio)
 - review delays and timeouts

 Changes in v2:
 - increase number of loops
 - remove initial delay

 Changes in v1:
 - review all loops, delays and timeouts

Signed-off-by: Gérald Kerma <drEagle@doukki.net>
Acked-by: Pantelis Antoniou <panto@antoniou-consulting.com>

diff --git a/drivers/mmc/mvebu_mmc.c b/drivers/mmc/mvebu_mmc.c
index 063d4dacbccb4b8b63c0093d08c43ff9fb6d434c..91a9be06e66df5b9ea3a38588d833e38dc67a40d 100644 (file)
--- a/drivers/mmc/mvebu_mmc.c
+++ b/drivers/mmc/mvebu_mmc.c
@@ -23,6 +23,8 @@ DECLARE_GLOBAL_DATA_PTR;
 
 #define MVEBU_TARGET_DRAM 0
 
+#define TIMEOUT_DELAY  5*CONFIG_SYS_HZ         /* wait 5 seconds */
+
 static void mvebu_mmc_write(u32 offs, u32 val)
 {
        writel(val, CONFIG_SYS_MMC_BASE + (offs));
@@ -63,7 +65,7 @@ static int mvebu_mmc_setup_data(struct mmc_data *data)
 static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
                              struct mmc_data *data)
 {
-       int timeout = 10;
+       ulong start;
        ushort waittype = 0;
        ushort resptype = 0;
        ushort xfertype = 0;
@@ -72,19 +74,33 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
        debug("cmdidx [0x%x] resp_type[0x%x] cmdarg[0x%x]\n",
              cmd->cmdidx, cmd->resp_type, cmd->cmdarg);
 
-       udelay(10*1000);
-
        debug("%s: cmd %d (hw state 0x%04x)\n", DRIVER_NAME,
              cmd->cmdidx, mvebu_mmc_read(SDIO_HW_STATE));
 
-       /* Checking if card is busy */
-       while ((mvebu_mmc_read(SDIO_HW_STATE) & CARD_BUSY)) {
-               if (timeout == 0) {
-                       printf("%s: card busy!\n", DRIVER_NAME);
-                       return -1;
-               }
-               timeout--;
-               udelay(1000);
+       /*
+        * Hardware weirdness.  The FIFO_EMPTY bit of the HW_STATE
+        * register is sometimes not set before a while when some
+        * "unusual" data block sizes are used (such as with the SWITCH
+        * command), even despite the fact that the XFER_DONE interrupt
+        * was raised.  And if another data transfer starts before
+        * this bit comes to good sense (which eventually happens by
+        * itself) then the new transfer simply fails with a timeout.
+        */
+       if (!(mvebu_mmc_read(SDIO_HW_STATE) & CMD_FIFO_EMPTY)) {
+               ushort hw_state, count = 0;
+
+               start = get_timer(0);
+               do {
+                       hw_state = mvebu_mmc_read(SDIO_HW_STATE);
+                       if ((get_timer(0) - start) > TIMEOUT_DELAY) {
+                               printf("%s : FIFO_EMPTY bit missing\n",
+                                      DRIVER_NAME);
+                               break;
+                       }
+                       count++;
+               } while (!(hw_state & CMD_FIFO_EMPTY));
+               debug("%s *** wait for FIFO_EMPTY bit (hw=0x%04x, count=%d, jiffies=%ld)\n",
+                     DRIVER_NAME, hw_state, count, (get_timer(0) - (start)));
        }
 
        /* Set up for a data transfer if we have one */
@@ -147,8 +163,7 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
        mvebu_mmc_write(SDIO_NOR_INTR_EN, SDIO_POLL_MASK);
        mvebu_mmc_write(SDIO_ERR_INTR_EN, SDIO_POLL_MASK);
 
-       /* Waiting for completion */
-       timeout = 1000000;
+       start = get_timer(0);
 
        while (!((mvebu_mmc_read(SDIO_NOR_INTR_STATUS)) & waittype)) {
                if (mvebu_mmc_read(SDIO_NOR_INTR_STATUS) & SDIO_NOR_ERROR) {
@@ -161,13 +176,12 @@ static int mvebu_mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd,
                        return COMM_ERR;
                }
 
-               timeout--;
-               udelay(1);
-               if (timeout <= 0) {
-                       printf("%s: command timed out\n", DRIVER_NAME);
+               if ((get_timer(0) - start) > TIMEOUT_DELAY) {
+                       debug("%s: command timed out\n", DRIVER_NAME);
                        return TIMEOUT;
                }
        }
+
        if (mvebu_mmc_read(SDIO_ERR_INTR_STATUS) &
                (SDIO_ERR_CMD_TIMEOUT | SDIO_ERR_DATA_TIMEOUT))
                return TIMEOUT;

diff --git a/include/mvebu_mmc.h b/include/mvebu_mmc.h
index 28d98fe148a804eb4136f8ee7fae9315c08a0d24..7fb71f721910853969380b6e341b94910d275100 100644 (file)
--- a/include/mvebu_mmc.h
+++ b/include/mvebu_mmc.h
@@ -79,6 +79,7 @@
 #define CMD_INHIBIT                            (1 << 0)
 #define CMD_TXACTIVE                           (1 << 8)
 #define CMD_RXACTIVE                           (1 << 9)
+#define CMD_FIFO_EMPTY                         (1 << 13)
 #define CMD_AUTOCMD12ACTIVE                    (1 << 14)
 #define CMD_BUS_BUSY                           (CMD_AUTOCMD12ACTIVE |  \
                                                CMD_RXACTIVE |  \