mvsdio: fix config failure with some high speed SDHC cards

[firefly-linux-kernel-4.4.55.git] / drivers / mmc / host / mvsdio.c

diff --git a/drivers/mmc/host/mvsdio.c b/drivers/mmc/host/mvsdio.c
index 9d3cfa9909c9c0f5d48247300462f9f82b6341f5..b56d72ff06e9efbf169d5b2f0c7af2c4f6e7589e 100644 (file)
--- a/drivers/mmc/host/mvsdio.c
+++ b/drivers/mmc/host/mvsdio.c
@@ -64,6 +64,31 @@ static int mvsd_setup_data(struct mvsd_host *host, struct mmc_data *data)
        unsigned int tmout;
        int tmout_index;
 
+       /*
+        * 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 (!(mvsd_read(MVSD_HW_STATE) & (1 << 13))) {
+               unsigned long t = jiffies + HZ;
+               unsigned int hw_state,  count = 0;
+               do {
+                       if (time_after(jiffies, t)) {
+                               dev_warn(host->dev, "FIFO_EMPTY bit missing\n");
+                               break;
+                       }
+                       hw_state = mvsd_read(MVSD_HW_STATE);
+                       count++;
+               } while (!(hw_state & (1 << 13)));
+               dev_dbg(host->dev, "*** wait for FIFO_EMPTY bit "
+                                  "(hw=0x%04x, count=%d, jiffies=%ld)\n",
+                                  hw_state, count, jiffies - (t - HZ));
+       }
+
        /* If timeout=0 then maximum timeout index is used. */
        tmout = DIV_ROUND_UP(data->timeout_ns, host->ns_per_clk);
        tmout += data->timeout_clks;