[PATCH 5/5] esdhc-xload: check for PRSSTAT_BREN only after each block

[Sascha Hauer]

The BREN bit tells us a watermark level sized buffer is ready for read.
Instead of testing it before each FIFO read we must only check it once
and then read a watermark level sized buffer. This is at least necessary
on Layerscape, otherwise timeouts occur while reading the buffer.

Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de>
---
 drivers/mci/imx-esdhc-pbl.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/mci/imx-esdhc-pbl.c b/drivers/mci/imx-esdhc-pbl.c
index 33d78aad05..f77530d310 100644
--- a/drivers/mci/imx-esdhc-pbl.c
+++ b/drivers/mci/imx-esdhc-pbl.c
@@ -84,28 +84,33 @@ static int esdhc_do_data(struct esdhc *esdhc, struct 
mci_data *data)
        u32 databuf;
        u32 size;
        u32 irqstat;
-       u32 timeout;
        u32 present;
 
        buffer = data->dest;
 
-       timeout = 1000000;
        size = data->blocksize * data->blocks;
        irqstat = esdhc_read32(esdhc, SDHCI_INT_STATUS);
 
        while (size) {
-               present = esdhc_read32(esdhc, SDHCI_PRESENT_STATE) & 
PRSSTAT_BREN;
-               if (present) {
+               int i;
+               int timeout = 1000000;
+
+               while (1) {
+                       present = esdhc_read32(esdhc, SDHCI_PRESENT_STATE) & 
PRSSTAT_BREN;
+                       if (present)
+                               break;
+                       if (!--timeout) {
+                               pr_err("read time out\n");
+                               return -ETIMEDOUT;
+                       }
+               }
+
+               for (i = 0; i < SECTOR_SIZE / sizeof(uint32_t); i++) {
                        databuf = esdhc_read32(esdhc, SDHCI_BUFFER);
                        *((u32 *)buffer) = databuf;
                        buffer += 4;
                        size -= 4;
                }
-
-               if (!timeout--) {
-                       pr_err("read time out\n");
-                       return -ETIMEDOUT;
-               }
        }
 
        return 0;
@@ -205,6 +210,8 @@ static int esdhc_read_blocks(struct esdhc *esdhc, void 
*dst, size_t len)
                      IRQSTATEN_DTOE | IRQSTATEN_DCE | IRQSTATEN_DEBE |
                      IRQSTATEN_DINT);
 
+       esdhc_write32(esdhc, IMX_SDHCI_WML, 0x0);
+
        val = esdhc_read32(esdhc, 
SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET);
        val |= SYSCTL_HCKEN | SYSCTL_IPGEN;
        esdhc_write32(esdhc, 
SDHCI_CLOCK_CONTROL__TIMEOUT_CONTROL__SOFTWARE_RESET, val);
-- 
2.20.1


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