mmc: renesas_sdhi_core: on R-Car 2+, make use of CBSY bit

Most registers need to wait until the command is completed, not
necessarily until the bus is free. At least, R-Car 2+ SoCs can signal
that via the CBSY bit, so let's use it there instead of SCLKDIVEN to
save a little bit of delay.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/renesas_sdhi_core.c b/drivers/mmc/host/renesas_sdhi_core.c
index c8d83fa..dd21572 100644 (file)
--- a/drivers/mmc/host/renesas_sdhi_core.c
+++ b/drivers/mmc/host/renesas_sdhi_core.c
@@ -398,12 +398,14 @@ static void renesas_sdhi_hw_reset(struct tmio_mmc_host *host)
                       sd_scc_read32(host, priv, SH_MOBILE_SDHI_SCC_RVSCNTL));
 }
 
-static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host)
+static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host, u32 bit)
 {
        int timeout = 1000;
+       /* CBSY is set when busy, SCLKDIVEN is cleared when busy */
+       u32 wait_state = (bit == TMIO_STAT_CMD_BUSY ? TMIO_STAT_CMD_BUSY : 0);
 
-       while (--timeout && !(sd_ctrl_read16_and_16_as_32(host, CTL_STATUS)
-                             & TMIO_STAT_SCLKDIVEN))
+       while (--timeout && (sd_ctrl_read16_and_16_as_32(host, CTL_STATUS)
+                             & bit) == wait_state)
                udelay(1);
 
        if (!timeout) {
@@ -416,17 +418,22 @@ static int renesas_sdhi_wait_idle(struct tmio_mmc_host *host)
 
 static int renesas_sdhi_write16_hook(struct tmio_mmc_host *host, int addr)
 {
+       u32 bit = TMIO_STAT_SCLKDIVEN;
+
        switch (addr) {
        case CTL_SD_CMD:
        case CTL_STOP_INTERNAL_ACTION:
        case CTL_XFER_BLK_COUNT:
-       case CTL_SD_CARD_CLK_CTL:
        case CTL_SD_XFER_LEN:
        case CTL_SD_MEM_CARD_OPT:
        case CTL_TRANSACTION_CTL:
        case CTL_DMA_ENABLE:
        case EXT_ACC:
-               return renesas_sdhi_wait_idle(host);
+               if (host->pdata->flags & TMIO_MMC_MIN_RCAR2)
+                       bit = TMIO_STAT_CMD_BUSY;
+               /* fallthrough */
+       case CTL_SD_CARD_CLK_CTL:
+               return renesas_sdhi_wait_idle(host, bit);
        }
 
        return 0;