mmc: core: Respect host's max_busy_timeout when sending sleep cmd

When sending the sleep command for host drivers supporting
MMC_CAP_WAIT_WHILE_BUSY, we need to confirm that max_busy_timeout is
big enough comparing to the sleep timeout specified from card's
EXT_CSD. If this isn't case, we use a R1 response instead of R1B and
fallback to use a delay instead.

Do note that a max_busy_timeout set to zero by the host, is interpreted
as it can cope with whatever timeout the mmc core provides it with.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Chris Ball <chris@printf.net>

diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 6b7ccef51bebaac4d9733c8eba5fb6b0f519fb84..1ab5f3a0af5b734a1829e732fe91b5bef8f24d2b 100644 (file)
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1358,6 +1358,7 @@ static int mmc_sleep(struct mmc_host *host)
 {
        struct mmc_command cmd = {0};
        struct mmc_card *card = host->card;
+       unsigned int timeout_ms = DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000);
        int err;
 
        err = mmc_deselect_cards(host);
@@ -1368,7 +1369,19 @@ static int mmc_sleep(struct mmc_host *host)
        cmd.arg = card->rca << 16;
        cmd.arg |= 1 << 15;
 
-       cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
+       /*
+        * If the max_busy_timeout of the host is specified, validate it against
+        * the sleep cmd timeout. A failure means we need to prevent the host
+        * from doing hw busy detection, which is done by converting to a R1
+        * response instead of a R1B.
+        */
+       if (host->max_busy_timeout && (timeout_ms > host->max_busy_timeout)) {
+               cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;
+       } else {
+               cmd.flags = MMC_RSP_R1B | MMC_CMD_AC;
+               cmd.busy_timeout = timeout_ms;
+       }
+
        err = mmc_wait_for_cmd(host, &cmd, 0);
        if (err)
                return err;
@@ -1379,8 +1392,8 @@ static int mmc_sleep(struct mmc_host *host)
         * SEND_STATUS command to poll the status because that command (and most
         * others) is invalid while the card sleeps.
         */
-       if (!(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
-               mmc_delay(DIV_ROUND_UP(card->ext_csd.sa_timeout, 10000));
+       if (!cmd.busy_timeout || !(host->caps & MMC_CAP_WAIT_WHILE_BUSY))
+               mmc_delay(timeout_ms);
 
        return err;
 }