mmc: core: Default to generic_cmd6_time as timeout in __mmc_switch()

All callers of __mmc_switch() should now be specifying a valid timeout for
the CMD6 command. However, just to be sure, let's print a warning and
default to use the generic_cmd6_time in case the provided timeout_ms
argument is zero.

In this context, let's also simplify some of the corresponding code and
clarify some related comments.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://lore.kernel.org/r/20200122142747.5690-4-ulf.hansson@linaro.org

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 1966abcbc7c00d34bb8b2d32572ab977bda2f85a..da425ee2d9bf50da3cee4962dcdb5b6fe341ab6e 100644 (file)
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -460,10 +460,6 @@ static int mmc_poll_for_busy(struct mmc_card *card, unsigned int timeout_ms,
        bool expired = false;
        bool busy = false;
 
-       /* We have an unspecified cmd timeout, use the fallback value. */
-       if (!timeout_ms)
-               timeout_ms = MMC_OPS_TIMEOUT_MS;
-
        /*
         * In cases when not allowed to poll by using CMD13 or because we aren't
         * capable of polling by using ->card_busy(), then rely on waiting the
@@ -536,14 +532,19 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 
        mmc_retune_hold(host);
 
+       if (!timeout_ms) {
+               pr_warn("%s: unspecified timeout for CMD6 - use generic\n",
+                       mmc_hostname(host));
+               timeout_ms = card->ext_csd.generic_cmd6_time;
+       }
+
        /*
-        * If the cmd timeout and the max_busy_timeout of the host are both
-        * specified, let's validate them. 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 the max_busy_timeout of the host is specified, make sure it's
+        * enough to fit the used timeout_ms. In case it's not, let's instruct
+        * the host to avoid HW busy detection, by converting to a R1 response
+        * instead of a R1B.
         */
-       if (timeout_ms && host->max_busy_timeout &&
-               (timeout_ms > host->max_busy_timeout))
+       if (host->max_busy_timeout && (timeout_ms > host->max_busy_timeout))
                use_r1b_resp = false;
 
        cmd.opcode = MMC_SWITCH;
@@ -554,10 +555,6 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
        cmd.flags = MMC_CMD_AC;
        if (use_r1b_resp) {
                cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;
-               /*
-                * A busy_timeout of zero means the host can decide to use
-                * whatever value it finds suitable.
-                */
                cmd.busy_timeout = timeout_ms;
        } else {
                cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;