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

commit 533a6cfe08 upstream

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
Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
[kamal: Drop non-existent hunks in 4.9's __mmc_switch]
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/mmc/core/mmc_ops.c

@@ -22,8 +22,6 @@
 #include "host.h"
 #include "mmc_ops.h"
 
-#define MMC_OPS_TIMEOUT_MS	(10 * 60 * 1000) /* 10 minute timeout */
-
 static const u8 tuning_blk_pattern_4bit[] = {
 	0xff, 0x0f, 0xff, 0x00, 0xff, 0xcc, 0xc3, 0xcc,
 	0xc3, 0x3c, 0xcc, 0xff, 0xfe, 0xff, 0xfe, 0xef,
@@ -530,8 +528,11 @@ int __mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
 		ignore_crc = false;
 
 	/* We have an unspecified cmd timeout, use the fallback value. */
-	if (!timeout_ms)
-		timeout_ms = MMC_OPS_TIMEOUT_MS;
+	if (!timeout_ms) {
+		pr_warn("%s: unspecified timeout for CMD6 - use generic\n",
+			mmc_hostname(host));
+		timeout_ms = card->ext_csd.generic_cmd6_time;
+	}
 
 	/* Must check status to be sure of no errors. */
 	timeout = jiffies + msecs_to_jiffies(timeout_ms) + 1;