[PATCH 3.19.y-ckt 100/170] mmc: sdhci: Fix override of timeout clk wrt max_busy_timeout

[Kamal Mostafa]

3.19.8-ckt18 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Adrian Hunter <adrian.hunter at intel.com>

commit 995136247915c5cee633d55ba23f6eebf67aa567 upstream.

Normally the timeout clock frequency is read from the capabilities
register.  It is also possible to set the value prior to calling
sdhci_add_host() in which case that value will override the
capabilities register value.  However that was being done after
calculating max_busy_timeout so that max_busy_timeout was being
calculated using the wrong value of timeout_clk.

Fix that by moving the override before max_busy_timeout is
calculated.

The result is that the max_busy_timeout and max_discard
increase for BSW devices so that, for example, the time for
mkfs.ext4 on a 64GB eMMC drops from about 1 minute 40 seconds
to about 20 seconds.

Note, in the future, the capabilities setting will be tidied up
and this override won't be used anymore.  However this fix is
needed for stable.

Signed-off-by: Adrian Hunter <adrian.hunter at intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson at linaro.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/mmc/host/sdhci.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index f68de85..17d79d8 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3080,14 +3080,14 @@ int sdhci_add_host(struct sdhci_host *host)
 		if (caps[0] & SDHCI_TIMEOUT_CLK_UNIT)
 			host->timeout_clk *= 1000;
 
+		if (override_timeout_clk)
+			host->timeout_clk = override_timeout_clk;
+
 		mmc->max_busy_timeout = host->ops->get_max_timeout_count ?
 			host->ops->get_max_timeout_count(host) : 1 << 27;
 		mmc->max_busy_timeout /= host->timeout_clk;
 	}
 
-	if (override_timeout_clk)
-		host->timeout_clk = override_timeout_clk;
-
 	mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
 	mmc->caps2 |= MMC_CAP2_SDIO_IRQ_NOTHREAD;
 
-- 
2.7.4