[PATCH] Powerpc/eSDHC: Calculate the applicable mmc erase timeout value

[Haijun Zhang <Haijun.Zhang@freescale.com>]

As large area erase needs long time usually a few minutes,
So we use max_discard_to to limit the size one request can
issue to avoid timeout. As our controller had the quirk
SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK so we need to assign the
timeout_clk and max_discard_to according to the max_dtr which
can be read after the card had setup and decoded, As esdhc-imx
also use this func and this quirk so this patch will also work
on esdhci-imx, but this patch only test on powerpc platform, if
there are any negative impact on esdhc-imx please let me know.

Signed-off-by: Haijun Zhang <Haijun.Zhang@freescale.com>
Signed-off-by: Jerry Huang <Chang-Ming.Huang@freescale.com>
Reviewed-by: Anton Vorontsov <cbouatmailru@gmail.com>
CC: Chris Ball <cjb@laptop.org>
---
changes for v5:
	- Split two variable in their own line
changes for v4:
	- Apply the timeout clk after the card setup and reuse quirk
changes for v3:
	- Add an empty line

 drivers/mmc/host/sdhci-esdhc.h |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
index d25f9ab..a9968e3 100644
--- a/drivers/mmc/host/sdhci-esdhc.h
+++ b/drivers/mmc/host/sdhci-esdhc.h
@@ -47,6 +47,7 @@ static inline void esdhc_set_clock(struct sdhci_host *host, unsigned int clock)
 	int pre_div = 2;
 	int div = 1;
 	u32 temp;
+	u32 actual_clk;
 
 	if (clock == 0)
 		goto out;
@@ -65,6 +66,8 @@ static inline void esdhc_set_clock(struct sdhci_host *host, unsigned int clock)
 	dev_dbg(mmc_dev(host->mmc), "desired SD clock: %d, actual: %d\n",
 		clock, host->max_clk / pre_div / div);
 
+	actual_clk = host->max_clk / pre_div / div;
+
 	pre_div >>= 1;
 	div--;
 
@@ -74,6 +77,12 @@ static inline void esdhc_set_clock(struct sdhci_host *host, unsigned int clock)
 		| (pre_div << ESDHC_PREDIV_SHIFT));
 	sdhci_writel(host, temp, ESDHC_SYSTEM_CONTROL);
 	mdelay(1);
+
+	if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK) {
+		host->timeout_clk = actual_clk / 1000;
+		host->mmc->max_discard_to = (1 << 27) / host->timeout_clk;
+	}
+
 out:
 	host->clock = clock;
 }
-- 
1.7.0.4