[PATCH v2 1/5] mmc: sdhci: add platfrom get_max_timeout_count hook

[Dong Aisheng]

Currently the max_discard_to is simply got by (1 << 27) / host->timeout_clk
which is assumed to be the maximum timeout value, however, some platforms
maximum timeout counter may not be 1 << 27, e.g. i.MX uSDHC is 1 << 28.
Thus 1 << 27 may not be correct for such platforms.

It is also possible that other platforms may have different problems.
To be flexible, we add a get_max_timeout_count hook to get the correct
maximum timeout value for these platforms.

Signed-off-by: Dong Aisheng <b29396 at freescale.com>
---
 drivers/mmc/host/sdhci.c |    4 +++-
 drivers/mmc/host/sdhci.h |    1 +
 2 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index cc00bed..7fef3bb 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2942,7 +2942,9 @@ int sdhci_add_host(struct sdhci_host *host)
 	if (host->quirks & SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK)
 		host->timeout_clk = mmc->f_max / 1000;
 
-	mmc->max_discard_to = (1 << 27) / host->timeout_clk;
+	mmc->max_discard_to = host->ops->get_max_timeout_count ?
+			host->ops->get_max_timeout_count(host) : 1 << 27;
+	mmc->max_discard_to /= host->timeout_clk;
 
 	mmc->caps |= MMC_CAP_SDIO_IRQ | MMC_CAP_ERASE | MMC_CAP_CMD23;
 
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 0a3ed01..acba9a7 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -281,6 +281,7 @@ struct sdhci_ops {
 	unsigned int	(*get_max_clock)(struct sdhci_host *host);
 	unsigned int	(*get_min_clock)(struct sdhci_host *host);
 	unsigned int	(*get_timeout_clock)(struct sdhci_host *host);
+	unsigned int	(*get_max_timeout_count)(struct sdhci_host *host);
 	int		(*platform_bus_width)(struct sdhci_host *host,
 					       int width);
 	void (*platform_send_init_74_clocks)(struct sdhci_host *host,
-- 
1.7.2.rc3