According to SD host spec (Capabilities Register, offset 0x40<43:40>),
if timer count for retuning return 0xF, it means get information from other 
source

Signed-off-by: Kevin Liu <kl...@marvell.com>
---
 drivers/mmc/host/sdhci.c |    8 ++++++++
 drivers/mmc/host/sdhci.h |    1 +
 2 files changed, 9 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 8a14927..122c4c92 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2945,6 +2945,14 @@ int sdhci_add_host(struct sdhci_host *host)
        /* Initial value for re-tuning timer count */
        host->tuning_count = (caps[1] & SDHCI_RETUNING_TIMER_COUNT_MASK) >>
                              SDHCI_RETUNING_TIMER_COUNT_SHIFT;
+       if (host->tuning_count == 0xF) {
+               if (host->ops->get_tuning_count)
+                       host->tuning_count =
+                               host->ops->get_tuning_count(host) & 0xF;
+               else
+                       pr_err("%s: Hardware doesn't specify tuning count.\n",
+                               mmc_hostname(mmc));
+       }
 
        /*
         * In case Re-tuning Timer is not disabled, the actual value of
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index c8d11b9..4a65dbe 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -282,6 +282,7 @@ struct sdhci_ops {
        void    (*platform_resume)(struct sdhci_host *host);
        void    (*adma_workaround)(struct sdhci_host *host, u32 intmask);
        void    (*platform_init)(struct sdhci_host *host);
+       unsigned int    (*get_tuning_count)(struct sdhci_host *host);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
-- 
1.7.9.5

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