sdhci: implement CAP_CLOCK_BASE_BROKEN quirk

Some hosts (e.g.  as found in CNS3xxx SOCs) report wrong value in
CLOCK_BASE capability field, and currently there is no way to force the
SDHCI core to use the platform-provided base clock value.

This patch implements CAP_CLOCK_BASE_BROKEN quirk.  When enabled, the
SDHCI core will always use base clock frequency provided by the platform.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Cc: Richard Röjfors <richard.rojfors@pelagicore.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Ben Dooks <ben@simtec.co.uk>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 1 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9d4fdfa685e5..02b365f5a4be 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1744,7 +1744,8 @@ int sdhci_add_host(struct sdhci_host *host)
         host->max_clk =
                 (caps & SDHCI_CLOCK_BASE_MASK) >> SDHCI_CLOCK_BASE_SHIFT;
         host->max_clk *= 1000000;
-        if (host->max_clk == 0) {
+        if (host->max_clk == 0 || host->quirks &
+                        SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN) {
                 if (!host->ops->get_max_clock) {
                         printk(KERN_ERR
                                "%s: Hardware doesn't specify base clock "
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 842f46f94284..831bf7f137f6 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -236,6 +236,8 @@ struct sdhci_host {
 #define SDHCI_QUIRK_DELAY_AFTER_POWER                   (1<<23)
 /* Controller uses SDCLK instead of TMCLK for data timeouts */
 #define SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK             (1<<24)
+/* Controller reports wrong base clock capability */
+#define SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN               (1<<25)
 
         int                     irq;            /* Device IRQ */
         void __iomem *          ioaddr;         /* Mapped address */