mmc: sdhci high speed support

The SDHCI spec implies that is is incorrect to set a clock
frequency above 25 MHz without setting the high speed bit.

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 54990ed26770..cd98117632d3 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -616,6 +616,7 @@ static void sdhci_finish_command(struct sdhci_host *host)
 static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 {
         int div;
+        u8 ctrl;
         u16 clk;
         unsigned long timeout;
 
@@ -624,6 +625,13 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
 
         writew(0, host->ioaddr + SDHCI_CLOCK_CONTROL);
 
+        ctrl = readb(host->ioaddr + SDHCI_HOST_CONTROL);
+        if (clock > 25000000)
+                ctrl |= SDHCI_CTRL_HISPD;
+        else
+                ctrl &= ~SDHCI_CTRL_HISPD;
+        writeb(ctrl, host->ioaddr + SDHCI_HOST_CONTROL);
+
         if (clock == 0)
                 goto out;
 
@@ -1291,6 +1299,13 @@ static int __devinit sdhci_probe_slot(struct pci_dev *pdev, int slot)
         else if (caps & SDHCI_CAN_VDD_180)
                 mmc->ocr_avail |= MMC_VDD_17_18|MMC_VDD_18_19;
 
+        if ((host->max_clk > 25000000) && !(caps & SDHCI_CAN_DO_HISPD)) {
+                printk(KERN_ERR "%s: Controller reports > 25 MHz base clock,"
+                        " but no high speed support.\n",
+                        host->slot_descr);
+                mmc->f_max = 25000000;
+        }
+
         if (mmc->ocr_avail == 0) {
                 printk(KERN_ERR "%s: Hardware doesn't report any "
                         "support voltages.\n", host->slot_descr);