olpc: sdhci: add quirk for the Marvell CaFe's interrupt timeout

The CaFe chip has a hardware bug that ends up with us getting a timeout
value that's too small, causing the following sorts of problems:

[   60.525138] mmcblk0: error -110 transferring data
[   60.531477] end_request: I/O error, dev mmcblk0, sector 1484353
[   60.533371] Buffer I/O error on device mmcblk0p2, logical block 181632
[   60.533371] lost page write due to I/O error on mmcblk0p2

Presumably this is an off-by-one error in the hardware.  Incrementing
the timeout count value that we stuff into the TIMEOUT_CONTROL register
gets us a value that works.  This bug was originally discovered by
Pierre Ossman, I believe.

[thanks to Robert Millan for proving that this was still a problem]

Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: Pierre Ossman <drzeus-list@drzeus.cx>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5b74c8c..2b3f06a 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -57,6 +57,8 @@ static unsigned int debug_quirks = 0;
 #define SDHCI_QUIRK_RESET_AFTER_REQUEST                        (1<<8)
 /* Controller needs voltage and power writes to happen separately */
 #define SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER            (1<<9)
+/* Controller has an off-by-one issue with timeout value */
+#define SDHCI_QUIRK_INCR_TIMEOUT_CONTROL               (1<<10)
 
 static const struct pci_device_id pci_ids[] __devinitdata = {
        {
@@ -134,7 +136,8 @@ static const struct pci_device_id pci_ids[] __devinitdata = {
                .device         = PCI_DEVICE_ID_MARVELL_CAFE_SD,
                .subvendor      = PCI_ANY_ID,
                .subdevice      = PCI_ANY_ID,
-               .driver_data    = SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER,
+               .driver_data    = SDHCI_QUIRK_NO_SIMULT_VDD_AND_POWER |
+                                 SDHCI_QUIRK_INCR_TIMEOUT_CONTROL,
        },
 
        {
@@ -479,6 +482,13 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_data *data)
                        break;
        }
 
+       /*
+        * Compensate for an off-by-one error in the CaFe hardware; otherwise,
+        * a too-small count gives us interrupt timeouts.
+        */
+       if ((host->chip->quirks & SDHCI_QUIRK_INCR_TIMEOUT_CONTROL))
+               count++;
+
        if (count >= 0xF) {
                printk(KERN_WARNING "%s: Too large timeout requested!\n",
                        mmc_hostname(host->mmc));