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Subject[PATCH] [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>
---
drivers/mmc/host/sdhci.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5b74c8c..2b3f06a 100644
--- 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));
--
1.5.5.3


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