[PATCH] [PATCH v2] mmc: Fix read-only detection with JMicron 388 chip

Takashi Iwai
2011-04-21T18:26:39Z

On HP laptops with JMicron 388 chip, the write-locked SD card isn't
detected correctly as read-only in many cases. This is because the
PRESENT_STATE register becomes unsable just after plugging, and it
returns the WRITE_PROTECT bit wrongly at the first read.

This patch fixes the read-only detection by adding a new sdhci quirk
indicating to check the register more intensively with a relatively
long delay.

The patch is tested with 2.6.39-rc4 kernel.

Cc: Aries Lee <arieslee@jmicron.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
v1->v2
rewritten to use a quirk

drivers/mmc/host/sdhci-pci.c | 5 +++++
drivers/mmc/host/sdhci.c | 28 ++++++++++++++++++++++++----
include/linux/mmc/sdhci.h | 2 ++
3 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci.c b/drivers/mmc/host/sdhci-pci.c
index a136be7..5781395 100644
--- a/drivers/mmc/host/sdhci-pci.c
+++ b/drivers/mmc/host/sdhci-pci.c
@@ -329,6 +329,11 @@ static int jmicron_probe(struct sdhci_pci_chip *chip)
return ret;
}

+ /* quirk for unsable RO-detection on JM388 chips */
+ if (chip->pdev->device == PCI_DEVICE_ID_JMICRON_JMB388_SD ||
+ chip->pdev->device == PCI_DEVICE_ID_JMICRON_JMB388_ESD)
+ chip->quirks |= SDHCI_QUIRK_UNSTABLE_RO_DETECT;
+
return 0;
}

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 9e15f41..8097171 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1237,14 +1237,11 @@ out:
spin_unlock_irqrestore(&host->lock, flags);
}

-static int sdhci_get_ro(struct mmc_host *mmc)
+static int check_ro(struct sdhci_host *host)
{
- struct sdhci_host *host;
unsigned long flags;
int is_readonly;

- host = mmc_priv(mmc);
-
spin_lock_irqsave(&host->lock, flags);

if (host->flags & SDHCI_DEVICE_DEAD)
@@ -1262,6 +1259,29 @@ static int sdhci_get_ro(struct mmc_host *mmc)
!is_readonly : is_readonly;
}

+#define SAMPLE_COUNT 5
+
+static int sdhci_get_ro(struct mmc_host *mmc)
+{
+ struct sdhci_host *host;
+ int i, ro_count;
+
+ host = mmc_priv(mmc);
+
+ if (!(host->quirks & SDHCI_QUIRK_UNSTABLE_RO_DETECT))
+ return check_ro(host);
+
+ ro_count = 0;
+ for (i = 0; i < SAMPLE_COUNT; i++) {
+ if (check_ro(host)) {
+ if (++ro_count > SAMPLE_COUNT / 2)
+ return 1;
+ }
+ msleep(30);
+ }
+ return 0;
+}
+
static void sdhci_enable_sdio_irq(struct mmc_host *mmc, int enable)
{
struct sdhci_host *host;
diff --git a/include/linux/mmc/sdhci.h b/include/linux/mmc/sdhci.h
index 83bd9f7..92e1c9a 100644
--- a/include/linux/mmc/sdhci.h
+++ b/include/linux/mmc/sdhci.h
@@ -85,6 +85,8 @@ struct sdhci_host {
#define SDHCI_QUIRK_NO_HISPD_BIT (1<<29)
/* Controller treats ADMA descriptors with length 0000h incorrectly */
#define SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC (1<<30)
+/* The read-only detection via SDHCI_PRESENT_STATE register is unstable */
+#define SDHCI_QUIRK_UNSTABLE_RO_DETECT (1<<31)

int irq; /* Device IRQ */
void __iomem *ioaddr; /* Mapped address */
--
1.7.4.2