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

Chris Ball
2011-04-24T00:37:38Z

Hi,

On Thu, Apr 21 2011, Takashi Iwai wrote:
> 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 */

Thanks, pushed to mmc-next for .39.

- Chris.
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child