| Message ID | 1430937082-27149-1-git-send-email-lars@metafoo.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 6 May 2015 at 20:31, Lars-Peter Clausen <lars@metafoo.de> wrote: > It is not uncommon to see systems where there is no physical write-protect > signal (e.g. when using eMMC or microSD card slots). For some controllers, > which have a dedicated write-protection detection logic (like SDHCI > controllers), the get_ro() callback can return bogus data in such a case. > > Instead of handling this on a per controller basis this patch adds a new > capability flag to the MMC core that can be set to specify that the result > of get_ro() is invalid. When the flag is set the core will not call > get_ro() and assume that the card is always read-write. > > Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Thanks, applied! Kind regards Uffe > --- > drivers/mmc/core/sd.c | 30 +++++++++++++++++++++++------- > include/linux/mmc/host.h | 1 + > 2 files changed, 24 insertions(+), 7 deletions(-) > > diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c > index 31a9ef2..8f6864a 100644 > --- a/drivers/mmc/core/sd.c > +++ b/drivers/mmc/core/sd.c > @@ -804,6 +804,28 @@ int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card) > return 0; > } > > +static int mmc_sd_get_ro(struct mmc_host *host) > +{ > + int ro; > + > + /* > + * Some systems don't feature a write-protect pin and don't need one. > + * E.g. because they only have micro-SD card slot. For those systems > + * assume that the SD card is always read-write. > + */ > + if (host->caps2 & MMC_CAP2_NO_WRITE_PROTECT) > + return 0; > + > + if (!host->ops->get_ro) > + return -1; > + > + mmc_host_clk_hold(host); > + ro = host->ops->get_ro(host); > + mmc_host_clk_release(host); > + > + return ro; > +} > + > int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card, > bool reinit) > { > @@ -855,13 +877,7 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card, > * Check if read-only switch is active. > */ > if (!reinit) { > - int ro = -1; > - > - if (host->ops->get_ro) { > - mmc_host_clk_hold(card->host); > - ro = host->ops->get_ro(host); > - mmc_host_clk_release(card->host); > - } > + int ro = mmc_sd_get_ro(host); > > if (ro < 0) { > pr_warn("%s: host does not support reading read-only switch, assuming write-enable\n", > diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h > index b5bedae..3b92fd4 100644 > --- a/include/linux/mmc/host.h > +++ b/include/linux/mmc/host.h > @@ -285,6 +285,7 @@ struct mmc_host { > MMC_CAP2_HS400_1_2V) > #define MMC_CAP2_HSX00_1_2V (MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V) > #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17) > +#define MMC_CAP2_NO_WRITE_PROTECT (1 << 18) /* No physical write protect pin, assume that card is always read-write */ > > mmc_pm_flag_t pm_caps; /* supported pm features */ > > -- > 1.8.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c index 31a9ef2..8f6864a 100644 --- a/drivers/mmc/core/sd.c +++ b/drivers/mmc/core/sd.c @@ -804,6 +804,28 @@ int mmc_sd_get_csd(struct mmc_host *host, struct mmc_card *card) return 0; } +static int mmc_sd_get_ro(struct mmc_host *host) +{ + int ro; + + /* + * Some systems don't feature a write-protect pin and don't need one. + * E.g. because they only have micro-SD card slot. For those systems + * assume that the SD card is always read-write. + */ + if (host->caps2 & MMC_CAP2_NO_WRITE_PROTECT) + return 0; + + if (!host->ops->get_ro) + return -1; + + mmc_host_clk_hold(host); + ro = host->ops->get_ro(host); + mmc_host_clk_release(host); + + return ro; +} + int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card, bool reinit) { @@ -855,13 +877,7 @@ int mmc_sd_setup_card(struct mmc_host *host, struct mmc_card *card, * Check if read-only switch is active. */ if (!reinit) { - int ro = -1; - - if (host->ops->get_ro) { - mmc_host_clk_hold(card->host); - ro = host->ops->get_ro(host); - mmc_host_clk_release(card->host); - } + int ro = mmc_sd_get_ro(host); if (ro < 0) { pr_warn("%s: host does not support reading read-only switch, assuming write-enable\n", diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h index b5bedae..3b92fd4 100644 --- a/include/linux/mmc/host.h +++ b/include/linux/mmc/host.h @@ -285,6 +285,7 @@ struct mmc_host { MMC_CAP2_HS400_1_2V) #define MMC_CAP2_HSX00_1_2V (MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V) #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17) +#define MMC_CAP2_NO_WRITE_PROTECT (1 << 18) /* No physical write protect pin, assume that card is always read-write */ mmc_pm_flag_t pm_caps; /* supported pm features */
It is not uncommon to see systems where there is no physical write-protect signal (e.g. when using eMMC or microSD card slots). For some controllers, which have a dedicated write-protection detection logic (like SDHCI controllers), the get_ro() callback can return bogus data in such a case. Instead of handling this on a per controller basis this patch adds a new capability flag to the MMC core that can be set to specify that the result of get_ro() is invalid. When the flag is set the core will not call get_ro() and assume that the card is always read-write. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> --- drivers/mmc/core/sd.c | 30 +++++++++++++++++++++++------- include/linux/mmc/host.h | 1 + 2 files changed, 24 insertions(+), 7 deletions(-)