| Message ID | 20190115162837.5399-2-thomas.petazzoni@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce support for WP GPIO in the core SDHCI | expand |
On Tue, Jan 15, 2019 at 05:28:35PM +0100, Thomas Petazzoni wrote: > Even though SDHCI controllers may have a dedicated WP pin that can be > queried using the SDHCI_PRESENT_STATE register, some platforms may > chose to use a separate regular GPIO to route the WP signal. Such a > GPIO is typically represented using the wp-gpios property in the > Device Tree. > > Unfortunately, the current sdhci_check_ro() function does not make use > of such GPIO when available: it either uses a host controller specific > ->get_ro() operation, or uses the SDHCI_PRESENT_STATE. Several host > controller specific ->get_ro() functions are implemented just to use > check a WP GPIO state. "use check" was probably meant to be just "check"? > > Instead of pushing this to more controller-specific implementations, > let's handle this in the core SDHCI code, just like it is already done > for the CD GPIO in sdhci_get_cd(). > > The below patch simply changes sdhci_check_ro() to use the value of > the WP GPIO if available. We need to adjust the prototype of the > function to use a mmc_host* as argument instead of sdhci_host*, since > the mmc_can_gpio_ro() and mmc_gpio_get_ro() helpers take a mmc_host*. > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> > --- > drivers/mmc/host/sdhci.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) Other than the typo in the commit message, this looks fine: Reviewed-by: Thierry Reding <treding@nvidia.com>
On 15/01/19 6:28 PM, Thomas Petazzoni wrote: > Even though SDHCI controllers may have a dedicated WP pin that can be > queried using the SDHCI_PRESENT_STATE register, some platforms may > chose to use a separate regular GPIO to route the WP signal. Such a > GPIO is typically represented using the wp-gpios property in the > Device Tree. > > Unfortunately, the current sdhci_check_ro() function does not make use > of such GPIO when available: it either uses a host controller specific > ->get_ro() operation, or uses the SDHCI_PRESENT_STATE. Several host > controller specific ->get_ro() functions are implemented just to use > check a WP GPIO state. > > Instead of pushing this to more controller-specific implementations, > let's handle this in the core SDHCI code, just like it is already done > for the CD GPIO in sdhci_get_cd(). > > The below patch simply changes sdhci_check_ro() to use the value of > the WP GPIO if available. We need to adjust the prototype of the > function to use a mmc_host* as argument instead of sdhci_host*, since > the mmc_can_gpio_ro() and mmc_gpio_get_ro() helpers take a mmc_host*. Why not just use host->mmc > > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> > --- > drivers/mmc/host/sdhci.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index df05352b6a4a..63cc4bd033b9 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2022,8 +2022,9 @@ static int sdhci_get_cd(struct mmc_host *mmc) > return !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT); > } > > -static int sdhci_check_ro(struct sdhci_host *host) > +static int sdhci_check_ro(struct mmc_host *mmc) > { > + struct sdhci_host *host = mmc_priv(mmc); > unsigned long flags; > int is_readonly; > > @@ -2031,6 +2032,8 @@ static int sdhci_check_ro(struct sdhci_host *host) > > if (host->flags & SDHCI_DEVICE_DEAD) > is_readonly = 0; > + else if (mmc_can_gpio_ro(mmc)) > + is_readonly = mmc_gpio_get_ro(mmc); Perhaps host->ops->get_ro should be checked before mmc_can_gpio_ro()? > else if (host->ops->get_ro) > is_readonly = host->ops->get_ro(host); > else > @@ -2052,11 +2055,11 @@ static int sdhci_get_ro(struct mmc_host *mmc) > int i, ro_count; > > if (!(host->quirks & SDHCI_QUIRK_UNSTABLE_RO_DETECT)) > - return sdhci_check_ro(host); > + return sdhci_check_ro(mmc); > > ro_count = 0; > for (i = 0; i < SAMPLE_COUNT; i++) { > - if (sdhci_check_ro(host)) { > + if (sdhci_check_ro(mmc)) { > if (++ro_count > SAMPLE_COUNT / 2) > return 1; > } >
Hello Adrian, On Wed, 16 Jan 2019 14:59:32 +0200, Adrian Hunter wrote: > > The below patch simply changes sdhci_check_ro() to use the value of > > the WP GPIO if available. We need to adjust the prototype of the > > function to use a mmc_host* as argument instead of sdhci_host*, since > > the mmc_can_gpio_ro() and mmc_gpio_get_ro() helpers take a mmc_host*. > > Why not just use host->mmc Could do that. I just found it weird that the calling function has the mmc_host structure, does some gymnastic to find sdhci_host, and then in the called function, we do the opposite gymnastic to find mmc_host from sdhci_host. But if that's the preference, I'm happy to change the patch accordingly. > > if (host->flags & SDHCI_DEVICE_DEAD) > > is_readonly = 0; > > + else if (mmc_can_gpio_ro(mmc)) > > + is_readonly = mmc_gpio_get_ro(mmc); > > Perhaps host->ops->get_ro should be checked before mmc_can_gpio_ro()? That is actually a good point, using ->get_ro() should come before using the GPIO. Indeed, some drivers may potentially have a ->get_ro with custom logic *and* a WP GPIO, and in this case, we want ->get_ro to take precedence. I'll send a v2 with this, once you let me know your decision about the previous point. Thanks, Thomas
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index df05352b6a4a..63cc4bd033b9 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2022,8 +2022,9 @@ static int sdhci_get_cd(struct mmc_host *mmc) return !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT); } -static int sdhci_check_ro(struct sdhci_host *host) +static int sdhci_check_ro(struct mmc_host *mmc) { + struct sdhci_host *host = mmc_priv(mmc); unsigned long flags; int is_readonly; @@ -2031,6 +2032,8 @@ static int sdhci_check_ro(struct sdhci_host *host) if (host->flags & SDHCI_DEVICE_DEAD) is_readonly = 0; + else if (mmc_can_gpio_ro(mmc)) + is_readonly = mmc_gpio_get_ro(mmc); else if (host->ops->get_ro) is_readonly = host->ops->get_ro(host); else @@ -2052,11 +2055,11 @@ static int sdhci_get_ro(struct mmc_host *mmc) int i, ro_count; if (!(host->quirks & SDHCI_QUIRK_UNSTABLE_RO_DETECT)) - return sdhci_check_ro(host); + return sdhci_check_ro(mmc); ro_count = 0; for (i = 0; i < SAMPLE_COUNT; i++) { - if (sdhci_check_ro(host)) { + if (sdhci_check_ro(mmc)) { if (++ro_count > SAMPLE_COUNT / 2) return 1; }
Even though SDHCI controllers may have a dedicated WP pin that can be queried using the SDHCI_PRESENT_STATE register, some platforms may chose to use a separate regular GPIO to route the WP signal. Such a GPIO is typically represented using the wp-gpios property in the Device Tree. Unfortunately, the current sdhci_check_ro() function does not make use of such GPIO when available: it either uses a host controller specific ->get_ro() operation, or uses the SDHCI_PRESENT_STATE. Several host controller specific ->get_ro() functions are implemented just to use check a WP GPIO state. Instead of pushing this to more controller-specific implementations, let's handle this in the core SDHCI code, just like it is already done for the CD GPIO in sdhci_get_cd(). The below patch simply changes sdhci_check_ro() to use the value of the WP GPIO if available. We need to adjust the prototype of the function to use a mmc_host* as argument instead of sdhci_host*, since the mmc_can_gpio_ro() and mmc_gpio_get_ro() helpers take a mmc_host*. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com> --- drivers/mmc/host/sdhci.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)