| Message ID | 1480645311-13004-2-git-send-email-yamada.masahiro@socionext.com |
|---|---|
| State | New |
| Headers | show |
On 02/12/16 04:21, Masahiro Yamada wrote: > Some SDHCI-compat controllers support not only SD, but also eMMC, > but they use different commands for tuning: CMD19 for SD, CMD21 for > eMMC. > > Due to the difference of the underlying mechanism, some controllers > (at least, the Cadence IP is the case) provide their own registers > for the eMMC tuning. > > This commit will be useful when we want to use platform-specific > tuning (to support eMMC HS200), but still let it reuse the code > provided by sdhci_execute_tuning() for SD timing. > > If sdhci_ops::platform_execute_tuning receives a timing it does not > take care of, it can return -ENOTSUPP. Then, it will fall back to > the SDHCI standard tuning. > > Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> > --- > > I want to use this in the next commit. > > The Cadence IP supports eMMC as well as SD. > > The tuning for SD is pretty simple; just set the "Execute Tuning" bit > of the HOST_CONTROL2 register. So, I can re-use the > sdhci_execute_tuning(). > > On the other hand, Cadence provides its own way for eMMC HS200 tuning; > I need to touch some registers that are specific to Cadence's design. > > > Changes in v3: None > Changes in v2: None > > drivers/mmc/host/sdhci.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 42ef3eb..cdce489 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -2004,7 +2004,9 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) > if (host->ops->platform_execute_tuning) { > spin_unlock_irqrestore(&host->lock, flags); > err = host->ops->platform_execute_tuning(host, opcode); > - return err; > + if (err != -ENOTSUPP) > + return err; > + spin_lock_irqsave(&host->lock, flags); platform_execute_tuning() should not exist. You could export sdhci_execute_tuning() and then provide your ->execute_tuning() (e.g. host->mmc_host_ops.execute_tuning = sdhci_cdns_execute_tuning) which can call sdhci_execute_tuning() if it needs to. > } > > ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2); > -- 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/host/sdhci.c b/drivers/mmc/host/sdhci.c index 42ef3eb..cdce489 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -2004,7 +2004,9 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode) if (host->ops->platform_execute_tuning) { spin_unlock_irqrestore(&host->lock, flags); err = host->ops->platform_execute_tuning(host, opcode); - return err; + if (err != -ENOTSUPP) + return err; + spin_lock_irqsave(&host->lock, flags); } ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
Some SDHCI-compat controllers support not only SD, but also eMMC, but they use different commands for tuning: CMD19 for SD, CMD21 for eMMC. Due to the difference of the underlying mechanism, some controllers (at least, the Cadence IP is the case) provide their own registers for the eMMC tuning. This commit will be useful when we want to use platform-specific tuning (to support eMMC HS200), but still let it reuse the code provided by sdhci_execute_tuning() for SD timing. If sdhci_ops::platform_execute_tuning receives a timing it does not take care of, it can return -ENOTSUPP. Then, it will fall back to the SDHCI standard tuning. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- I want to use this in the next commit. The Cadence IP supports eMMC as well as SD. The tuning for SD is pretty simple; just set the "Execute Tuning" bit of the HOST_CONTROL2 register. So, I can re-use the sdhci_execute_tuning(). On the other hand, Cadence provides its own way for eMMC HS200 tuning; I need to touch some registers that are specific to Cadence's design. Changes in v3: None Changes in v2: None drivers/mmc/host/sdhci.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) -- 2.7.4 -- 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