| Message ID | 20211202134948.18448-1-pshete@nvidia.com |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | [v2] mmc: sdhci-tegra: Fix switch to HS400ES mode | expand |
On 02/12/2021 15:49, Prathamesh Shete wrote: > When CMD13 is sent after switching to HS400ES mode, the bus > is operating at either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. > To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI > interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host > controller CAR clock and the interface clock are rate matched. > > Signed-off-by: Prathamesh Shete <pshete@nvidia.com> > --- > drivers/mmc/host/sdhci-tegra.c | 43 ++++++++++++++++++++-------------- > 1 file changed, 26 insertions(+), 17 deletions(-) > > diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c > index 387ce9cdbd7c..ca261cce9b37 100644 > --- a/drivers/mmc/host/sdhci-tegra.c > +++ b/drivers/mmc/host/sdhci-tegra.c > @@ -354,23 +354,6 @@ static void tegra_sdhci_set_tap(struct sdhci_host *host, unsigned int tap) > } > } > > -static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, > - struct mmc_ios *ios) > -{ > - struct sdhci_host *host = mmc_priv(mmc); > - u32 val; > - > - val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > - > - if (ios->enhanced_strobe) > - val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > - else > - val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > - > - sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > - > -} > - > static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask) > { > struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > @@ -791,6 +774,32 @@ static void tegra_sdhci_set_clock(struct sdhci_host *host, unsigned int clock) > } > } > > +static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, > + struct mmc_ios *ios) > +{ > + struct sdhci_host *host = mmc_priv(mmc); > + u32 val; > + > + val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > + > + if (ios->enhanced_strobe) > + val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > + else > + val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > + > + sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > + > + /* > + * When CMD13 is sent from mmc_select_hs400es() after > + * switching to HS400ES mode, the bus is operating at > + * either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. > + * To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI > + * interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host > + * controller CAR clock and the interface clock are rate matched. Still doesn't explain why you want to set MMC_HS200_MAX_DTR when ios->enhanced_strobe is false e.g. mmc_set_initial_state() > + */ > + tegra_sdhci_set_clock(host, MMC_HS200_MAX_DTR); > +} > + > static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host *host) > { > struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); >
Thanks for review! Updated the programming sequence and Pushed version v3. Thanks Prathamesh. > -----Original Message----- > From: Adrian Hunter <adrian.hunter@intel.com> > Sent: Thursday, December 2, 2021 8:05 PM > To: Prathamesh Shete <pshete@nvidia.com>; ulf.hansson@linaro.org; > thierry.reding@gmail.com; Jonathan Hunter <jonathanh@nvidia.com>; > p.zabel@pengutronix.de; linux-mmc@vger.kernel.org; linux- > tegra@vger.kernel.org; linux-kernel@vger.kernel.org > Cc: Aniruddha Tvs Rao <anrao@nvidia.com>; Suresh Mangipudi > <smangipudi@nvidia.com> > Subject: Re: [PATCH v2] mmc: sdhci-tegra: Fix switch to HS400ES mode > > External email: Use caution opening links or attachments > > > On 02/12/2021 15:49, Prathamesh Shete wrote: > > When CMD13 is sent after switching to HS400ES mode, the bus is > > operating at either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. > > To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI interface > > clock to MMC_HS200_MAX_DTR (200 MHz) so that host controller CAR clock > > and the interface clock are rate matched. > > > > Signed-off-by: Prathamesh Shete <pshete@nvidia.com> > > --- > > drivers/mmc/host/sdhci-tegra.c | 43 > > ++++++++++++++++++++-------------- > > 1 file changed, 26 insertions(+), 17 deletions(-) > > > > diff --git a/drivers/mmc/host/sdhci-tegra.c > > b/drivers/mmc/host/sdhci-tegra.c index 387ce9cdbd7c..ca261cce9b37 > > 100644 > > --- a/drivers/mmc/host/sdhci-tegra.c > > +++ b/drivers/mmc/host/sdhci-tegra.c > > @@ -354,23 +354,6 @@ static void tegra_sdhci_set_tap(struct sdhci_host > *host, unsigned int tap) > > } > > } > > > > -static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, > > - struct mmc_ios *ios) > > -{ > > - struct sdhci_host *host = mmc_priv(mmc); > > - u32 val; > > - > > - val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > > - > > - if (ios->enhanced_strobe) > > - val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > > - else > > - val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > > - > > - sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > > - > > -} > > - > > static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask) { > > struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); @@ > > -791,6 +774,32 @@ static void tegra_sdhci_set_clock(struct sdhci_host *host, > unsigned int clock) > > } > > } > > > > +static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, > > + struct mmc_ios *ios) { > > + struct sdhci_host *host = mmc_priv(mmc); > > + u32 val; > > + > > + val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > > + > > + if (ios->enhanced_strobe) > > + val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > > + else > > + val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; > > + > > + sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); > > + > > + /* > > + * When CMD13 is sent from mmc_select_hs400es() after > > + * switching to HS400ES mode, the bus is operating at > > + * either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. > > + * To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI > > + * interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host > > + * controller CAR clock and the interface clock are rate matched. > > Still doesn't explain why you want to set MMC_HS200_MAX_DTR when > ios->enhanced_strobe is false e.g. mmc_set_initial_state() That’s a good catch. Updated the code sequence and pushed v3. > > + */ > > + tegra_sdhci_set_clock(host, MMC_HS200_MAX_DTR); } > > + > > static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host > > *host) { > > struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); > >
diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c index 387ce9cdbd7c..ca261cce9b37 100644 --- a/drivers/mmc/host/sdhci-tegra.c +++ b/drivers/mmc/host/sdhci-tegra.c @@ -354,23 +354,6 @@ static void tegra_sdhci_set_tap(struct sdhci_host *host, unsigned int tap) } } -static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, - struct mmc_ios *ios) -{ - struct sdhci_host *host = mmc_priv(mmc); - u32 val; - - val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); - - if (ios->enhanced_strobe) - val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; - else - val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; - - sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); - -} - static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); @@ -791,6 +774,32 @@ static void tegra_sdhci_set_clock(struct sdhci_host *host, unsigned int clock) } } +static void tegra_sdhci_hs400_enhanced_strobe(struct mmc_host *mmc, + struct mmc_ios *ios) +{ + struct sdhci_host *host = mmc_priv(mmc); + u32 val; + + val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); + + if (ios->enhanced_strobe) + val |= SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; + else + val &= ~SDHCI_TEGRA_SYS_SW_CTRL_ENHANCED_STROBE; + + sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_SYS_SW_CTRL); + + /* + * When CMD13 is sent from mmc_select_hs400es() after + * switching to HS400ES mode, the bus is operating at + * either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. + * To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI + * interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host + * controller CAR clock and the interface clock are rate matched. + */ + tegra_sdhci_set_clock(host, MMC_HS200_MAX_DTR); +} + static unsigned int tegra_sdhci_get_max_clock(struct sdhci_host *host) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
When CMD13 is sent after switching to HS400ES mode, the bus is operating at either MMC_HIGH_26_MAX_DTR or MMC_HIGH_52_MAX_DTR. To meet Tegra SDHCI requirement at HS400ES mode, force SDHCI interface clock to MMC_HS200_MAX_DTR (200 MHz) so that host controller CAR clock and the interface clock are rate matched. Signed-off-by: Prathamesh Shete <pshete@nvidia.com> --- drivers/mmc/host/sdhci-tegra.c | 43 ++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 17 deletions(-)