| Message ID | 1464505484-3661-3-git-send-email-wens@csie.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi, On 29-05-16 09:04, Chen-Yu Tsai wrote: > The MMC clock timings were incorrectly calculated, when the conversion > from delay value to delay phase was done. > > The 50M DDR and 50M DDR 8bit timings are off, and make eMMC DDR > unusable. Unfortunately it seems different controllers on the same SoC > have different timings. The new settings are taken from mmc2, which is > commonly used with eMMC. Hmm, I'm not really all that familiar with mmc, but can't an external sdcard connected to mmc0 use DDR too ? Assuming the answer is yes, then we really need to update the driver to use the right per controller timings. > The settings for the slower timing modes seem to work despite being > wrong, so leave them be. If you're sure the timings are wrong, please fix them. Sometimes wrong timings do seem to work, but lead to unreliable communication, or turn out to work on some boards and not on others due to routing differences. Thanks & Regards, Hans > > Signed-off-by: Chen-Yu Tsai <wens@csie.org> > --- > drivers/mmc/host/sunxi-mmc.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c > index 7fc8b7aa83f0..5873dc344ab2 100644 > --- a/drivers/mmc/host/sunxi-mmc.c > +++ b/drivers/mmc/host/sunxi-mmc.c > @@ -970,8 +970,8 @@ static const struct sunxi_mmc_clk_delay sun9i_mmc_clk_delays[] = { > [SDXC_CLK_400K] = { .output = 180, .sample = 180 }, > [SDXC_CLK_25M] = { .output = 180, .sample = 75 }, > [SDXC_CLK_50M] = { .output = 150, .sample = 120 }, > - [SDXC_CLK_50M_DDR] = { .output = 90, .sample = 120 }, > - [SDXC_CLK_50M_DDR_8BIT] = { .output = 90, .sample = 120 }, > + [SDXC_CLK_50M_DDR] = { .output = 54, .sample = 36 }, > + [SDXC_CLK_50M_DDR_8BIT] = { .output = 72, .sample = 72 }, > }; > > static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host, > -- 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
On Mon, May 30, 2016 at 7:34 PM, Hans de Goede <hdegoede@redhat.com> wrote: > Hi, > > On 29-05-16 09:04, Chen-Yu Tsai wrote: >> >> The MMC clock timings were incorrectly calculated, when the conversion >> from delay value to delay phase was done. >> >> The 50M DDR and 50M DDR 8bit timings are off, and make eMMC DDR >> unusable. Unfortunately it seems different controllers on the same SoC >> have different timings. The new settings are taken from mmc2, which is >> commonly used with eMMC. > > > Hmm, I'm not really all that familiar with mmc, but can't an external > sdcard connected to mmc0 use DDR too ? Assuming the answer is yes, then > we really need to update the driver to use the right per controller > timings. I would very much like that to happen. However, SD card UHS-1 DDR modes require 1.8V signaling, which is unavailable on _all_ sunxi boards. This seems like a limit of most of the SoCs not having a separate IO voltage rail for mmc pins. Until then, I wouldn't worry that much. >> The settings for the slower timing modes seem to work despite being >> wrong, so leave them be. > > > If you're sure the timings are wrong, please fix them. Sometimes wrong > timings do seem to work, but lead to unreliable communication, or turn > out to work on some boards and not on others due to routing differences. Unfortunately I did try putting in the correct numbers for them, and my eMMC then failed to probe. It seems the core switches up from 400kHz to 50MHz then to 50MHz DDR, and it fails somewhere in there, maybe at 50MHz. I'm not sure if we need to add DT bindings to specify different delays for different controllers, though. Seems like we'll never actually use it. Hope this answers your questions. Regards ChenYu > Thanks & Regards, > > Hans > > > >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> >> --- >> drivers/mmc/host/sunxi-mmc.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c >> index 7fc8b7aa83f0..5873dc344ab2 100644 >> --- a/drivers/mmc/host/sunxi-mmc.c >> +++ b/drivers/mmc/host/sunxi-mmc.c >> @@ -970,8 +970,8 @@ static const struct sunxi_mmc_clk_delay >> sun9i_mmc_clk_delays[] = { >> [SDXC_CLK_400K] = { .output = 180, .sample = 180 }, >> [SDXC_CLK_25M] = { .output = 180, .sample = 75 }, >> [SDXC_CLK_50M] = { .output = 150, .sample = 120 }, >> - [SDXC_CLK_50M_DDR] = { .output = 90, .sample = 120 }, >> - [SDXC_CLK_50M_DDR_8BIT] = { .output = 90, .sample = 120 }, >> + [SDXC_CLK_50M_DDR] = { .output = 54, .sample = 36 }, >> + [SDXC_CLK_50M_DDR_8BIT] = { .output = 72, .sample = 72 }, >> }; >> >> static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host, >> > -- 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
On Mon, May 30, 2016 at 8:59 PM, Chen-Yu Tsai <wens@csie.org> wrote: > On Mon, May 30, 2016 at 7:34 PM, Hans de Goede <hdegoede@redhat.com> wrote: >> Hi, >> >> On 29-05-16 09:04, Chen-Yu Tsai wrote: >>> >>> The MMC clock timings were incorrectly calculated, when the conversion >>> from delay value to delay phase was done. >>> >>> The 50M DDR and 50M DDR 8bit timings are off, and make eMMC DDR >>> unusable. Unfortunately it seems different controllers on the same SoC >>> have different timings. The new settings are taken from mmc2, which is >>> commonly used with eMMC. >> >> >> Hmm, I'm not really all that familiar with mmc, but can't an external >> sdcard connected to mmc0 use DDR too ? Assuming the answer is yes, then >> we really need to update the driver to use the right per controller >> timings. > > I would very much like that to happen. However, SD card UHS-1 DDR modes > require 1.8V signaling, which is unavailable on _all_ sunxi boards. > This seems like a limit of most of the SoCs not having a separate IO > voltage rail for mmc pins. > > Until then, I wouldn't worry that much. P.S. I also tried the settings from mmc0 in Allwinner sources. They gave horrible results ( < 5 MB/s read ) on my CC-A80, while my Optimus wasn't really affected. I wonder if there's some kind of auto-retry mechanism in the MMC controller, or driver? ChenYu >>> The settings for the slower timing modes seem to work despite being >>> wrong, so leave them be. >> >> >> If you're sure the timings are wrong, please fix them. Sometimes wrong >> timings do seem to work, but lead to unreliable communication, or turn >> out to work on some boards and not on others due to routing differences. > > Unfortunately I did try putting in the correct numbers for them, and my > eMMC then failed to probe. It seems the core switches up from 400kHz to > 50MHz then to 50MHz DDR, and it fails somewhere in there, maybe at 50MHz. > > I'm not sure if we need to add DT bindings to specify different delays > for different controllers, though. Seems like we'll never actually use > it. > > Hope this answers your questions. > > Regards > ChenYu > >> Thanks & Regards, >> >> Hans >> >> >> >>> >>> Signed-off-by: Chen-Yu Tsai <wens@csie.org> >>> --- >>> drivers/mmc/host/sunxi-mmc.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c >>> index 7fc8b7aa83f0..5873dc344ab2 100644 >>> --- a/drivers/mmc/host/sunxi-mmc.c >>> +++ b/drivers/mmc/host/sunxi-mmc.c >>> @@ -970,8 +970,8 @@ static const struct sunxi_mmc_clk_delay >>> sun9i_mmc_clk_delays[] = { >>> [SDXC_CLK_400K] = { .output = 180, .sample = 180 }, >>> [SDXC_CLK_25M] = { .output = 180, .sample = 75 }, >>> [SDXC_CLK_50M] = { .output = 150, .sample = 120 }, >>> - [SDXC_CLK_50M_DDR] = { .output = 90, .sample = 120 }, >>> - [SDXC_CLK_50M_DDR_8BIT] = { .output = 90, .sample = 120 }, >>> + [SDXC_CLK_50M_DDR] = { .output = 54, .sample = 36 }, >>> + [SDXC_CLK_50M_DDR_8BIT] = { .output = 72, .sample = 72 }, >>> }; >>> >>> static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host, >>> >> -- 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
Hi, On 30-05-16 14:59, Chen-Yu Tsai wrote: > On Mon, May 30, 2016 at 7:34 PM, Hans de Goede <hdegoede@redhat.com> wrote: >> Hi, >> >> On 29-05-16 09:04, Chen-Yu Tsai wrote: >>> >>> The MMC clock timings were incorrectly calculated, when the conversion >>> from delay value to delay phase was done. >>> >>> The 50M DDR and 50M DDR 8bit timings are off, and make eMMC DDR >>> unusable. Unfortunately it seems different controllers on the same SoC >>> have different timings. The new settings are taken from mmc2, which is >>> commonly used with eMMC. >> >> >> Hmm, I'm not really all that familiar with mmc, but can't an external >> sdcard connected to mmc0 use DDR too ? Assuming the answer is yes, then >> we really need to update the driver to use the right per controller >> timings. > > I would very much like that to happen. However, SD card UHS-1 DDR modes > require 1.8V signaling, which is unavailable on _all_ sunxi boards. > This seems like a limit of most of the SoCs not having a separate IO > voltage rail for mmc pins. > > Until then, I wouldn't worry that much. > >>> The settings for the slower timing modes seem to work despite being >>> wrong, so leave them be. >> >> >> If you're sure the timings are wrong, please fix them. Sometimes wrong >> timings do seem to work, but lead to unreliable communication, or turn >> out to work on some boards and not on others due to routing differences. > > Unfortunately I did try putting in the correct numbers for them, and my > eMMC then failed to probe. It seems the core switches up from 400kHz to > 50MHz then to 50MHz DDR, and it fails somewhere in there, maybe at 50MHz. > > I'm not sure if we need to add DT bindings to specify different delays > for different controllers, though. Seems like we'll never actually use > it. > > Hope this answers your questions. Yes that answers my questions, and with my questions answered, this series is: Acked-by: Hans de Goede <hdegoede@redhat.com> Regards, Hans -- 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/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c index 7fc8b7aa83f0..5873dc344ab2 100644 --- a/drivers/mmc/host/sunxi-mmc.c +++ b/drivers/mmc/host/sunxi-mmc.c @@ -970,8 +970,8 @@ static const struct sunxi_mmc_clk_delay sun9i_mmc_clk_delays[] = { [SDXC_CLK_400K] = { .output = 180, .sample = 180 }, [SDXC_CLK_25M] = { .output = 180, .sample = 75 }, [SDXC_CLK_50M] = { .output = 150, .sample = 120 }, - [SDXC_CLK_50M_DDR] = { .output = 90, .sample = 120 }, - [SDXC_CLK_50M_DDR_8BIT] = { .output = 90, .sample = 120 }, + [SDXC_CLK_50M_DDR] = { .output = 54, .sample = 36 }, + [SDXC_CLK_50M_DDR_8BIT] = { .output = 72, .sample = 72 }, }; static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
The MMC clock timings were incorrectly calculated, when the conversion from delay value to delay phase was done. The 50M DDR and 50M DDR 8bit timings are off, and make eMMC DDR unusable. Unfortunately it seems different controllers on the same SoC have different timings. The new settings are taken from mmc2, which is commonly used with eMMC. The settings for the slower timing modes seem to work despite being wrong, so leave them be. Signed-off-by: Chen-Yu Tsai <wens@csie.org> --- drivers/mmc/host/sunxi-mmc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)