[U-Boot] [PATCH 1/1] sunxi: mmc: Fix phase delays

[U-Boot] [PATCH 1/1] sunxi: mmc: Fix phase delays

[Stefan Mavrodiev]

U-boot driver for sunxi-mmc uses PLL6, unlike linux kernel where
PLL5 is used, with clock rates respectively 600MHz and 768MHz.
Thus there are different phase degree steps - 24 for the kernel and
30 for u-boot.

In the kernel driver the phase is set 90 deg for output and 120 for
sample. Dividing by 30 will result values 3 and 4. Those are the
values set in the u-boot driver.

However, the condition defining delays is wrong. MMC core driver
requests clock of 52MHz, sunxi-driver sets clock of 50MHz, but
phase is set 30 deg for output and 120 deg for sample.

Apparently this works for most cards.
On A20-SOM204-EVB-eMMC there is eMMC card (KLMAG2GEND) which complains
about it. Maybe there is other boards with similar problem?
So the fix is to match delays for both u-boot and kernel.

Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
---
 drivers/mmc/sunxi_mmc.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/sunxi_mmc.c b/drivers/mmc/sunxi_mmc.c
index 4edb4be..be55dc4 100644
--- a/drivers/mmc/sunxi_mmc.c
+++ b/drivers/mmc/sunxi_mmc.c
@@ -146,19 +146,19 @@ static int mmc_set_mod_clk(struct sunxi_mmc_priv *priv, unsigned int hz)
 		oclk_dly = 0;
 		sclk_dly = 5;
 #ifdef CONFIG_MACH_SUN9I
-	} else if (hz <= 50000000) {
+	} else if (hz <= 52000000) {
 		oclk_dly = 5;
 		sclk_dly = 4;
 	} else {
-		/* hz > 50000000 */
+		/* hz > 52000000 */
 		oclk_dly = 2;
 		sclk_dly = 4;
 #else
-	} else if (hz <= 50000000) {
+	} else if (hz <= 52000000) {
 		oclk_dly = 3;
 		sclk_dly = 4;
 	} else {
-		/* hz > 50000000 */
+		/* hz > 52000000 */
 		oclk_dly = 1;
 		sclk_dly = 4;
 #endif
-- 
2.7.4

[U-Boot] [PATCH 1/1] sunxi: mmc: Fix phase delays

[Maxime Ripard]

On Tue, Mar 27, 2018 at 04:57:23PM +0300, Stefan Mavrodiev wrote:
> U-boot driver for sunxi-mmc uses PLL6, unlike linux kernel where
> PLL5 is used, with clock rates respectively 600MHz and 768MHz.
> Thus there are different phase degree steps - 24 for the kernel and
> 30 for u-boot.
> 
> In the kernel driver the phase is set 90 deg for output and 120 for
> sample. Dividing by 30 will result values 3 and 4. Those are the
> values set in the u-boot driver.
> 
> However, the condition defining delays is wrong. MMC core driver
> requests clock of 52MHz, sunxi-driver sets clock of 50MHz, but
> phase is set 30 deg for output and 120 deg for sample.
> 
> Apparently this works for most cards.
> On A20-SOM204-EVB-eMMC there is eMMC card (KLMAG2GEND) which complains
> about it. Maybe there is other boards with similar problem?
> So the fix is to match delays for both u-boot and kernel.
> 
> Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: not available
URL: <http://lists.denx.de/pipermail/u-boot/attachments/20180329/048472a5/attachment.sig>

[U-Boot] [PATCH 1/1] sunxi: mmc: Fix phase delays

[Jagan Teki]

On Thu, Mar 29, 2018 at 6:52 PM, Maxime Ripard
<maxime.ripard@bootlin.com> wrote:
> On Tue, Mar 27, 2018 at 04:57:23PM +0300, Stefan Mavrodiev wrote:
>> U-boot driver for sunxi-mmc uses PLL6, unlike linux kernel where
>> PLL5 is used, with clock rates respectively 600MHz and 768MHz.
>> Thus there are different phase degree steps - 24 for the kernel and
>> 30 for u-boot.
>>
>> In the kernel driver the phase is set 90 deg for output and 120 for
>> sample. Dividing by 30 will result values 3 and 4. Those are the
>> values set in the u-boot driver.
>>
>> However, the condition defining delays is wrong. MMC core driver
>> requests clock of 52MHz, sunxi-driver sets clock of 50MHz, but
>> phase is set 30 deg for output and 120 deg for sample.
>>
>> Apparently this works for most cards.
>> On A20-SOM204-EVB-eMMC there is eMMC card (KLMAG2GEND) which complains
>> about it. Maybe there is other boards with similar problem?
>> So the fix is to match delays for both u-boot and kernel.
>>
>> Signed-off-by: Stefan Mavrodiev <stefan@olimex.com>
>
> Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>

Applied to u-boot-sunxi/master