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

Stefan Mavrodiev stefan at olimex.com
Tue Mar 27 13:57:23 UTC 2018


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 at 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



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