Commit be953af7 authored by Haibo Chen's avatar Haibo Chen Committed by Ulf Hansson
Browse files

mmc: sdhci-esdhc-imx: widen auto-tuning window for standard tuning 



Expand the auto-tuning window width from 2 to 3 for standard tuning to
account for sampling point shifts caused by temperature change. This change
is based on hardware recommendation, providing 50% more margin for the
auto-tuning logic to locate valid sampling points.

Signed-off-by: default avatarHaibo Chen <haibo.chen@nxp.com>
Signed-off-by: default avatarLuke Wang <ziniu.wang_1@nxp.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20250409075550.3413032-4-ziniu.wang_1@nxp.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent d0aac7d8

drivers/mmc/host/sdhci-esdhc-imx.c

+13 −0
Original line number Diff line number Diff line
@@ -108,6 +108,7 @@ 


#define ESDHC_TUNING_CTRL		0xcc

#define ESDHC_STD_TUNING_EN		(1 << 24)

#define ESDHC_TUNING_WINDOW_MASK	GENMASK(22, 20)

/* NOTE: the minimum valid tuning start tap for mx6sl is 1 */

#define ESDHC_TUNING_START_TAP_DEFAULT	0x1

#define ESDHC_TUNING_START_TAP_MASK	0x7f
@@ -209,6 +210,8 @@ 
/* The IP does not have GPIO CD wake capabilities */

#define ESDHC_FLAG_SKIP_CD_WAKE		BIT(18)



#define ESDHC_AUTO_TUNING_WINDOW	3



enum wp_types {

	ESDHC_WP_NONE,		/* no WP, neither controller nor gpio */

	ESDHC_WP_CONTROLLER,	/* mmc controller internal WP */
@@ -1553,6 +1556,16 @@ static void sdhci_esdhc_imx_hwinit(struct sdhci_host *host) 
					<< ESDHC_TUNING_STEP_SHIFT;

			}



			/*

			 * Config the tuning window to the hardware suggested value 3.

			 * This tuning window is used for auto tuning logic. The default

			 * tuning window is 2, here change to 3 make the window a bit

			 * wider, give auto tuning enough space to handle the sample

			 * point shift cause by temperature change.

			 */

			 tmp &= ~ESDHC_TUNING_WINDOW_MASK;

			 tmp |= FIELD_PREP(ESDHC_TUNING_WINDOW_MASK, ESDHC_AUTO_TUNING_WINDOW);



			/* Disable the CMD CRC check for tuning, if not, need to

			 * add some delay after every tuning command, because

			 * hardware standard tuning logic will directly go to next