Commit 8cdba343 authored by Haibo Chen's avatar Haibo Chen Committed by Ulf Hansson
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mmc: sdhci-esdhc-imx: widen auto-tuning window for manual tuning 



Expand the auto-tuning window width from 0 to 3 for manual tuning to
account for sampling point shifts caused by temperature change. This change
is based on hardware recommendation, providing enough margin for the
auto-tuning logic to locate valid sampling points.

When config the manual tuning final sample delay, need deduct the auto
tuning window width according to the IP logic.

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/20250409075550.3413032-5-ziniu.wang_1@nxp.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent be953af7

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

+26 −2
Original line number Diff line number Diff line
@@ -85,7 +85,8 @@ 
#define  ESDHC_TUNE_CTRL_MAX		((1 << 7) - 1)

#define  ESDHC_TUNE_CTRL_STATUS_TAP_SEL_PRE_MASK	GENMASK(30, 24)

#define  ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_PRE_MASK	GENMASK(14, 8)



#define  ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_OUT_MASK	GENMASK(7, 4)

#define  ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_POST_MASK	GENMASK(3, 0)

/* strobe dll register */

#define ESDHC_STROBE_DLL_CTRL		0x70

#define ESDHC_STROBE_DLL_CTRL_ENABLE	(1 << 0)
@@ -243,6 +244,7 @@ struct esdhc_platform_data { 
	unsigned int tuning_start_tap;	/* The start delay cell point in tuning procedure */

	unsigned int strobe_dll_delay_target;	/* The delay cell for strobe pad (read clock) */

	unsigned int saved_tuning_delay_cell;	/* save the value of tuning delay cell */

	unsigned int saved_auto_tuning_window;  /* save the auto tuning window width */

};



struct esdhc_soc_data {
@@ -1211,6 +1213,7 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode) 
{

	int min, max, avg, ret;

	int win_length, target_min, target_max, target_win_length;

	u32 clk_tune_ctrl_status;



	min = ESDHC_TUNE_CTRL_MIN;

	max = ESDHC_TUNE_CTRL_MIN;
@@ -1250,6 +1253,23 @@ static int esdhc_executing_tuning(struct sdhci_host *host, u32 opcode) 
	/* use average delay to get the best timing */

	avg = (target_min + target_max) / 2;

	esdhc_prepare_tuning(host, avg);



	/*

	 * adjust the delay according to tuning window, make preparation

	 * for the auto-tuning logic. According to hardware suggest, need

	 * to config the auto tuning window width to 3, to make the auto

	 * tuning logic have enough space to handle the sample point shift

	 * caused by temperature change.

	 */

	clk_tune_ctrl_status = FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_PRE_MASK,

					  avg - ESDHC_AUTO_TUNING_WINDOW) |

			       FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_OUT_MASK,

					  ESDHC_AUTO_TUNING_WINDOW) |

			       FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_POST_MASK,

					  ESDHC_AUTO_TUNING_WINDOW);



	writel(clk_tune_ctrl_status, host->ioaddr + ESDHC_TUNE_CTRL_STATUS);



	ret = mmc_send_tuning(host->mmc, opcode, NULL);

	esdhc_post_tuning(host);
@@ -1652,7 +1672,11 @@ static void sdhc_esdhc_tuning_restore(struct sdhci_host *host) 
		writel(reg, host->ioaddr + ESDHC_MIX_CTRL);



		writel(FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_PRE_MASK,

				  imx_data->boarddata.saved_tuning_delay_cell),

				  imx_data->boarddata.saved_tuning_delay_cell) |

		       FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_OUT_MASK,

				  ESDHC_AUTO_TUNING_WINDOW) |

		       FIELD_PREP(ESDHC_TUNE_CTRL_STATUS_DLY_CELL_SET_POST_MASK,

				  ESDHC_AUTO_TUNING_WINDOW),

		       host->ioaddr + ESDHC_TUNE_CTRL_STATUS);

	}

}