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

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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: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Luke Wang <ziniu.wang_1@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20250409075550.3413032-5-ziniu.wang_1@nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Haibo Chen 2025-04-09 15:55:48 +08:00 committed by Ulf Hansson
parent be953af79c
commit 8cdba34313
1 changed files with 26 additions and 2 deletions
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28
drivers/mmc/host/sdhci-esdhc-imx.c
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@ -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);
}
}