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path: root/drivers/mmc/host/sdhci-esdhc-imx.c
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Diffstat (limited to 'drivers/mmc/host/sdhci-esdhc-imx.c')
-rw-r--r--drivers/mmc/host/sdhci-esdhc-imx.c52
1 files changed, 36 insertions, 16 deletions
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index 3b8030f355..40a6e2f814 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -1154,32 +1154,52 @@ static void esdhc_post_tuning(struct sdhci_host *host)
writel(reg, host->ioaddr + ESDHC_MIX_CTRL);
}
+/*
+ * find the largest pass window, and use the average delay of this
+ * largest window to get the best timing.
+ */
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;
- /* find the mininum delay first which can pass tuning */
min = ESDHC_TUNE_CTRL_MIN;
- while (min < ESDHC_TUNE_CTRL_MAX) {
- esdhc_prepare_tuning(host, min);
- if (!mmc_send_tuning(host->mmc, opcode, NULL))
- break;
- min += ESDHC_TUNE_CTRL_STEP;
- }
-
- /* find the maxinum delay which can not pass tuning */
- max = min + ESDHC_TUNE_CTRL_STEP;
+ max = ESDHC_TUNE_CTRL_MIN;
+ target_win_length = 0;
while (max < ESDHC_TUNE_CTRL_MAX) {
- esdhc_prepare_tuning(host, max);
- if (mmc_send_tuning(host->mmc, opcode, NULL)) {
- max -= ESDHC_TUNE_CTRL_STEP;
- break;
+ /* find the mininum delay first which can pass tuning */
+ while (min < ESDHC_TUNE_CTRL_MAX) {
+ esdhc_prepare_tuning(host, min);
+ if (!mmc_send_tuning(host->mmc, opcode, NULL))
+ break;
+ min += ESDHC_TUNE_CTRL_STEP;
}
- max += ESDHC_TUNE_CTRL_STEP;
+
+ /* find the maxinum delay which can not pass tuning */
+ max = min + ESDHC_TUNE_CTRL_STEP;
+ while (max < ESDHC_TUNE_CTRL_MAX) {
+ esdhc_prepare_tuning(host, max);
+ if (mmc_send_tuning(host->mmc, opcode, NULL)) {
+ max -= ESDHC_TUNE_CTRL_STEP;
+ break;
+ }
+ max += ESDHC_TUNE_CTRL_STEP;
+ }
+
+ win_length = max - min + 1;
+ /* get the largest pass window */
+ if (win_length > target_win_length) {
+ target_win_length = win_length;
+ target_min = min;
+ target_max = max;
+ }
+
+ /* continue to find the next pass window */
+ min = max + ESDHC_TUNE_CTRL_STEP;
}
/* use average delay to get the best timing */
- avg = (min + max) / 2;
+ avg = (target_min + target_max) / 2;
esdhc_prepare_tuning(host, avg);
ret = mmc_send_tuning(host->mmc, opcode, NULL);
esdhc_post_tuning(host);