From: Adrian Hunter <adrian.hunter@xxxxxxxxx>
The delay between tuning commands for SD cards is not part of the
specification. A driver that needs it probably needs it for eMMC
too, whereas most drivers would probably like to set it to 0. Make
it a host member (host->tuning_delay) that defaults to the existing
behaviour. Drivers can set it to zero to eliminate the delay, or
set it to a positive value to always have a delay.
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
---
Changes for v2:
- None
Changes for v3:
- Used a host member for tuning delay instead of a quirk.(Adrian's patch)
- Addressed warning in checkpatch.
---
drivers/mmc/host/sdhci.c | 11 ++++++++---
drivers/mmc/host/sdhci.h | 2 ++
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 0d4485d..ffd1607 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2100,9 +2100,9 @@ static void __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode)
break;
}
- /* eMMC spec does not require a delay between tuning cycles */
- if (opcode == MMC_SEND_TUNING_BLOCK)
- mdelay(1);
+ /* Spec does not require a delay between tuning cycles */
+ if (host->tuning_delay > 0)
+ mdelay(host->tuning_delay);
}
pr_info("%s: Tuning failed, falling back to fixed sampling clock\n",
@@ -2164,6 +2164,9 @@ int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
host->mmc->retune_period = tuning_count;
+ if (host->tuning_delay < 0)
+ host->tuning_delay = opcode == MMC_SEND_TUNING_BLOCK;
+
sdhci_start_tuning(host);
__sdhci_execute_tuning(host, opcode);
@@ -3108,6 +3111,8 @@ struct sdhci_host *sdhci_alloc_host(struct device *dev,
host->cqe_ier = SDHCI_CQE_INT_MASK;
host->cqe_err_ier = SDHCI_CQE_INT_ERR_MASK;
+ host->tuning_delay = -1;
+
return host;
}
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index fdb5d7e..2407960 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -538,6 +538,8 @@ struct sdhci_host {
#define SDHCI_TUNING_MODE_1 0
#define SDHCI_TUNING_MODE_2 1
#define SDHCI_TUNING_MODE_3 2
+ /* Delay (ms) between tuning commands */
+ int tuning_delay;
unsigned long private[0] ____cacheline_aligned;
};
--
2.1.0.27.g96db324
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