[PATCH V2 4/9] mmc: sdhci: Always allow tuning to fall back to fixed sampling

Adrian Hunter
2016-12-02T13:19:45Z

SDHCI falls back to fixed sampling if there is an error during tuning.
However it also reports an error unless there is periodic re-tuning.
That is not the best option because:
a) there is a reasonable chance that fixed sampling will work, especially
at room temperature.
b) re-tuning will be done again anyway if there are CRC errors.
Change to return no error always when falling back to fixed sampling.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
drivers/mmc/host/sdhci.c | 20 ++------------------
1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ad2f2c6113e4..a23887799f43 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2098,8 +2098,6 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
sdhci_do_reset(host, SDHCI_RESET_CMD);
sdhci_do_reset(host, SDHCI_RESET_DATA);

- err = -EIO;
-
if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)
goto out;

@@ -2137,24 +2135,10 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
}
- if (!(ctrl & SDHCI_CTRL_TUNED_CLK)) {
+ if (!(ctrl & SDHCI_CTRL_TUNED_CLK))
pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");
- err = -EIO;
- }
-
out:
- if (tuning_count) {
- /*
- * In case tuning fails, host controllers which support
- * re-tuning can try tuning again at a later time, when the
- * re-tuning timer expires. So for these controllers, we
- * return 0. Since there might be other controllers who do not
- * have this capability, we return error for them.
- */
- err = 0;
- }
-
- host->mmc->retune_period = err ? 0 : tuning_count;
+ host->mmc->retune_period = tuning_count;

sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
--
1.9.1