Re: [PATCH v2 11/40] mmc: sdhci: Add a quirk to skip clearing the transfer mode register on tuning
From: Adrian Hunter <adrian.hunter@intel.com>
Date: 2018-08-27 11:03:41
Also in:
linux-mmc, linux-tegra, lkml
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, secure digital host controller interface (sdhci) driver, the rest · Maintainers:
Ulf Hansson, Adrian Hunter, Linus Torvalds
On 10/08/18 21:08, Aapo Vienamo wrote:
quoted hunk ↗ jump to hunk
Add SDHCI_QUIRK2_TUNE_SKIP_XFERRMODE_REG_PROG to skip programming the SDHCI_TRANSFER_MODE in sdhci_set_transfer_mode() if tuning command is being sent. On Tegra210 and Tegra186 the tuning sequence hangs if the SDHCI transfer mode register is touched. Signed-off-by: Aapo Vienamo <redacted> --- drivers/mmc/host/sdhci.c | 6 ++++++ drivers/mmc/host/sdhci.h | 2 ++ 2 files changed, 8 insertions(+)diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index a7b5602..04dc443 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c@@ -1028,6 +1028,12 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host, if (data == NULL) { if (host->quirks2 & + SDHCI_QUIRK2_TUNE_SKIP_XFERMODE_REG_PROG && + (cmd->opcode == MMC_SEND_TUNING_BLOCK || + cmd->opcode == MMC_SEND_TUNING_BLOCK_HS200)) { + return; + }
Rather than introduce a quirk, can't we just dodge the unnecessary write e.g.
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1b3fbd9bd5c5..68af6a67e397 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c@@ -1033,10 +1033,19 @@ static void sdhci_set_transfer_mode(struct sdhci_host *host, if (cmd->opcode != MMC_SEND_TUNING_BLOCK_HS200) sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE); } else { - /* clear Auto CMD settings for no data CMDs */ + u16 orig; + + /* clear Auto CMD settings for no data CMDs */ mode = sdhci_readw(host, SDHCI_TRANSFER_MODE); - sdhci_writew(host, mode & ~(SDHCI_TRNS_AUTO_CMD12 | - SDHCI_TRNS_AUTO_CMD23), SDHCI_TRANSFER_MODE); + orig = mode; + mode &= ~(SDHCI_TRNS_AUTO_CMD12 | SDHCI_TRNS_AUTO_CMD23); + /* + * Do not write transfer mode unnecessarily because it + * can upset some host controllers (e.g. sdhci-tregra) + * during tuning. + */ + if (mode != orig) + sdhci_writew(host, new_mode, SDHCI_TRANSFER_MODE); } return; }
Alternatively
quoted hunk ↗ jump to hunk
+ if (host->quirks2 & SDHCI_QUIRK2_CLEAR_TRANSFERMODE_REG_BEFORE_CMD) { sdhci_writew(host, 0x0, SDHCI_TRANSFER_MODE); } else {diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h index 23966f8..0a99008 100644 --- a/drivers/mmc/host/sdhci.h +++ b/drivers/mmc/host/sdhci.h@@ -450,6 +450,8 @@ struct sdhci_host { * obtainable timeout. */ #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT (1<<17) +/* Don't clear the SDHCI_TRANSFER_MODE register on tuning commands */ +#define SDHCI_QUIRK2_TUNE_SKIP_XFERMODE_REG_PROG (1<<18) int irq; /* Device IRQ */ void __iomem *ioaddr; /* Mapped address */