From: Hannes Schmelzer oe5hpm@oevsv.at
Some IP-core implementations of the SDHCI have different troubles on the silicon where they are placed.
On ZYNQ platform for example Xilinx doesn't accept the hold timing of an eMMC chip which operates in High-Speed mode and must be forced to operate in non high-speed mode. To get rid of this "SDHCI_QUIRK_BROKEN_HISPD_MODE" is introduced.
For more details about this refer to the Xilinx answer-recor #59999 https://www.xilinx.com/support/answers/59999.html
This commit: - doesn't set HISPD bit on the host-conroller - reflects this fact within the host-controller capabilities
Upon this the layer above (mmc-driver) can setup the card correctly.
Otherwise the MMC card will be switched into high-speed mode and causes possible timing violation on the host-controller side.
Signed-off-by: Hannes Schmelzer oe5hpm@oevsv.at
Signed-off-by: Hannes Schmelzer hannes.schmelzer@br-automation.com ---
Changes in v3: - cleanup sign-off tag - fix typo (sdci -> sdhci) - combine the if instruction SDHCI_QUIRK_BROKEN_HISPD_MODE with the existing SDHCI_QUIRK_NO_HISPD_BIT
Changes in v2: - don't use the SDHCI_QUIRK_NO_HISPD_BIT for getting rid of this, since this quirk was designed for another purpose. Instead introduce the new SDHCI_QUIRK_BROKEN_HISPD_MODE quirk.
drivers/mmc/sdhci.c | 8 +++++++- include/sdhci.h | 6 ++++++ 2 files changed, 13 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c index d31793a..1e5e8a6 100644 --- a/drivers/mmc/sdhci.c +++ b/drivers/mmc/sdhci.c @@ -462,7 +462,8 @@ static int sdhci_set_ios(struct mmc *mmc) else ctrl &= ~SDHCI_CTRL_HISPD;
- if (host->quirks & SDHCI_QUIRK_NO_HISPD_BIT) + if ((host->quirks & SDHCI_QUIRK_NO_HISPD_BIT) || + (host->quirks & SDHCI_QUIRK_BROKEN_HISPD_MODE)) ctrl &= ~SDHCI_CTRL_HISPD;
sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL); @@ -602,6 +603,11 @@ int sdhci_setup_cfg(struct mmc_config *cfg, struct sdhci_host *host, cfg->host_caps &= ~MMC_MODE_8BIT; }
+ if (host->quirks & SDHCI_QUIRK_BROKEN_HISPD_MODE) { + cfg->host_caps &= ~MMC_MODE_HS; + cfg->host_caps &= ~MMC_MODE_HS_52MHz; + } + if (host->host_caps) cfg->host_caps |= host->host_caps;
diff --git a/include/sdhci.h b/include/sdhci.h index 7e84012..ed35f04 100644 --- a/include/sdhci.h +++ b/include/sdhci.h @@ -213,6 +213,12 @@ #define SDHCI_QUIRK_BROKEN_R1B (1 << 2) #define SDHCI_QUIRK_NO_HISPD_BIT (1 << 3) #define SDHCI_QUIRK_BROKEN_VOLTAGE (1 << 4) +/* + * SDHCI_QUIRK_BROKEN_HISPD_MODE + * the hardware cannot operate correctly in high-speed mode, + * this quirk forces the sdhci host-controller to non high-speed mode + */ +#define SDHCI_QUIRK_BROKEN_HISPD_MODE BIT(5) #define SDHCI_QUIRK_WAIT_SEND_CMD (1 << 6) #define SDHCI_QUIRK_USE_WIDE8 (1 << 8)