Add a verify option to driver to print out an error message if a potential back to back write could cause a clock domain issue.
Signed-off-by: Scott Branden <[email protected]> --- drivers/mmc/host/Kconfig | 9 +++++++++ drivers/mmc/host/sdhci-bcm2835.c | 17 +++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig index 1386065..020de98 100644 --- a/drivers/mmc/host/Kconfig +++ b/drivers/mmc/host/Kconfig @@ -292,6 +292,15 @@ config MMC_SDHCI_BCM2835 If unsure, say N. +config MMC_SDHCI_BCM2835_VERIFY_WORKAROUND + bool "Verify BCM2835 workaround does not do back to back writes" + depends on MMC_SDHCI_BCM2835 + default y + help + This enables code that verifies the bcm2835 workaround. + The verification code checks that back to back writes to the same + register do not occur. + config MMC_MOXART tristate "MOXART SD/MMC Host Controller support" depends on ARCH_MOXART && MMC diff --git a/drivers/mmc/host/sdhci-bcm2835.c b/drivers/mmc/host/sdhci-bcm2835.c index f8c450a..11af27f 100644 --- a/drivers/mmc/host/sdhci-bcm2835.c +++ b/drivers/mmc/host/sdhci-bcm2835.c @@ -27,6 +27,9 @@ struct bcm2835_sdhci_host { u32 shadow_cmd; u32 shadow_blk; +#ifdef CONFIG_MMC_SDHCI_BCM2835_VERIFY_WORKAROUND + int previous_reg; +#endif }; #define REG_OFFSET_IN_BITS(reg) ((reg) << 3 & 0x18) @@ -58,6 +61,20 @@ static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg) static inline void bcm2835_sdhci_writel(struct sdhci_host *host, u32 val, int reg) { +#ifdef CONFIG_MMC_SDHCI_BCM2835_VERIFY_WORKAROUND + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct bcm2835_sdhci_host *bcm2835_host = pltfm_host->priv; + + if (bcm2835_host->previous_reg == reg) { + if ((reg != SDHCI_HOST_CONTROL) + && (reg != SDHCI_CLOCK_CONTROL)) { + dev_err(mmc_dev(host->mmc), + "back-to-back write to 0x%x\n", reg); + } + } + bcm2835_host->previous_reg = reg; +#endif + writel(val, host->ioaddr + reg); } -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
