From 401b2d06c4ed69f5d491f9297651bed3fbbfe69b Mon Sep 17 00:00:00 2001 From: Sahitya Tummala Date: Wed, 27 Sep 2017 11:04:41 +0530 Subject: [PATCH] mmc: sdhci-msm: Fix HW issue with power IRQ handling during reset There is a rare scenario in HW, where the first clear pulse could be lost when the actual reset and clear/read of status register are happening at the same time. Fix this by retrying upto 10 times to ensure the status register gets cleared. Otherwise, this will lead to a spurious power IRQ which results in system instability. Signed-off-by: Sahitya Tummala Signed-off-by: Vijay Viswanath Acked-by: Adrian Hunter Signed-off-by: Ulf Hansson --- drivers/mmc/host/sdhci-msm.c | 46 ++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index ba2bc20..79cb0606 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -995,17 +995,52 @@ static void sdhci_msm_set_uhs_signaling(struct sdhci_host *host, sdhci_msm_hs400(host, &mmc->ios); } -static void sdhci_msm_voltage_switch(struct sdhci_host *host) +static void sdhci_msm_dump_pwr_ctrl_regs(struct sdhci_host *host) +{ + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); + struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); + + pr_err("%s: PWRCTL_STATUS: 0x%08x | PWRCTL_MASK: 0x%08x | PWRCTL_CTL: 0x%08x\n", + mmc_hostname(host->mmc), + readl_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS), + readl_relaxed(msm_host->core_mem + CORE_PWRCTL_MASK), + readl_relaxed(msm_host->core_mem + CORE_PWRCTL_CTL)); +} + +static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq) { struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); u32 irq_status, irq_ack = 0; + int retry = 10; irq_status = readl_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS); irq_status &= INT_MASK; writel_relaxed(irq_status, msm_host->core_mem + CORE_PWRCTL_CLEAR); + /* + * There is a rare HW scenario where the first clear pulse could be + * lost when actual reset and clear/read of status register is + * happening at a time. Hence, retry for at least 10 times to make + * sure status register is cleared. Otherwise, this will result in + * a spurious power IRQ resulting in system instability. + */ + while (irq_status & readl_relaxed(msm_host->core_mem + + CORE_PWRCTL_STATUS)) { + if (retry == 0) { + pr_err("%s: Timedout clearing (0x%x) pwrctl status register\n", + mmc_hostname(host->mmc), irq_status); + sdhci_msm_dump_pwr_ctrl_regs(host); + WARN_ON(1); + break; + } + writel_relaxed(irq_status, + msm_host->core_mem + CORE_PWRCTL_CLEAR); + retry--; + udelay(10); + } + if (irq_status & (CORE_PWRCTL_BUS_ON | CORE_PWRCTL_BUS_OFF)) irq_ack |= CORE_PWRCTL_BUS_SUCCESS; if (irq_status & (CORE_PWRCTL_IO_LOW | CORE_PWRCTL_IO_HIGH)) @@ -1017,13 +1052,17 @@ static void sdhci_msm_voltage_switch(struct sdhci_host *host) * switches are handled by the sdhci core, so just report success. */ writel_relaxed(irq_ack, msm_host->core_mem + CORE_PWRCTL_CTL); + + pr_debug("%s: %s: Handled IRQ(%d), irq_status=0x%x, ack=0x%x\n", + mmc_hostname(msm_host->mmc), __func__, irq, irq_status, + irq_ack); } static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data) { struct sdhci_host *host = (struct sdhci_host *)data; - sdhci_msm_voltage_switch(host); + sdhci_msm_handle_pwr_irq(host, irq); return IRQ_HANDLED; } @@ -1107,7 +1146,6 @@ static const struct sdhci_ops sdhci_msm_ops = { .get_max_clock = sdhci_msm_get_max_clock, .set_bus_width = sdhci_set_bus_width, .set_uhs_signaling = sdhci_msm_set_uhs_signaling, - .voltage_switch = sdhci_msm_voltage_switch, }; static const struct sdhci_pltfm_data sdhci_msm_pdata = { @@ -1269,7 +1307,7 @@ static int sdhci_msm_probe(struct platform_device *pdev) * acknowledged. Otherwise power irq interrupt handler would be * fired prematurely. */ - sdhci_msm_voltage_switch(host); + sdhci_msm_handle_pwr_irq(host, 0); /* * Ensure that above writes are propogated before interrupt enablement -- 2.7.4