Messages in this thread | | | Subject | Re: [PATCH 2/5] mmc: sdhci-msm: Fix HW issue with power IRQ handling during reset | From | Vijay Viswanath <> | Date | Mon, 28 Aug 2017 18:04:06 +0530 |
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On 8/24/2017 1:12 PM, Adrian Hunter wrote: > On 18/08/17 08:19, Vijay Viswanath wrote: >> From: Sahitya Tummala <stummala@codeaurora.org> >> >> 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 <stummala@codeaurora.org> >> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org> >> --- >> drivers/mmc/host/sdhci-msm.c | 43 ++++++++++++++++++++++++++++++++++++++++--- >> 1 file changed, 40 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c >> index 0957199..f3e0489 100644 >> --- a/drivers/mmc/host/sdhci-msm.c >> +++ b/drivers/mmc/host/sdhci-msm.c >> @@ -995,17 +995,51 @@ 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); > > Is it your intention to loop forever here? > A bad mistake from my side. Will add break here. >> + } >> + 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 +1051,17 @@ 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; >> } >> @@ -1106,7 +1144,6 @@ static void sdhci_msm_set_clock(struct sdhci_host *host, unsigned int clock) >> .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 = { >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-mmc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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