On Tue, 22 Nov 2016 19:48:56 -0800 Jeremy McNicoll wrote:

On 2016-11-22 7:36 PM, Jisheng Zhang wrote:

quoted

On Tue, 22 Nov 2016 17:09:48 -0800
Jeremy McNicoll [off-list ref] wrote:
 

quoted

On msm8992 it has been observed that IRQs were not getting
ACK'd correctly when clocked at speeds greater than 400KHz.

Signed-off-by: Jeremy McNicoll <redacted>
---
 drivers/mmc/host/sdhci-msm.c |  7 +++++++
 drivers/mmc/host/sdhci.c     | 12 ++++++++++--
 drivers/mmc/host/sdhci.h     |  2 ++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
index 1fcda96..459003c 100644
--- a/drivers/mmc/host/sdhci-msm.c
+++ b/drivers/mmc/host/sdhci-msm.c

@@ -1303,6 +1303,13 @@ static int sdhci_msm_probe(struct platform_device *pdev)
 			       CORE_VENDOR_SPEC_CAPABILITIES0);
 	}

+	/* Enable delayed IRQ handling workaround on 8992 */
+	if (core_major == 1 && core_minor == 0x3e) {
+		/* Add 40us delay in interrupt handler when operating
+		 * at initialization frequency of 400KHz. */
+		host->quirks2 |= SDHCI_QUIRK2_SLOW_INT_CLR;
+	}
+
 	/* Setup IRQ for handling power/voltage tasks with PMIC */
 	msm_host->pwr_irq = platform_get_irq_byname(pdev, "pwr_irq");
 	if (msm_host->pwr_irq < 0) {

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5911f98..c1aae22 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c

@@ -2703,11 +2703,19 @@ static irqreturn_t sdhci_irq(int irq, void *dev_id)
 			result = IRQ_WAKE_THREAD;
 		}

-		if (intmask & SDHCI_INT_CMD_MASK)
+		if (intmask & SDHCI_INT_CMD_MASK) {
+			if ((host->quirks2 & SDHCI_QUIRK2_SLOW_INT_CLR) && (host->clock <= 400000)) {
+				udelay(40);
+			}
 			sdhci_cmd_irq(host, intmask & SDHCI_INT_CMD_MASK);
+		}

-		if (intmask & SDHCI_INT_DATA_MASK)
+		if (intmask & SDHCI_INT_DATA_MASK) {
+			if ((host->quirks2 & SDHCI_QUIRK2_SLOW_INT_CLR) && (host->clock <= 400000)) {
+				udelay(40);
+			}
 			sdhci_data_irq(host, intmask & SDHCI_INT_DATA_MASK);
+		}

 		if (intmask & SDHCI_INT_BUS_POWER)
 			pr_err("%s: Card is consuming too much power!\n",

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index c055e24..5f8301e 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h

@@ -24,6 +24,8 @@
  * Controller registers
  */

+#define SDHCI_QUIRK2_SLOW_INT_CLR	(1<<5)  

IIRC, new quirk isn't allowed now.
 

Why not?

IIRC, mmc subsystem will behave as a lib in the long run, so the community
and developers call for no new quirk. For your case, we may need to handle
the udelay in sdhci-msm.c, export sdhci_irq as a helper function?

Thanks
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