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FAILED: patch "[PATCH] i2c: designware: fix IO timeout issue for AMD controller" failed to apply to 4.3-stable tree

PATCH [email protected] 1 participant 1 message Feb 13, 2016

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Stable branch I2C subsystem host drivers Intel LPSS (Low Power SubSystem) drivers Synopsys DesignWare I2C driver
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The patch below does not apply to the 4.3-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 2d244c81481fa5142a2ba6656ab7a8e40c849c27 Mon Sep 17 00:00:00 2001

From: Xiangliang Yu <[email protected]>
Date: Fri, 11 Dec 2015 20:02:53 +0800
Subject: [PATCH] i2c: designware: fix IO timeout issue for AMD controller

Because of some hardware limitation, AMD I2C controller can't trigger pending interrupt if interrupt status has been changed after clearing interrupt status bits. Then, I2C will lost interrupt and IO timeout.

According to hardware design, this patch implements a workaround to disable i2c controller interrupt and re-enable i2c interrupt before exiting ISR.

To reduce the performance impacts on other vendors, use unlikely function to check flag in ISR.

Signed-off-by Xiangliang Yu <[email protected]>
Acked-by Jarkko Nikula <[email protected]>
Signed-off-by Wolfram Sang <[email protected]>
Cc [email protected]
drivers/i2c/busses/i2c-designware-core.c +6 -0
index 8c48b27ba059..de7fbbb374cd 100644
@@ -813,6 +813,12 @@ static irqreturn_t i2c_dw_isr(int this_irq, void *dev_id)
 tx_aborted:
 	if ((stat & (DW_IC_INTR_TX_ABRT | DW_IC_INTR_STOP_DET)) || dev->msg_err)
 		complete(&dev->cmd_complete);
+	else if (unlikely(dev->accessor_flags & ACCESS_INTR_MASK)) {
+		/* workaround to trigger pending interrupt */
+		stat = dw_readl(dev, DW_IC_INTR_MASK);
+		i2c_dw_disable_int(dev);
+		dw_writel(dev, stat, DW_IC_INTR_MASK);
+	}
 
 	return IRQ_HANDLED;
 }
drivers/i2c/busses/i2c-designware-core.h +1 -0
index 1d50898e7b24..9ffb63a60f95 100644
@@ -111,6 +111,7 @@ struct dw_i2c_dev {
 
 #define ACCESS_SWAP		0x00000001
 #define ACCESS_16BIT		0x00000002
+#define ACCESS_INTR_MASK	0x00000004
 
 extern int i2c_dw_init(struct dw_i2c_dev *dev);
 extern void i2c_dw_disable(struct dw_i2c_dev *dev);
drivers/i2c/busses/i2c-designware-platdrv.c +6 -1
index 809579ecb5a4..f03ea71d6519 100644
@@ -93,6 +93,7 @@ static void dw_i2c_acpi_params(struct platform_device *pdev, char method[],
 static int dw_i2c_acpi_configure(struct platform_device *pdev)
 {
 	struct dw_i2c_dev *dev = platform_get_drvdata(pdev);
+	const struct acpi_device_id *id;
 
 	dev->adapter.nr = -1;
 	dev->tx_fifo_depth = 32;

@@ -106,6 +107,10 @@ static int dw_i2c_acpi_configure(struct platform_device *pdev)
 	dw_i2c_acpi_params(pdev, "FMCN", &dev->fs_hcnt, &dev->fs_lcnt,
 			   &dev->sda_hold_time);
 
+	id = acpi_match_device(pdev->dev.driver->acpi_match_table, &pdev->dev);
+	if (id && id->driver_data)
+		dev->accessor_flags |= (u32)id->driver_data;
+
 	return 0;
 }
 

@@ -116,7 +121,7 @@ static const struct acpi_device_id dw_i2c_acpi_match[] = {
 	{ "INT3433", 0 },
 	{ "80860F41", 0 },
 	{ "808622C1", 0 },
-	{ "AMD0010", 0 },
+	{ "AMD0010", ACCESS_INTR_MASK },
 	{ }
 };
 MODULE_DEVICE_TABLE(acpi, dw_i2c_acpi_match);