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 <Xiangliang.Yu@amd.com>
Acked-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Cc: stable@kernel.org

diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c
index 8c48b27ba05975e51a40ddaab979e7b23302e3e0..de7fbbb374cd34fce1cc8fffb11c45b21755bead 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -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;
 }

diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h
index 1d50898e7b2403868c239f2ebc236a240a755bc7..9ffb63a60f95454ebbaf43f6a12bbe922de66179 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -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);

diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c
index 809579ecb5a44fed6745af1274ed46864763651c..f03ea71d651986059f5a111d124550c638b5fd58 100644 (file)
--- a/drivers/i2c/busses/i2c-designware-platdrv.c
+++ b/drivers/i2c/busses/i2c-designware-platdrv.c
@@ -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);