i2c: tegra: recover from spurious interrupt storm
Re-init the I2C controller when an IRQ arrives with no
I2C_INT_STATUS bits set to indicate why the interrupt was sent.
Storms of such mystery interrupts are infrequently seen.
Dump some more status when these interrupts arrive. Set an error
for the current request and wake up the requester (rather than
timing out the request or possibly silently ignoring the interrupts).
If the I2C block is inside the DVC, also ACK the DVC I2C transfer
done interrupt in the ISR error return path, as is done for the
normal return path.
Signed-off-by: Todd Poynor <toddpoynor@google.com>
[swarren: Fix minor checkpatch whitespace issue, commit tag]
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c
index 5f1b92c..c0b9aa7 100644
--- a/drivers/i2c/busses/i2c-tegra.c
+++ b/drivers/i2c/busses/i2c-tegra.c
@@ -37,6 +37,7 @@
#define I2C_CNFG 0x000
#define I2C_CNFG_PACKET_MODE_EN (1<<10)
#define I2C_CNFG_NEW_MASTER_FSM (1<<11)
+#define I2C_STATUS 0x01C
#define I2C_SL_CNFG 0x020
#define I2C_SL_CNFG_NEWSL (1<<2)
#define I2C_SL_ADDR1 0x02c
@@ -77,6 +78,7 @@
#define I2C_ERR_NONE 0x00
#define I2C_ERR_NO_ACK 0x01
#define I2C_ERR_ARBITRATION_LOST 0x02
+#define I2C_ERR_UNKNOWN_INTERRUPT 0x04
#define PACKET_HEADER0_HEADER_SIZE_SHIFT 28
#define PACKET_HEADER0_PACKET_ID_SHIFT 16
@@ -121,6 +123,7 @@
void __iomem *base;
int cont_id;
int irq;
+ bool irq_disabled;
int is_dvc;
struct completion msg_complete;
int msg_err;
@@ -343,6 +346,12 @@
err = -ETIMEDOUT;
clk_disable(i2c_dev->clk);
+
+ if (i2c_dev->irq_disabled) {
+ i2c_dev->irq_disabled = 0;
+ enable_irq(i2c_dev->irq);
+ }
+
return err;
}
@@ -355,8 +364,19 @@
status = i2c_readl(i2c_dev, I2C_INT_STATUS);
if (status == 0) {
- dev_warn(i2c_dev->dev, "interrupt with no status\n");
- return IRQ_NONE;
+ dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
+ i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
+ i2c_readl(i2c_dev, I2C_STATUS),
+ i2c_readl(i2c_dev, I2C_CNFG));
+ i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
+
+ if (!i2c_dev->irq_disabled) {
+ disable_irq_nosync(i2c_dev->irq);
+ i2c_dev->irq_disabled = 1;
+ }
+
+ complete(&i2c_dev->msg_complete);
+ goto err;
}
if (unlikely(status & status_err)) {
@@ -396,6 +416,8 @@
I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
I2C_INT_RX_FIFO_DATA_REQ);
i2c_writel(i2c_dev, status, I2C_INT_STATUS);
+ if (i2c_dev->is_dvc)
+ dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
return IRQ_HANDLED;
}