| Message ID | alpine.DEB.2.02.1304221508050.31571@localhost |
|---|---|
| State | Superseded |
| Headers | show |
On Mon, Apr 22, 2013 at 03:08:59PM +0100, Josef Ahmad wrote: > From a969728248c3b439dc97a69e7dac133b5efa34e7 Mon Sep 17 00:00:00 2001 > From: Josef Ahmad <josef.ahmad@linux.intel.com> > Date: Fri, 19 Apr 2013 17:28:10 +0100 > Subject: [PATCH] i2c-designware: fix RX FIFO overrun > > i2c_dw_xfer_msg() pushes a number of bytes to transmit/receive > to/from the bus into the TX FIFO. > For master-rx transactions, the maximum amount of data that can be > received is calculated depending solely on TX and RX FIFO load. > > This is racy - TX FIFO may contain master-rx data yet to be > processed, which will eventually land into the RX FIFO. This > data is not taken into account and the function may request more > data than the controller is actually capable of storing. > > This patch ensures the driver takes into account the outstanding > master-rx data in TX FIFO to prevent RX FIFO overrun. > > Signed-off-by: Josef Ahmad <josef.ahmad@linux.intel.com> > Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> This driver had a major cleanup meanwhile. Could you rebase your patch on top of my for-next branch? I guess this version should make it into stable? -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> On Mon, Apr 22, 2013 at 03:08:59PM +0100, Josef Ahmad wrote: >> From a969728248c3b439dc97a69e7dac133b5efa34e7 Mon Sep 17 00:00:00 2001 >> From: Josef Ahmad <josef.ahmad@linux.intel.com> >> Date: Fri, 19 Apr 2013 17:28:10 +0100 >> Subject: [PATCH] i2c-designware: fix RX FIFO overrun >> >> i2c_dw_xfer_msg() pushes a number of bytes to transmit/receive >> to/from the bus into the TX FIFO. >> For master-rx transactions, the maximum amount of data that can be >> received is calculated depending solely on TX and RX FIFO load. >> >> This is racy - TX FIFO may contain master-rx data yet to be >> processed, which will eventually land into the RX FIFO. This >> data is not taken into account and the function may request more >> data than the controller is actually capable of storing. >> >> This patch ensures the driver takes into account the outstanding >> master-rx data in TX FIFO to prevent RX FIFO overrun. >> >> Signed-off-by: Josef Ahmad <josef.ahmad@linux.intel.com> >> Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> > > This driver had a major cleanup meanwhile. Could you rebase your patch > on top of my for-next branch? I guess this version should make it into > stable? > Hi Wolfram This patch applies just fine on top of your i2c-embedded/for-next branch. -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
> > This driver had a major cleanup meanwhile. Could you rebase your patch > > on top of my for-next branch? I guess this version should make it into > > stable? > > > > This patch applies just fine on top of your i2c-embedded/for-next branch. i2c-embedded? Ah, this one is outdated. Please check git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git i2c/for-next. Thanks, Wolfram -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 94fd818..8dbeef1 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -426,8 +426,14 @@ i2c_dw_xfer_msg(struct dw_i2c_dev *dev) cmd |= BIT(9); if (msgs[dev->msg_write_idx].flags & I2C_M_RD) { + + /* avoid rx buffer overrun */ + if (rx_limit - dev->rx_outstanding <= 0) + break; + dw_writel(dev, cmd | 0x100, DW_IC_DATA_CMD); rx_limit--; + dev->rx_outstanding++; } else dw_writel(dev, cmd | *buf++, DW_IC_DATA_CMD); tx_limit--; buf_len--; @@ -480,8 +486,10 @@ i2c_dw_read(struct dw_i2c_dev *dev) rx_valid = dw_readl(dev, DW_IC_RXFLR); - for (; len > 0 && rx_valid > 0; len--, rx_valid--) + for (; len > 0 && rx_valid > 0; len--, rx_valid--) { *buf++ = dw_readl(dev, DW_IC_DATA_CMD); + dev->rx_outstanding--; + } if (len > 0) { dev->status |= STATUS_READ_IN_PROGRESS; @@ -539,6 +547,7 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) dev->msg_err = 0; dev->status = STATUS_IDLE; dev->abort_source = 0; + dev->rx_outstanding = 0; ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 9c1840e..e761ad1 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -60,6 +60,7 @@ * @adapter: i2c subsystem adapter node * @tx_fifo_depth: depth of the hardware tx fifo * @rx_fifo_depth: depth of the hardware rx fifo + * @rx_outstanding: current master-rx elements in tx fifo */ struct dw_i2c_dev { struct device *dev; @@ -88,6 +89,7 @@ struct dw_i2c_dev { u32 master_cfg; unsigned int tx_fifo_depth; unsigned int rx_fifo_depth; + int rx_outstanding; }; #define ACCESS_SWAP 0x00000001