From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Anderson Subject: [PATCH] i2c: tegra: Check for overflow errors with BUG_ON. Date: Mon, 15 Aug 2011 11:49:32 -0700 Message-ID: <1313434172-18319-1-git-send-email-dianders@chromium.org> Return-path: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ben Dooks , Stephen Warren , Vincent Palatin , Rhyland Klein Cc: Jean Delvare , Rakesh Iyer , Doug Anderson , Lucas De Marchi , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org List-Id: linux-i2c@vger.kernel.org This change doesn't fix any known problems but turns on the overflow detection feature of the i2c controller in the hopes of flushing out any current (or future) bugs in the i2c driver. Inspired by a change on nvidia's git server: http://nv-tegra.nvidia.com/gitweb/?p=linux-2.6.git;a=commit;h=266d1b7397284505e55d06254b497cb32be07b69 Signed-off-by: Doug Anderson --- drivers/i2c/busses/i2c-tegra.c | 11 ++++++++--- 1 files changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 2440b74..4dbba23 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -367,7 +367,8 @@ static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev) static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) { u32 status; - const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; + const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | + I2C_INT_TX_FIFO_OVERFLOW; struct tegra_i2c_dev *i2c_dev = dev_id; status = i2c_readl(i2c_dev, I2C_INT_STATUS); @@ -389,6 +390,9 @@ static irqreturn_t tegra_i2c_isr(int irq, void *dev_id) } if (unlikely(status & status_err)) { + /* Don't pass this back--it can only happen due to a bug. */ + BUG_ON(status & I2C_INT_TX_FIFO_OVERFLOW); + if (status & I2C_INT_NO_ACK) i2c_dev->msg_err |= I2C_ERR_NO_ACK; if (status & I2C_INT_ARBITRATION_LOST) @@ -423,7 +427,7 @@ err: /* An error occurred, mask all interrupts */ tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ | - I2C_INT_RX_FIFO_DATA_REQ); + I2C_INT_RX_FIFO_DATA_REQ | I2C_INT_TX_FIFO_OVERFLOW); i2c_writel(i2c_dev, status, I2C_INT_STATUS); if (i2c_dev->is_dvc) dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS); @@ -473,7 +477,8 @@ static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev, if (!(msg->flags & I2C_M_RD)) tegra_i2c_fill_tx_fifo(i2c_dev); - int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST; + int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST | + I2C_INT_TX_FIFO_OVERFLOW; if (msg->flags & I2C_M_RD) int_mask |= I2C_INT_RX_FIFO_DATA_REQ; else if (i2c_dev->msg_buf_remaining) -- 1.7.3.1