From mboxrd@z Thu Jan 1 00:00:00 1970 From: Troy Kisky Subject: [PATCH 3/3] I2C: DaVinci: fix signal handling bug Date: Wed, 30 Apr 2008 16:53:58 -0700 Message-ID: <1209599638-17057-3-git-send-email-troy.kisky@boundarydevices.com> References: <1209599638-17057-1-git-send-email-troy.kisky@boundarydevices.com> <1209599638-17057-2-git-send-email-troy.kisky@boundarydevices.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1209599638-17057-2-git-send-email-troy.kisky-Q5RJGjKts06CY9SHAMCTRUEOCMrvLtNR@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Errors-To: i2c-bounces-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org To: i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org Cc: Kevin Hilman List-Id: linux-i2c@vger.kernel.org If wait_for_completion_interruptible_timeout exits due to a signal, the i2c bus was locking up. Signed-off-by: Troy Kisky Signed-off-by: Kevin Hilman --- drivers/i2c/busses/i2c-davinci.c | 62 +++++++++++++++++++++++++++++++------ 1 files changed, 52 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c index 77c9822..c44ef4a 100644 --- a/drivers/i2c/busses/i2c-davinci.c +++ b/drivers/i2c/busses/i2c-davinci.c @@ -85,6 +85,7 @@ #define DAVINCI_I2C_MDR_MST (1 << 10) #define DAVINCI_I2C_MDR_TRX (1 << 9) #define DAVINCI_I2C_MDR_XA (1 << 8) +#define DAVINCI_I2C_MDR_RM (1 << 7) #define DAVINCI_I2C_MDR_IRS (1 << 5) #define DAVINCI_I2C_IMR_AAS (1 << 6) @@ -112,6 +113,7 @@ struct davinci_i2c_dev { u8 *buf; size_t buf_len; int irq; + u8 terminate; struct i2c_adapter adapter; }; @@ -283,20 +285,34 @@ i2c_davinci_xfer_msg(struct i2c_adapter *adap, struct i2c_msg *msg, int stop) MOD_REG_BIT(w, DAVINCI_I2C_IMR_XRDY, 1); davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); + dev->terminate = 0; /* write the data into mode register */ davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, flag); r = wait_for_completion_interruptible_timeout(&dev->cmd_complete, DAVINCI_I2C_TIMEOUT); - dev->buf_len = 0; - if (r < 0) - return r; - if (r == 0) { dev_err(dev->dev, "controller timed out\n"); i2c_davinci_init(dev); + dev->buf_len = 0; return -ETIMEDOUT; } + if (dev->buf_len) { + /* This should be 0 if all bytes were transferred + * or dev->cmd_err denotes an error. + * A signal may have aborted the transfer. + */ + if (r >= 0) { + dev_err(dev->dev, "abnormal termination buf_len=%i\n", + dev->buf_len); + r = -EREMOTEIO; + } + dev->terminate = 1; + wmb(); + dev->buf_len = 0; + } + if (r < 0) + return r; /* no error */ if (likely(!dev->cmd_err)) @@ -353,6 +369,27 @@ static u32 i2c_davinci_func(struct i2c_adapter *adap) return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK); } +static void terminate_read(struct davinci_i2c_dev *dev) +{ + u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); + w |= DAVINCI_I2C_MDR_NACK; + davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); + + /* Throw away data */ + davinci_i2c_read_reg(dev, DAVINCI_I2C_DRR_REG); + if (!dev->terminate) + dev_err(dev->dev, "RDR IRQ while no data requested\n"); +} +static void terminate_write(struct davinci_i2c_dev *dev) +{ + u16 w = davinci_i2c_read_reg(dev, DAVINCI_I2C_MDR_REG); + w |= DAVINCI_I2C_MDR_RM | DAVINCI_I2C_MDR_STP; + davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, w); + + if (!dev->terminate) + dev_err(dev->dev, "TDR IRQ while no data to send\n"); +} + /* * Interrupt service routine. This gets called whenever an I2C interrupt * occurs. @@ -373,12 +410,15 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) switch (stat) { case DAVINCI_I2C_IVR_AL: + /* Arbitration lost, must retry */ dev->cmd_err |= DAVINCI_I2C_STR_AL; + dev->buf_len = 0; complete(&dev->cmd_complete); break; case DAVINCI_I2C_IVR_NACK: dev->cmd_err |= DAVINCI_I2C_STR_NACK; + dev->buf_len = 0; complete(&dev->cmd_complete); break; @@ -400,9 +440,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) davinci_i2c_write_reg(dev, DAVINCI_I2C_STR_REG, DAVINCI_I2C_IMR_RRDY); - } else - dev_err(dev->dev, "RDR IRQ while no " - "data requested\n"); + } else { + /* signal can terminate transfer */ + terminate_read(dev); + } break; case DAVINCI_I2C_IVR_XRDY: @@ -419,9 +460,10 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id) davinci_i2c_write_reg(dev, DAVINCI_I2C_IMR_REG, w); - } else - dev_err(dev->dev, "TDR IRQ while no data to " - "send\n"); + } else { + /* signal can terminate transfer */ + terminate_write(dev); + } break; case DAVINCI_I2C_IVR_SCD: -- 1.5.4 _______________________________________________ i2c mailing list i2c-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org http://lists.lm-sensors.org/mailman/listinfo/i2c