The FIFO buffer size is different with different CPU stepping. Define it as 32-byte; it is safe for all CPU stepping.
There is a problem when xfer size is greater then FIFO buffer size. Implement software fragmentation in host bus driver. So that I2C slave device driver need not to do modify. Signed-off-by: Major Lee <[email protected]> --- i2c-intel-mid.c | 95 +++++++++++++++++++++++++++----------------------------- 1 file changed, 46 insertions(+), 49 deletions(-) diff -uprN a/drivers/i2c/busses/i2c-intel-mid.c b/drivers/i2c/busses/i2c-intel-mid.c --- a/drivers/i2c/busses/i2c-intel-mid.c 2010-11-23 09:36:29.750000000 +0800 +++ b/drivers/i2c/busses/i2c-intel-mid.c 2010-11-26 14:25:25.274961000 +0800 @@ -54,6 +54,10 @@ enum mid_i2c_status { STATUS_STANDBY }; +/* The FIFO buffer size is different with different CPU stepping */ +/* Define it as 32-byte; it is safe for all CPU stepping */ +#define I2C_FIFO_SIZE 32 + /** * struct intel_mid_i2c_private - per device I²C context * @adap: core i2c layer adapter information @@ -62,7 +66,6 @@ enum mid_i2c_status { * @speed: speed mode for this port * @complete: completion object for transaction wait * @abort: reason for last abort - * @rx_buf: pointer into working receive buffer * @rx_buf_len: receive buffer length * @status: adapter state machine * @msg: the message we are currently processing @@ -79,7 +82,6 @@ struct intel_mid_i2c_private { int speed; struct completion complete; int abort; - u8 *rx_buf; int rx_buf_len; enum mid_i2c_status status; struct i2c_msg *msg; @@ -531,17 +533,15 @@ static int xfer_read(struct i2c_adapter int i = length; int err; - if (length >= 256) { - dev_err(&adap->dev, - "I2C FIFO cannot support larger than 256 bytes\n"); - return -EMSGSIZE; - } - INIT_COMPLETION(i2c->complete); readl(i2c->base + IC_CLR_INTR); writel(0x0044, i2c->base + IC_INTR_MASK); + i2c->rx_buf_len = length; + /* set receive FIFO threshold */ + writel((uint16_t)(length - 1), i2c->base + IC_RX_TL); + i2c->status = STATUS_READ_START; while (i--) @@ -584,12 +584,6 @@ static int xfer_write(struct i2c_adapter struct intel_mid_i2c_private *i2c = i2c_get_adapdata(adap); int i, err; - if (length >= 256) { - dev_err(&adap->dev, - "I2C FIFO cannot support larger than 256 bytes\n"); - return -EMSGSIZE; - } - INIT_COMPLETION(i2c->complete); readl(i2c->base + IC_CLR_INTR); @@ -717,6 +711,9 @@ static int intel_mid_i2c_xfer(struct i2c { struct intel_mid_i2c_private *i2c = i2c_get_adapdata(adap); int i, err = 0; + u16 len; + u8 *buf; + u16 xfer_len; /* if number of messages equal 0*/ if (num == 0) @@ -757,13 +754,35 @@ static int intel_mid_i2c_xfer(struct i2c for (i = 0; i < num; i++) { i2c->msg = pmsg; i2c->status = STATUS_IDLE; - /* Read or Write */ - if (pmsg->flags & I2C_M_RD) { - dev_dbg(&adap->dev, "I2C_M_RD\n"); - err = xfer_read(adap, pmsg->buf, pmsg->len); - } else { - dev_dbg(&adap->dev, "I2C_M_WR\n"); - err = xfer_write(adap, pmsg->buf, pmsg->len); + + if (pmsg->len && pmsg->buf) { + len = pmsg->len; + buf = pmsg->buf; + xfer_len = 0; + + while (len && buf) { + /* Fragment xfer data */ + if (len >= I2C_FIFO_SIZE) + xfer_len = I2C_FIFO_SIZE; + else + xfer_len = len; + /* Read or Write */ + if (pmsg->flags & I2C_M_RD) { + dev_dbg(&adap->dev, "I2C_M_RD\n"); + err = xfer_read(adap, buf, xfer_len); + } else { + dev_dbg(&adap->dev, "I2C_M_WR\n"); + err = xfer_write(adap, buf, xfer_len); + } + if (err < 0) + break; + + len -= xfer_len; + if (len) + buf += xfer_len; + else /* len == 0 */ + break; + } } if (err < 0) break; @@ -837,32 +856,12 @@ static int intel_mid_i2c_runtime_resume( static void i2c_isr_read(struct intel_mid_i2c_private *i2c) { struct i2c_msg *msg = i2c->msg; - int rx_num; - u32 len; - u8 *buf; - - if (!(msg->flags & I2C_M_RD)) - return; + u32 len = i2c->rx_buf_len; + u8 *buf = msg->buf; - if (i2c->status != STATUS_READ_IN_PROGRESS) { - len = msg->len; - buf = msg->buf; - } else { - len = i2c->rx_buf_len; - buf = i2c->rx_buf; - } - - rx_num = readl(i2c->base + IC_RXFLR); - - for (; len > 0 && rx_num > 0; len--, rx_num--) + while (len--) *buf++ = readl(i2c->base + IC_DATA_CMD); - - if (len > 0) { - i2c->status = STATUS_READ_IN_PROGRESS; - i2c->rx_buf_len = len; - i2c->rx_buf = buf; - } else - i2c->status = STATUS_READ_SUCCESS; + i2c->status = STATUS_READ_SUCCESS; return; } @@ -898,10 +897,8 @@ static irqreturn_t intel_mid_i2c_isr(int goto exit; } - if (stat & TX_EMPTY) { - if (readl(i2c->base + IC_STATUS) & 0x4) - i2c->status = STATUS_WRITE_SUCCESS; - } + if (stat & TX_EMPTY) + i2c->status = STATUS_WRITE_SUCCESS; exit: if (i2c->status == STATUS_READ_SUCCESS || _______________________________________________ MeeGo-kernel mailing list [email protected] http://lists.meego.com/listinfo/meego-kernel
