From: Siva Durga Prasad Paladugu <[email protected]> This patch adds support for handling arbitration lost in case of multi master mode. When an arbitration lost is detected, it retries for 10 times before failing.
Signed-off-by: Siva Durga Prasad Paladugu <[email protected]> Signed-off-by: Michal Simek <[email protected]> --- drivers/i2c/i2c-cdns.c | 66 ++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 53 insertions(+), 13 deletions(-) diff --git a/drivers/i2c/i2c-cdns.c b/drivers/i2c/i2c-cdns.c index b391c0ba49b8..1af94d176145 100644 --- a/drivers/i2c/i2c-cdns.c +++ b/drivers/i2c/i2c-cdns.c @@ -80,6 +80,8 @@ struct cdns_i2c_regs { #define CDNS_I2C_BROKEN_HOLD_BIT BIT(0) +#define CDNS_I2C_ARB_LOST_MAX_RETRIES 10 + #ifdef DEBUG static void cdns_i2c_debug_status(struct cdns_i2c_regs *cdns_i2c) { @@ -234,11 +236,17 @@ static int cdns_i2c_set_bus_speed(struct udevice *dev, unsigned int speed) return 0; } +static inline u32 is_arbitration_lost(struct cdns_i2c_regs *regs) +{ + return (readl(®s->interrupt_status) & CDNS_I2C_INTERRUPT_ARBLOST); +} + static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, u32 len) { u8 *cur_data = data; struct cdns_i2c_regs *regs = i2c_bus->regs; + u32 ret; /* Set the controller in Master transmit mode and clear FIFO */ setbits_le32(®s->control, CDNS_I2C_CONTROL_CLR_FIFO); @@ -255,25 +263,38 @@ static int cdns_i2c_write_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, writel(addr, ®s->address); - while (len--) { + while (len-- && !is_arbitration_lost(regs)) { writel(*(cur_data++), ®s->data); if (readl(®s->transfer_size) == CDNS_I2C_FIFO_DEPTH) { - if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) { - /* Release the bus */ - clrbits_le32(®s->control, - CDNS_I2C_CONTROL_HOLD); - return -ETIMEDOUT; - } + ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP | + CDNS_I2C_INTERRUPT_ARBLOST); + if (ret & CDNS_I2C_INTERRUPT_ARBLOST) + return -EAGAIN; + if (ret & CDNS_I2C_INTERRUPT_COMP) + continue; + /* Release the bus */ + clrbits_le32(®s->control, + CDNS_I2C_CONTROL_HOLD); + return -ETIMEDOUT; } } + if (len && is_arbitration_lost(regs)) + return -EAGAIN; + /* All done... release the bus */ if (!i2c_bus->hold_flag) clrbits_le32(®s->control, CDNS_I2C_CONTROL_HOLD); /* Wait for the address and data to be sent */ - if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) + ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP | + CDNS_I2C_INTERRUPT_ARBLOST); + if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST | + CDNS_I2C_INTERRUPT_COMP))) return -ETIMEDOUT; + if (ret & CDNS_I2C_INTERRUPT_ARBLOST) + return -EAGAIN; + return 0; } @@ -289,6 +310,7 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, struct cdns_i2c_regs *regs = i2c_bus->regs; int curr_recv_count; int updatetx, hold_quirk; + u32 ret; /* Check the hardware can handle the requested bytes */ if ((recv_count < 0)) @@ -317,7 +339,7 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, hold_quirk = (i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx; - while (recv_count) { + while (recv_count && !is_arbitration_lost(regs)) { while (readl(®s->status) & CDNS_I2C_STATUS_RXDV) { if (recv_count < CDNS_I2C_FIFO_DEPTH && !i2c_bus->hold_flag) { @@ -366,8 +388,13 @@ static int cdns_i2c_read_data(struct i2c_cdns_bus *i2c_bus, u32 addr, u8 *data, } /* Wait for the address and data to be sent */ - if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) + ret = cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP | + CDNS_I2C_INTERRUPT_ARBLOST); + if (!(ret & (CDNS_I2C_INTERRUPT_ARBLOST | + CDNS_I2C_INTERRUPT_COMP))) return -ETIMEDOUT; + if (ret & CDNS_I2C_INTERRUPT_ARBLOST) + return -EAGAIN; return 0; } @@ -376,8 +403,11 @@ static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs) { struct i2c_cdns_bus *i2c_bus = dev_get_priv(dev); - int ret, count; + int ret = 0; + int count; bool hold_quirk; + struct i2c_msg *message = msg; + int num_msgs = nmsgs; hold_quirk = !!(i2c_bus->quirks & CDNS_I2C_BROKEN_HOLD_BIT); @@ -403,7 +433,8 @@ static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, } debug("i2c_xfer: %d messages\n", nmsgs); - for (; nmsgs > 0; nmsgs--, msg++) { + for (u8 retry = 0; retry < CDNS_I2C_ARB_LOST_MAX_RETRIES && + nmsgs > 0; nmsgs--, msg++) { debug("i2c_xfer: chip=0x%x, len=0x%x\n", msg->addr, msg->len); if (msg->flags & I2C_M_RD) { ret = cdns_i2c_read_data(i2c_bus, msg->addr, msg->buf, @@ -412,13 +443,22 @@ static int cdns_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, ret = cdns_i2c_write_data(i2c_bus, msg->addr, msg->buf, msg->len); } + if (ret == -EAGAIN) { + msg = message; + nmsgs = num_msgs; + retry++; + printf("%s,arbitration lost, retrying:%d\n", __func__, + retry); + continue; + } + if (ret) { debug("i2c_write: error sending\n"); return -EREMOTEIO; } } - return 0; + return ret; } static int cdns_i2c_ofdata_to_platdata(struct udevice *dev) -- 1.9.1 _______________________________________________ U-Boot mailing list [email protected] https://lists.denx.de/listinfo/u-boot
