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i2c: i2c_cdns: Add support for handling arbitration lost

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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 <siva.durga.paladugu@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
This commit is contained in:
Siva Durga Prasad Paladugu 2019-03-07 11:52:49 +01:00 • committed by Heiko Schocher
parent 006265d063
commit bc00512438
1 changed files with 53 additions and 13 deletions

66
drivers/i2c/i2c-cdns.c
View file

@ -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(&regs->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(&regs->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, &regs->address);
while (len--) {
while (len-- && !is_arbitration_lost(regs)) {
writel(*(cur_data++), &regs->data);
if (readl(&regs->transfer_size) == CDNS_I2C_FIFO_DEPTH) {
if (!cdns_i2c_wait(regs, CDNS_I2C_INTERRUPT_COMP)) {
/* Release the bus */
clrbits_le32(&regs->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(&regs->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(&regs->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(&regs->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)