On 06/04/2018 02:14 PM, Andy Shevchenko wrote:
On Mon, Jun 4, 2018 at 10:00 PM, Eddie James <eaja...@linux.vnet.ibm.com> wrote:Execute I2C transfers from the FSI-attached I2C master. Use polling instead of interrupts as we have no hardware IRQ over FSI. Signed-off-by: Eddie James <eaja...@linux.vnet.ibm.com> --- drivers/i2c/busses/i2c-fsi.c | 195 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 193 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 101b9c5..4e5964e 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -150,6 +150,7 @@ struct fsi_i2c_port { struct i2c_adapter adapter; struct fsi_i2c_master *master; u16 port; + u16 xfrd; }; static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg, @@ -225,6 +226,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy); } +static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg, + bool stop) +{ + struct fsi_i2c_master *i2c = port->master; + u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR; + + port->xfrd = 0; + + if (msg->flags & I2C_M_RD) + cmd |= I2C_CMD_READ; + + if (stop || msg->flags & I2C_M_STOP) + cmd |= I2C_CMD_WITH_STOP; + + cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr >> 1);Did you consider to unify READ + ADDR as ADDR_8BIT?
Yes, however the result from the i2c_8bit_addr_from_msg function is not equivalent. This hardware expects the 8-bit address to be concatenated with the read/not write bit. Also the function returns a u8, which won't work for addresses with bit 7 set, since it left-shifts by one.
+ cmd |= FIELD_PREP(I2C_CMD_LEN, msg->len); + + return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd); +} + +static int fsi_i2c_get_op_bytes(int op_bytes) +{ + /* fsi is limited to max 4 byte aligned ops */ + if (op_bytes > 4) + return 4; + else if (op_bytes == 3)Since you dropped one of 'else', another also is not needed.
True.
+ return 2; + return op_bytes; +} + +static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, + u8 fifo_count) +{ + int write; + int rc; + struct fsi_i2c_master *i2c = port->master; + int bytes_to_write = i2c->fifo_size - fifo_count; + int bytes_remaining = msg->len - port->xfrd; + + bytes_to_write = min(bytes_to_write, bytes_remaining); + + while (bytes_to_write) { + write = fsi_i2c_get_op_bytes(bytes_to_write); + + rc = fsi_device_write(i2c->fsi, I2C_FSI_FIFO, + &msg->buf[port->xfrd], write); + if (rc) + return rc; + + port->xfrd += write; + bytes_to_write -= write; + }Just to be sure, if by some reason write == 0 in the loop for a while, would it become infinite loop?
It's not possible that write == 0. Same for read below. Thanks, Eddie
+ + return 0; +} + +static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, + u8 fifo_count) +{ + int read; + int rc; + struct fsi_i2c_master *i2c = port->master; + int bytes_to_read; + int xfr_remaining = msg->len - port->xfrd; + u32 dummy; + + bytes_to_read = min_t(int, fifo_count, xfr_remaining); + + while (bytes_to_read) { + read = fsi_i2c_get_op_bytes(bytes_to_read); + + if (xfr_remaining) { + rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, + &msg->buf[port->xfrd], read); + if (rc) + return rc; + + port->xfrd += read; + xfr_remaining -= read; + } else { + /* no more buffer but data in fifo, need to clear it */ + rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &dummy, + read); + if (rc) + return rc; + } + + bytes_to_read -= read; + }Ditto for read == 0.+ + return 0; +} + static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c) { int i, rc; @@ -388,17 +482,114 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) return -ETIMEDOUT; } +static int fsi_i2c_handle_status(struct fsi_i2c_port *port, + struct i2c_msg *msg, u32 status) +{ + int rc; + u8 fifo_count; + + if (status & I2C_STAT_ERR) { + rc = fsi_i2c_abort(port, status); + if (rc) + return rc; + + if (status & I2C_STAT_INV_CMD) + return -EINVAL; + + if (status & (I2C_STAT_PARITY | I2C_STAT_BE_OVERRUN | + I2C_STAT_BE_ACCESS)) + return -EPROTO; + + if (status & I2C_STAT_NACK) + return -ENXIO; + + if (status & I2C_STAT_LOST_ARB) + return -EAGAIN; + + if (status & I2C_STAT_STOP_ERR) + return -EBADMSG; + + return -EIO; + } + + if (status & I2C_STAT_DAT_REQ) { + fifo_count = FIELD_GET(I2C_STAT_FIFO_COUNT, status); + + if (msg->flags & I2C_M_RD) + return fsi_i2c_read_fifo(port, msg, fifo_count); + + return fsi_i2c_write_fifo(port, msg, fifo_count); + } + + if (status & I2C_STAT_CMD_COMP) { + if (port->xfrd < msg->len) + return -ENODATA; + + return msg->len; + } + + return 0; +} + +static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg, + unsigned long timeout) +{ + u32 status = 0; + int rc; + unsigned long start = jiffies; + + do { + rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT, + &status); + if (rc) + return rc; + + if (status & I2C_STAT_ANY_RESP) { + rc = fsi_i2c_handle_status(port, msg, status); + if (rc < 0) + return rc; + + /* cmd complete and all data xfrd */ + if (rc == msg->len) + return 0; + + /* need to xfr more data, but maybe don't need wait */ + continue; + } + + usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US); + } while (time_after(start + timeout, jiffies)); + + return -ETIMEDOUT; +} + static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { - int rc; + int i, rc; + unsigned long start_time; struct fsi_i2c_port *port = adap->algo_data; + struct i2c_msg *msg; rc = fsi_i2c_set_port(port); if (rc) return rc; - return -EOPNOTSUPP; + for (i = 0; i < num; i++) { + msg = msgs + i; + start_time = jiffies; + + rc = fsi_i2c_start(port, msg, i == num - 1); + if (rc) + return rc; + + rc = fsi_i2c_wait(port, msg, + adap->timeout - (jiffies - start_time)); + if (rc) + return rc; + } + + return 0; } static u32 fsi_i2c_functionality(struct i2c_adapter *adap) -- 1.8.3.1
