| From patchwork Wed May 10 15:52:39 2017 |
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| Subject: [linux, dev-4.10, v2, |
| 3/6] drivers: i2c: Add transfer implementation for FSI algorithm |
| From: eajames@linux.vnet.ibm.com |
| X-Patchwork-Id: 760702 |
| Message-Id: <1494431562-25101-4-git-send-email-eajames@linux.vnet.ibm.com> |
| To: openbmc@lists.ozlabs.org |
| Cc: "Edward A. James" <eajames@us.ibm.com>, cbostic@linux.vnet.ibm.com |
| Date: Wed, 10 May 2017 10:52:39 -0500 |
| |
| From: "Edward A. James" <eajames@us.ibm.com> |
| |
| 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: Edward A. James <eajames@us.ibm.com> |
| --- |
| drivers/i2c/busses/i2c-fsi.c | 193 ++++++++++++++++++++++++++++++++++++++++++- |
| 1 file changed, 191 insertions(+), 2 deletions(-) |
| |
| diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c |
| index cdebc99..f690b16 100644 |
| --- a/drivers/i2c/busses/i2c-fsi.c |
| +++ b/drivers/i2c/busses/i2c-fsi.c |
| @@ -143,6 +143,7 @@ struct fsi_i2c_port { |
| struct i2c_adapter adapter; |
| struct fsi_i2c_master *master; |
| u16 port; |
| + u16 xfrd; |
| }; |
| |
| static DEFINE_IDA(fsi_i2c_ida); |
| @@ -229,17 +230,205 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) |
| return rc; |
| } |
| |
| +static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg, |
| + bool stop) |
| +{ |
| + int rc; |
| + 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 = SETFIELD(I2C_CMD_ADDR, cmd, msg->addr >> 1); |
| + cmd = SETFIELD(I2C_CMD_LEN, cmd, msg->len); |
| + |
| + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd); |
| + |
| + return rc; |
| +} |
| + |
| +static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, |
| + u8 fifo_count) |
| +{ |
| + int write; |
| + int rc = 0; |
| + struct fsi_i2c_master *i2c = port->master; |
| + int bytes_to_write = i2c->fifo_size - fifo_count; |
| + int bytes_remaining = msg->len - port->xfrd; |
| + |
| + if (bytes_to_write > bytes_remaining) |
| + bytes_to_write = bytes_remaining; |
| + |
| + while (bytes_to_write > 0) { |
| + write = bytes_to_write; |
| + /* fsi limited to max 4 byte aligned ops */ |
| + if (bytes_to_write > 4) |
| + write = 4; |
| + else if (write == 3) |
| + write = 2; |
| + |
| + 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; |
| + } |
| + |
| + return rc; |
| +} |
| + |
| +static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, |
| + u8 fifo_count) |
| +{ |
| + int read; |
| + int rc = 0; |
| + struct fsi_i2c_master *i2c = port->master; |
| + int xfr_remaining = msg->len - port->xfrd; |
| + u32 dummy; |
| + |
| + while (fifo_count) { |
| + read = fifo_count; |
| + /* fsi limited to max 4 byte aligned ops */ |
| + if (fifo_count > 4) |
| + read = 4; |
| + else if (read == 3) |
| + read = 2; |
| + |
| + if (xfr_remaining) { |
| + if (xfr_remaining < read) |
| + read = 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; |
| + } |
| + |
| + fifo_count -= read; |
| + } |
| + |
| + return rc; |
| +} |
| + |
| +static int fsi_i2c_handle_status(struct fsi_i2c_port *port, |
| + struct i2c_msg *msg, u32 status) |
| +{ |
| + int rc; |
| + u8 fifo_count; |
| + struct fsi_i2c_master *i2c = port->master; |
| + u32 dummy = 0; |
| + |
| + if (status & I2C_STAT_ERR) { |
| + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); |
| + if (rc) |
| + return rc; |
| + |
| + if (status & I2C_STAT_NACK) |
| + return -EFAULT; |
| + |
| + return -EIO; |
| + } |
| + |
| + if (status & I2C_STAT_DAT_REQ) { |
| + fifo_count = GETFIELD(I2C_STAT_FIFO_COUNT, status); |
| + |
| + if (msg->flags & I2C_M_RD) |
| + rc = fsi_i2c_read_fifo(port, msg, fifo_count); |
| + else |
| + rc = fsi_i2c_write_fifo(port, msg, fifo_count); |
| + |
| + return rc; |
| + } |
| + |
| + if (status & I2C_STAT_CMD_COMP) { |
| + if (port->xfrd < msg->len) |
| + rc = -ENODATA; |
| + else |
| + rc = msg->len; |
| + } |
| + |
| + return rc; |
| +} |
| + |
| +static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg, |
| + unsigned long timeout) |
| +{ |
| + const unsigned long local_timeout = 2; /* jiffies */ |
| + u32 status = 0; |
| + int rc; |
| + |
| + 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; |
| + } |
| + |
| + set_current_state(TASK_UNINTERRUPTIBLE); |
| + schedule_timeout(local_timeout); |
| + timeout = (timeout < local_timeout) ? 0 : |
| + timeout - local_timeout; |
| + } while (timeout); |
| + |
| + return -ETIME; |
| +} |
| + |
| 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 -ENOSYS; |
| + 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) |