From: "Edward A. James" <eajames@xxxxxxxxxx> 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@xxxxxxxxxx> --- drivers/i2c/busses/i2c-fsi.c | 197 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 195 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 4b52147..f86595b 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -13,10 +13,12 @@ #include <linux/errno.h> #include <linux/fsi.h> #include <linux/i2c.h> +#include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/sched.h> #define FSI_ENGID_I2C 0x7 @@ -140,6 +142,7 @@ 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, @@ -224,17 +227,207 @@ 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; + } + + return 0; +} + +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 -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