Messages in this thread | | | From | Andy Shevchenko <> | Date | Wed, 30 May 2018 03:08:02 +0300 | Subject | Re: [PATCH v7 5/7] drivers/i2c: Add transfer implementation for FSI algorithm |
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On Wed, May 30, 2018 at 1:24 AM, Eddie James <eajames@linux.vnet.ibm.com> wrote: > 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.
> + if (msg->flags & I2C_M_RD) > + cmd |= I2C_CMD_READ;
I think we have a helper for this, though not sure.
> +static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, > + u8 fifo_count) > +{ > + int write;
> + int rc = 0;
Redundant assignment.
> + 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;
_write = min(_write, _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;
write = min_t(int, 4, rounddown_pow_of_two(bytes_to_write));
Also check it carefully, it might be optimized even more, though I didn't think much.
> + }
> + return rc;
How it can be non-zero?
> +}
> + > +static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, > + u8 fifo_count) > +{ > + int read;
> + int rc = 0;
Redundant assignment.
> + 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;
See above for write case and do in similar way.
> + > + if (xfr_remaining) {
> + if (xfr_remaining < read) > + read = xfr_remaining;
read = min(read, _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;
How non-zero possible here?
> +}
> + if (port->xfrd < msg->len) > + rc = -ENODATA; > + else > + rc = msg->len; > + > + return rc;
if (...) return -ENODATA; return msg->len; ?
> + u32 status = 0;
Redundant assignment.
> + return -ETIME;
ETIMEDOUT ?
-- With Best Regards, Andy Shevchenko
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