Commit 504b8277 authored by Eddie James's avatar Eddie James Committed by Wolfram Sang

i2c: fsi: Add transfer implementation

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: default avatarEddie James <eajames@linux.vnet.ibm.com>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 6cdf5e39
...@@ -155,6 +155,7 @@ struct fsi_i2c_port { ...@@ -155,6 +155,7 @@ struct fsi_i2c_port {
struct i2c_adapter adapter; struct i2c_adapter adapter;
struct fsi_i2c_master *master; struct fsi_i2c_master *master;
u16 port; u16 port;
u16 xfrd;
}; };
static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg, static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg,
...@@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) ...@@ -230,6 +231,99 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port)
return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy); 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);
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)
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;
}
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;
}
return 0;
}
static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port) static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port)
{ {
int rc; int rc;
...@@ -305,17 +399,114 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) ...@@ -305,17 +399,114 @@ static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status)
return -ETIMEDOUT; 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, static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num) int num)
{ {
int rc; int i, rc;
unsigned long start_time;
struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_port *port = adap->algo_data;
struct i2c_msg *msg;
rc = fsi_i2c_set_port(port); rc = fsi_i2c_set_port(port);
if (rc) if (rc)
return 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 num;
} }
static u32 fsi_i2c_functionality(struct i2c_adapter *adap) static u32 fsi_i2c_functionality(struct i2c_adapter *adap)
......
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