Commit 6cdf5e39 authored by Eddie James's avatar Eddie James Committed by Wolfram Sang

i2c: fsi: Add abort and hardware reset procedures

Add abort procedure for failed transfers. Add engine reset procedure
that is executed during the abort to recover from various fault
conditions.
Signed-off-by: default avatarEddie James <eajames@linux.vnet.ibm.com>
Tested-by: default avatarJoel Stanley <joel@jms.id.au>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 19b4887a
...@@ -12,10 +12,12 @@ ...@@ -12,10 +12,12 @@
#include <linux/bitfield.h> #include <linux/bitfield.h>
#include <linux/bitops.h> #include <linux/bitops.h>
#include <linux/delay.h>
#include <linux/device.h> #include <linux/device.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/fsi.h> #include <linux/fsi.h>
#include <linux/i2c.h> #include <linux/i2c.h>
#include <linux/jiffies.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/list.h> #include <linux/list.h>
#include <linux/module.h> #include <linux/module.h>
...@@ -128,6 +130,20 @@ ...@@ -128,6 +130,20 @@
#define I2C_ESTAT_SELF_BUSY BIT(6) #define I2C_ESTAT_SELF_BUSY BIT(6)
#define I2C_ESTAT_VERSION GENMASK(4, 0) #define I2C_ESTAT_VERSION GENMASK(4, 0)
/* port busy register */
#define I2C_PORT_BUSY_RESET BIT(31)
/* wait for command complete or data request */
#define I2C_CMD_SLEEP_MAX_US 500
#define I2C_CMD_SLEEP_MIN_US 50
/* wait after reset; choose time from legacy driver */
#define I2C_RESET_SLEEP_MAX_US 2000
#define I2C_RESET_SLEEP_MIN_US 1000
/* choose timeout length from legacy driver; it's well tested */
#define I2C_ABORT_TIMEOUT msecs_to_jiffies(100)
struct fsi_i2c_master { struct fsi_i2c_master {
struct fsi_device *fsi; struct fsi_device *fsi;
u8 fifo_size; u8 fifo_size;
...@@ -214,6 +230,81 @@ static int fsi_i2c_set_port(struct fsi_i2c_port *port) ...@@ -214,6 +230,81 @@ 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_reset_engine(struct fsi_i2c_master *i2c, u16 port)
{
int rc;
u32 mode, dummy = 0;
/* reset engine */
rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy);
if (rc)
return rc;
/* re-init engine */
rc = fsi_i2c_dev_init(i2c);
if (rc)
return rc;
rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode);
if (rc)
return rc;
/* set port; default after reset is 0 */
if (port) {
mode &= ~I2C_MODE_PORT;
mode |= FIELD_PREP(I2C_MODE_PORT, port);
rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode);
if (rc)
return rc;
}
/* reset busy register; hw workaround */
dummy = I2C_PORT_BUSY_RESET;
rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_PORT_BUSY, &dummy);
if (rc)
return rc;
return 0;
}
static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status)
{
int rc;
unsigned long start;
u32 cmd = I2C_CMD_WITH_STOP;
struct fsi_i2c_master *i2c = port->master;
struct fsi_device *fsi = i2c->fsi;
rc = fsi_i2c_reset_engine(i2c, port->port);
if (rc)
return rc;
/* skip final stop command for these errors */
if (status & (I2C_STAT_PARITY | I2C_STAT_LOST_ARB | I2C_STAT_STOP_ERR))
return 0;
/* write stop command */
rc = fsi_i2c_write_reg(fsi, I2C_FSI_CMD, &cmd);
if (rc)
return rc;
/* wait until we see command complete in the master */
start = jiffies;
do {
rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &status);
if (rc)
return rc;
if (status & I2C_STAT_CMD_COMP)
return 0;
usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US);
} while (time_after(start + I2C_ABORT_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)
{ {
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment