| Message ID | 1507840944-421-1-git-send-email-eajames@linux.vnet.ibm.com |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [linux,dev-4.10] drivers: i2c: fsi: Add proper abort method | expand |
On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: > > From: "Edward A. James" <eajames@us.ibm.com> > > Driver wasn't cleaning up on timeout or in an error situation properly. > Need to do a full reset if we fail in order to re-stablish a good state > of the engine. Was there a particular use-case that triggered this behaviour or was this just found in general use? I feel a bit more context would be helpful here. It's a fairly sizeable patch and I'm surprised recovery was overlooked initially. Cheers, Andrew
On 10/13/2017 01:18 AM, Andrew Jeffery wrote: > On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: >>> From: "Edward A. James" <eajames@us.ibm.com> >> >> Driver wasn't cleaning up on timeout or in an error situation properly. >> Need to do a full reset if we fail in order to re-stablish a good state >> of the engine. > Was there a particular use-case that triggered this behaviour or was this just > found in general use? I feel a bit more context would be helpful here. It's a > fairly sizeable patch and I'm surprised recovery was overlooked initially. You'd have to hit either a timeout or some non-NACK error condition in order to trigger the problem. Somehow NACK doesn't cause the I2C engine to get into a bad state. And timeouts it seems to be somewhat intermittent. Probably depends what state the bus is in when the driver actually bails out. Thanks, Eddie > > Cheers, > > Andrew
On Fri, 2017-10-13 at 10:20 -0500, Eddie James wrote: > > On 10/13/2017 01:18 AM, Andrew Jeffery wrote: > > On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: > > > > From: "Edward A. James" <eajames@us.ibm.com> > > > > > > > > > Driver wasn't cleaning up on timeout or in an error situation properly. > > > Need to do a full reset if we fail in order to re-stablish a good state > > > of the engine. > > > > Was there a particular use-case that triggered this behaviour or was this just > > found in general use? I feel a bit more context would be helpful here. It's a > > fairly sizeable patch and I'm surprised recovery was overlooked initially. > > You'd have to hit either a timeout or some non-NACK error condition in > order to trigger the problem. Somehow NACK doesn't cause the I2C engine > to get into a bad state. And timeouts it seems to be somewhat > intermittent. Probably depends what state the bus is in when the driver > actually bails out. I asked off-list about finding someone to provide at least a Tested-by (and I'm hoping for a Reviewed-by) tag, did we get anyone? Cheers, Andrew
On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: > From: "Edward A. James" <eajames@us.ibm.com> > > Driver wasn't cleaning up on timeout or in an error situation properly. > Need to do a full reset if we fail in order to re-stablish a good state > of the engine. > > Signed-off-by: Edward A. James <eajames@us.ibm.com> > --- > drivers/i2c/busses/i2c-fsi.c | 259 +++++++++++++++++++++++++++++++------------ > 1 file changed, 191 insertions(+), 68 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c > index 1af9c01..6c582d8 100644 > --- a/drivers/i2c/busses/i2c-fsi.c > +++ b/drivers/i2c/busses/i2c-fsi.c > @@ -133,6 +133,11 @@ > #define I2C_ESTAT_SELF_BUSY 0x00000040 > #define I2C_ESTAT_VERSION 0x0000001f > > +#define I2C_PORT_BUSY_RESET 0x80000000 > + > +#define I2C_LOCAL_WAIT_TIMEOUT 2 /* jiffies */ > +#define I2C_ABORT_TIMEOUT msecs_to_jiffies(100) > + > struct fsi_i2c_master { > struct fsi_device *fsi; > u8 fifo_size; > @@ -351,22 +356,185 @@ static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, > return rc; > } > > +static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c) > +{ > + int i, rc; > + u32 mode, dummy = 0; > + > + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); > + if (rc) > + return rc; > + > + mode |= I2C_MODE_DIAG; > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); > + if (rc) > + return rc; > + > + for (i = 0; i < 9; ++i) { > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); > + if (rc) > + return rc; > + > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); > + if (rc) > + return rc; > + } > + > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); > + if (rc) > + return rc; > + > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); > + if (rc) > + return rc; > + > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); > + if (rc) > + return rc; > + > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); > + if (rc) > + return rc; > + > + mode &= ~I2C_MODE_DIAG; > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); > + > + return rc; > +} > + > +static int fsi_i2c_reset(struct fsi_i2c_master *i2c, u16 port) > +{ > + int rc; > + u32 mode, stat, 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 = SETFIELD(I2C_MODE_PORT, mode, 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; > + > + /* force bus reset */ > + rc = fsi_i2c_reset_bus(i2c); > + if (rc) > + return rc; > + > + /* reset errors */ > + dummy = 0; > + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); > + if (rc) > + return rc; > + > + /* wait for command complete */ > + set_current_state(TASK_INTERRUPTIBLE); > + schedule_timeout(I2C_LOCAL_WAIT_TIMEOUT); Shouldn't we use the uninterruptible state to ensure we get at least I2C_LOCAL_WAIT_TIMEOUT in the face of signals? Andrew
On 10/20/2017 12:15 AM, Andrew Jeffery wrote: > On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: >> From: "Edward A. James" <eajames@us.ibm.com> >> >> Driver wasn't cleaning up on timeout or in an error situation properly. >> Need to do a full reset if we fail in order to re-stablish a good state >> of the engine. >> >> Signed-off-by: Edward A. James <eajames@us.ibm.com> >> --- >> drivers/i2c/busses/i2c-fsi.c | 259 +++++++++++++++++++++++++++++++------------ >> 1 file changed, 191 insertions(+), 68 deletions(-) >> >> diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c >> index 1af9c01..6c582d8 100644 >> --- a/drivers/i2c/busses/i2c-fsi.c >> +++ b/drivers/i2c/busses/i2c-fsi.c >> @@ -133,6 +133,11 @@ >> #define I2C_ESTAT_SELF_BUSY 0x00000040 >> #define I2C_ESTAT_VERSION 0x0000001f >> >> +#define I2C_PORT_BUSY_RESET 0x80000000 >> + >> +#define I2C_LOCAL_WAIT_TIMEOUT 2 /* jiffies */ >> +#define I2C_ABORT_TIMEOUT msecs_to_jiffies(100) >> + >> struct fsi_i2c_master { >> struct fsi_device *fsi; >> u8 fifo_size; >> @@ -351,22 +356,185 @@ static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, >> return rc; >> } >> >> +static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c) >> +{ >> + int i, rc; >> + u32 mode, dummy = 0; >> + >> + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); >> + if (rc) >> + return rc; >> + >> + mode |= I2C_MODE_DIAG; >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); >> + if (rc) >> + return rc; >> + >> + for (i = 0; i < 9; ++i) { >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); >> + if (rc) >> + return rc; >> + >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); >> + if (rc) >> + return rc; >> + } >> + >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); >> + if (rc) >> + return rc; >> + >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); >> + if (rc) >> + return rc; >> + >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); >> + if (rc) >> + return rc; >> + >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); >> + if (rc) >> + return rc; >> + >> + mode &= ~I2C_MODE_DIAG; >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); >> + >> + return rc; >> +} >> + >> +static int fsi_i2c_reset(struct fsi_i2c_master *i2c, u16 port) >> +{ >> + int rc; >> + u32 mode, stat, 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 = SETFIELD(I2C_MODE_PORT, mode, 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; >> + >> + /* force bus reset */ >> + rc = fsi_i2c_reset_bus(i2c); >> + if (rc) >> + return rc; >> + >> + /* reset errors */ >> + dummy = 0; >> + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); >> + if (rc) >> + return rc; >> + >> + /* wait for command complete */ >> + set_current_state(TASK_INTERRUPTIBLE); >> + schedule_timeout(I2C_LOCAL_WAIT_TIMEOUT); > Shouldn't we use the uninterruptible state to ensure we get at least > I2C_LOCAL_WAIT_TIMEOUT in the face of signals? Good point, I'll switch that. Thanks! Eddie > > Andrew
On 10/19/2017 11:45 PM, Andrew Jeffery wrote: > On Fri, 2017-10-13 at 10:20 -0500, Eddie James wrote: >> On 10/13/2017 01:18 AM, Andrew Jeffery wrote: >>> On Thu, 2017-10-12 at 15:42 -0500, Eddie James wrote: >>>>> From: "Edward A. James" <eajames@us.ibm.com> >>>> >>>> Driver wasn't cleaning up on timeout or in an error situation properly. >>>> Need to do a full reset if we fail in order to re-stablish a good state >>>> of the engine. >>> Was there a particular use-case that triggered this behaviour or was this just >>> found in general use? I feel a bit more context would be helpful here. It's a >>> fairly sizeable patch and I'm surprised recovery was overlooked initially. >> You'd have to hit either a timeout or some non-NACK error condition in >> order to trigger the problem. Somehow NACK doesn't cause the I2C engine >> to get into a bad state. And timeouts it seems to be somewhat >> intermittent. Probably depends what state the bus is in when the driver >> actually bails out. > I asked off-list about finding someone to provide at least a Tested-by > (and I'm hoping for a Reviewed-by) tag, did we get anyone? Sivas ran it through the usual suite of power-on and reboot tests, but I'm not sure how extensively the i2c path is exercised there. I can ask him to add Tested-by when he returns from vacation. Eddie > > Cheers, > > Andrew
diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 1af9c01..6c582d8 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -133,6 +133,11 @@ #define I2C_ESTAT_SELF_BUSY 0x00000040 #define I2C_ESTAT_VERSION 0x0000001f +#define I2C_PORT_BUSY_RESET 0x80000000 + +#define I2C_LOCAL_WAIT_TIMEOUT 2 /* jiffies */ +#define I2C_ABORT_TIMEOUT msecs_to_jiffies(100) + struct fsi_i2c_master { struct fsi_device *fsi; u8 fifo_size; @@ -351,22 +356,185 @@ static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, return rc; } +static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c) +{ + int i, rc; + u32 mode, dummy = 0; + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + mode |= I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + if (rc) + return rc; + + for (i = 0; i < 9; ++i) { + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + } + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); + if (rc) + return rc; + + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); + if (rc) + return rc; + + mode &= ~I2C_MODE_DIAG; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); + + return rc; +} + +static int fsi_i2c_reset(struct fsi_i2c_master *i2c, u16 port) +{ + int rc; + u32 mode, stat, 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 = SETFIELD(I2C_MODE_PORT, mode, 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; + + /* force bus reset */ + rc = fsi_i2c_reset_bus(i2c); + if (rc) + return rc; + + /* reset errors */ + dummy = 0; + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); + if (rc) + return rc; + + /* wait for command complete */ + set_current_state(TASK_INTERRUPTIBLE); + schedule_timeout(I2C_LOCAL_WAIT_TIMEOUT); + + rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); + if (rc) + return rc; + + if (stat & I2C_STAT_CMD_COMP) + return 0; + + /* failed to get command complete; reset engine again */ + rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + if (rc) + return rc; + + /* re-init engine again */ + rc = fsi_i2c_dev_init(i2c); + 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_device *fsi = port->master->fsi; + + rc = fsi_i2c_reset(port->master, 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; + + rc = fsi_i2c_write_reg(fsi, I2C_FSI_CMD, &cmd); + if (rc) + return rc; + + 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; + + set_current_state(TASK_INTERRUPTIBLE); + if (schedule_timeout(I2C_LOCAL_WAIT_TIMEOUT) > 0) + return -EINTR; + + } while (time_after(start + I2C_ABORT_TIMEOUT, jiffies)); + + return -ETIME; +} + 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); + 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 -EFAULT; + if (status & I2C_STAT_LOST_ARB) + return -ECANCELED; + + if (status & I2C_STAT_STOP_ERR) + return -EBADMSG; + return -EIO; } @@ -396,9 +564,9 @@ static int fsi_i2c_handle_status(struct fsi_i2c_port *port, 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; + int rc, rc_abort; + unsigned long start = jiffies; do { rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT, @@ -419,13 +587,21 @@ static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg, continue; } - set_current_state(TASK_UNINTERRUPTIBLE); - schedule_timeout(local_timeout); - timeout = (timeout < local_timeout) ? 0 : - timeout - local_timeout; - } while (timeout); + set_current_state(TASK_INTERRUPTIBLE); + if (schedule_timeout(I2C_LOCAL_WAIT_TIMEOUT) > 0) { + rc = -EINTR; + goto abort; + } + } while (time_after(start + timeout, jiffies)); - return -ETIME; + rc = -ETIME; + +abort: + rc_abort = fsi_i2c_abort(port, status); + if (rc_abort) + return rc_abort; + + return rc; } static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, @@ -469,72 +645,19 @@ static u32 fsi_i2c_functionality(struct i2c_adapter *adap) | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA; } -static int fsi_i2c_low_level_recover_bus(struct fsi_i2c_master *i2c) -{ - int i, rc; - u32 mode, dummy = 0; - - rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); - if (rc) - return rc; - - mode |= I2C_MODE_DIAG; - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); - if (rc) - return rc; - - for (i = 0; i < 9; ++i) { - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); - if (rc) - return rc; - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); - if (rc) - return rc; - } - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); - if (rc) - return rc; - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); - if (rc) - return rc; - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); - if (rc) - return rc; - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); - if (rc) - return rc; - - mode &= ~I2C_MODE_DIAG; - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); - - return rc; -} - static int fsi_i2c_recover_bus(struct i2c_adapter *adap) { int rc; - u32 dummy = 0; struct fsi_i2c_port *port = adap->algo_data; - struct fsi_i2c_master *i2c = port->master; + struct fsi_i2c_master *master = port->master; - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); + rc = fsi_i2c_lock_master(master, adap->timeout); if (rc) return rc; - rc = fsi_i2c_dev_init(i2c); - if (rc) - return rc; + rc = fsi_i2c_reset(master, port->port); - rc = fsi_i2c_low_level_recover_bus(i2c); - if (rc) - return rc; - - rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); + fsi_i2c_unlock_master(master); return rc; }