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| author | Eddie James <eajames@linux.vnet.ibm.com> | 2018-07-17 18:31:02 +0300 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2018-07-21 01:07:08 +0300 |
| commit | 6cdf5e397a0b863fcc3f703c7619e628a63664ee (patch) | |
| tree | da238f5a1735a8a4534bb4546ad43ba36ead4cf9 /drivers/i2c | |
| parent | 19b4887af7155a224b7d07301463ea32349b9965 (diff) | |
| download | linux-6cdf5e397a0b863fcc3f703c7619e628a63664ee.tar.xz | |
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: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-fsi.c | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-fsi.c b/drivers/i2c/busses/i2c-fsi.c index 1d9e9bf60a9e..0f0bc888e194 100644 --- a/drivers/i2c/busses/i2c-fsi.c +++ b/drivers/i2c/busses/i2c-fsi.c @@ -12,10 +12,12 @@ #include <linux/bitfield.h> #include <linux/bitops.h> +#include <linux/delay.h> #include <linux/device.h> #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> @@ -128,6 +130,20 @@ #define I2C_ESTAT_SELF_BUSY BIT(6) #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_device *fsi; u8 fifo_size; @@ -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); } +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, int num) { |