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authorEddie James <eajames@linux.vnet.ibm.com>2018-07-17 10:31:02 -0500
committerWolfram Sang <wsa@the-dreams.de>2018-07-21 00:07:08 +0200
commit6cdf5e397a0b863fcc3f703c7619e628a63664ee (patch)
treeda238f5a1735a8a4534bb4546ad43ba36ead4cf9 /drivers/i2c/busses
parent19b4887af7155a224b7d07301463ea32349b9965 (diff)
downloadlinux-stericsson-6cdf5e397a0b863fcc3f703c7619e628a63664ee.tar.gz
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/busses')
-rw-r--r--drivers/i2c/busses/i2c-fsi.c91
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)
{