i2c: octeon: thunderx: Limit register access retries

Do not infinitely retry register readq and writeq operations
in order to not lock up the CPU in case the TWSI gets stuck.

Return -ETIMEDOUT in case of a failed data read. For all other
cases just return so subsequent operations will fail.

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
index 5e63b17..419b54b 100644 (file)
--- a/drivers/i2c/busses/i2c-octeon-core.c
+++ b/drivers/i2c/busses/i2c-octeon-core.c
@@ -381,7 +381,9 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
                if (result)
                        return result;
 
-               data[i] = octeon_i2c_data_read(i2c);
+               data[i] = octeon_i2c_data_read(i2c, &result);
+               if (result)
+                       return result;
                if (recv_len && i == 0) {
                        if (data[i] > I2C_SMBUS_BLOCK_MAX + 1)
                                return -EPROTO;

diff --git a/drivers/i2c/busses/i2c-octeon-core.h b/drivers/i2c/busses/i2c-octeon-core.h
index 87151ea..1db7c83 100644 (file)
--- a/drivers/i2c/busses/i2c-octeon-core.h
+++ b/drivers/i2c/busses/i2c-octeon-core.h
@@ -5,6 +5,7 @@
 #include <linux/i2c.h>
 #include <linux/i2c-smbus.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
 
@@ -144,9 +145,9 @@ static inline void octeon_i2c_reg_write(struct octeon_i2c *i2c, u64 eop_reg, u8
        u64 tmp;
 
        __raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI(i2c));
-       do {
-               tmp = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
-       } while ((tmp & SW_TWSI_V) != 0);
+
+       readq_poll_timeout(i2c->twsi_base + SW_TWSI(i2c), tmp, tmp & SW_TWSI_V,
+                          I2C_OCTEON_EVENT_WAIT, i2c->adap.timeout);
 }
 
 #define octeon_i2c_ctl_write(i2c, val)                                 \
@@ -163,24 +164,28 @@ static inline void octeon_i2c_reg_write(struct octeon_i2c *i2c, u64 eop_reg, u8
  *
  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
  */
-static inline u8 octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg)
+static inline int octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg,
+                                     int *error)
 {
        u64 tmp;
+       int ret;
 
        __raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI(i2c));
-       do {
-               tmp = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
-       } while ((tmp & SW_TWSI_V) != 0);
 
+       ret = readq_poll_timeout(i2c->twsi_base + SW_TWSI(i2c), tmp,
+                                tmp & SW_TWSI_V, I2C_OCTEON_EVENT_WAIT,
+                                i2c->adap.timeout);
+       if (error)
+               *error = ret;
        return tmp & 0xFF;
 }
 
 #define octeon_i2c_ctl_read(i2c)                                       \
-       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_CTL)
-#define octeon_i2c_data_read(i2c)                                      \
-       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_DATA)
+       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_CTL, NULL)
+#define octeon_i2c_data_read(i2c, error)                               \
+       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_DATA, error)
 #define octeon_i2c_stat_read(i2c)                                      \
-       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT)
+       octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT, NULL)
 
 /**
  * octeon_i2c_read_int - read the TWSI_INT register