Revert "i2c: octeon: thunderx: Limit register access retries"

This reverts commit 70121f7f3725 ("i2c: octeon: thunderx: Limit register access retries").
Using readq_poll_timeout instead of __raw_readq triggers the following
debug warning:

[   78.871568] ipmi_ssif: Trying hotmod-specified SSIF interface at i2c address 0x12, adapter Cavium ThunderX i2c adapter at 0000:01:09.4, slave address 0x0
[   78.886107] do not call blocking ops when !TASK_RUNNING; state=2 set at [<fffffc00080e0088>] prepare_to_wait_event+0x58/0x10c
[   78.897436] ------------[ cut here ]------------
[   78.902050] WARNING: CPU: 6 PID: 2235 at kernel/sched/core.c:7718 __might_sleep+0x80/0x88

[...]

[   79.133553] [<fffffc00080c3aac>] __might_sleep+0x80/0x88
[   79.138862] [<fffffc0000e30138>] octeon_i2c_test_iflg+0x4c/0xbc [i2c_thunderx]
[   79.146077] [<fffffc0000e30958>] octeon_i2c_test_ready+0x18/0x70 [i2c_thunderx]
[   79.153379] [<fffffc0000e30b04>] octeon_i2c_wait+0x154/0x1a4 [i2c_thunderx]
[   79.160334] [<fffffc0000e310bc>] octeon_i2c_xfer+0xf4/0xf60 [i2c_thunderx]

Signed-off-by: Jan Glauber <jglauber@cavium.com>
Acked-by: Steven J. Hill <steven.hill@cavium.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/i2c-octeon-core.c

@@ -381,9 +381,7 @@ static int octeon_i2c_read(struct octeon_i2c *i2c, int target,
 		if (result)
 			return result;
 
-		data[i] = octeon_i2c_data_read(i2c, &result);
-		if (result)
-			return result;
+		data[i] = octeon_i2c_data_read(i2c);
 		if (recv_len && i == 0) {
 			if (data[i] > I2C_SMBUS_BLOCK_MAX + 1)
 				return -EPROTO;

drivers/i2c/busses/i2c-octeon-core.h

@@ -5,7 +5,6 @@
 #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>
 
@@ -145,9 +144,9 @@ 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));
-
-	readq_poll_timeout(i2c->twsi_base + SW_TWSI(i2c), tmp, tmp & SW_TWSI_V,
-			   I2C_OCTEON_EVENT_WAIT, i2c->adap.timeout);
+	do {
+		tmp = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
+	} while ((tmp & SW_TWSI_V) != 0);
 }
 
 #define octeon_i2c_ctl_write(i2c, val)					\
@@ -164,28 +163,24 @@ 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 int octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg,
-				      int *error)
+static inline u8 octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg)
 {
 	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, NULL)
-#define octeon_i2c_data_read(i2c, error)				\
-	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_DATA, error)
+	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)
 #define octeon_i2c_stat_read(i2c)					\
-	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT, NULL)
+	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT)
 
 /**
  * octeon_i2c_read_int - read the TWSI_INT register