Commit 493ff7e2 authored by Jan Glauber's avatar Jan Glauber Committed by Wolfram Sang
Browse files

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 -EIO in case of a failed data read. For all other
cases just return so subsequent operations will fail
and trigger the recovery.

Signed-off-by: default avatarJan Glauber <jglauber@cavium.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 59331c21

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

+3 −1
Original line number Diff line number Diff line
@@ -342,7 +342,9 @@ 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;

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

+16 −5
Original line number Diff line number Diff line
@@ -141,11 +141,14 @@ static inline void octeon_i2c_writeq_flush(u64 val, void __iomem *addr) 
 */

static inline void octeon_i2c_reg_write(struct octeon_i2c *i2c, u64 eop_reg, u8 data)

{

	int tries = 1000;

	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));

		if (--tries < 0)

			return;

	} while ((tmp & SW_TWSI_V) != 0);

}
@@ -163,24 +166,32 @@ 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)

{

	int tries = 1000;

	u64 tmp;



	__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));

		if (--tries < 0) {

			/* signal that the returned data is invalid */

			if (error)

				*error = -EIO;

			return 0;

		}

	} while ((tmp & SW_TWSI_V) != 0);



	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

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