* [PATCH v2 1/2] i2c: octeon: thunderx: Check bus state before starting a transaction
2016-09-23 9:40 [PATCH v2 0/2] i2c: octeon: thunderx: Recovery fixes and improvements Jan Glauber
@ 2016-09-23 9:40 ` Jan Glauber
2016-09-24 9:24 ` Wolfram Sang
2016-09-23 9:40 ` [PATCH v2 2/2] i2c: octeon: thunderx: Limit register access retries Jan Glauber
1 sibling, 1 reply; 6+ messages in thread
From: Jan Glauber @ 2016-09-23 9:40 UTC (permalink / raw)
To: Wolfram Sang; +Cc: linux-kernel, linux-i2c, Dmitry Bazhenov, Jan Glauber
Add an additional status check before starting a transaction. If the
check fails wait for some time to tolerate multi-master mode. After the
timeout expires trigger the recovery.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
drivers/i2c/busses/i2c-octeon-core.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
index 5e63b17..f526511 100644
--- a/drivers/i2c/busses/i2c-octeon-core.c
+++ b/drivers/i2c/busses/i2c-octeon-core.c
@@ -630,6 +630,31 @@ static int octeon_i2c_hlc_comp_write(struct octeon_i2c *i2c, struct i2c_msg *msg
return ret;
}
+static int octeon_i2c_check_bus(struct octeon_i2c *i2c)
+{
+ u64 end = get_jiffies_64() + i2c->adap.timeout;
+ int stat, lines;
+
+ while (time_before64(get_jiffies_64(), end)) {
+ stat = octeon_i2c_stat_read(i2c);
+
+ /* get I2C line state */
+ lines = octeon_i2c_read_int(i2c) & (TWSI_INT_SCL | TWSI_INT_SDA);
+
+ if (stat == STAT_IDLE && lines == (TWSI_INT_SCL | TWSI_INT_SDA))
+ return 0;
+
+ if (stat == STAT_LOST_ARB_38 || stat == STAT_LOST_ARB_68 ||
+ stat == STAT_LOST_ARB_78 || stat == STAT_LOST_ARB_B0)
+ break;
+
+ usleep_range(I2C_OCTEON_EVENT_WAIT / 2, I2C_OCTEON_EVENT_WAIT);
+ }
+
+ /* bus check failed, try to recover */
+ return octeon_i2c_recovery(i2c);
+}
+
/**
* octeon_i2c_xfer - The driver's master_xfer function
* @adap: Pointer to the i2c_adapter structure
@@ -643,6 +668,10 @@ int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
struct octeon_i2c *i2c = i2c_get_adapdata(adap);
int i, ret = 0;
+ ret = octeon_i2c_check_bus(i2c);
+ if (ret)
+ goto out;
+
if (num == 1) {
if (msgs[0].len > 0 && msgs[0].len <= 8) {
if (msgs[0].flags & I2C_M_RD)
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH v2 2/2] i2c: octeon: thunderx: Limit register access retries
2016-09-23 9:40 [PATCH v2 0/2] i2c: octeon: thunderx: Recovery fixes and improvements Jan Glauber
2016-09-23 9:40 ` [PATCH v2 1/2] i2c: octeon: thunderx: Check bus state before starting a transaction Jan Glauber
@ 2016-09-23 9:40 ` Jan Glauber
2016-09-24 9:24 ` Wolfram Sang
1 sibling, 1 reply; 6+ messages in thread
From: Jan Glauber @ 2016-09-23 9:40 UTC (permalink / raw)
To: Wolfram Sang; +Cc: linux-kernel, linux-i2c, Dmitry Bazhenov, Jan Glauber
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
and trigger the recovery.
Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
drivers/i2c/busses/i2c-octeon-core.c | 4 +++-
drivers/i2c/busses/i2c-octeon-core.h | 27 ++++++++++++++++-----------
2 files changed, 19 insertions(+), 12 deletions(-)
diff --git a/drivers/i2c/busses/i2c-octeon-core.c b/drivers/i2c/busses/i2c-octeon-core.c
index f526511..1dfc4b8 100644
--- 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
--- 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
--
1.9.1
^ permalink raw reply related [flat|nested] 6+ messages in thread