* RE: Designeware I2C slave confusing IC_INTR_STOP_DET handle
2020-10-07 13:08 ` Jarkko Nikula
@ 2020-10-08 9:21 ` Michael.Wu
2020-10-16 7:26 ` Michael.Wu
1 sibling, 0 replies; 5+ messages in thread
From: Michael.Wu @ 2020-10-08 9:21 UTC (permalink / raw)
To: jarkko.nikula, andriy.shevchenko, mika.westerberg
Cc: linux-i2c, morgan.chang, dean.hsiao, paul.chen
Hi Sir,
On 10/7/20 9:08 PM, jarkko.nikula@linux.intel.com wrote:
> Hi
>
> Unfortunately I don't have right now a setup to try myself but could you
> try these ideas to read and clear interrupt status in one place only and
> move I2C_SLAVE_WRITE_REQUESTED reporting after
> I2C_SLAVE_WRITE_RECEIVED
> like in a patch below?
>
> diff --git a/drivers/i2c/busses/i2c-designware-slave.c
> b/drivers/i2c/busses/i2c-designware-slave.c
> index 44974b53a626..97131e888e24 100644
> --- a/drivers/i2c/busses/i2c-designware-slave.c
> +++ b/drivers/i2c/busses/i2c-designware-slave.c
> @@ -159,7 +159,6 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> u32 raw_stat, stat, enabled, tmp;
> u8 val = 0, slave_activity;
>
> - regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
> regmap_read(dev->map, DW_IC_ENABLE, &enabled);
> regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
> regmap_read(dev->map, DW_IC_STATUS, &tmp);
> @@ -168,13 +167,11 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
> return 0;
>
> + stat = i2c_dw_read_clear_intrbits_slave(dev);
> dev_dbg(dev->dev,
> "%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x :
> INTR_STAT=%#x\n",
> enabled, slave_activity, raw_stat, stat);
>
> - if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
> - i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
> -
> if (stat & DW_IC_INTR_RD_REQ) {
> if (slave_activity) {
> if (stat & DW_IC_INTR_RX_FULL) {
> @@ -188,11 +185,9 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> val);
> }
> regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> } else {
> regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
> regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &tmp);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> }
> if (!i2c_slave_event(dev->slave,
> I2C_SLAVE_READ_REQUESTED,
> @@ -207,7 +202,6 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> regmap_read(dev->map, DW_IC_CLR_RX_DONE, &tmp);
>
> i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> return 1;
> }
>
> @@ -219,9 +213,11 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> dev_vdbg(dev->dev, "Byte %X acked!", val);
> } else {
> i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> }
>
> + if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
> + i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
> +
> return 1;
> }
>
> @@ -230,7 +226,6 @@ static irqreturn_t i2c_dw_isr_slave(int this_irq,
> void *dev_id)
> struct dw_i2c_dev *dev = dev_id;
> int ret;
>
> - i2c_dw_read_clear_intrbits_slave(dev);
> ret = i2c_dw_irq_handler_slave(dev);
> if (ret > 0)
> complete(&dev->cmd_complete);
After adding your suggestion, it seems work fine with drivers/i2c/i2c-slave-eeprom.c.
The log was usually:
# i2cset -f -y 2 0x42 0x00 0x41;dmesg -c
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x710 : INTR_STAT=0x200
STOP
Sometimes it wound be:
# i2cset -f -y 2 0x42 0x08 0x45;dmesg -c
0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
WRITE_RECEIVED
0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204
WRITE_RECEIVED
WRITE_REQUESTED
drivers/i2c/i2c-slave-eeprom.c does the same action when triggered by either I2C_SLAVE_STOP or I2C_SLAVE_WRITE_REQUESTED, so one of them being the last event are fine.
But Documentation/i2c/slave-interface.rst said that I2C_SLAVE_WRITE_REQUESTED comes without any data arrived. It means I2C_SLAVE_WRITE_REQUESTED should be front of any WRITE_RECEIVED in a write-request. The second log should be an illegal result.
I2C_SLAVE_WRITE_REQUESTED is made when RX_FULL and STOP_DET are both rising. What situation meet this condition? I guess this STOP_DET was left by previous transmission and then the system is finally handling it while data of the next request arrived. If yes, put "if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))" in front of other handling is correct but it violates I2C_SLAVE_WRITE_REQUESTED dentition when these two interrupts of one request have to handle in one ISR. I think there have to be a solution to distinguish these two cases.
Note that my Linux is 4.9.170 and back-ported drivers/i2c/i2c-designware-slave.c from 4.13 (commit 9f3e065c54b05b03bd39dbbcc5a44f2f1807994d).
--
BR,
Michael Wu
^ permalink raw reply [flat|nested] 5+ messages in thread
* RE: Designeware I2C slave confusing IC_INTR_STOP_DET handle
2020-10-07 13:08 ` Jarkko Nikula
2020-10-08 9:21 ` Michael.Wu
@ 2020-10-16 7:26 ` Michael.Wu
2020-10-16 8:13 ` Jarkko Nikula
1 sibling, 1 reply; 5+ messages in thread
From: Michael.Wu @ 2020-10-16 7:26 UTC (permalink / raw)
To: jarkko.nikula
Cc: andriy.shevchenko, mika.westerberg, linux-i2c, morgan.chang,
dean.hsiao, paul.chen
Hi Jarkko,
On 10/7/20 9:08 PM, jarkko.nikula@linux.intel.com wrote:
> diff --git a/drivers/i2c/busses/i2c-designware-slave.c
> b/drivers/i2c/busses/i2c-designware-slave.c
> index 44974b53a626..97131e888e24 100644
> --- a/drivers/i2c/busses/i2c-designware-slave.c
> +++ b/drivers/i2c/busses/i2c-designware-slave.c
> @@ -159,7 +159,6 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> u32 raw_stat, stat, enabled, tmp;
> u8 val = 0, slave_activity;
>
> - regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
> regmap_read(dev->map, DW_IC_ENABLE, &enabled);
> regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
> regmap_read(dev->map, DW_IC_STATUS, &tmp);
> @@ -168,13 +167,11 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
> return 0;
>
> + stat = i2c_dw_read_clear_intrbits_slave(dev);
> dev_dbg(dev->dev,
> "%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x :
> INTR_STAT=%#x\n",
> enabled, slave_activity, raw_stat, stat);
>
> - if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
> - i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
> -
> if (stat & DW_IC_INTR_RD_REQ) {
> if (slave_activity) {
> if (stat & DW_IC_INTR_RX_FULL) {
> @@ -188,11 +185,9 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> val);
> }
> regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> } else {
> regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
> regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &tmp);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> }
> if (!i2c_slave_event(dev->slave,
> I2C_SLAVE_READ_REQUESTED,
> @@ -207,7 +202,6 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> regmap_read(dev->map, DW_IC_CLR_RX_DONE, &tmp);
>
> i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> return 1;
> }
>
> @@ -219,9 +213,11 @@ static int i2c_dw_irq_handler_slave(struct
> dw_i2c_dev *dev)
> dev_vdbg(dev->dev, "Byte %X acked!", val);
> } else {
> i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
> - stat = i2c_dw_read_clear_intrbits_slave(dev);
> }
>
> + if ((stat & DW_IC_INTR_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
> + i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
> +
> return 1;
> }
>
> @@ -230,7 +226,6 @@ static irqreturn_t i2c_dw_isr_slave(int this_irq,
> void *dev_id)
> struct dw_i2c_dev *dev = dev_id;
> int ret;
>
> - i2c_dw_read_clear_intrbits_slave(dev);
> ret = i2c_dw_irq_handler_slave(dev);
> if (ret > 0)
> complete(&dev->cmd_complete);
I would like to submit your patch in order to do my modification based on this idea.
You're the author but you didn't leave commit description.
I prepared one for this patch.
i2c: designware: call i2c_dw_read_clear_intrbits_slave() once
i2c_dw_read_clear_intrbits_slave() was called per each interrupt handle.
It caused some interrupt bits which haven't been handled yet were cleared,
the corresponding handlers would do nothing due to interrupt bits been
discarded. For example,
$ i2cset -f -y 2 0x42 0x00 0x41; dmesg -c
[0][clear_intrbits]0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
[1][irq_handler ]0x1 STATUS SLAVE_ACTIVITY=0x1 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
WRITE_RECEIVED
[0][clear_intrbits]0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x714 : INTR_STAT=0x204
[1][irq_handler ]0x1 STATUS SLAVE_ACTIVITY=0x0 : RAW_INTR_STAT=0x514 : INTR_STAT=0x4
WRITE_RECEIVED
t1: ISR with the 1st IC_INTR_RX_FULL.
t2: Clear listed IC_INTR bits by i2c_dw_read_clear_intrbits_slave().
t3: Enter i2c_dw_irq_handler_slave() and then do
i2c_slave_event(WRITE_RECEIVED) because
if (stat & DW_IC_INTR_RX_FULL).
t4: ISR with both IC_INTR_STOP_DET and the 2nd IC_INTR_RX_FULL.
t5: Clear listed IC_INTR bits by i2c_dw_read_clear_intrbits_slave(). The
current IC_INTR_STOP_DET is cleared by this
i2c_dw_read_clear_intrbits_slave().
t6: Enter i2c_dw_irq_handler_slave() and then do
i2c_slave_event(WRITE_RECEIVED) because
if (stat & DW_IC_INTR_RX_FULL).
t7: i2c_slave_event(STOP) never be done because IC_INTR_STOP_DET was
cleared in t5.
The root cause is that i2c_dw_read_clear_intrbits_slave() was called many
times. Calling i2c_dw_read_clear_intrbits_slave() once in one ISR and take
the returned stat for later handling is the solution.
I'll submit it if you accept it, or you have other suggestions....?
--
Michael Wu
^ permalink raw reply [flat|nested] 5+ messages in thread