* [PATCH] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once
@ 2020-10-20 8:33 Michael Wu
2020-10-21 12:22 ` Jarkko Nikula
0 siblings, 1 reply; 2+ messages in thread
From: Michael Wu @ 2020-10-20 8:33 UTC (permalink / raw)
To: Jarkko Nikula, Andy Shevchenko, Mika Westerberg, linux-i2c, linux-kernel
Cc: Morgan Chang, Michael Wu
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.
Signed-off-by: Michael Wu <michael.wu@vatics.com>
---
drivers/i2c/busses/i2c-designware-slave.c | 16 +++++-----------
1 file changed, 5 insertions(+), 11 deletions(-)
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
index 44974b53a626..02e7c5171827 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;
}
@@ -217,10 +211,11 @@ static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
&val))
dev_vdbg(dev->dev, "Byte %X acked!", val);
- } else {
+ } 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 +225,6 @@ 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);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once
2020-10-20 8:33 [PATCH] i2c: designware: call i2c_dw_read_clear_intrbits_slave() once Michael Wu
@ 2020-10-21 12:22 ` Jarkko Nikula
0 siblings, 0 replies; 2+ messages in thread
From: Jarkko Nikula @ 2020-10-21 12:22 UTC (permalink / raw)
To: Michael Wu, Andy Shevchenko, Mika Westerberg, linux-i2c, linux-kernel
Cc: Morgan Chang
Hi
On 10/20/20 11:33 AM, Michael Wu wrote:
> 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.
>
> Signed-off-by: Michael Wu <michael.wu@vatics.com>
> ---
> drivers/i2c/busses/i2c-designware-slave.c | 16 +++++-----------
> 1 file changed, 5 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
> index 44974b53a626..02e7c5171827 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_RX_FULL) && (stat & DW_IC_INTR_STOP_DET))
> + i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED, &val);
Was this move a leftover that got committed by accident? I think it's
better to have this logic change in another patch. Or was it even
questionable to move the I2C_SLAVE_WRITE_REQUESTED reporting after all
other?
Jarkko
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-10-21 12:22 ` Jarkko Nikula
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