Some masters may drive the transfers with low enough latency between
the nak/stop phase of the current command and the start/address phase
of the following command that the interrupts are coalesced by the
time we process them.
Handle the stop conditions before processing SLAVE_MATCH to fix the
complaints that sometimes occur below.
"aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
0x00000086, but was 0x00000084"
Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
Signed-off-by: Quan Nguyen <[email protected]>
---
v3:
+ Change to handle the coalesced stop condition with the start
conditions [Andrew]
+ Revised commit message [Quan]
v2:
+ Split to separate series [Joel]
+ Added the Fixes line [Joel]
+ Revised commit message [Quan]
v1:
+ First introduced in
https://lore.kernel.org/all/[email protected]/
---
drivers/i2c/busses/i2c-aspeed.c | 47 ++++++++++++++++++++++-----------
1 file changed, 31 insertions(+), 16 deletions(-)
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 28e2a5fc4528..1c2a4f4c4e1b 100644
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -249,18 +249,45 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
if (!slave)
return 0;
- command = readl(bus->base + ASPEED_I2C_CMD_REG);
+ /*
+ * Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
+ * transfers with low enough latency between the nak/stop phase of the current
+ * command and the start/address phase of the following command that the
+ * interrupts are coalesced by the time we process them.
+ */
+ if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
+ irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
- /* Slave was requested, restart state machine. */
+ if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
+ bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
+ irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
+ bus->slave_state = ASPEED_I2C_SLAVE_STOP;
+ }
+
+ /* Propagate any stop conditions to the slave implementation. */
+ if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
+ i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
+ bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
+ }
+ /*
+ * Now that we've dealt with any potentially coalesced stop conditions,
+ * address any start conditions.
+ */
if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
bus->slave_state = ASPEED_I2C_SLAVE_START;
}
- /* Slave is not currently active, irq was for someone else. */
+ /*
+ * If the slave has been stopped and not started then slave interrupt
+ * handling is complete.
+ */
if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
return irq_handled;
+ command = readl(bus->base + ASPEED_I2C_CMD_REG);
dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
irq_status, command);
@@ -279,17 +306,6 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
}
- /* Slave was asked to stop. */
- if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
- irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
- bus->slave_state = ASPEED_I2C_SLAVE_STOP;
- }
- if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
- bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
- irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
- bus->slave_state = ASPEED_I2C_SLAVE_STOP;
- }
-
switch (bus->slave_state) {
case ASPEED_I2C_SLAVE_READ_REQUESTED:
if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))
@@ -324,8 +340,7 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
break;
case ASPEED_I2C_SLAVE_STOP:
- i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
- bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
+ /* Stop event handling is done early. Unreachable. */
break;
case ASPEED_I2C_SLAVE_START:
/* Slave was just started. Waiting for the next event. */;
--
2.35.1
On Fri, 2023-12-08 at 10:31 +0700, Quan Nguyen wrote:
> Some masters may drive the transfers with low enough latency between
> the nak/stop phase of the current command and the start/address phase
> of the following command that the interrupts are coalesced by the
> time we process them.
> Handle the stop conditions before processing SLAVE_MATCH to fix the
> complaints that sometimes occur below.
>
> "aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
> 0x00000086, but was 0x00000084"
>
> Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
> Signed-off-by: Quan Nguyen <[email protected]>
> ---
> v3:
> + Change to handle the coalesced stop condition with the start
> conditions [Andrew]
> + Revised commit message [Quan]
>
> v2:
> + Split to separate series [Joel]
> + Added the Fixes line [Joel]
> + Revised commit message [Quan]
>
> v1:
> + First introduced in
> https://lore.kernel.org/all/[email protected]/
> ---
> drivers/i2c/busses/i2c-aspeed.c | 47 ++++++++++++++++++++++-----------
> 1 file changed, 31 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
> index 28e2a5fc4528..1c2a4f4c4e1b 100644
> --- a/drivers/i2c/busses/i2c-aspeed.c
> +++ b/drivers/i2c/busses/i2c-aspeed.c
> @@ -249,18 +249,45 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
> if (!slave)
> return 0;
>
> - command = readl(bus->base + ASPEED_I2C_CMD_REG);
> + /*
> + * Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
> + * transfers with low enough latency between the nak/stop phase of the current
> + * command and the start/address phase of the following command that the
> + * interrupts are coalesced by the time we process them.
> + */
> + if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
> + irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
> + bus->slave_state = ASPEED_I2C_SLAVE_STOP;
> + }
>
> - /* Slave was requested, restart state machine. */
> + if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
> + bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
> + irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
> + bus->slave_state = ASPEED_I2C_SLAVE_STOP;
> + }
> +
> + /* Propagate any stop conditions to the slave implementation. */
> + if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
> + i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
> + bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
> + }
> + /*
If there's a reason to do a v4 then an extra empty line above the
comment would be nice. But let's not get hung up on that if everyone
else is happy.
Thanks for the fixes!
Reviewed-by: Andrew Jeffery <[email protected]>
> + * Now that we've dealt with any potentially coalesced stop conditions,
> + * address any start conditions.
> + */
> if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
> irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
> bus->slave_state = ASPEED_I2C_SLAVE_START;
> }
>
Hi Quan,
On Fri, Dec 08, 2023 at 10:31:41AM +0700, Quan Nguyen wrote:
> Some masters may drive the transfers with low enough latency between
> the nak/stop phase of the current command and the start/address phase
> of the following command that the interrupts are coalesced by the
> time we process them.
> Handle the stop conditions before processing SLAVE_MATCH to fix the
> complaints that sometimes occur below.
>
> "aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
> 0x00000086, but was 0x00000084"
>
> Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
> Signed-off-by: Quan Nguyen <[email protected]>
Reviewed-by: Andi Shyti <[email protected]>
Thanks,
Andi
On 08/12/2023 10:56, Andrew Jeffery wrote:
> On Fri, 2023-12-08 at 10:31 +0700, Quan Nguyen wrote:
>> Some masters may drive the transfers with low enough latency between
>> the nak/stop phase of the current command and the start/address phase
>> of the following command that the interrupts are coalesced by the
>> time we process them.
>> Handle the stop conditions before processing SLAVE_MATCH to fix the
>> complaints that sometimes occur below.
>>
>> "aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
>> 0x00000086, but was 0x00000084"
>>
>> Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
>> Signed-off-by: Quan Nguyen <[email protected]>
>> ---
>> v3:
>> + Change to handle the coalesced stop condition with the start
>> conditions [Andrew]
>> + Revised commit message [Quan]
>>
>> v2:
>> + Split to separate series [Joel]
>> + Added the Fixes line [Joel]
>> + Revised commit message [Quan]
>>
>> v1:
>> + First introduced in
>> https://lore.kernel.org/all/[email protected]/
>> ---
>> drivers/i2c/busses/i2c-aspeed.c | 47 ++++++++++++++++++++++-----------
>> 1 file changed, 31 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
>> index 28e2a5fc4528..1c2a4f4c4e1b 100644
>> --- a/drivers/i2c/busses/i2c-aspeed.c
>> +++ b/drivers/i2c/busses/i2c-aspeed.c
>> @@ -249,18 +249,45 @@ static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
>> if (!slave)
>> return 0;
>>
>> - command = readl(bus->base + ASPEED_I2C_CMD_REG);
>> + /*
>> + * Handle stop conditions early, prior to SLAVE_MATCH. Some masters may drive
>> + * transfers with low enough latency between the nak/stop phase of the current
>> + * command and the start/address phase of the following command that the
>> + * interrupts are coalesced by the time we process them.
>> + */
>> + if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
>> + irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
>> + bus->slave_state = ASPEED_I2C_SLAVE_STOP;
>> + }
>>
>> - /* Slave was requested, restart state machine. */
>> + if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
>> + bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
>> + irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
>> + bus->slave_state = ASPEED_I2C_SLAVE_STOP;
>> + }
>> +
>> + /* Propagate any stop conditions to the slave implementation. */
>> + if (bus->slave_state == ASPEED_I2C_SLAVE_STOP) {
>> + i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
>> + bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
>> + }
>> + /*
>
> If there's a reason to do a v4 then an extra empty line above the
> comment would be nice. But let's not get hung up on that if everyone
> else is happy.
>
> Thanks for the fixes!
>
> Reviewed-by: Andrew Jeffery <[email protected]>
>
Thanks Andrew,
I'll add your Reviewed-by in my v4 with that extra empty lime before the
comment.
Thanks for the review
- Quan
On 10/12/2023 03:28, Andi Shyti wrote:
> Hi Quan,
>
> On Fri, Dec 08, 2023 at 10:31:41AM +0700, Quan Nguyen wrote:
>> Some masters may drive the transfers with low enough latency between
>> the nak/stop phase of the current command and the start/address phase
>> of the following command that the interrupts are coalesced by the
>> time we process them.
>> Handle the stop conditions before processing SLAVE_MATCH to fix the
>> complaints that sometimes occur below.
>>
>> "aspeed-i2c-bus 1e78a040.i2c-bus: irq handled != irq. Expected
>> 0x00000086, but was 0x00000084"
>>
>> Fixes: f9eb91350bb2 ("i2c: aspeed: added slave support for Aspeed I2C driver")
>> Signed-off-by: Quan Nguyen <[email protected]>
>
> Reviewed-by: Andi Shyti <[email protected]>
>
Thanks Andi,
I'll add your Reviewed-by in v4
Thanks,
- Quan