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 <quan@xxxxxxxxxxxxxxxxxxxxxx>
---
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/20210519074934.20712-1-quan@xxxxxxxxxxxxxxxxxxxxxx/
---
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 <andrew@xxxxxxxxxxxxxxxxxxxx>
Thanks Andrew,
I'll add your Reviewed-by in my v4 with that extra empty lime before the
comment.
Thanks for the review
- Quan
