@@ -606,8 +606,9 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
spin_lock(&bus->lock);
irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
- /* Ack all interrupts except for Rx done */
- writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
+ /* Ack all interrupts except for Rx done and Tx done with/without ACK */
+ writel(irq_received &
+ ~(ASPEED_I2CD_INTR_RX_DONE | ASPEED_I2CD_INTR_TX_ACK | ASPEED_I2CD_INTR_TX_NAK),
bus->base + ASPEED_I2C_INTR_STS_REG);
readl(bus->base + ASPEED_I2C_INTR_STS_REG);
irq_received &= ASPEED_I2CD_INTR_RECV_MASK;
@@ -652,12 +653,12 @@ static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
"irq handled != irq. expected 0x%08x, but was 0x%08x\n",
irq_received, irq_handled);
- /* Ack Rx done */
- if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {
- writel(ASPEED_I2CD_INTR_RX_DONE,
- bus->base + ASPEED_I2C_INTR_STS_REG);
- readl(bus->base + ASPEED_I2C_INTR_STS_REG);
- }
+ /* Ack Rx done and Tx done with/without ACK */
+ writel(irq_received &
+ (ASPEED_I2CD_INTR_RX_DONE | ASPEED_I2CD_INTR_TX_ACK | ASPEED_I2CD_INTR_TX_NAK),
+ bus->base + ASPEED_I2C_INTR_STS_REG);
+ readl(bus->base + ASPEED_I2C_INTR_STS_REG);
+
spin_unlock(&bus->lock);
return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
}
Commit 2be6b47211e1 ("i2c: aspeed: Acknowledge most interrupts early in interrupt handler") acknowledges most interrupts early before the slave irq handler is executed, except for the "Receive Done Interrupt status" which is acknowledged late in the interrupt. However, it is observed that the early acknowledgment of "Transmit Done Interrupt Status" (with ACK or NACK) often causes the interrupt to be raised in READ REQUEST state, resulting in "Unexpected ACK on read request." complaint messages. Assuming that the "Transmit Done" interrupt should only be acknowledged once it is truly processed, this commit fixes this issue by acknowledging this interrupt for both ACK and NACK cases late in the interrupt handler also. Fixes: 2be6b47211e1 (i2c: aspeed: Acknowledge most interrupts early in interrupt handler) Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> --- v2: + Split to separate series [Joel] + Added the Fixes line [Joel] + Fixed multiline comment [Joel] + Refactor irq clearing code [Joel, Guenter] + Revised commit message [Joel] + Revised commit message [Quan] + About a note to remind why the readl() should immediately follow the writel() to fix the race condition when clearing irq status from commit c926c87b8e36 ("i2c: aspeed: Avoid i2c interrupt status clear race condition"), I think it looks straight forward in this patch and decided not to add that note. [Joel] v1: + First introduced in https://lkml.org/lkml/2021/5/19/205 drivers/i2c/busses/i2c-aspeed.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)