This is a note to let you know that I've just added the patch titled
i2c: aspeed: Avoid i2c interrupt status clear race condition.
to the 5.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
i2c-aspeed-avoid-i2c-interrupt-status-clear-race-condition.patch
and it can be found in the queue-5.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c926c87b8e36dcc0ea5c2a0a0227ed4f32d0516a Mon Sep 17 00:00:00 2001
From: ryan_chen <ryan_chen@xxxxxxxxxxxxxx>
Date: Wed, 29 Apr 2020 11:37:37 +0800
Subject: i2c: aspeed: Avoid i2c interrupt status clear race condition.
From: ryan_chen <ryan_chen@xxxxxxxxxxxxxx>
commit c926c87b8e36dcc0ea5c2a0a0227ed4f32d0516a upstream.
In AST2600 there have a slow peripheral bus between CPU and i2c
controller. Therefore GIC i2c interrupt status clear have delay timing,
when CPU issue write clear i2c controller interrupt status. To avoid
this issue, the driver need have read after write clear at i2c ISR.
Fixes: f327c686d3ba ("i2c: aspeed: added driver for Aspeed I2C")
Signed-off-by: ryan_chen <ryan_chen@xxxxxxxxxxxxxx>
Acked-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
[wsa: added Fixes tag]
Signed-off-by: Wolfram Sang <wsa@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-aspeed.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
--- a/drivers/i2c/busses/i2c-aspeed.c
+++ b/drivers/i2c/busses/i2c-aspeed.c
@@ -603,6 +603,7 @@ static irqreturn_t aspeed_i2c_bus_irq(in
/* Ack all interrupts except for Rx done */
writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
bus->base + ASPEED_I2C_INTR_STS_REG);
+ readl(bus->base + ASPEED_I2C_INTR_STS_REG);
irq_remaining = irq_received;
#if IS_ENABLED(CONFIG_I2C_SLAVE)
@@ -645,9 +646,11 @@ static irqreturn_t aspeed_i2c_bus_irq(in
irq_received, irq_handled);
/* Ack Rx done */
- if (irq_received & ASPEED_I2CD_INTR_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);
+ }
spin_unlock(&bus->lock);
return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
}
Patches currently in stable-queue which might be from ryan_chen@xxxxxxxxxxxxxx are
queue-5.6/i2c-aspeed-avoid-i2c-interrupt-status-clear-race-condition.patch
