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authorryan_chen <ryan_chen@aspeedtech.com>2020-04-29 11:37:37 +0800
committerWolfram Sang <wsa@the-dreams.de>2020-04-30 16:12:33 +0200
commitc926c87b8e36dcc0ea5c2a0a0227ed4f32d0516a (patch)
tree47801a236531ba89857e864f0c5241bc718185c7
parentac2b0813fceaf7cb3d8d46c7b33c90bae9fa49db (diff)
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i2c: aspeed: Avoid i2c interrupt status clear race condition.
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@aspeedtech.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [wsa: added Fixes tag] Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
-rw-r--r--drivers/i2c/busses/i2c-aspeed.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/i2c/busses/i2c-aspeed.c b/drivers/i2c/busses/i2c-aspeed.c
index 07c1993274c5..f51702d86a90 100644
--- 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(int irq, void *dev_id)
/* 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(int irq, void *dev_id)
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;
}