openwrtv4/target/linux/brcm2708/patches-4.1/0148-pinctrl-bcm2835-Clear-the-event-latch-register-when-.patch
Felix Fietkau 0b5d87fd30 brcm2708: update 4.1 patches
As usual, this patches were taken (and rebased) from
https://github.com/raspberrypi/linux/commits/rpi-4.1.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

SVN-Revision: 46853
2015-09-11 16:32:00 +00:00

37 lines
1.6 KiB
Diff

From 909e2b2c6b73991394f89769aa3fca05ab146d72 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.org>
Date: Tue, 30 Jun 2015 12:35:39 +0100
Subject: [PATCH 148/171] pinctrl: bcm2835: Clear the event latch register when
disabling interrupts
It's possible to hit a race condition if interrupts are generated on a GPIO
pin when the IRQ line in question is being disabled.
If the interrupt is freed, bcm2835_gpio_irq_disable() is called which
disables the event generation sources (edge, level). If an event occurred
between the last disabling of hard IRQs and the write to the event
source registers, a bit would be set in the GPIO event detect register
(GPEDSn) which goes unacknowledged by bcm2835_gpio_irq_handler()
so Linux complains loudly.
There is no per-GPIO mask register, so when disabling GPIO interrupts
write 1 to the relevant bit in GPEDSn to clear out any stale events.
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
drivers/pinctrl/bcm/pinctrl-bcm2835.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/pinctrl/bcm/pinctrl-bcm2835.c
+++ b/drivers/pinctrl/bcm/pinctrl-bcm2835.c
@@ -503,6 +503,8 @@ static void bcm2835_gpio_irq_disable(str
spin_lock_irqsave(&pc->irq_lock[bank], flags);
bcm2835_gpio_irq_config(pc, gpio, false);
+ /* Clear events that were latched prior to clearing event sources */
+ bcm2835_gpio_set_bit(pc, GPEDS0, gpio);
clear_bit(offset, &pc->enabled_irq_map[bank]);
spin_unlock_irqrestore(&pc->irq_lock[bank], flags);
}