6.13-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johan Korsnes <johan.korsnes@xxxxxxxxxxxxx>
commit 4e667a1968099c6deadee2313ecd648f8f0a8956 upstream.
Add locking to `vf610_gpio_direction_input|output()` functions. Without
this locking, a race condition exists between concurrent calls to these
functions, potentially leading to incorrect GPIO direction settings.
To verify the correctness of this fix, a `trylock` patch was applied,
where after a couple of reboots the race was confirmed. I.e., one user
had to wait before acquiring the lock. With this patch the race has not
been encountered. It's worth mentioning that any type of debugging
(printing, tracing, etc.) would "resolve"/hide the issue.
Fixes: 659d8a62311f ("gpio: vf610: add imx7ulp support")
Signed-off-by: Johan Korsnes <johan.korsnes@xxxxxxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Haibo Chen <haibo.chen@xxxxxxx>
Cc: Bartosz Golaszewski <brgl@xxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20250217091643.679644-1-johan.korsnes@xxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpio/gpio-vf610.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/drivers/gpio/gpio-vf610.c
+++ b/drivers/gpio/gpio-vf610.c
@@ -36,6 +36,7 @@ struct vf610_gpio_port {
struct clk *clk_port;
struct clk *clk_gpio;
int irq;
+ spinlock_t lock; /* protect gpio direction registers */
};
#define GPIO_PDOR 0x00
@@ -124,6 +125,7 @@ static int vf610_gpio_direction_input(st
u32 val;
if (port->sdata->have_paddr) {
+ guard(spinlock_irqsave)(&port->lock);
val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
val &= ~mask;
vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -142,6 +144,7 @@ static int vf610_gpio_direction_output(s
vf610_gpio_set(chip, gpio, value);
if (port->sdata->have_paddr) {
+ guard(spinlock_irqsave)(&port->lock);
val = vf610_gpio_readl(port->gpio_base + GPIO_PDDR);
val |= mask;
vf610_gpio_writel(val, port->gpio_base + GPIO_PDDR);
@@ -297,6 +300,7 @@ static int vf610_gpio_probe(struct platf
return -ENOMEM;
port->sdata = device_get_match_data(dev);
+ spin_lock_init(&port->lock);
dual_base = port->sdata->have_dual_base;
