gpiolib: Support 'gpio-reserved-ranges' property
Some qcom platforms make some GPIOs or pins unavailable for use by
non-secure operating systems, and thus reading or writing the registers
for those pins will cause access control issues. Add support for a DT
property to describe the set of GPIOs that are available for use so that
higher level OSes are able to know what pins to avoid reading/writing.
Non-DT platforms can add support by directly updating the
chip->valid_mask.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Tested-by: Timur Tabi <timur@codeaurora.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index db3788d..fecbb55 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -351,6 +351,43 @@ static unsigned long *gpiochip_allocate_mask(struct gpio_chip *chip)
return p;
}
+static int gpiochip_init_valid_mask(struct gpio_chip *gpiochip)
+{
+#ifdef CONFIG_OF_GPIO
+ int size;
+ struct device_node *np = gpiochip->of_node;
+
+ size = of_property_count_u32_elems(np, "gpio-reserved-ranges");
+ if (size > 0 && size % 2 == 0)
+ gpiochip->need_valid_mask = true;
+#endif
+
+ if (!gpiochip->need_valid_mask)
+ return 0;
+
+ gpiochip->valid_mask = gpiochip_allocate_mask(gpiochip);
+ if (!gpiochip->valid_mask)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void gpiochip_free_valid_mask(struct gpio_chip *gpiochip)
+{
+ kfree(gpiochip->valid_mask);
+ gpiochip->valid_mask = NULL;
+}
+
+bool gpiochip_line_is_valid(const struct gpio_chip *gpiochip,
+ unsigned int offset)
+{
+ /* No mask means all valid */
+ if (likely(!gpiochip->valid_mask))
+ return true;
+ return test_bit(offset, gpiochip->valid_mask);
+}
+EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
+
/*
* GPIO line handle management
*/
@@ -1275,6 +1312,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
if (status)
goto err_remove_from_list;
+ status = gpiochip_init_valid_mask(chip);
+ if (status)
+ goto err_remove_irqchip_mask;
+
status = gpiochip_add_irqchip(chip, lock_key, request_key);
if (status)
goto err_remove_chip;
@@ -1304,6 +1345,8 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
acpi_gpiochip_remove(chip);
gpiochip_free_hogs(chip);
of_gpiochip_remove(chip);
+ gpiochip_free_valid_mask(chip);
+err_remove_irqchip_mask:
gpiochip_irqchip_free_valid_mask(chip);
err_remove_from_list:
spin_lock_irqsave(&gpio_lock, flags);
@@ -1360,6 +1403,7 @@ void gpiochip_remove(struct gpio_chip *chip)
acpi_gpiochip_remove(chip);
gpiochip_remove_pin_ranges(chip);
of_gpiochip_remove(chip);
+ gpiochip_free_valid_mask(chip);
/*
* We accept no more calls into the driver from this point, so
* NULL the driver data pointer
@@ -1536,6 +1580,8 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip)
bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
unsigned int offset)
{
+ if (!gpiochip_line_is_valid(gpiochip, offset))
+ return false;
/* No mask means all valid */
if (likely(!gpiochip->irq.valid_mask))
return true;