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gpiolib: Support 'gpio-reserved-ranges' property

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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>
This commit is contained in:
Stephen Boyd
2018-03-23 09:34:52 -07:00
committed by Linus Walleij
parent ace56935ff
commit 726cb3ba49
3 changed files with 86 additions and 0 deletions
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46
drivers/gpio/gpiolib.c
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@@ -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 @@ err_remove_chip:
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;