Commit 726cb3ba authored by Stephen Boyd's avatar Stephen Boyd Committed by Linus Walleij
Browse files

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: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarStephen Boyd <swboyd@chromium.org>
Tested-by: default avatarTimur Tabi <timur@codeaurora.org>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent ace56935

drivers/gpio/gpiolib-of.c

+24 −0
Original line number Diff line number Diff line
@@ -511,6 +511,28 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc) 
}

EXPORT_SYMBOL(of_mm_gpiochip_remove);



static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)

{

	int len, i;

	u32 start, count;

	struct device_node *np = chip->of_node;



	len = of_property_count_u32_elems(np,  "gpio-reserved-ranges");

	if (len < 0 || len % 2 != 0)

		return;



	for (i = 0; i < len; i += 2) {

		of_property_read_u32_index(np, "gpio-reserved-ranges",

					   i, &start);

		of_property_read_u32_index(np, "gpio-reserved-ranges",

					   i + 1, &count);

		if (start >= chip->ngpio || start + count >= chip->ngpio)

			continue;



		bitmap_clear(chip->valid_mask, start, count);

	}

};



#ifdef CONFIG_PINCTRL

static int of_gpiochip_add_pin_range(struct gpio_chip *chip)

{
@@ -615,6 +637,8 @@ int of_gpiochip_add(struct gpio_chip *chip) 
	if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)

		return -EINVAL;



	of_gpiochip_init_valid_mask(chip);



	status = of_gpiochip_add_pin_range(chip);

	if (status)

		return status;

drivers/gpio/gpiolib.c

+46 −0
Original line number Diff line number Diff line
@@ -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;

include/linux/gpio/driver.h

+16 −0
Original line number Diff line number Diff line
@@ -288,6 +288,21 @@ struct gpio_chip { 
	struct gpio_irq_chip irq;

#endif



	/**

	 * @need_valid_mask:

	 *

	 * If set core allocates @valid_mask with all bits set to one.

	 */

	bool need_valid_mask;



	/**

	 * @valid_mask:

	 *

	 * If not %NULL holds bitmask of GPIOs which are valid to be used

	 * from the chip.

	 */

	unsigned long *valid_mask;



#if defined(CONFIG_OF_GPIO)

	/*

	 * If CONFIG_OF is enabled, then all GPIO controllers described in the
@@ -384,6 +399,7 @@ bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset); 


/* Sleep persistence inquiry for drivers */

bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset);

bool gpiochip_line_is_valid(const struct gpio_chip *chip, unsigned int offset);



/* get driver data */

void *gpiochip_get_data(struct gpio_chip *chip);

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