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>
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@ -511,6 +511,28 @@ void of_mm_gpiochip_remove(struct of_mm_gpio_chip *mm_gc)
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}
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EXPORT_SYMBOL(of_mm_gpiochip_remove);
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static void of_gpiochip_init_valid_mask(struct gpio_chip *chip)
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{
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int len, i;
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u32 start, count;
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struct device_node *np = chip->of_node;
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len = of_property_count_u32_elems(np, "gpio-reserved-ranges");
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if (len < 0 || len % 2 != 0)
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return;
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for (i = 0; i < len; i += 2) {
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of_property_read_u32_index(np, "gpio-reserved-ranges",
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i, &start);
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of_property_read_u32_index(np, "gpio-reserved-ranges",
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i + 1, &count);
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if (start >= chip->ngpio || start + count >= chip->ngpio)
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continue;
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bitmap_clear(chip->valid_mask, start, count);
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}
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};
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#ifdef CONFIG_PINCTRL
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static int of_gpiochip_add_pin_range(struct gpio_chip *chip)
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{
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@ -615,6 +637,8 @@ int of_gpiochip_add(struct gpio_chip *chip)
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if (chip->of_gpio_n_cells > MAX_PHANDLE_ARGS)
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return -EINVAL;
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of_gpiochip_init_valid_mask(chip);
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status = of_gpiochip_add_pin_range(chip);
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if (status)
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return status;
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@ -351,6 +351,43 @@ static unsigned long *gpiochip_allocate_mask(struct gpio_chip *chip)
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return p;
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}
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static int gpiochip_init_valid_mask(struct gpio_chip *gpiochip)
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{
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#ifdef CONFIG_OF_GPIO
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int size;
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struct device_node *np = gpiochip->of_node;
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size = of_property_count_u32_elems(np, "gpio-reserved-ranges");
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if (size > 0 && size % 2 == 0)
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gpiochip->need_valid_mask = true;
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#endif
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if (!gpiochip->need_valid_mask)
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return 0;
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gpiochip->valid_mask = gpiochip_allocate_mask(gpiochip);
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if (!gpiochip->valid_mask)
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return -ENOMEM;
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return 0;
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}
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static void gpiochip_free_valid_mask(struct gpio_chip *gpiochip)
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{
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kfree(gpiochip->valid_mask);
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gpiochip->valid_mask = NULL;
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}
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bool gpiochip_line_is_valid(const struct gpio_chip *gpiochip,
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unsigned int offset)
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{
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/* No mask means all valid */
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if (likely(!gpiochip->valid_mask))
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return true;
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return test_bit(offset, gpiochip->valid_mask);
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}
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EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
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/*
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* GPIO line handle management
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*/
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@ -1275,6 +1312,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
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if (status)
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goto err_remove_from_list;
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status = gpiochip_init_valid_mask(chip);
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if (status)
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goto err_remove_irqchip_mask;
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status = gpiochip_add_irqchip(chip, lock_key, request_key);
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if (status)
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goto err_remove_chip;
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@ -1304,6 +1345,8 @@ err_remove_chip:
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acpi_gpiochip_remove(chip);
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gpiochip_free_hogs(chip);
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of_gpiochip_remove(chip);
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gpiochip_free_valid_mask(chip);
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err_remove_irqchip_mask:
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gpiochip_irqchip_free_valid_mask(chip);
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err_remove_from_list:
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spin_lock_irqsave(&gpio_lock, flags);
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@ -1360,6 +1403,7 @@ void gpiochip_remove(struct gpio_chip *chip)
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acpi_gpiochip_remove(chip);
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gpiochip_remove_pin_ranges(chip);
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of_gpiochip_remove(chip);
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gpiochip_free_valid_mask(chip);
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/*
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* We accept no more calls into the driver from this point, so
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* NULL the driver data pointer
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@ -1536,6 +1580,8 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip)
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bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gpiochip,
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unsigned int offset)
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{
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if (!gpiochip_line_is_valid(gpiochip, offset))
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return false;
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/* No mask means all valid */
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if (likely(!gpiochip->irq.valid_mask))
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return true;
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@ -288,6 +288,21 @@ struct gpio_chip {
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struct gpio_irq_chip irq;
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#endif
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/**
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* @need_valid_mask:
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*
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* If set core allocates @valid_mask with all bits set to one.
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*/
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bool need_valid_mask;
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/**
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* @valid_mask:
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*
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* If not %NULL holds bitmask of GPIOs which are valid to be used
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* from the chip.
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*/
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unsigned long *valid_mask;
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#if defined(CONFIG_OF_GPIO)
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/*
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* If CONFIG_OF is enabled, then all GPIO controllers described in the
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@ -384,6 +399,7 @@ bool gpiochip_line_is_open_source(struct gpio_chip *chip, unsigned int offset);
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/* Sleep persistence inquiry for drivers */
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bool gpiochip_line_is_persistent(struct gpio_chip *chip, unsigned int offset);
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bool gpiochip_line_is_valid(const struct gpio_chip *chip, unsigned int offset);
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/* get driver data */
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void *gpiochip_get_data(struct gpio_chip *chip);
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