From: Stephen Boyd Date: Fri, 23 Mar 2018 16:34:52 +0000 (-0700) Subject: gpiolib: Support 'gpio-reserved-ranges' property X-Git-Tag: v4.19~1299^2~4^2~1 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=726cb3ba49692bdae6caff457755e7cdb432efa4;p=platform%2Fkernel%2Flinux-rpi.git 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 Signed-off-by: Stephen Boyd Tested-by: Timur Tabi Reviewed-by: Andy Shevchenko Signed-off-by: Linus Walleij --- diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index 84e5a9d..ed81d9a 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -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; 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 @@ 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; diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 1ba9a33..5382b51 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -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);