Now IRQ mappings are always created for all (allowed) GPIOs in gpiochip in gpiochip_irqchip_add_key() which goes against the idea of SPARSE_IRQ and, as result, leads to: - increasing of memory consumption for IRQ descriptors most of which will never ever be used (espessially on platform with a high number of GPIOs). (sizeof(struct irq_desc) == 256 on my tested platforms) - imposibility to use GPIO irqchip APIs by gpio drivers when HW implements GPIO IRQ functionality as IRQ crossbar/router which has only limited number of IRQ outputs (example from [1], all GPIOs can be mapped on only 8 IRQs).
Hence, remove static IRQ mapping code from gpiochip_irqchip_add_key() and instead replace irq_find_mapping() with irq_create_mapping() in gpiochip_to_irq(). Also add additional gpiochip_irqchip_irq_valid() calls in gpiochip_to_irq() and gpiochip_irq_map(). After this change gpio2irq mapping will happen the following way when GPIO irqchip APIs are used by gpio driver: - IRQ mappings will be created statically if driver passes first_irq>0 vlaue in gpiochip_irqchip_add_key(). - IRQ mappings will be created dynamically from gpio_to_irq() or of_irq_get(). Tested on am335x-evm and dra72-evm-revc. - dra72-evm-revc: number of created irq mappings decreased from 402 -> 135 Mem savings 267*256 = 68352 (66kB) - am335x-evm: number of created irq mappings decreased from 188 -> 63 Mem savings 125*256 = 32000 (31kB) [1] https://lkml.org/lkml/2017/6/15/428 Signed-off-by: Grygorii Strashko <grygorii.stras...@ti.com> --- Changes in v2: - restored struct gpio_chip->irq_base to fix buld of gpio-mockup.c Link on v1: - https://patchwork.kernel.org/patch/9831565/ drivers/gpio/gpiolib.c | 29 ++++++----------------------- 1 file changed, 6 insertions(+), 23 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 9568708..ee6ba07 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1605,6 +1605,9 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, { struct gpio_chip *chip = d->host_data; + if (!gpiochip_irqchip_irq_valid(chip, hwirq)) + return -ENXIO; + irq_set_chip_data(irq, chip); /* * This lock class tells lockdep that GPIO irqs are in a different @@ -1671,7 +1674,9 @@ static void gpiochip_irq_relres(struct irq_data *d) static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset) { - return irq_find_mapping(chip->irqdomain, offset); + if (!gpiochip_irqchip_irq_valid(chip, offset)) + return -ENXIO; + return irq_create_mapping(chip->irqdomain, offset); } /** @@ -1747,9 +1752,6 @@ int gpiochip_irqchip_add_key(struct gpio_chip *gpiochip, struct lock_class_key *lock_key) { struct device_node *of_node; - bool irq_base_set = false; - unsigned int offset; - unsigned irq_base = 0; if (!gpiochip || !irqchip) return -EINVAL; @@ -1806,25 +1808,6 @@ int gpiochip_irqchip_add_key(struct gpio_chip *gpiochip, irqchip->irq_release_resources = gpiochip_irq_relres; } - /* - * Prepare the mapping since the irqchip shall be orthogonal to - * any gpiochip calls. If the first_irq was zero, this is - * necessary to allocate descriptors for all IRQs. - */ - for (offset = 0; offset < gpiochip->ngpio; offset++) { - if (!gpiochip_irqchip_irq_valid(gpiochip, offset)) - continue; - irq_base = irq_create_mapping(gpiochip->irqdomain, offset); - if (!irq_base_set) { - /* - * Store the base into the gpiochip to be used when - * unmapping the irqs. - */ - gpiochip->irq_base = irq_base; - irq_base_set = true; - } - } - acpi_gpiochip_request_interrupts(gpiochip); return 0; -- 2.10.1
