gpiolib: allow gpio irqchip to map irqs dynamically
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.strashko@ti.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
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@ -1615,6 +1615,9 @@ static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
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{
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struct gpio_chip *chip = d->host_data;
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if (!gpiochip_irqchip_irq_valid(chip, hwirq))
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return -ENXIO;
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irq_set_chip_data(irq, chip);
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/*
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* This lock class tells lockdep that GPIO irqs are in a different
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@ -1681,7 +1684,9 @@ static void gpiochip_irq_relres(struct irq_data *d)
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static int gpiochip_to_irq(struct gpio_chip *chip, unsigned offset)
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{
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return irq_find_mapping(chip->irqdomain, offset);
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if (!gpiochip_irqchip_irq_valid(chip, offset))
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return -ENXIO;
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return irq_create_mapping(chip->irqdomain, offset);
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}
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/**
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@ -1757,9 +1762,6 @@ int gpiochip_irqchip_add_key(struct gpio_chip *gpiochip,
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struct lock_class_key *lock_key)
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{
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struct device_node *of_node;
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bool irq_base_set = false;
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unsigned int offset;
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unsigned irq_base = 0;
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if (!gpiochip || !irqchip)
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return -EINVAL;
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@ -1816,25 +1818,6 @@ int gpiochip_irqchip_add_key(struct gpio_chip *gpiochip,
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irqchip->irq_release_resources = gpiochip_irq_relres;
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}
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/*
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* Prepare the mapping since the irqchip shall be orthogonal to
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* any gpiochip calls. If the first_irq was zero, this is
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* necessary to allocate descriptors for all IRQs.
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*/
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for (offset = 0; offset < gpiochip->ngpio; offset++) {
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if (!gpiochip_irqchip_irq_valid(gpiochip, offset))
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continue;
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irq_base = irq_create_mapping(gpiochip->irqdomain, offset);
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if (!irq_base_set) {
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/*
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* Store the base into the gpiochip to be used when
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* unmapping the irqs.
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*/
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gpiochip->irq_base = irq_base;
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irq_base_set = true;
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}
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}
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acpi_gpiochip_request_interrupts(gpiochip);
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return 0;
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