From 6c846d026d490b2383d395bc8e7b06336219667b Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Apr 2022 15:18:37 +0100 Subject: gpio: Don't fiddle with irqchips marked as immutable In order to move away from gpiolib messing with the internals of unsuspecting irqchips, add a flag by which irqchips advertise that they are not to be messed with, and do solemnly swear that they correctly call into the gpiolib helpers when required. Also nudge the users into converting their drivers to the new model. Reviewed-by: Andy Shevchenko Reviewed-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220419141846.598305-2-maz@kernel.org --- drivers/gpio/gpiolib.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index e59884cc12a7..48191e62a3cc 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1475,6 +1475,11 @@ static void gpiochip_set_irq_hooks(struct gpio_chip *gc) { struct irq_chip *irqchip = gc->irq.chip; + if (irqchip->flags & IRQCHIP_IMMUTABLE) + return; + + chip_warn(gc, "not an immutable chip, please consider fixing it!\n"); + if (!irqchip->irq_request_resources && !irqchip->irq_release_resources) { irqchip->irq_request_resources = gpiochip_irq_reqres; @@ -1633,7 +1638,7 @@ static void gpiochip_irqchip_remove(struct gpio_chip *gc) irq_domain_remove(gc->irq.domain); } - if (irqchip) { + if (irqchip && !(irqchip->flags & IRQCHIP_IMMUTABLE)) { if (irqchip->irq_request_resources == gpiochip_irq_reqres) { irqchip->irq_request_resources = NULL; irqchip->irq_release_resources = NULL; -- cgit v1.2.3 From 704f08753b6dcd0e08c1953af0b2c7f3fac87111 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Apr 2022 15:18:38 +0100 Subject: gpio: Expose the gpiochip_irq_re[ql]res helpers The GPIO subsystem has a couple of internal helpers to manage resources on behalf of the irqchip. Expose them so that GPIO drivers can use them directly. Reviewed-by: Andy Shevchenko Reviewed-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220419141846.598305-3-maz@kernel.org --- drivers/gpio/gpiolib.c | 6 ++++-- include/linux/gpio/driver.h | 4 ++++ 2 files changed, 8 insertions(+), 2 deletions(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 48191e62a3cc..36e436a66e09 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1423,19 +1423,21 @@ static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset) return irq_create_mapping(domain, offset); } -static int gpiochip_irq_reqres(struct irq_data *d) +int gpiochip_irq_reqres(struct irq_data *d) { struct gpio_chip *gc = irq_data_get_irq_chip_data(d); return gpiochip_reqres_irq(gc, d->hwirq); } +EXPORT_SYMBOL(gpiochip_irq_reqres); -static void gpiochip_irq_relres(struct irq_data *d) +void gpiochip_irq_relres(struct irq_data *d) { struct gpio_chip *gc = irq_data_get_irq_chip_data(d); gpiochip_relres_irq(gc, d->hwirq); } +EXPORT_SYMBOL(gpiochip_irq_relres); static void gpiochip_irq_mask(struct irq_data *d) { diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index 98c93510640e..066bcfdf878d 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -579,6 +579,10 @@ void gpiochip_relres_irq(struct gpio_chip *gc, unsigned int offset); void gpiochip_disable_irq(struct gpio_chip *gc, unsigned int offset); void gpiochip_enable_irq(struct gpio_chip *gc, unsigned int offset); +/* irq_data versions of the above */ +int gpiochip_irq_reqres(struct irq_data *data); +void gpiochip_irq_relres(struct irq_data *data); + /* Line status inquiry for drivers */ bool gpiochip_line_is_open_drain(struct gpio_chip *gc, unsigned int offset); bool gpiochip_line_is_open_source(struct gpio_chip *gc, unsigned int offset); -- cgit v1.2.3 From bba00555ede79ad8a743da908f708466f6bac0f8 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Apr 2022 15:18:40 +0100 Subject: gpio: tegra186: Make the irqchip immutable Prevent gpiolib from messing with the irqchip by advertising the irq_chip structure as immutable, making it const, and adding the various calls that gpiolib relies upon. Acked-by: Thierry Reding Reviewed-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220419141846.598305-5-maz@kernel.org --- drivers/gpio/gpio-tegra186.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpio-tegra186.c b/drivers/gpio/gpio-tegra186.c index 031fe105b58e..84c4f1e9fb0c 100644 --- a/drivers/gpio/gpio-tegra186.c +++ b/drivers/gpio/gpio-tegra186.c @@ -80,7 +80,6 @@ struct tegra_gpio_soc { struct tegra_gpio { struct gpio_chip gpio; - struct irq_chip intc; unsigned int num_irq; unsigned int *irq; @@ -372,6 +371,8 @@ static void tegra186_irq_mask(struct irq_data *data) value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG); value &= ~TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT; writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG); + + gpiochip_disable_irq(&gpio->gpio, data->hwirq); } static void tegra186_irq_unmask(struct irq_data *data) @@ -385,6 +386,8 @@ static void tegra186_irq_unmask(struct irq_data *data) if (WARN_ON(base == NULL)) return; + gpiochip_enable_irq(&gpio->gpio, data->hwirq); + value = readl(base + TEGRA186_GPIO_ENABLE_CONFIG); value |= TEGRA186_GPIO_ENABLE_CONFIG_INTERRUPT; writel(value, base + TEGRA186_GPIO_ENABLE_CONFIG); @@ -456,6 +459,24 @@ static int tegra186_irq_set_wake(struct irq_data *data, unsigned int on) return 0; } +static void tegra186_irq_print_chip(struct irq_data *data, struct seq_file *p) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(data); + + seq_printf(p, dev_name(gc->parent)); +} + +static const struct irq_chip tegra186_gpio_irq_chip = { + .irq_ack = tegra186_irq_ack, + .irq_mask = tegra186_irq_mask, + .irq_unmask = tegra186_irq_unmask, + .irq_set_type = tegra186_irq_set_type, + .irq_set_wake = tegra186_irq_set_wake, + .irq_print_chip = tegra186_irq_print_chip, + .flags = IRQCHIP_IMMUTABLE, + GPIOCHIP_IRQ_RESOURCE_HELPERS, +}; + static void tegra186_gpio_irq(struct irq_desc *desc) { struct tegra_gpio *gpio = irq_desc_get_handler_data(desc); @@ -760,15 +781,8 @@ static int tegra186_gpio_probe(struct platform_device *pdev) gpio->gpio.of_xlate = tegra186_gpio_of_xlate; #endif /* CONFIG_OF_GPIO */ - gpio->intc.name = dev_name(&pdev->dev); - gpio->intc.irq_ack = tegra186_irq_ack; - gpio->intc.irq_mask = tegra186_irq_mask; - gpio->intc.irq_unmask = tegra186_irq_unmask; - gpio->intc.irq_set_type = tegra186_irq_set_type; - gpio->intc.irq_set_wake = tegra186_irq_set_wake; - irq = &gpio->gpio.irq; - irq->chip = &gpio->intc; + gpio_irq_chip_set_chip(irq, &tegra186_gpio_irq_chip); irq->fwnode = of_node_to_fwnode(pdev->dev.of_node); irq->child_to_parent_hwirq = tegra186_gpio_child_to_parent_hwirq; irq->populate_parent_alloc_arg = tegra186_gpio_populate_parent_fwspec; -- cgit v1.2.3 From 15d8c14ac849f41f2d41dbddb69f402aaf73ff8b Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Apr 2022 15:18:41 +0100 Subject: gpio: pl061: Make the irqchip immutable Prevent gpiolib from messing with the irqchip by advertising the irq_chip structure as immutable, making it const, and adding the various calls that gpiolib relies upon. Reviewed-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220419141846.598305-6-maz@kernel.org --- drivers/gpio/gpio-pl061.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpio-pl061.c b/drivers/gpio/gpio-pl061.c index 4ecab700f23f..6464056cb6ae 100644 --- a/drivers/gpio/gpio-pl061.c +++ b/drivers/gpio/gpio-pl061.c @@ -52,7 +52,6 @@ struct pl061 { void __iomem *base; struct gpio_chip gc; - struct irq_chip irq_chip; int parent_irq; #ifdef CONFIG_PM @@ -241,6 +240,8 @@ static void pl061_irq_mask(struct irq_data *d) gpioie = readb(pl061->base + GPIOIE) & ~mask; writeb(gpioie, pl061->base + GPIOIE); raw_spin_unlock(&pl061->lock); + + gpiochip_disable_irq(gc, d->hwirq); } static void pl061_irq_unmask(struct irq_data *d) @@ -250,6 +251,8 @@ static void pl061_irq_unmask(struct irq_data *d) u8 mask = BIT(irqd_to_hwirq(d) % PL061_GPIO_NR); u8 gpioie; + gpiochip_enable_irq(gc, d->hwirq); + raw_spin_lock(&pl061->lock); gpioie = readb(pl061->base + GPIOIE) | mask; writeb(gpioie, pl061->base + GPIOIE); @@ -283,6 +286,24 @@ static int pl061_irq_set_wake(struct irq_data *d, unsigned int state) return irq_set_irq_wake(pl061->parent_irq, state); } +static void pl061_irq_print_chip(struct irq_data *data, struct seq_file *p) +{ + struct gpio_chip *gc = irq_data_get_irq_chip_data(data); + + seq_printf(p, dev_name(gc->parent)); +} + +static const struct irq_chip pl061_irq_chip = { + .irq_ack = pl061_irq_ack, + .irq_mask = pl061_irq_mask, + .irq_unmask = pl061_irq_unmask, + .irq_set_type = pl061_irq_type, + .irq_set_wake = pl061_irq_set_wake, + .irq_print_chip = pl061_irq_print_chip, + .flags = IRQCHIP_IMMUTABLE, + GPIOCHIP_IRQ_RESOURCE_HELPERS, +}; + static int pl061_probe(struct amba_device *adev, const struct amba_id *id) { struct device *dev = &adev->dev; @@ -315,13 +336,6 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id) /* * irq_chip support */ - pl061->irq_chip.name = dev_name(dev); - pl061->irq_chip.irq_ack = pl061_irq_ack; - pl061->irq_chip.irq_mask = pl061_irq_mask; - pl061->irq_chip.irq_unmask = pl061_irq_unmask; - pl061->irq_chip.irq_set_type = pl061_irq_type; - pl061->irq_chip.irq_set_wake = pl061_irq_set_wake; - writeb(0, pl061->base + GPIOIE); /* disable irqs */ irq = adev->irq[0]; if (!irq) @@ -329,7 +343,7 @@ static int pl061_probe(struct amba_device *adev, const struct amba_id *id) pl061->parent_irq = irq; girq = &pl061->gc.irq; - girq->chip = &pl061->irq_chip; + gpio_irq_chip_set_chip(girq, &pl061_irq_chip); girq->parent_handler = pl061_irq_handler; girq->num_parents = 1; girq->parents = devm_kcalloc(dev, 1, sizeof(*girq->parents), -- cgit v1.2.3 From afefc3266272d40cdcd0fd713c7b42008fea19d5 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 19 Apr 2022 15:18:45 +0100 Subject: gpio: Update TODO to mention immutable irq_chip structures 5 drivers are converted, a few hundred to go. Definitely worth of a TODO entry, in the hope that someone will notice it and do a bulk update. Reviewed-by: Andy Shevchenko Reviewed-by: Bartosz Golaszewski Signed-off-by: Marc Zyngier Link: https://lore.kernel.org/r/20220419141846.598305-10-maz@kernel.org --- drivers/gpio/TODO | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'drivers/gpio') diff --git a/drivers/gpio/TODO b/drivers/gpio/TODO index b8b1473a5b1e..f87ff3fa8a53 100644 --- a/drivers/gpio/TODO +++ b/drivers/gpio/TODO @@ -178,3 +178,22 @@ discussed but the idea is to provide a low-level access point for debugging and hacking and to expose all lines without the need of any exporting. Also provide ample ammunition to shoot oneself in the foot, because this is debugfs after all. + + +Moving over to immutable irq_chip structures + +Most of the gpio chips implementing interrupt support rely on gpiolib +intercepting some of the irq_chip callbacks, preventing the structures +from being made read-only and forcing duplication of structures that +should otherwise be unique. + +The solution is to call into the gpiolib code when needed (resource +management, enable/disable or unmask/mask callbacks), and to let the +core code know about that by exposing a flag (IRQCHIP_IMMUTABLE) in +the irq_chip structure. The irq_chip structure can then be made unique +and const. + +A small number of drivers have been converted (pl061, tegra186, msm, +amd, apple), and can be used as examples of how to proceed with this +conversion. Note that drivers using the generic irqchip framework +cannot be converted yet, but watch this space! -- cgit v1.2.3