Devices in the BCM2835 AUX block share a common interrupt line, with a register indicating which devices have active IRQs. Expose this as a nested interrupt controller to avoid IRQ sharing problems (easily observed if UART1 and SPI1/2 are enabled simultaneously).
Signed-off-by: Phil Elwell <[email protected]> --- drivers/irqchip/Makefile | 2 +- drivers/irqchip/irq-bcm2835-aux.c | 155 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 156 insertions(+), 1 deletion(-) create mode 100644 drivers/irqchip/irq-bcm2835-aux.c diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile index b64c59b..cf01920 100644 --- a/drivers/irqchip/Makefile +++ b/drivers/irqchip/Makefile @@ -3,7 +3,7 @@ obj-$(CONFIG_IRQCHIP) += irqchip.o obj-$(CONFIG_ALPINE_MSI) += irq-alpine-msi.o obj-$(CONFIG_ATH79) += irq-ath79-cpu.o obj-$(CONFIG_ATH79) += irq-ath79-misc.o -obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o +obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o irq-bcm2835-aux.o obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2836.o obj-$(CONFIG_ARCH_EXYNOS) += exynos-combiner.o obj-$(CONFIG_FARADAY_FTINTC010) += irq-ftintc010.o diff --git a/drivers/irqchip/irq-bcm2835-aux.c b/drivers/irqchip/irq-bcm2835-aux.c new file mode 100644 index 0000000..545f12e --- /dev/null +++ b/drivers/irqchip/irq-bcm2835-aux.c @@ -0,0 +1,155 @@ +/* + * Copyright (C) 2017 Raspberry Pi (Trading) Ltd. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/interrupt.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/of_irq.h> +#include <linux/platform_device.h> +#include <dt-bindings/interrupt-controller/bcm2835-aux-intc.h> + +#define BCM2835_AUXIRQ 0x00 + +#define BCM2835_AUX_IRQ_UART_MASK BIT(BCM2835_AUX_IRQ_UART) +#define BCM2835_AUX_IRQ_SPI1_MASK BIT(BCM2835_AUX_IRQ_SPI1) +#define BCM2835_AUX_IRQ_SPI2_MASK BIT(BCM2835_AUX_IRQ_SPI2) + +#define BCM2835_AUX_IRQ_ALL_MASK \ + (BCM2835_AUX_IRQ_UART_MASK | \ + BCM2835_AUX_IRQ_SPI1_MASK | \ + BCM2835_AUX_IRQ_SPI2_MASK) + +struct aux_irq_state { + void __iomem *status; + struct irq_domain *domain; +}; + +static struct aux_irq_state aux_irq __read_mostly; + +static irqreturn_t bcm2835_aux_irq_handler(int irq, void *dev_id) +{ + u32 stat = readl_relaxed(aux_irq.status); + + if (stat & BCM2835_AUX_IRQ_UART_MASK) + generic_handle_irq(irq_linear_revmap(aux_irq.domain, + BCM2835_AUX_IRQ_UART)); + + if (stat & BCM2835_AUX_IRQ_SPI1_MASK) + generic_handle_irq(irq_linear_revmap(aux_irq.domain, + BCM2835_AUX_IRQ_SPI1)); + + if (stat & BCM2835_AUX_IRQ_SPI2_MASK) + generic_handle_irq(irq_linear_revmap(aux_irq.domain, + BCM2835_AUX_IRQ_SPI2)); + + return (stat & BCM2835_AUX_IRQ_ALL_MASK) ? IRQ_HANDLED : IRQ_NONE; +} + +static int bcm2835_aux_irq_xlate(struct irq_domain *d, + struct device_node *ctrlr, + const u32 *intspec, unsigned int intsize, + unsigned long *out_hwirq, + unsigned int *out_type) +{ + if (WARN_ON(intsize != 1)) + return -EINVAL; + + if (WARN_ON(intspec[0] >= BCM2835_AUX_IRQ_COUNT)) + return -EINVAL; + + *out_hwirq = intspec[0]; + *out_type = IRQ_TYPE_NONE; + + return 0; +} + +/* + * The irq_mask and irq_unmask function pointers are used without + * validity checks, so they must not be NULL. Create a dummy function + * with the expected type for use as a no-op. + */ +static void bcm2835_aux_irq_dummy(struct irq_data *data) +{ +} + +static struct irq_chip bcm2835_aux_irq_chip = { + .name = "bcm2835-aux_irq", + .irq_mask = bcm2835_aux_irq_dummy, + .irq_unmask = bcm2835_aux_irq_dummy, +}; + +static const struct irq_domain_ops bcm2835_aux_irq_ops = { + .xlate = bcm2835_aux_irq_xlate +}; + +static int bcm2835_aux_irq_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + struct device_node *node = dev->of_node; + int parent_irq; + struct resource *res; + void __iomem *reg; + int i; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + reg = devm_ioremap_resource(dev, res); + if (IS_ERR(reg)) + return PTR_ERR(reg); + + parent_irq = irq_of_parse_and_map(node, 0); + if (!parent_irq) + return -ENXIO; + + aux_irq.status = reg + BCM2835_AUXIRQ; + aux_irq.domain = irq_domain_add_linear(node, + BCM2835_AUX_IRQ_COUNT, + &bcm2835_aux_irq_ops, + NULL); + if (!aux_irq.domain) + return -ENXIO; + + for (i = 0; i < BCM2835_AUX_IRQ_COUNT; i++) { + unsigned int irq = irq_create_mapping(aux_irq.domain, i); + + if (irq == 0) + return -ENXIO; + + irq_set_chip_and_handler(irq, &bcm2835_aux_irq_chip, + handle_level_irq); + } + + return devm_request_irq(dev, parent_irq, bcm2835_aux_irq_handler, + 0, "bcm2835-aux-intc", NULL); +} + +static const struct of_device_id bcm2835_aux_irq_of_match[] = { + { .compatible = "brcm,bcm2835-aux-intc", }, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm2835_aux_irq_of_match); + +static struct platform_driver bcm2835_aux_irq_driver = { + .driver = { + .name = "bcm2835-aux-intc", + .of_match_table = bcm2835_aux_irq_of_match, + }, + .probe = bcm2835_aux_irq_probe, +}; +builtin_platform_driver(bcm2835_aux_irq_driver); + +MODULE_AUTHOR("Phil Elwell <[email protected]>"); +MODULE_DESCRIPTION("BCM2835 auxiliary peripheral interrupt driver"); +MODULE_LICENSE("GPL v2"); -- 1.9.1
