diff options
Diffstat (limited to 'drivers/irqchip/irq-crossbar.c')
| -rw-r--r-- | drivers/irqchip/irq-crossbar.c | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c new file mode 100644 index 000000000000..fc817d28d1fe --- /dev/null +++ b/drivers/irqchip/irq-crossbar.c @@ -0,0 +1,208 @@ +/* + * drivers/irqchip/irq-crossbar.c + * + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com + * Author: Sricharan R <r.sricharan@ti.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + */ +#include <linux/err.h> +#include <linux/io.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/slab.h> +#include <linux/irqchip/arm-gic.h> + +#define IRQ_FREE -1 +#define GIC_IRQ_START 32 + +/* + * @int_max: maximum number of supported interrupts + * @irq_map: array of interrupts to crossbar number mapping + * @crossbar_base: crossbar base address + * @register_offsets: offsets for each irq number + */ +struct crossbar_device { + uint int_max; + uint *irq_map; + void __iomem *crossbar_base; + int *register_offsets; + void (*write) (int, int); +}; + +static struct crossbar_device *cb; + +static inline void crossbar_writel(int irq_no, int cb_no) +{ + writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static inline void crossbar_writew(int irq_no, int cb_no) +{ + writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static inline void crossbar_writeb(int irq_no, int cb_no) +{ + writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static inline int allocate_free_irq(int cb_no) +{ + int i; + + for (i = 0; i < cb->int_max; i++) { + if (cb->irq_map[i] == IRQ_FREE) { + cb->irq_map[i] = cb_no; + return i; + } + } + + return -ENODEV; +} + +static int crossbar_domain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hw) +{ + cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]); + return 0; +} + +static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq) +{ + irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq; + + if (hw > GIC_IRQ_START) + cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE; +} + +static int crossbar_domain_xlate(struct irq_domain *d, + struct device_node *controller, + const u32 *intspec, unsigned int intsize, + unsigned long *out_hwirq, + unsigned int *out_type) +{ + unsigned long ret; + + ret = allocate_free_irq(intspec[1]); + + if (IS_ERR_VALUE(ret)) + return ret; + + *out_hwirq = ret + GIC_IRQ_START; + return 0; +} + +const struct irq_domain_ops routable_irq_domain_ops = { + .map = crossbar_domain_map, + .unmap = crossbar_domain_unmap, + .xlate = crossbar_domain_xlate +}; + +static int __init crossbar_of_init(struct device_node *node) +{ + int i, size, max, reserved = 0, entry; + const __be32 *irqsr; + + cb = kzalloc(sizeof(struct cb_device *), GFP_KERNEL); + + if (!cb) + return -ENOMEM; + + cb->crossbar_base = of_iomap(node, 0); + if (!cb->crossbar_base) + goto err1; + + of_property_read_u32(node, "ti,max-irqs", &max); + cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL); + if (!cb->irq_map) + goto err2; + + cb->int_max = max; + + for (i = 0; i < max; i++) + cb->irq_map[i] = IRQ_FREE; + + /* Get and mark reserved irqs */ + irqsr = of_get_property(node, "ti,irqs-reserved", &size); + if (irqsr) { + size /= sizeof(__be32); + + for (i = 0; i < size; i++) { + of_property_read_u32_index(node, + "ti,irqs-reserved", + i, &entry); + if (entry > max) { + pr_err("Invalid reserved entry\n"); + goto err3; + } + cb->irq_map[entry] = 0; + } + } + + cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL); + if (!cb->register_offsets) + goto err3; + + of_property_read_u32(node, "ti,reg-size", &size); + + switch (size) { + case 1: + cb->write = crossbar_writeb; + break; + case 2: + cb->write = crossbar_writew; + break; + case 4: + cb->write = crossbar_writel; + break; + default: + pr_err("Invalid reg-size property\n"); + goto err4; + break; + } + + /* + * Register offsets are not linear because of the + * reserved irqs. so find and store the offsets once. + */ + for (i = 0; i < max; i++) { + if (!cb->irq_map[i]) + continue; + + cb->register_offsets[i] = reserved; + reserved += size; + } + + register_routable_domain_ops(&routable_irq_domain_ops); + return 0; + +err4: + kfree(cb->register_offsets); +err3: + kfree(cb->irq_map); +err2: + iounmap(cb->crossbar_base); +err1: + kfree(cb); + return -ENOMEM; +} + +static const struct of_device_id crossbar_match[] __initconst = { + { .compatible = "ti,irq-crossbar" }, + {} +}; + +int __init irqcrossbar_init(void) +{ + struct device_node *np; + np = of_find_matching_node(NULL, crossbar_match); + if (!np) + return -ENODEV; + + crossbar_of_init(np); + return 0; +} |