diff options
Diffstat (limited to 'drivers/irqchip/irq-crossbar.c')
| -rw-r--r-- | drivers/irqchip/irq-crossbar.c | 366 |
1 files changed, 366 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c new file mode 100644 index 000000000..a05a7501e --- /dev/null +++ b/drivers/irqchip/irq-crossbar.c @@ -0,0 +1,366 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * drivers/irqchip/irq-crossbar.c + * + * Copyright (C) 2013 Texas Instruments Incorporated - http://www.ti.com + * Author: Sricharan R <r.sricharan@ti.com> + */ +#include <linux/err.h> +#include <linux/io.h> +#include <linux/irqchip.h> +#include <linux/irqdomain.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/slab.h> + +#define IRQ_FREE -1 +#define IRQ_RESERVED -2 +#define IRQ_SKIP -3 +#define GIC_IRQ_START 32 + +/** + * struct crossbar_device - crossbar device description + * @lock: spinlock serializing access to @irq_map + * @int_max: maximum number of supported interrupts + * @safe_map: safe default value to initialize the crossbar + * @max_crossbar_sources: Maximum number of crossbar sources + * @irq_map: array of interrupts to crossbar number mapping + * @crossbar_base: crossbar base address + * @register_offsets: offsets for each irq number + * @write: register write function pointer + */ +struct crossbar_device { + raw_spinlock_t lock; + uint int_max; + uint safe_map; + uint max_crossbar_sources; + uint *irq_map; + void __iomem *crossbar_base; + int *register_offsets; + void (*write)(int, int); +}; + +static struct crossbar_device *cb; + +static void crossbar_writel(int irq_no, int cb_no) +{ + writel(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static void crossbar_writew(int irq_no, int cb_no) +{ + writew(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static void crossbar_writeb(int irq_no, int cb_no) +{ + writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]); +} + +static struct irq_chip crossbar_chip = { + .name = "CBAR", + .irq_eoi = irq_chip_eoi_parent, + .irq_mask = irq_chip_mask_parent, + .irq_unmask = irq_chip_unmask_parent, + .irq_retrigger = irq_chip_retrigger_hierarchy, + .irq_set_type = irq_chip_set_type_parent, + .flags = IRQCHIP_MASK_ON_SUSPEND | + IRQCHIP_SKIP_SET_WAKE, +#ifdef CONFIG_SMP + .irq_set_affinity = irq_chip_set_affinity_parent, +#endif +}; + +static int allocate_gic_irq(struct irq_domain *domain, unsigned virq, + irq_hw_number_t hwirq) +{ + struct irq_fwspec fwspec; + int i; + int err; + + if (!irq_domain_get_of_node(domain->parent)) + return -EINVAL; + + raw_spin_lock(&cb->lock); + for (i = cb->int_max - 1; i >= 0; i--) { + if (cb->irq_map[i] == IRQ_FREE) { + cb->irq_map[i] = hwirq; + break; + } + } + raw_spin_unlock(&cb->lock); + + if (i < 0) + return -ENODEV; + + fwspec.fwnode = domain->parent->fwnode; + fwspec.param_count = 3; + fwspec.param[0] = 0; /* SPI */ + fwspec.param[1] = i; + fwspec.param[2] = IRQ_TYPE_LEVEL_HIGH; + + err = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec); + if (err) + cb->irq_map[i] = IRQ_FREE; + else + cb->write(i, hwirq); + + return err; +} + +static int crossbar_domain_alloc(struct irq_domain *d, unsigned int virq, + unsigned int nr_irqs, void *data) +{ + struct irq_fwspec *fwspec = data; + irq_hw_number_t hwirq; + int i; + + if (fwspec->param_count != 3) + return -EINVAL; /* Not GIC compliant */ + if (fwspec->param[0] != 0) + return -EINVAL; /* No PPI should point to this domain */ + + hwirq = fwspec->param[1]; + if ((hwirq + nr_irqs) > cb->max_crossbar_sources) + return -EINVAL; /* Can't deal with this */ + + for (i = 0; i < nr_irqs; i++) { + int err = allocate_gic_irq(d, virq + i, hwirq + i); + + if (err) + return err; + + irq_domain_set_hwirq_and_chip(d, virq + i, hwirq + i, + &crossbar_chip, NULL); + } + + return 0; +} + +/** + * crossbar_domain_free - unmap/free a crossbar<->irq connection + * @domain: domain of irq to unmap + * @virq: virq number + * @nr_irqs: number of irqs to free + * + * We do not maintain a use count of total number of map/unmap + * calls for a particular irq to find out if a irq can be really + * unmapped. This is because unmap is called during irq_dispose_mapping(irq), + * after which irq is anyways unusable. So an explicit map has to be called + * after that. + */ +static void crossbar_domain_free(struct irq_domain *domain, unsigned int virq, + unsigned int nr_irqs) +{ + int i; + + raw_spin_lock(&cb->lock); + for (i = 0; i < nr_irqs; i++) { + struct irq_data *d = irq_domain_get_irq_data(domain, virq + i); + + irq_domain_reset_irq_data(d); + cb->irq_map[d->hwirq] = IRQ_FREE; + cb->write(d->hwirq, cb->safe_map); + } + raw_spin_unlock(&cb->lock); +} + +static int crossbar_domain_translate(struct irq_domain *d, + struct irq_fwspec *fwspec, + unsigned long *hwirq, + unsigned int *type) +{ + if (is_of_node(fwspec->fwnode)) { + if (fwspec->param_count != 3) + return -EINVAL; + + /* No PPI should point to this domain */ + if (fwspec->param[0] != 0) + return -EINVAL; + + *hwirq = fwspec->param[1]; + *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK; + return 0; + } + + return -EINVAL; +} + +static const struct irq_domain_ops crossbar_domain_ops = { + .alloc = crossbar_domain_alloc, + .free = crossbar_domain_free, + .translate = crossbar_domain_translate, +}; + +static int __init crossbar_of_init(struct device_node *node) +{ + u32 max = 0, entry, reg_size; + int i, size, reserved = 0; + const __be32 *irqsr; + int ret = -ENOMEM; + + cb = kzalloc(sizeof(*cb), GFP_KERNEL); + + if (!cb) + return ret; + + cb->crossbar_base = of_iomap(node, 0); + if (!cb->crossbar_base) + goto err_cb; + + of_property_read_u32(node, "ti,max-crossbar-sources", + &cb->max_crossbar_sources); + if (!cb->max_crossbar_sources) { + pr_err("missing 'ti,max-crossbar-sources' property\n"); + ret = -EINVAL; + goto err_base; + } + + of_property_read_u32(node, "ti,max-irqs", &max); + if (!max) { + pr_err("missing 'ti,max-irqs' property\n"); + ret = -EINVAL; + goto err_base; + } + cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL); + if (!cb->irq_map) + goto err_base; + + 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"); + ret = -EINVAL; + goto err_irq_map; + } + cb->irq_map[entry] = IRQ_RESERVED; + } + } + + /* Skip irqs hardwired to bypass the crossbar */ + irqsr = of_get_property(node, "ti,irqs-skip", &size); + if (irqsr) { + size /= sizeof(__be32); + + for (i = 0; i < size; i++) { + of_property_read_u32_index(node, + "ti,irqs-skip", + i, &entry); + if (entry >= max) { + pr_err("Invalid skip entry\n"); + ret = -EINVAL; + goto err_irq_map; + } + cb->irq_map[entry] = IRQ_SKIP; + } + } + + + cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL); + if (!cb->register_offsets) + goto err_irq_map; + + of_property_read_u32(node, "ti,reg-size", ®_size); + + switch (reg_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"); + ret = -EINVAL; + goto err_reg_offset; + 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] == IRQ_RESERVED) + continue; + + cb->register_offsets[i] = reserved; + reserved += reg_size; + } + + of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map); + /* Initialize the crossbar with safe map to start with */ + for (i = 0; i < max; i++) { + if (cb->irq_map[i] == IRQ_RESERVED || + cb->irq_map[i] == IRQ_SKIP) + continue; + + cb->write(i, cb->safe_map); + } + + raw_spin_lock_init(&cb->lock); + + return 0; + +err_reg_offset: + kfree(cb->register_offsets); +err_irq_map: + kfree(cb->irq_map); +err_base: + iounmap(cb->crossbar_base); +err_cb: + kfree(cb); + + cb = NULL; + return ret; +} + +static int __init irqcrossbar_init(struct device_node *node, + struct device_node *parent) +{ + struct irq_domain *parent_domain, *domain; + int err; + + if (!parent) { + pr_err("%pOF: no parent, giving up\n", node); + return -ENODEV; + } + + parent_domain = irq_find_host(parent); + if (!parent_domain) { + pr_err("%pOF: unable to obtain parent domain\n", node); + return -ENXIO; + } + + err = crossbar_of_init(node); + if (err) + return err; + + domain = irq_domain_add_hierarchy(parent_domain, 0, + cb->max_crossbar_sources, + node, &crossbar_domain_ops, + NULL); + if (!domain) { + pr_err("%pOF: failed to allocated domain\n", node); + return -ENOMEM; + } + + return 0; +} + +IRQCHIP_DECLARE(ti_irqcrossbar, "ti,irq-crossbar", irqcrossbar_init); |