diff options
Diffstat (limited to 'drivers/irqchip/irq-versatile-fpga.c')
| -rw-r--r-- | drivers/irqchip/irq-versatile-fpga.c | 245 |
1 files changed, 245 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-versatile-fpga.c b/drivers/irqchip/irq-versatile-fpga.c new file mode 100644 index 0000000000..5018a06060 --- /dev/null +++ b/drivers/irqchip/irq-versatile-fpga.c @@ -0,0 +1,245 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for Versatile FPGA-based IRQ controllers + */ +#include <linux/bitops.h> +#include <linux/irq.h> +#include <linux/io.h> +#include <linux/irqchip.h> +#include <linux/irqchip/chained_irq.h> +#include <linux/irqdomain.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_address.h> +#include <linux/of_irq.h> +#include <linux/seq_file.h> + +#include <asm/exception.h> +#include <asm/mach/irq.h> + +#define IRQ_STATUS 0x00 +#define IRQ_RAW_STATUS 0x04 +#define IRQ_ENABLE_SET 0x08 +#define IRQ_ENABLE_CLEAR 0x0c +#define INT_SOFT_SET 0x10 +#define INT_SOFT_CLEAR 0x14 +#define FIQ_STATUS 0x20 +#define FIQ_RAW_STATUS 0x24 +#define FIQ_ENABLE 0x28 +#define FIQ_ENABLE_SET 0x28 +#define FIQ_ENABLE_CLEAR 0x2C + +#define PIC_ENABLES 0x20 /* set interrupt pass through bits */ + +/** + * struct fpga_irq_data - irq data container for the FPGA IRQ controller + * @base: memory offset in virtual memory + * @domain: IRQ domain for this instance + * @valid: mask for valid IRQs on this controller + * @used_irqs: number of active IRQs on this controller + */ +struct fpga_irq_data { + void __iomem *base; + u32 valid; + struct irq_domain *domain; + u8 used_irqs; +}; + +/* we cannot allocate memory when the controllers are initially registered */ +static struct fpga_irq_data fpga_irq_devices[CONFIG_VERSATILE_FPGA_IRQ_NR]; +static int fpga_irq_id; + +static void fpga_irq_mask(struct irq_data *d) +{ + struct fpga_irq_data *f = irq_data_get_irq_chip_data(d); + u32 mask = 1 << d->hwirq; + + writel(mask, f->base + IRQ_ENABLE_CLEAR); +} + +static void fpga_irq_unmask(struct irq_data *d) +{ + struct fpga_irq_data *f = irq_data_get_irq_chip_data(d); + u32 mask = 1 << d->hwirq; + + writel(mask, f->base + IRQ_ENABLE_SET); +} + +static void fpga_irq_print_chip(struct irq_data *d, struct seq_file *p) +{ + struct fpga_irq_data *f = irq_data_get_irq_chip_data(d); + + seq_printf(p, irq_domain_get_of_node(f->domain)->name); +} + +static const struct irq_chip fpga_chip = { + .irq_ack = fpga_irq_mask, + .irq_mask = fpga_irq_mask, + .irq_unmask = fpga_irq_unmask, + .irq_print_chip = fpga_irq_print_chip, +}; + +static void fpga_irq_handle(struct irq_desc *desc) +{ + struct irq_chip *chip = irq_desc_get_chip(desc); + struct fpga_irq_data *f = irq_desc_get_handler_data(desc); + u32 status; + + chained_irq_enter(chip, desc); + + status = readl(f->base + IRQ_STATUS); + if (status == 0) { + do_bad_IRQ(desc); + goto out; + } + + do { + unsigned int irq = ffs(status) - 1; + + status &= ~(1 << irq); + generic_handle_domain_irq(f->domain, irq); + } while (status); + +out: + chained_irq_exit(chip, desc); +} + +/* + * Handle each interrupt in a single FPGA IRQ controller. Returns non-zero + * if we've handled at least one interrupt. This does a single read of the + * status register and handles all interrupts in order from LSB first. + */ +static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs) +{ + int handled = 0; + int irq; + u32 status; + + while ((status = readl(f->base + IRQ_STATUS))) { + irq = ffs(status) - 1; + generic_handle_domain_irq(f->domain, irq); + handled = 1; + } + + return handled; +} + +/* + * Keep iterating over all registered FPGA IRQ controllers until there are + * no pending interrupts. + */ +static asmlinkage void __exception_irq_entry fpga_handle_irq(struct pt_regs *regs) +{ + int i, handled; + + do { + for (i = 0, handled = 0; i < fpga_irq_id; ++i) + handled |= handle_one_fpga(&fpga_irq_devices[i], regs); + } while (handled); +} + +static int fpga_irqdomain_map(struct irq_domain *d, unsigned int irq, + irq_hw_number_t hwirq) +{ + struct fpga_irq_data *f = d->host_data; + + /* Skip invalid IRQs, only register handlers for the real ones */ + if (!(f->valid & BIT(hwirq))) + return -EPERM; + irq_set_chip_data(irq, f); + irq_set_chip_and_handler(irq, &fpga_chip, handle_level_irq); + irq_set_probe(irq); + return 0; +} + +static const struct irq_domain_ops fpga_irqdomain_ops = { + .map = fpga_irqdomain_map, + .xlate = irq_domain_xlate_onetwocell, +}; + +static void __init fpga_irq_init(void __iomem *base, int parent_irq, + u32 valid, struct device_node *node) +{ + struct fpga_irq_data *f; + int i; + + if (fpga_irq_id >= ARRAY_SIZE(fpga_irq_devices)) { + pr_err("%s: too few FPGA IRQ controllers, increase CONFIG_VERSATILE_FPGA_IRQ_NR\n", __func__); + return; + } + f = &fpga_irq_devices[fpga_irq_id]; + f->base = base; + f->valid = valid; + + if (parent_irq != -1) { + irq_set_chained_handler_and_data(parent_irq, fpga_irq_handle, + f); + } + + f->domain = irq_domain_add_linear(node, fls(valid), + &fpga_irqdomain_ops, f); + + /* This will allocate all valid descriptors in the linear case */ + for (i = 0; i < fls(valid); i++) + if (valid & BIT(i)) { + /* Is this still required? */ + irq_create_mapping(f->domain, i); + f->used_irqs++; + } + + pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs", + fpga_irq_id, node->name, base, f->used_irqs); + if (parent_irq != -1) + pr_cont(", parent IRQ: %d\n", parent_irq); + else + pr_cont("\n"); + + fpga_irq_id++; +} + +#ifdef CONFIG_OF +static int __init fpga_irq_of_init(struct device_node *node, + struct device_node *parent) +{ + void __iomem *base; + u32 clear_mask; + u32 valid_mask; + int parent_irq; + + if (WARN_ON(!node)) + return -ENODEV; + + base = of_iomap(node, 0); + WARN(!base, "unable to map fpga irq registers\n"); + + if (of_property_read_u32(node, "clear-mask", &clear_mask)) + clear_mask = 0; + + if (of_property_read_u32(node, "valid-mask", &valid_mask)) + valid_mask = 0; + + writel(clear_mask, base + IRQ_ENABLE_CLEAR); + writel(clear_mask, base + FIQ_ENABLE_CLEAR); + + /* Some chips are cascaded from a parent IRQ */ + parent_irq = irq_of_parse_and_map(node, 0); + if (!parent_irq) { + set_handle_irq(fpga_handle_irq); + parent_irq = -1; + } + + fpga_irq_init(base, parent_irq, valid_mask, node); + + /* + * On Versatile AB/PB, some secondary interrupts have a direct + * pass-thru to the primary controller for IRQs 20 and 22-31 which need + * to be enabled. See section 3.10 of the Versatile AB user guide. + */ + if (of_device_is_compatible(node, "arm,versatile-sic")) + writel(0xffd00000, base + PIC_ENABLES); + + return 0; +} +IRQCHIP_DECLARE(arm_fpga, "arm,versatile-fpga-irq", fpga_irq_of_init); +IRQCHIP_DECLARE(arm_fpga_sic, "arm,versatile-sic", fpga_irq_of_init); +#endif |