1 /* 2 * Support for Versatile FPGA-based IRQ controllers 3 */ 4 #include <linux/bitops.h> 5 #include <linux/irq.h> 6 #include <linux/io.h> 7 #include <linux/irqchip/versatile-fpga.h> 8 #include <linux/irqdomain.h> 9 #include <linux/module.h> 10 #include <linux/of.h> 11 #include <linux/of_address.h> 12 13 #include <asm/exception.h> 14 #include <asm/mach/irq.h> 15 16 #define IRQ_STATUS 0x00 17 #define IRQ_RAW_STATUS 0x04 18 #define IRQ_ENABLE_SET 0x08 19 #define IRQ_ENABLE_CLEAR 0x0c 20 #define INT_SOFT_SET 0x10 21 #define INT_SOFT_CLEAR 0x14 22 #define FIQ_STATUS 0x20 23 #define FIQ_RAW_STATUS 0x24 24 #define FIQ_ENABLE 0x28 25 #define FIQ_ENABLE_SET 0x28 26 #define FIQ_ENABLE_CLEAR 0x2C 27 28 /** 29 * struct fpga_irq_data - irq data container for the FPGA IRQ controller 30 * @base: memory offset in virtual memory 31 * @chip: chip container for this instance 32 * @domain: IRQ domain for this instance 33 * @valid: mask for valid IRQs on this controller 34 * @used_irqs: number of active IRQs on this controller 35 */ 36 struct fpga_irq_data { 37 void __iomem *base; 38 struct irq_chip chip; 39 u32 valid; 40 struct irq_domain *domain; 41 u8 used_irqs; 42 }; 43 44 /* we cannot allocate memory when the controllers are initially registered */ 45 static struct fpga_irq_data fpga_irq_devices[CONFIG_VERSATILE_FPGA_IRQ_NR]; 46 static int fpga_irq_id; 47 48 static void fpga_irq_mask(struct irq_data *d) 49 { 50 struct fpga_irq_data *f = irq_data_get_irq_chip_data(d); 51 u32 mask = 1 << d->hwirq; 52 53 writel(mask, f->base + IRQ_ENABLE_CLEAR); 54 } 55 56 static void fpga_irq_unmask(struct irq_data *d) 57 { 58 struct fpga_irq_data *f = irq_data_get_irq_chip_data(d); 59 u32 mask = 1 << d->hwirq; 60 61 writel(mask, f->base + IRQ_ENABLE_SET); 62 } 63 64 static void fpga_irq_handle(unsigned int irq, struct irq_desc *desc) 65 { 66 struct fpga_irq_data *f = irq_desc_get_handler_data(desc); 67 u32 status = readl(f->base + IRQ_STATUS); 68 69 if (status == 0) { 70 do_bad_IRQ(irq, desc); 71 return; 72 } 73 74 do { 75 irq = ffs(status) - 1; 76 status &= ~(1 << irq); 77 generic_handle_irq(irq_find_mapping(f->domain, irq)); 78 } while (status); 79 } 80 81 /* 82 * Handle each interrupt in a single FPGA IRQ controller. Returns non-zero 83 * if we've handled at least one interrupt. This does a single read of the 84 * status register and handles all interrupts in order from LSB first. 85 */ 86 static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs) 87 { 88 int handled = 0; 89 int irq; 90 u32 status; 91 92 while ((status = readl(f->base + IRQ_STATUS))) { 93 irq = ffs(status) - 1; 94 handle_IRQ(irq_find_mapping(f->domain, irq), regs); 95 handled = 1; 96 } 97 98 return handled; 99 } 100 101 /* 102 * Keep iterating over all registered FPGA IRQ controllers until there are 103 * no pending interrupts. 104 */ 105 asmlinkage void __exception_irq_entry fpga_handle_irq(struct pt_regs *regs) 106 { 107 int i, handled; 108 109 do { 110 for (i = 0, handled = 0; i < fpga_irq_id; ++i) 111 handled |= handle_one_fpga(&fpga_irq_devices[i], regs); 112 } while (handled); 113 } 114 115 static int fpga_irqdomain_map(struct irq_domain *d, unsigned int irq, 116 irq_hw_number_t hwirq) 117 { 118 struct fpga_irq_data *f = d->host_data; 119 120 /* Skip invalid IRQs, only register handlers for the real ones */ 121 if (!(f->valid & BIT(hwirq))) 122 return -EPERM; 123 irq_set_chip_data(irq, f); 124 irq_set_chip_and_handler(irq, &f->chip, 125 handle_level_irq); 126 set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); 127 return 0; 128 } 129 130 static struct irq_domain_ops fpga_irqdomain_ops = { 131 .map = fpga_irqdomain_map, 132 .xlate = irq_domain_xlate_onetwocell, 133 }; 134 135 void __init fpga_irq_init(void __iomem *base, const char *name, int irq_start, 136 int parent_irq, u32 valid, struct device_node *node) 137 { 138 struct fpga_irq_data *f; 139 int i; 140 141 if (fpga_irq_id >= ARRAY_SIZE(fpga_irq_devices)) { 142 pr_err("%s: too few FPGA IRQ controllers, increase CONFIG_VERSATILE_FPGA_IRQ_NR\n", __func__); 143 return; 144 } 145 f = &fpga_irq_devices[fpga_irq_id]; 146 f->base = base; 147 f->chip.name = name; 148 f->chip.irq_ack = fpga_irq_mask; 149 f->chip.irq_mask = fpga_irq_mask; 150 f->chip.irq_unmask = fpga_irq_unmask; 151 f->valid = valid; 152 153 if (parent_irq != -1) { 154 irq_set_handler_data(parent_irq, f); 155 irq_set_chained_handler(parent_irq, fpga_irq_handle); 156 } 157 158 /* This will also allocate irq descriptors */ 159 f->domain = irq_domain_add_simple(node, fls(valid), irq_start, 160 &fpga_irqdomain_ops, f); 161 162 /* This will allocate all valid descriptors in the linear case */ 163 for (i = 0; i < fls(valid); i++) 164 if (valid & BIT(i)) { 165 if (!irq_start) 166 irq_create_mapping(f->domain, i); 167 f->used_irqs++; 168 } 169 170 pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs\n", 171 fpga_irq_id, name, base, f->used_irqs); 172 173 fpga_irq_id++; 174 } 175 176 #ifdef CONFIG_OF 177 int __init fpga_irq_of_init(struct device_node *node, 178 struct device_node *parent) 179 { 180 void __iomem *base; 181 u32 clear_mask; 182 u32 valid_mask; 183 184 if (WARN_ON(!node)) 185 return -ENODEV; 186 187 base = of_iomap(node, 0); 188 WARN(!base, "unable to map fpga irq registers\n"); 189 190 if (of_property_read_u32(node, "clear-mask", &clear_mask)) 191 clear_mask = 0; 192 193 if (of_property_read_u32(node, "valid-mask", &valid_mask)) 194 valid_mask = 0; 195 196 fpga_irq_init(base, node->name, 0, -1, valid_mask, node); 197 198 writel(clear_mask, base + IRQ_ENABLE_CLEAR); 199 writel(clear_mask, base + FIQ_ENABLE_CLEAR); 200 201 return 0; 202 } 203 #endif 204