drivers/irqchip/irq-versatile-fpga.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Support for Versatile FPGA-based IRQ controllers
   4  */
   5 #include <linux/bitops.h>
   6 #include <linux/irq.h>
   7 #include <linux/io.h>
   8 #include <linux/irqchip.h>
   9 #include <linux/irqchip/chained_irq.h>
  10 #include <linux/irqchip/versatile-fpga.h>
  11 #include <linux/irqdomain.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/of_address.h>
  15 #include <linux/of_irq.h>
  16
  17 #include <asm/exception.h>
  18 #include <asm/mach/irq.h>
  19
  20 #define IRQ_STATUS              0x00
  21 #define IRQ_RAW_STATUS          0x04
  22 #define IRQ_ENABLE_SET          0x08
  23 #define IRQ_ENABLE_CLEAR        0x0c
  24 #define INT_SOFT_SET            0x10
  25 #define INT_SOFT_CLEAR          0x14
  26 #define FIQ_STATUS              0x20
  27 #define FIQ_RAW_STATUS          0x24
  28 #define FIQ_ENABLE              0x28
  29 #define FIQ_ENABLE_SET          0x28
  30 #define FIQ_ENABLE_CLEAR        0x2C
  31
  32 #define PIC_ENABLES             0x20    /* set interrupt pass through bits */
  33
  34 /**
  35  * struct fpga_irq_data - irq data container for the FPGA IRQ controller
  36  * @base: memory offset in virtual memory
  37  * @chip: chip container for this instance
  38  * @domain: IRQ domain for this instance
  39  * @valid: mask for valid IRQs on this controller
  40  * @used_irqs: number of active IRQs on this controller
  41  */
  42 struct fpga_irq_data {
  43         void __iomem *base;
  44         struct irq_chip chip;
  45         u32 valid;
  46         struct irq_domain *domain;
  47         u8 used_irqs;
  48 };
  49
  50 /* we cannot allocate memory when the controllers are initially registered */
  51 static struct fpga_irq_data fpga_irq_devices[CONFIG_VERSATILE_FPGA_IRQ_NR];
  52 static int fpga_irq_id;
  53
  54 static void fpga_irq_mask(struct irq_data *d)
  55 {
  56         struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
  57         u32 mask = 1 << d->hwirq;
  58
  59         writel(mask, f->base + IRQ_ENABLE_CLEAR);
  60 }
  61
  62 static void fpga_irq_unmask(struct irq_data *d)
  63 {
  64         struct fpga_irq_data *f = irq_data_get_irq_chip_data(d);
  65         u32 mask = 1 << d->hwirq;
  66
  67         writel(mask, f->base + IRQ_ENABLE_SET);
  68 }
  69
  70 static void fpga_irq_handle(struct irq_desc *desc)
  71 {
  72         struct irq_chip *chip = irq_desc_get_chip(desc);
  73         struct fpga_irq_data *f = irq_desc_get_handler_data(desc);
  74         u32 status;
  75
  76         chained_irq_enter(chip, desc);
  77
  78         status = readl(f->base + IRQ_STATUS);
  79         if (status == 0) {
  80                 do_bad_IRQ(desc);
  81                 goto out;
  82         }
  83
  84         do {
  85                 unsigned int irq = ffs(status) - 1;
  86
  87                 status &= ~(1 << irq);
  88                 generic_handle_irq(irq_find_mapping(f->domain, irq));
  89         } while (status);
  90
  91 out:
  92         chained_irq_exit(chip, desc);
  93 }
  94
  95 /*
  96  * Handle each interrupt in a single FPGA IRQ controller.  Returns non-zero
  97  * if we've handled at least one interrupt.  This does a single read of the
  98  * status register and handles all interrupts in order from LSB first.
  99  */
 100 static int handle_one_fpga(struct fpga_irq_data *f, struct pt_regs *regs)
 101 {
 102         int handled = 0;
 103         int irq;
 104         u32 status;
 105
 106         while ((status  = readl(f->base + IRQ_STATUS))) {
 107                 irq = ffs(status) - 1;
 108                 handle_domain_irq(f->domain, irq, regs);
 109                 handled = 1;
 110         }
 111
 112         return handled;
 113 }
 114
 115 /*
 116  * Keep iterating over all registered FPGA IRQ controllers until there are
 117  * no pending interrupts.
 118  */
 119 asmlinkage void __exception_irq_entry fpga_handle_irq(struct pt_regs *regs)
 120 {
 121         int i, handled;
 122
 123         do {
 124                 for (i = 0, handled = 0; i < fpga_irq_id; ++i)
 125                         handled |= handle_one_fpga(&fpga_irq_devices[i], regs);
 126         } while (handled);
 127 }
 128
 129 static int fpga_irqdomain_map(struct irq_domain *d, unsigned int irq,
 130                 irq_hw_number_t hwirq)
 131 {
 132         struct fpga_irq_data *f = d->host_data;
 133
 134         /* Skip invalid IRQs, only register handlers for the real ones */
 135         if (!(f->valid & BIT(hwirq)))
 136                 return -EPERM;
 137         irq_set_chip_data(irq, f);
 138         irq_set_chip_and_handler(irq, &f->chip,
 139                                 handle_level_irq);
 140         irq_set_probe(irq);
 141         return 0;
 142 }
 143
 144 static const struct irq_domain_ops fpga_irqdomain_ops = {
 145         .map = fpga_irqdomain_map,
 146         .xlate = irq_domain_xlate_onetwocell,
 147 };
 148
 149 void __init fpga_irq_init(void __iomem *base, const char *name, int irq_start,
 150                           int parent_irq, u32 valid, struct device_node *node)
 151 {
 152         struct fpga_irq_data *f;
 153         int i;
 154
 155         if (fpga_irq_id >= ARRAY_SIZE(fpga_irq_devices)) {
 156                 pr_err("%s: too few FPGA IRQ controllers, increase CONFIG_VERSATILE_FPGA_IRQ_NR\n", __func__);
 157                 return;
 158         }
 159         f = &fpga_irq_devices[fpga_irq_id];
 160         f->base = base;
 161         f->chip.name = name;
 162         f->chip.irq_ack = fpga_irq_mask;
 163         f->chip.irq_mask = fpga_irq_mask;
 164         f->chip.irq_unmask = fpga_irq_unmask;
 165         f->valid = valid;
 166
 167         if (parent_irq != -1) {
 168                 irq_set_chained_handler_and_data(parent_irq, fpga_irq_handle,
 169                                                  f);
 170         }
 171
 172         /* This will also allocate irq descriptors */
 173         f->domain = irq_domain_add_simple(node, fls(valid), irq_start,
 174                                           &fpga_irqdomain_ops, f);
 175
 176         /* This will allocate all valid descriptors in the linear case */
 177         for (i = 0; i < fls(valid); i++)
 178                 if (valid & BIT(i)) {
 179                         if (!irq_start)
 180                                 irq_create_mapping(f->domain, i);
 181                         f->used_irqs++;
 182                 }
 183
 184         pr_info("FPGA IRQ chip %d \"%s\" @ %p, %u irqs",
 185                 fpga_irq_id, name, base, f->used_irqs);
 186         if (parent_irq != -1)
 187                 pr_cont(", parent IRQ: %d\n", parent_irq);
 188         else
 189                 pr_cont("\n");
 190
 191         fpga_irq_id++;
 192 }
 193
 194 #ifdef CONFIG_OF
 195 int __init fpga_irq_of_init(struct device_node *node,
 196                             struct device_node *parent)
 197 {
 198         void __iomem *base;
 199         u32 clear_mask;
 200         u32 valid_mask;
 201         int parent_irq;
 202
 203         if (WARN_ON(!node))
 204                 return -ENODEV;
 205
 206         base = of_iomap(node, 0);
 207         WARN(!base, "unable to map fpga irq registers\n");
 208
 209         if (of_property_read_u32(node, "clear-mask", &clear_mask))
 210                 clear_mask = 0;
 211
 212         if (of_property_read_u32(node, "valid-mask", &valid_mask))
 213                 valid_mask = 0;
 214
 215         writel(clear_mask, base + IRQ_ENABLE_CLEAR);
 216         writel(clear_mask, base + FIQ_ENABLE_CLEAR);
 217
 218         /* Some chips are cascaded from a parent IRQ */
 219         parent_irq = irq_of_parse_and_map(node, 0);
 220         if (!parent_irq) {
 221                 set_handle_irq(fpga_handle_irq);
 222                 parent_irq = -1;
 223         }
 224
 225         fpga_irq_init(base, node->name, 0, parent_irq, valid_mask, node);
 226
 227         /*
 228          * On Versatile AB/PB, some secondary interrupts have a direct
 229          * pass-thru to the primary controller for IRQs 20 and 22-31 which need
 230          * to be enabled. See section 3.10 of the Versatile AB user guide.
 231          */
 232         if (of_device_is_compatible(node, "arm,versatile-sic"))
 233                 writel(0xffd00000, base + PIC_ENABLES);
 234
 235         return 0;
 236 }
 237 IRQCHIP_DECLARE(arm_fpga, "arm,versatile-fpga-irq", fpga_irq_of_init);
 238 IRQCHIP_DECLARE(arm_fpga_sic, "arm,versatile-sic", fpga_irq_of_init);
 239 IRQCHIP_DECLARE(ox810se_rps, "oxsemi,ox810se-rps-irq", fpga_irq_of_init);
 240 #endif