drivers/irqchip/irq-versatile-fpga.c

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