drivers/irqchip/irq-zevio.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  linux/drivers/irqchip/irq-zevio.c
   4  *
   5  *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
   6  */
   7
   8 #include <linux/io.h>
   9 #include <linux/irq.h>
  10 #include <linux/irqchip.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13 #include <linux/of_irq.h>
  14
  15 #include <asm/mach/irq.h>
  16 #include <asm/exception.h>
  17
  18 #define IO_STATUS       0x000
  19 #define IO_RAW_STATUS   0x004
  20 #define IO_ENABLE       0x008
  21 #define IO_DISABLE      0x00C
  22 #define IO_CURRENT      0x020
  23 #define IO_RESET        0x028
  24 #define IO_MAX_PRIOTY   0x02C
  25
  26 #define IO_IRQ_BASE     0x000
  27 #define IO_FIQ_BASE     0x100
  28
  29 #define IO_INVERT_SEL   0x200
  30 #define IO_STICKY_SEL   0x204
  31 #define IO_PRIORITY_SEL 0x300
  32
  33 #define MAX_INTRS       32
  34 #define FIQ_START       MAX_INTRS
  35
  36 static struct irq_domain *zevio_irq_domain;
  37 static void __iomem *zevio_irq_io;
  38
  39 static void zevio_irq_ack(struct irq_data *irqd)
  40 {
  41         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(irqd);
  42         struct irq_chip_regs *regs = &irq_data_get_chip_type(irqd)->regs;
  43
  44         readl(gc->reg_base + regs->ack);
  45 }
  46
  47 static void __exception_irq_entry zevio_handle_irq(struct pt_regs *regs)
  48 {
  49         int irqnr;
  50
  51         while (readl(zevio_irq_io + IO_STATUS)) {
  52                 irqnr = readl(zevio_irq_io + IO_CURRENT);
  53                 handle_domain_irq(zevio_irq_domain, irqnr, regs);
  54         };
  55 }
  56
  57 static void __init zevio_init_irq_base(void __iomem *base)
  58 {
  59         /* Disable all interrupts */
  60         writel(~0, base + IO_DISABLE);
  61
  62         /* Accept interrupts of all priorities */
  63         writel(0xF, base + IO_MAX_PRIOTY);
  64
  65         /* Reset existing interrupts */
  66         readl(base + IO_RESET);
  67 }
  68
  69 static int __init zevio_of_init(struct device_node *node,
  70                                 struct device_node *parent)
  71 {
  72         unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
  73         struct irq_chip_generic *gc;
  74         int ret;
  75
  76         if (WARN_ON(zevio_irq_io || zevio_irq_domain))
  77                 return -EBUSY;
  78
  79         zevio_irq_io = of_iomap(node, 0);
  80         BUG_ON(!zevio_irq_io);
  81
  82         /* Do not invert interrupt status bits */
  83         writel(~0, zevio_irq_io + IO_INVERT_SEL);
  84
  85         /* Disable sticky interrupts */
  86         writel(0, zevio_irq_io + IO_STICKY_SEL);
  87
  88         /* We don't use IRQ priorities. Set each IRQ to highest priority. */
  89         memset_io(zevio_irq_io + IO_PRIORITY_SEL, 0, MAX_INTRS * sizeof(u32));
  90
  91         /* Init IRQ and FIQ */
  92         zevio_init_irq_base(zevio_irq_io + IO_IRQ_BASE);
  93         zevio_init_irq_base(zevio_irq_io + IO_FIQ_BASE);
  94
  95         zevio_irq_domain = irq_domain_add_linear(node, MAX_INTRS,
  96                                                  &irq_generic_chip_ops, NULL);
  97         BUG_ON(!zevio_irq_domain);
  98
  99         ret = irq_alloc_domain_generic_chips(zevio_irq_domain, MAX_INTRS, 1,
 100                                              "zevio_intc", handle_level_irq,
 101                                              clr, 0, IRQ_GC_INIT_MASK_CACHE);
 102         BUG_ON(ret);
 103
 104         gc = irq_get_domain_generic_chip(zevio_irq_domain, 0);
 105         gc->reg_base                            = zevio_irq_io;
 106         gc->chip_types[0].chip.irq_ack          = zevio_irq_ack;
 107         gc->chip_types[0].chip.irq_mask         = irq_gc_mask_disable_reg;
 108         gc->chip_types[0].chip.irq_unmask       = irq_gc_unmask_enable_reg;
 109         gc->chip_types[0].regs.mask             = IO_IRQ_BASE + IO_ENABLE;
 110         gc->chip_types[0].regs.enable           = IO_IRQ_BASE + IO_ENABLE;
 111         gc->chip_types[0].regs.disable          = IO_IRQ_BASE + IO_DISABLE;
 112         gc->chip_types[0].regs.ack              = IO_IRQ_BASE + IO_RESET;
 113
 114         set_handle_irq(zevio_handle_irq);
 115
 116         pr_info("TI-NSPIRE classic IRQ controller\n");
 117         return 0;
 118 }
 119
 120 IRQCHIP_DECLARE(zevio_irq, "lsi,zevio-intc", zevio_of_init);