arch/m68k/virt/ints.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/delay.h>
   4 #include <linux/interrupt.h>
   5 #include <linux/irq.h>
   6 #include <linux/kernel.h>
   7 #include <linux/sched.h>
   8 #include <linux/sched/debug.h>
   9 #include <linux/types.h>
  10 #include <linux/ioport.h>
  11
  12 #include <asm/hwtest.h>
  13 #include <asm/irq.h>
  14 #include <asm/irq_regs.h>
  15 #include <asm/processor.h>
  16 #include <asm/virt.h>
  17
  18 #define GFPIC_REG_IRQ_PENDING           0x04
  19 #define GFPIC_REG_IRQ_DISABLE_ALL       0x08
  20 #define GFPIC_REG_IRQ_DISABLE           0x0c
  21 #define GFPIC_REG_IRQ_ENABLE            0x10
  22
  23 static struct resource picres[6];
  24 static const char *picname[6] = {
  25         "goldfish_pic.0",
  26         "goldfish_pic.1",
  27         "goldfish_pic.2",
  28         "goldfish_pic.3",
  29         "goldfish_pic.4",
  30         "goldfish_pic.5"
  31 };
  32
  33 /*
  34  * 6 goldfish-pic for CPU IRQ #1 to IRQ #6
  35  * CPU IRQ #1 -> PIC #1
  36  *               IRQ #1 to IRQ #31 -> unused
  37  *               IRQ #32 -> goldfish-tty
  38  * CPU IRQ #2 -> PIC #2
  39  *               IRQ #1 to IRQ #32 -> virtio-mmio from 1 to 32
  40  * CPU IRQ #3 -> PIC #3
  41  *               IRQ #1 to IRQ #32 -> virtio-mmio from 33 to 64
  42  * CPU IRQ #4 -> PIC #4
  43  *               IRQ #1 to IRQ #32 -> virtio-mmio from 65 to 96
  44  * CPU IRQ #5 -> PIC #5
  45  *               IRQ #1 to IRQ #32 -> virtio-mmio from 97 to 128
  46  * CPU IRQ #6 -> PIC #6
  47  *               IRQ #1 -> goldfish-timer
  48  *               IRQ #2 -> goldfish-rtc
  49  *               IRQ #3 to IRQ #32 -> unused
  50  * CPU IRQ #7 -> NMI
  51  */
  52
  53 static u32 gfpic_read(int pic, int reg)
  54 {
  55         void __iomem *base = (void __iomem *)(virt_bi_data.pic.mmio +
  56                                               pic * 0x1000);
  57
  58         return ioread32be(base + reg);
  59 }
  60
  61 static void gfpic_write(u32 value, int pic, int reg)
  62 {
  63         void __iomem *base = (void __iomem *)(virt_bi_data.pic.mmio +
  64                                               pic * 0x1000);
  65
  66         iowrite32be(value, base + reg);
  67 }
  68
  69 #define GF_PIC(irq) ((irq - IRQ_USER) / 32)
  70 #define GF_IRQ(irq) ((irq - IRQ_USER) % 32)
  71
  72 static void virt_irq_enable(struct irq_data *data)
  73 {
  74         gfpic_write(BIT(GF_IRQ(data->irq)), GF_PIC(data->irq),
  75                     GFPIC_REG_IRQ_ENABLE);
  76 }
  77
  78 static void virt_irq_disable(struct irq_data *data)
  79 {
  80         gfpic_write(BIT(GF_IRQ(data->irq)), GF_PIC(data->irq),
  81                     GFPIC_REG_IRQ_DISABLE);
  82 }
  83
  84 static unsigned int virt_irq_startup(struct irq_data *data)
  85 {
  86         virt_irq_enable(data);
  87         return 0;
  88 }
  89
  90 static irqreturn_t virt_nmi_handler(int irq, void *dev_id)
  91 {
  92         static int in_nmi;
  93
  94         if (READ_ONCE(in_nmi))
  95                 return IRQ_HANDLED;
  96         WRITE_ONCE(in_nmi, 1);
  97
  98         pr_warn("Non-Maskable Interrupt\n");
  99         show_registers(get_irq_regs());
 100
 101         WRITE_ONCE(in_nmi, 0);
 102         return IRQ_HANDLED;
 103 }
 104
 105 static struct irq_chip virt_irq_chip = {
 106         .name           = "virt",
 107         .irq_enable     = virt_irq_enable,
 108         .irq_disable    = virt_irq_disable,
 109         .irq_startup    = virt_irq_startup,
 110         .irq_shutdown   = virt_irq_disable,
 111 };
 112
 113 static void goldfish_pic_irq(struct irq_desc *desc)
 114 {
 115         u32 irq_pending;
 116         unsigned int irq_num;
 117         unsigned int pic = desc->irq_data.irq - 1;
 118
 119         irq_pending = gfpic_read(pic, GFPIC_REG_IRQ_PENDING);
 120         irq_num = IRQ_USER + pic * 32;
 121
 122         do {
 123                 if (irq_pending & 1)
 124                         generic_handle_irq(irq_num);
 125                 ++irq_num;
 126                 irq_pending >>= 1;
 127         } while (irq_pending);
 128 }
 129
 130 void __init virt_init_IRQ(void)
 131 {
 132         unsigned int i;
 133
 134         m68k_setup_irq_controller(&virt_irq_chip, handle_simple_irq, IRQ_USER,
 135                                   NUM_VIRT_SOURCES - IRQ_USER);
 136
 137         for (i = 0; i < 6; i++) {
 138
 139                 picres[i] = (struct resource)
 140                     DEFINE_RES_MEM_NAMED(virt_bi_data.pic.mmio + i * 0x1000,
 141                                          0x1000, picname[i]);
 142                 if (request_resource(&iomem_resource, &picres[i])) {
 143                         pr_err("Cannot allocate %s resource\n", picname[i]);
 144                         return;
 145                 }
 146
 147                 irq_set_chained_handler(virt_bi_data.pic.irq + i,
 148                                         goldfish_pic_irq);
 149         }
 150
 151         if (request_irq(IRQ_AUTO_7, virt_nmi_handler, 0, "NMI",
 152                         virt_nmi_handler))
 153                 pr_err("Couldn't register NMI\n");
 154 }