arch/powerpc/sysdev/i8259.c

   1 /*
   2  * i8259 interrupt controller driver.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version
   7  * 2 of the License, or (at your option) any later version.
   8  */
   9 #undef DEBUG
  10
  11 #include <linux/init.h>
  12 #include <linux/ioport.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/kernel.h>
  15 #include <linux/delay.h>
  16 #include <asm/io.h>
  17 #include <asm/i8259.h>
  18 #include <asm/prom.h>
  19
  20 static volatile void __iomem *pci_intack; /* RO, gives us the irq vector */
  21
  22 static unsigned char cached_8259[2] = { 0xff, 0xff };
  23 #define cached_A1 (cached_8259[0])
  24 #define cached_21 (cached_8259[1])
  25
  26 static DEFINE_SPINLOCK(i8259_lock);
  27
  28 static struct irq_host *i8259_host;
  29
  30 /*
  31  * Acknowledge the IRQ using either the PCI host bridge's interrupt
  32  * acknowledge feature or poll.  How i8259_init() is called determines
  33  * which is called.  It should be noted that polling is broken on some
  34  * IBM and Motorola PReP boxes so we must use the int-ack feature on them.
  35  */
  36 unsigned int i8259_irq(void)
  37 {
  38         int irq;
  39         int lock = 0;
  40
  41         /* Either int-ack or poll for the IRQ */
  42         if (pci_intack)
  43                 irq = readb(pci_intack);
  44         else {
  45                 spin_lock(&i8259_lock);
  46                 lock = 1;
  47
  48                 /* Perform an interrupt acknowledge cycle on controller 1. */
  49                 outb(0x0C, 0x20);               /* prepare for poll */
  50                 irq = inb(0x20) & 7;
  51                 if (irq == 2 ) {
  52                         /*
  53                          * Interrupt is cascaded so perform interrupt
  54                          * acknowledge on controller 2.
  55                          */
  56                         outb(0x0C, 0xA0);       /* prepare for poll */
  57                         irq = (inb(0xA0) & 7) + 8;
  58                 }
  59         }
  60
  61         if (irq == 7) {
  62                 /*
  63                  * This may be a spurious interrupt.
  64                  *
  65                  * Read the interrupt status register (ISR). If the most
  66                  * significant bit is not set then there is no valid
  67                  * interrupt.
  68                  */
  69                 if (!pci_intack)
  70                         outb(0x0B, 0x20);       /* ISR register */
  71                 if(~inb(0x20) & 0x80)
  72                         irq = NO_IRQ;
  73         } else if (irq == 0xff)
  74                 irq = NO_IRQ;
  75
  76         if (lock)
  77                 spin_unlock(&i8259_lock);
  78         return irq;
  79 }
  80
  81 static void i8259_mask_and_ack_irq(unsigned int irq_nr)
  82 {
  83         unsigned long flags;
  84
  85         spin_lock_irqsave(&i8259_lock, flags);
  86         if (irq_nr > 7) {
  87                 cached_A1 |= 1 << (irq_nr-8);
  88                 inb(0xA1);      /* DUMMY */
  89                 outb(cached_A1, 0xA1);
  90                 outb(0x20, 0xA0);       /* Non-specific EOI */
  91                 outb(0x20, 0x20);       /* Non-specific EOI to cascade */
  92         } else {
  93                 cached_21 |= 1 << irq_nr;
  94                 inb(0x21);      /* DUMMY */
  95                 outb(cached_21, 0x21);
  96                 outb(0x20, 0x20);       /* Non-specific EOI */
  97         }
  98         spin_unlock_irqrestore(&i8259_lock, flags);
  99 }
 100
 101 static void i8259_set_irq_mask(int irq_nr)
 102 {
 103         outb(cached_A1,0xA1);
 104         outb(cached_21,0x21);
 105 }
 106
 107 static void i8259_mask_irq(unsigned int irq_nr)
 108 {
 109         unsigned long flags;
 110
 111         pr_debug("i8259_mask_irq(%d)\n", irq_nr);
 112
 113         spin_lock_irqsave(&i8259_lock, flags);
 114         if (irq_nr < 8)
 115                 cached_21 |= 1 << irq_nr;
 116         else
 117                 cached_A1 |= 1 << (irq_nr-8);
 118         i8259_set_irq_mask(irq_nr);
 119         spin_unlock_irqrestore(&i8259_lock, flags);
 120 }
 121
 122 static void i8259_unmask_irq(unsigned int irq_nr)
 123 {
 124         unsigned long flags;
 125
 126         pr_debug("i8259_unmask_irq(%d)\n", irq_nr);
 127
 128         spin_lock_irqsave(&i8259_lock, flags);
 129         if (irq_nr < 8)
 130                 cached_21 &= ~(1 << irq_nr);
 131         else
 132                 cached_A1 &= ~(1 << (irq_nr-8));
 133         i8259_set_irq_mask(irq_nr);
 134         spin_unlock_irqrestore(&i8259_lock, flags);
 135 }
 136
 137 static struct irq_chip i8259_pic = {
 138         .typename       = " i8259    ",
 139         .mask           = i8259_mask_irq,
 140         .disable        = i8259_mask_irq,
 141         .unmask         = i8259_unmask_irq,
 142         .mask_ack       = i8259_mask_and_ack_irq,
 143 };
 144
 145 static struct resource pic1_iores = {
 146         .name = "8259 (master)",
 147         .start = 0x20,
 148         .end = 0x21,
 149         .flags = IORESOURCE_BUSY,
 150 };
 151
 152 static struct resource pic2_iores = {
 153         .name = "8259 (slave)",
 154         .start = 0xa0,
 155         .end = 0xa1,
 156         .flags = IORESOURCE_BUSY,
 157 };
 158
 159 static struct resource pic_edgectrl_iores = {
 160         .name = "8259 edge control",
 161         .start = 0x4d0,
 162         .end = 0x4d1,
 163         .flags = IORESOURCE_BUSY,
 164 };
 165
 166 static int i8259_host_match(struct irq_host *h, struct device_node *node)
 167 {
 168         return h->of_node == NULL || h->of_node == node;
 169 }
 170
 171 static int i8259_host_map(struct irq_host *h, unsigned int virq,
 172                           irq_hw_number_t hw)
 173 {
 174         pr_debug("i8259_host_map(%d, 0x%lx)\n", virq, hw);
 175
 176         /* We block the internal cascade */
 177         if (hw == 2)
 178                 get_irq_desc(virq)->status |= IRQ_NOREQUEST;
 179
 180         /* We use the level handler only for now, we might want to
 181          * be more cautious here but that works for now
 182          */
 183         get_irq_desc(virq)->status |= IRQ_LEVEL;
 184         set_irq_chip_and_handler(virq, &i8259_pic, handle_level_irq);
 185         return 0;
 186 }
 187
 188 static void i8259_host_unmap(struct irq_host *h, unsigned int virq)
 189 {
 190         /* Make sure irq is masked in hardware */
 191         i8259_mask_irq(virq);
 192
 193         /* remove chip and handler */
 194         set_irq_chip_and_handler(virq, NULL, NULL);
 195
 196         /* Make sure it's completed */
 197         synchronize_irq(virq);
 198 }
 199
 200 static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
 201                             u32 *intspec, unsigned int intsize,
 202                             irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 203 {
 204         static unsigned char map_isa_senses[4] = {
 205                 IRQ_TYPE_LEVEL_LOW,
 206                 IRQ_TYPE_LEVEL_HIGH,
 207                 IRQ_TYPE_EDGE_FALLING,
 208                 IRQ_TYPE_EDGE_RISING,
 209         };
 210
 211         *out_hwirq = intspec[0];
 212         if (intsize > 1 && intspec[1] < 4)
 213                 *out_flags = map_isa_senses[intspec[1]];
 214         else
 215                 *out_flags = IRQ_TYPE_NONE;
 216
 217         return 0;
 218 }
 219
 220 static struct irq_host_ops i8259_host_ops = {
 221         .match = i8259_host_match,
 222         .map = i8259_host_map,
 223         .unmap = i8259_host_unmap,
 224         .xlate = i8259_host_xlate,
 225 };
 226
 227 struct irq_host *i8259_get_host(void)
 228 {
 229         return i8259_host;
 230 }
 231
 232 /**
 233  * i8259_init - Initialize the legacy controller
 234  * @node: device node of the legacy PIC (can be NULL, but then, it will match
 235  *        all interrupts, so beware)
 236  * @intack_addr: PCI interrupt acknowledge (real) address which will return
 237  *               the active irq from the 8259
 238  */
 239 void i8259_init(struct device_node *node, unsigned long intack_addr)
 240 {
 241         unsigned long flags;
 242
 243         /* initialize the controller */
 244         spin_lock_irqsave(&i8259_lock, flags);
 245
 246         /* Mask all first */
 247         outb(0xff, 0xA1);
 248         outb(0xff, 0x21);
 249
 250         /* init master interrupt controller */
 251         outb(0x11, 0x20); /* Start init sequence */
 252         outb(0x00, 0x21); /* Vector base */
 253         outb(0x04, 0x21); /* edge tiggered, Cascade (slave) on IRQ2 */
 254         outb(0x01, 0x21); /* Select 8086 mode */
 255
 256         /* init slave interrupt controller */
 257         outb(0x11, 0xA0); /* Start init sequence */
 258         outb(0x08, 0xA1); /* Vector base */
 259         outb(0x02, 0xA1); /* edge triggered, Cascade (slave) on IRQ2 */
 260         outb(0x01, 0xA1); /* Select 8086 mode */
 261
 262         /* That thing is slow */
 263         udelay(100);
 264
 265         /* always read ISR */
 266         outb(0x0B, 0x20);
 267         outb(0x0B, 0xA0);
 268
 269         /* Unmask the internal cascade */
 270         cached_21 &= ~(1 << 2);
 271
 272         /* Set interrupt masks */
 273         outb(cached_A1, 0xA1);
 274         outb(cached_21, 0x21);
 275
 276         spin_unlock_irqrestore(&i8259_lock, flags);
 277
 278         /* create a legacy host */
 279         i8259_host = irq_alloc_host(of_node_get(node), IRQ_HOST_MAP_LEGACY,
 280                                     0, &i8259_host_ops, 0);
 281         if (i8259_host == NULL) {
 282                 printk(KERN_ERR "i8259: failed to allocate irq host !\n");
 283                 return;
 284         }
 285
 286         /* reserve our resources */
 287         /* XXX should we continue doing that ? it seems to cause problems
 288          * with further requesting of PCI IO resources for that range...
 289          * need to look into it.
 290          */
 291         request_resource(&ioport_resource, &pic1_iores);
 292         request_resource(&ioport_resource, &pic2_iores);
 293         request_resource(&ioport_resource, &pic_edgectrl_iores);
 294
 295         if (intack_addr != 0)
 296                 pci_intack = ioremap(intack_addr, 1);
 297
 298         printk(KERN_INFO "i8259 legacy interrupt controller initialized\n");
 299 }