arch/powerpc/platforms/wsp/opb_pic.c

   1 /*
   2  * IBM Onboard Peripheral Bus Interrupt Controller
   3  *
   4  * Copyright 2010 Jack Miller, IBM Corporation.
   5  *
   6  * This program is free software; you can redistribute  it and/or modify it
   7  * under  the terms of  the GNU General  Public License as published by the
   8  * Free Software Foundation;  either version 2 of the  License, or (at your
   9  * option) any later version.
  10  */
  11
  12 #include <linux/interrupt.h>
  13 #include <linux/io.h>
  14 #include <linux/irq.h>
  15 #include <linux/of.h>
  16 #include <linux/slab.h>
  17 #include <linux/time.h>
  18
  19 #include <asm/reg_a2.h>
  20 #include <asm/irq.h>
  21
  22 #define OPB_NR_IRQS 32
  23
  24 #define OPB_MLSASIER    0x04    /* MLS Accumulated Status IER */
  25 #define OPB_MLSIR       0x50    /* MLS Interrupt Register */
  26 #define OPB_MLSIER      0x54    /* MLS Interrupt Enable Register */
  27 #define OPB_MLSIPR      0x58    /* MLS Interrupt Polarity Register */
  28 #define OPB_MLSIIR      0x5c    /* MLS Interrupt Inputs Register */
  29
  30 static int opb_index = 0;
  31
  32 struct opb_pic {
  33         struct irq_domain *host;
  34         void *regs;
  35         int index;
  36         spinlock_t lock;
  37 };
  38
  39 static u32 opb_in(struct opb_pic *opb, int offset)
  40 {
  41         return in_be32(opb->regs + offset);
  42 }
  43
  44 static void opb_out(struct opb_pic *opb, int offset, u32 val)
  45 {
  46         out_be32(opb->regs + offset, val);
  47 }
  48
  49 static void opb_unmask_irq(struct irq_data *d)
  50 {
  51         struct opb_pic *opb;
  52         unsigned long flags;
  53         u32 ier, bitset;
  54
  55         opb = d->chip_data;
  56         bitset = (1 << (31 - irqd_to_hwirq(d)));
  57
  58         spin_lock_irqsave(&opb->lock, flags);
  59
  60         ier = opb_in(opb, OPB_MLSIER);
  61         opb_out(opb, OPB_MLSIER, ier | bitset);
  62         ier = opb_in(opb, OPB_MLSIER);
  63
  64         spin_unlock_irqrestore(&opb->lock, flags);
  65 }
  66
  67 static void opb_mask_irq(struct irq_data *d)
  68 {
  69         struct opb_pic *opb;
  70         unsigned long flags;
  71         u32 ier, mask;
  72
  73         opb = d->chip_data;
  74         mask = ~(1 << (31 - irqd_to_hwirq(d)));
  75
  76         spin_lock_irqsave(&opb->lock, flags);
  77
  78         ier = opb_in(opb, OPB_MLSIER);
  79         opb_out(opb, OPB_MLSIER, ier & mask);
  80         ier = opb_in(opb, OPB_MLSIER); // Flush posted writes
  81
  82         spin_unlock_irqrestore(&opb->lock, flags);
  83 }
  84
  85 static void opb_ack_irq(struct irq_data *d)
  86 {
  87         struct opb_pic *opb;
  88         unsigned long flags;
  89         u32 bitset;
  90
  91         opb = d->chip_data;
  92         bitset = (1 << (31 - irqd_to_hwirq(d)));
  93
  94         spin_lock_irqsave(&opb->lock, flags);
  95
  96         opb_out(opb, OPB_MLSIR, bitset);
  97         opb_in(opb, OPB_MLSIR); // Flush posted writes
  98
  99         spin_unlock_irqrestore(&opb->lock, flags);
 100 }
 101
 102 static void opb_mask_ack_irq(struct irq_data *d)
 103 {
 104         struct opb_pic *opb;
 105         unsigned long flags;
 106         u32 bitset;
 107         u32 ier, ir;
 108
 109         opb = d->chip_data;
 110         bitset = (1 << (31 - irqd_to_hwirq(d)));
 111
 112         spin_lock_irqsave(&opb->lock, flags);
 113
 114         ier = opb_in(opb, OPB_MLSIER);
 115         opb_out(opb, OPB_MLSIER, ier & ~bitset);
 116         ier = opb_in(opb, OPB_MLSIER); // Flush posted writes
 117
 118         opb_out(opb, OPB_MLSIR, bitset);
 119         ir = opb_in(opb, OPB_MLSIR); // Flush posted writes
 120
 121         spin_unlock_irqrestore(&opb->lock, flags);
 122 }
 123
 124 static int opb_set_irq_type(struct irq_data *d, unsigned int flow)
 125 {
 126         struct opb_pic *opb;
 127         unsigned long flags;
 128         int invert, ipr, mask, bit;
 129
 130         opb = d->chip_data;
 131
 132         /* The only information we're interested in in the type is whether it's
 133          * a high or low trigger. For high triggered interrupts, the polarity
 134          * set for it in the MLS Interrupt Polarity Register is 0, for low
 135          * interrupts it's 1 so that the proper input in the MLS Interrupt Input
 136          * Register is interrupted as asserting the interrupt. */
 137
 138         switch (flow) {
 139                 case IRQ_TYPE_NONE:
 140                         opb_mask_irq(d);
 141                         return 0;
 142
 143                 case IRQ_TYPE_LEVEL_HIGH:
 144                         invert = 0;
 145                         break;
 146
 147                 case IRQ_TYPE_LEVEL_LOW:
 148                         invert = 1;
 149                         break;
 150
 151                 default:
 152                         return -EINVAL;
 153         }
 154
 155         bit = (1 << (31 - irqd_to_hwirq(d)));
 156         mask = ~bit;
 157
 158         spin_lock_irqsave(&opb->lock, flags);
 159
 160         ipr = opb_in(opb, OPB_MLSIPR);
 161         ipr = (ipr & mask) | (invert ? bit : 0);
 162         opb_out(opb, OPB_MLSIPR, ipr);
 163         ipr = opb_in(opb, OPB_MLSIPR);  // Flush posted writes
 164
 165         spin_unlock_irqrestore(&opb->lock, flags);
 166
 167         /* Record the type in the interrupt descriptor */
 168         irqd_set_trigger_type(d, flow);
 169
 170         return 0;
 171 }
 172
 173 static struct irq_chip opb_irq_chip = {
 174         .name           = "OPB",
 175         .irq_mask       = opb_mask_irq,
 176         .irq_unmask     = opb_unmask_irq,
 177         .irq_mask_ack   = opb_mask_ack_irq,
 178         .irq_ack        = opb_ack_irq,
 179         .irq_set_type   = opb_set_irq_type
 180 };
 181
 182 static int opb_host_map(struct irq_domain *host, unsigned int virq,
 183                 irq_hw_number_t hwirq)
 184 {
 185         struct opb_pic *opb;
 186
 187         opb = host->host_data;
 188
 189         /* Most of the important stuff is handled by the generic host code, like
 190          * the lookup, so just attach some info to the virtual irq */
 191
 192         irq_set_chip_data(virq, opb);
 193         irq_set_chip_and_handler(virq, &opb_irq_chip, handle_level_irq);
 194         irq_set_irq_type(virq, IRQ_TYPE_NONE);
 195
 196         return 0;
 197 }
 198
 199 static const struct irq_domain_ops opb_host_ops = {
 200         .map = opb_host_map,
 201         .xlate = irq_domain_xlate_twocell,
 202 };
 203
 204 irqreturn_t opb_irq_handler(int irq, void *private)
 205 {
 206         struct opb_pic *opb;
 207         u32 ir, src, subvirq;
 208
 209         opb = (struct opb_pic *) private;
 210
 211         /* Read the OPB MLS Interrupt Register for
 212          * asserted interrupts */
 213         ir = opb_in(opb, OPB_MLSIR);
 214         if (!ir)
 215                 return IRQ_NONE;
 216
 217         do {
 218                 /* Get 1 - 32 source, *NOT* bit */
 219                 src = 32 - ffs(ir);
 220
 221                 /* Translate from the OPB's conception of interrupt number to
 222                  * Linux's virtual IRQ */
 223
 224                 subvirq = irq_linear_revmap(opb->host, src);
 225
 226                 generic_handle_irq(subvirq);
 227         } while ((ir = opb_in(opb, OPB_MLSIR)));
 228
 229         return IRQ_HANDLED;
 230 }
 231
 232 struct opb_pic *opb_pic_init_one(struct device_node *dn)
 233 {
 234         struct opb_pic *opb;
 235         struct resource res;
 236
 237         if (of_address_to_resource(dn, 0, &res)) {
 238                 printk(KERN_ERR "opb: Couldn't translate resource\n");
 239                 return  NULL;
 240         }
 241
 242         opb = kzalloc(sizeof(struct opb_pic), GFP_KERNEL);
 243         if (!opb) {
 244                 printk(KERN_ERR "opb: Failed to allocate opb struct!\n");
 245                 return NULL;
 246         }
 247
 248         /* Get access to the OPB MMIO registers */
 249         opb->regs = ioremap(res.start + 0x10000, 0x1000);
 250         if (!opb->regs) {
 251                 printk(KERN_ERR "opb: Failed to allocate register space!\n");
 252                 goto free_opb;
 253         }
 254
 255         /* Allocate an irq domain so that Linux knows that despite only
 256          * having one interrupt to issue, we're the controller for multiple
 257          * hardware IRQs, so later we can lookup their virtual IRQs. */
 258
 259         opb->host = irq_domain_add_linear(dn, OPB_NR_IRQS, &opb_host_ops, opb);
 260         if (!opb->host) {
 261                 printk(KERN_ERR "opb: Failed to allocate IRQ host!\n");
 262                 goto free_regs;
 263         }
 264
 265         opb->index = opb_index++;
 266         spin_lock_init(&opb->lock);
 267
 268         /* Disable all interrupts by default */
 269         opb_out(opb, OPB_MLSASIER, 0);
 270         opb_out(opb, OPB_MLSIER, 0);
 271
 272         /* ACK any interrupts left by FW */
 273         opb_out(opb, OPB_MLSIR, 0xFFFFFFFF);
 274
 275         return opb;
 276
 277 free_regs:
 278         iounmap(opb->regs);
 279 free_opb:
 280         kfree(opb);
 281         return NULL;
 282 }
 283
 284 void __init opb_pic_init(void)
 285 {
 286         struct device_node *dn;
 287         struct opb_pic *opb;
 288         int virq;
 289         int rc;
 290
 291         /* Call init_one for each OPB device */
 292         for_each_compatible_node(dn, NULL, "ibm,opb") {
 293
 294                 /* Fill in an OPB struct */
 295                 opb = opb_pic_init_one(dn);
 296                 if (!opb) {
 297                         printk(KERN_WARNING "opb: Failed to init node, skipped!\n");
 298                         continue;
 299                 }
 300
 301                 /* Map / get opb's hardware virtual irq */
 302                 virq = irq_of_parse_and_map(dn, 0);
 303                 if (virq <= 0) {
 304                         printk("opb: irq_op_parse_and_map failed!\n");
 305                         continue;
 306                 }
 307
 308                 /* Attach opb interrupt handler to new virtual IRQ */
 309                 rc = request_irq(virq, opb_irq_handler, IRQF_NO_THREAD,
 310                                  "OPB LS Cascade", opb);
 311                 if (rc) {
 312                         printk("opb: request_irq failed: %d\n", rc);
 313                         continue;
 314                 }
 315
 316                 printk("OPB%d init with %d IRQs at %p\n", opb->index,
 317                                 OPB_NR_IRQS, opb->regs);
 318         }
 319 }