linux/arch/powerpc/sysdev/uic.c
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   1/*
   2 * arch/powerpc/sysdev/uic.c
   3 *
   4 * IBM PowerPC 4xx Universal Interrupt Controller
   5 *
   6 * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
   7 *
   8 * This program is free software; you can redistribute  it and/or modify it
   9 * under  the terms of  the GNU General  Public License as published by the
  10 * Free Software Foundation;  either version 2 of the  License, or (at your
  11 * option) any later version.
  12 */
  13#include <linux/kernel.h>
  14#include <linux/init.h>
  15#include <linux/errno.h>
  16#include <linux/reboot.h>
  17#include <linux/slab.h>
  18#include <linux/stddef.h>
  19#include <linux/sched.h>
  20#include <linux/signal.h>
  21#include <linux/sysdev.h>
  22#include <linux/device.h>
  23#include <linux/bootmem.h>
  24#include <linux/spinlock.h>
  25#include <linux/irq.h>
  26#include <linux/interrupt.h>
  27#include <linux/kernel_stat.h>
  28#include <asm/irq.h>
  29#include <asm/io.h>
  30#include <asm/prom.h>
  31#include <asm/dcr.h>
  32
  33#define NR_UIC_INTS     32
  34
  35#define UIC_SR          0x0
  36#define UIC_ER          0x2
  37#define UIC_CR          0x3
  38#define UIC_PR          0x4
  39#define UIC_TR          0x5
  40#define UIC_MSR         0x6
  41#define UIC_VR          0x7
  42#define UIC_VCR         0x8
  43
  44struct uic *primary_uic;
  45
  46struct uic {
  47        int index;
  48        int dcrbase;
  49
  50        spinlock_t lock;
  51
  52        /* The remapper for this UIC */
  53        struct irq_host *irqhost;
  54};
  55
  56static void uic_unmask_irq(struct irq_data *d)
  57{
  58        struct uic *uic = irq_data_get_irq_chip_data(d);
  59        unsigned int src = irqd_to_hwirq(d);
  60        unsigned long flags;
  61        u32 er, sr;
  62
  63        sr = 1 << (31-src);
  64        spin_lock_irqsave(&uic->lock, flags);
  65        /* ack level-triggered interrupts here */
  66        if (irqd_is_level_type(d))
  67                mtdcr(uic->dcrbase + UIC_SR, sr);
  68        er = mfdcr(uic->dcrbase + UIC_ER);
  69        er |= sr;
  70        mtdcr(uic->dcrbase + UIC_ER, er);
  71        spin_unlock_irqrestore(&uic->lock, flags);
  72}
  73
  74static void uic_mask_irq(struct irq_data *d)
  75{
  76        struct uic *uic = irq_data_get_irq_chip_data(d);
  77        unsigned int src = irqd_to_hwirq(d);
  78        unsigned long flags;
  79        u32 er;
  80
  81        spin_lock_irqsave(&uic->lock, flags);
  82        er = mfdcr(uic->dcrbase + UIC_ER);
  83        er &= ~(1 << (31 - src));
  84        mtdcr(uic->dcrbase + UIC_ER, er);
  85        spin_unlock_irqrestore(&uic->lock, flags);
  86}
  87
  88static void uic_ack_irq(struct irq_data *d)
  89{
  90        struct uic *uic = irq_data_get_irq_chip_data(d);
  91        unsigned int src = irqd_to_hwirq(d);
  92        unsigned long flags;
  93
  94        spin_lock_irqsave(&uic->lock, flags);
  95        mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
  96        spin_unlock_irqrestore(&uic->lock, flags);
  97}
  98
  99static void uic_mask_ack_irq(struct irq_data *d)
 100{
 101        struct uic *uic = irq_data_get_irq_chip_data(d);
 102        unsigned int src = irqd_to_hwirq(d);
 103        unsigned long flags;
 104        u32 er, sr;
 105
 106        sr = 1 << (31-src);
 107        spin_lock_irqsave(&uic->lock, flags);
 108        er = mfdcr(uic->dcrbase + UIC_ER);
 109        er &= ~sr;
 110        mtdcr(uic->dcrbase + UIC_ER, er);
 111        /* On the UIC, acking (i.e. clearing the SR bit)
 112         * a level irq will have no effect if the interrupt
 113         * is still asserted by the device, even if
 114         * the interrupt is already masked. Therefore
 115         * we only ack the egde interrupts here, while
 116         * level interrupts are ack'ed after the actual
 117         * isr call in the uic_unmask_irq()
 118         */
 119        if (!irqd_is_level_type(d))
 120                mtdcr(uic->dcrbase + UIC_SR, sr);
 121        spin_unlock_irqrestore(&uic->lock, flags);
 122}
 123
 124static int uic_set_irq_type(struct irq_data *d, unsigned int flow_type)
 125{
 126        struct uic *uic = irq_data_get_irq_chip_data(d);
 127        unsigned int src = irqd_to_hwirq(d);
 128        unsigned long flags;
 129        int trigger, polarity;
 130        u32 tr, pr, mask;
 131
 132        switch (flow_type & IRQ_TYPE_SENSE_MASK) {
 133        case IRQ_TYPE_NONE:
 134                uic_mask_irq(d);
 135                return 0;
 136
 137        case IRQ_TYPE_EDGE_RISING:
 138                trigger = 1; polarity = 1;
 139                break;
 140        case IRQ_TYPE_EDGE_FALLING:
 141                trigger = 1; polarity = 0;
 142                break;
 143        case IRQ_TYPE_LEVEL_HIGH:
 144                trigger = 0; polarity = 1;
 145                break;
 146        case IRQ_TYPE_LEVEL_LOW:
 147                trigger = 0; polarity = 0;
 148                break;
 149        default:
 150                return -EINVAL;
 151        }
 152
 153        mask = ~(1 << (31 - src));
 154
 155        spin_lock_irqsave(&uic->lock, flags);
 156        tr = mfdcr(uic->dcrbase + UIC_TR);
 157        pr = mfdcr(uic->dcrbase + UIC_PR);
 158        tr = (tr & mask) | (trigger << (31-src));
 159        pr = (pr & mask) | (polarity << (31-src));
 160
 161        mtdcr(uic->dcrbase + UIC_PR, pr);
 162        mtdcr(uic->dcrbase + UIC_TR, tr);
 163
 164        spin_unlock_irqrestore(&uic->lock, flags);
 165
 166        return 0;
 167}
 168
 169static struct irq_chip uic_irq_chip = {
 170        .name           = "UIC",
 171        .irq_unmask     = uic_unmask_irq,
 172        .irq_mask       = uic_mask_irq,
 173        .irq_mask_ack   = uic_mask_ack_irq,
 174        .irq_ack        = uic_ack_irq,
 175        .irq_set_type   = uic_set_irq_type,
 176};
 177
 178static int uic_host_map(struct irq_host *h, unsigned int virq,
 179                        irq_hw_number_t hw)
 180{
 181        struct uic *uic = h->host_data;
 182
 183        irq_set_chip_data(virq, uic);
 184        /* Despite the name, handle_level_irq() works for both level
 185         * and edge irqs on UIC.  FIXME: check this is correct */
 186        irq_set_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
 187
 188        /* Set default irq type */
 189        irq_set_irq_type(virq, IRQ_TYPE_NONE);
 190
 191        return 0;
 192}
 193
 194static int uic_host_xlate(struct irq_host *h, struct device_node *ct,
 195                          const u32 *intspec, unsigned int intsize,
 196                          irq_hw_number_t *out_hwirq, unsigned int *out_type)
 197
 198{
 199        /* UIC intspecs must have 2 cells */
 200        BUG_ON(intsize != 2);
 201        *out_hwirq = intspec[0];
 202        *out_type = intspec[1];
 203        return 0;
 204}
 205
 206static struct irq_host_ops uic_host_ops = {
 207        .map    = uic_host_map,
 208        .xlate  = uic_host_xlate,
 209};
 210
 211void uic_irq_cascade(unsigned int virq, struct irq_desc *desc)
 212{
 213        struct irq_chip *chip = irq_desc_get_chip(desc);
 214        struct irq_data *idata = irq_desc_get_irq_data(desc);
 215        struct uic *uic = irq_get_handler_data(virq);
 216        u32 msr;
 217        int src;
 218        int subvirq;
 219
 220        raw_spin_lock(&desc->lock);
 221        if (irqd_is_level_type(idata))
 222                chip->irq_mask(idata);
 223        else
 224                chip->irq_mask_ack(idata);
 225        raw_spin_unlock(&desc->lock);
 226
 227        msr = mfdcr(uic->dcrbase + UIC_MSR);
 228        if (!msr) /* spurious interrupt */
 229                goto uic_irq_ret;
 230
 231        src = 32 - ffs(msr);
 232
 233        subvirq = irq_linear_revmap(uic->irqhost, src);
 234        generic_handle_irq(subvirq);
 235
 236uic_irq_ret:
 237        raw_spin_lock(&desc->lock);
 238        if (irqd_is_level_type(idata))
 239                chip->irq_ack(idata);
 240        if (!irqd_irq_disabled(idata) && chip->irq_unmask)
 241                chip->irq_unmask(idata);
 242        raw_spin_unlock(&desc->lock);
 243}
 244
 245static struct uic * __init uic_init_one(struct device_node *node)
 246{
 247        struct uic *uic;
 248        const u32 *indexp, *dcrreg;
 249        int len;
 250
 251        BUG_ON(! of_device_is_compatible(node, "ibm,uic"));
 252
 253        uic = kzalloc(sizeof(*uic), GFP_KERNEL);
 254        if (! uic)
 255                return NULL; /* FIXME: panic? */
 256
 257        spin_lock_init(&uic->lock);
 258        indexp = of_get_property(node, "cell-index", &len);
 259        if (!indexp || (len != sizeof(u32))) {
 260                printk(KERN_ERR "uic: Device node %s has missing or invalid "
 261                       "cell-index property\n", node->full_name);
 262                return NULL;
 263        }
 264        uic->index = *indexp;
 265
 266        dcrreg = of_get_property(node, "dcr-reg", &len);
 267        if (!dcrreg || (len != 2*sizeof(u32))) {
 268                printk(KERN_ERR "uic: Device node %s has missing or invalid "
 269                       "dcr-reg property\n", node->full_name);
 270                return NULL;
 271        }
 272        uic->dcrbase = *dcrreg;
 273
 274        uic->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR,
 275                                      NR_UIC_INTS, &uic_host_ops, -1);
 276        if (! uic->irqhost)
 277                return NULL; /* FIXME: panic? */
 278
 279        uic->irqhost->host_data = uic;
 280
 281        /* Start with all interrupts disabled, level and non-critical */
 282        mtdcr(uic->dcrbase + UIC_ER, 0);
 283        mtdcr(uic->dcrbase + UIC_CR, 0);
 284        mtdcr(uic->dcrbase + UIC_TR, 0);
 285        /* Clear any pending interrupts, in case the firmware left some */
 286        mtdcr(uic->dcrbase + UIC_SR, 0xffffffff);
 287
 288        printk ("UIC%d (%d IRQ sources) at DCR 0x%x\n", uic->index,
 289                NR_UIC_INTS, uic->dcrbase);
 290
 291        return uic;
 292}
 293
 294void __init uic_init_tree(void)
 295{
 296        struct device_node *np;
 297        struct uic *uic;
 298        const u32 *interrupts;
 299
 300        /* First locate and initialize the top-level UIC */
 301        for_each_compatible_node(np, NULL, "ibm,uic") {
 302                interrupts = of_get_property(np, "interrupts", NULL);
 303                if (!interrupts)
 304                        break;
 305        }
 306
 307        BUG_ON(!np); /* uic_init_tree() assumes there's a UIC as the
 308                      * top-level interrupt controller */
 309        primary_uic = uic_init_one(np);
 310        if (!primary_uic)
 311                panic("Unable to initialize primary UIC %s\n", np->full_name);
 312
 313        irq_set_default_host(primary_uic->irqhost);
 314        of_node_put(np);
 315
 316        /* The scan again for cascaded UICs */
 317        for_each_compatible_node(np, NULL, "ibm,uic") {
 318                interrupts = of_get_property(np, "interrupts", NULL);
 319                if (interrupts) {
 320                        /* Secondary UIC */
 321                        int cascade_virq;
 322
 323                        uic = uic_init_one(np);
 324                        if (! uic)
 325                                panic("Unable to initialize a secondary UIC %s\n",
 326                                      np->full_name);
 327
 328                        cascade_virq = irq_of_parse_and_map(np, 0);
 329
 330                        irq_set_handler_data(cascade_virq, uic);
 331                        irq_set_chained_handler(cascade_virq, uic_irq_cascade);
 332
 333                        /* FIXME: setup critical cascade?? */
 334                }
 335        }
 336}
 337
 338/* Return an interrupt vector or NO_IRQ if no interrupt is pending. */
 339unsigned int uic_get_irq(void)
 340{
 341        u32 msr;
 342        int src;
 343
 344        BUG_ON(! primary_uic);
 345
 346        msr = mfdcr(primary_uic->dcrbase + UIC_MSR);
 347        src = 32 - ffs(msr);
 348
 349        return irq_linear_revmap(primary_uic->irqhost, src);
 350}
 351