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