arch/powerpc/platforms/4xx/uic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * arch/powerpc/sysdev/uic.c
   4  *
   5  * IBM PowerPC 4xx Universal Interrupt Controller
   6  *
   7  * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/errno.h>
  12 #include <linux/reboot.h>
  13 #include <linux/slab.h>
  14 #include <linux/stddef.h>
  15 #include <linux/sched.h>
  16 #include <linux/signal.h>
  17 #include <linux/device.h>
  18 #include <linux/spinlock.h>
  19 #include <linux/irq.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/kernel_stat.h>
  22 #include <asm/irq.h>
  23 #include <asm/io.h>
  24 #include <asm/prom.h>
  25 #include <asm/dcr.h>
  26
  27 #define NR_UIC_INTS     32
  28
  29 #define UIC_SR          0x0
  30 #define UIC_ER          0x2
  31 #define UIC_CR          0x3
  32 #define UIC_PR          0x4
  33 #define UIC_TR          0x5
  34 #define UIC_MSR         0x6
  35 #define UIC_VR          0x7
  36 #define UIC_VCR         0x8
  37
  38 struct uic *primary_uic;
  39
  40 struct uic {
  41         int index;
  42         int dcrbase;
  43
  44         raw_spinlock_t lock;
  45
  46         /* The remapper for this UIC */
  47         struct irq_domain       *irqhost;
  48 };
  49
  50 static void uic_unmask_irq(struct irq_data *d)
  51 {
  52         struct uic *uic = irq_data_get_irq_chip_data(d);
  53         unsigned int src = irqd_to_hwirq(d);
  54         unsigned long flags;
  55         u32 er, sr;
  56
  57         sr = 1 << (31-src);
  58         raw_spin_lock_irqsave(&uic->lock, flags);
  59         /* ack level-triggered interrupts here */
  60         if (irqd_is_level_type(d))
  61                 mtdcr(uic->dcrbase + UIC_SR, sr);
  62         er = mfdcr(uic->dcrbase + UIC_ER);
  63         er |= sr;
  64         mtdcr(uic->dcrbase + UIC_ER, er);
  65         raw_spin_unlock_irqrestore(&uic->lock, flags);
  66 }
  67
  68 static void uic_mask_irq(struct irq_data *d)
  69 {
  70         struct uic *uic = irq_data_get_irq_chip_data(d);
  71         unsigned int src = irqd_to_hwirq(d);
  72         unsigned long flags;
  73         u32 er;
  74
  75         raw_spin_lock_irqsave(&uic->lock, flags);
  76         er = mfdcr(uic->dcrbase + UIC_ER);
  77         er &= ~(1 << (31 - src));
  78         mtdcr(uic->dcrbase + UIC_ER, er);
  79         raw_spin_unlock_irqrestore(&uic->lock, flags);
  80 }
  81
  82 static void uic_ack_irq(struct irq_data *d)
  83 {
  84         struct uic *uic = irq_data_get_irq_chip_data(d);
  85         unsigned int src = irqd_to_hwirq(d);
  86         unsigned long flags;
  87
  88         raw_spin_lock_irqsave(&uic->lock, flags);
  89         mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
  90         raw_spin_unlock_irqrestore(&uic->lock, flags);
  91 }
  92
  93 static void uic_mask_ack_irq(struct irq_data *d)
  94 {
  95         struct uic *uic = irq_data_get_irq_chip_data(d);
  96         unsigned int src = irqd_to_hwirq(d);
  97         unsigned long flags;
  98         u32 er, sr;
  99
 100         sr = 1 << (31-src);
 101         raw_spin_lock_irqsave(&uic->lock, flags);
 102         er = mfdcr(uic->dcrbase + UIC_ER);
 103         er &= ~sr;
 104         mtdcr(uic->dcrbase + UIC_ER, er);
 105         /* On the UIC, acking (i.e. clearing the SR bit)
 106          * a level irq will have no effect if the interrupt
 107          * is still asserted by the device, even if
 108          * the interrupt is already masked. Therefore
 109          * we only ack the egde interrupts here, while
 110          * level interrupts are ack'ed after the actual
 111          * isr call in the uic_unmask_irq()
 112          */
 113         if (!irqd_is_level_type(d))
 114                 mtdcr(uic->dcrbase + UIC_SR, sr);
 115         raw_spin_unlock_irqrestore(&uic->lock, flags);
 116 }
 117
 118 static int uic_set_irq_type(struct irq_data *d, unsigned int flow_type)
 119 {
 120         struct uic *uic = irq_data_get_irq_chip_data(d);
 121         unsigned int src = irqd_to_hwirq(d);
 122         unsigned long flags;
 123         int trigger, polarity;
 124         u32 tr, pr, mask;
 125
 126         switch (flow_type & IRQ_TYPE_SENSE_MASK) {
 127         case IRQ_TYPE_NONE:
 128                 uic_mask_irq(d);
 129                 return 0;
 130
 131         case IRQ_TYPE_EDGE_RISING:
 132                 trigger = 1; polarity = 1;
 133                 break;
 134         case IRQ_TYPE_EDGE_FALLING:
 135                 trigger = 1; polarity = 0;
 136                 break;
 137         case IRQ_TYPE_LEVEL_HIGH:
 138                 trigger = 0; polarity = 1;
 139                 break;
 140         case IRQ_TYPE_LEVEL_LOW:
 141                 trigger = 0; polarity = 0;
 142                 break;
 143         default:
 144                 return -EINVAL;
 145         }
 146
 147         mask = ~(1 << (31 - src));
 148
 149         raw_spin_lock_irqsave(&uic->lock, flags);
 150         tr = mfdcr(uic->dcrbase + UIC_TR);
 151         pr = mfdcr(uic->dcrbase + UIC_PR);
 152         tr = (tr & mask) | (trigger << (31-src));
 153         pr = (pr & mask) | (polarity << (31-src));
 154
 155         mtdcr(uic->dcrbase + UIC_PR, pr);
 156         mtdcr(uic->dcrbase + UIC_TR, tr);
 157         mtdcr(uic->dcrbase + UIC_SR, ~mask);
 158
 159         raw_spin_unlock_irqrestore(&uic->lock, flags);
 160
 161         return 0;
 162 }
 163
 164 static struct irq_chip uic_irq_chip = {
 165         .name           = "UIC",
 166         .irq_unmask     = uic_unmask_irq,
 167         .irq_mask       = uic_mask_irq,
 168         .irq_mask_ack   = uic_mask_ack_irq,
 169         .irq_ack        = uic_ack_irq,
 170         .irq_set_type   = uic_set_irq_type,
 171 };
 172
 173 static int uic_host_map(struct irq_domain *h, unsigned int virq,
 174                         irq_hw_number_t hw)
 175 {
 176         struct uic *uic = h->host_data;
 177
 178         irq_set_chip_data(virq, uic);
 179         /* Despite the name, handle_level_irq() works for both level
 180          * and edge irqs on UIC.  FIXME: check this is correct */
 181         irq_set_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
 182
 183         /* Set default irq type */
 184         irq_set_irq_type(virq, IRQ_TYPE_NONE);
 185
 186         return 0;
 187 }
 188
 189 static const struct irq_domain_ops uic_host_ops = {
 190         .map    = uic_host_map,
 191         .xlate  = irq_domain_xlate_twocell,
 192 };
 193
 194 static void uic_irq_cascade(struct irq_desc *desc)
 195 {
 196         struct irq_chip *chip = irq_desc_get_chip(desc);
 197         struct irq_data *idata = irq_desc_get_irq_data(desc);
 198         struct uic *uic = irq_desc_get_handler_data(desc);
 199         u32 msr;
 200         int src;
 201         int subvirq;
 202
 203         raw_spin_lock(&desc->lock);
 204         if (irqd_is_level_type(idata))
 205                 chip->irq_mask(idata);
 206         else
 207                 chip->irq_mask_ack(idata);
 208         raw_spin_unlock(&desc->lock);
 209
 210         msr = mfdcr(uic->dcrbase + UIC_MSR);
 211         if (!msr) /* spurious interrupt */
 212                 goto uic_irq_ret;
 213
 214         src = 32 - ffs(msr);
 215
 216         subvirq = irq_linear_revmap(uic->irqhost, src);
 217         generic_handle_irq(subvirq);
 218
 219 uic_irq_ret:
 220         raw_spin_lock(&desc->lock);
 221         if (irqd_is_level_type(idata))
 222                 chip->irq_ack(idata);
 223         if (!irqd_irq_disabled(idata) && chip->irq_unmask)
 224                 chip->irq_unmask(idata);
 225         raw_spin_unlock(&desc->lock);
 226 }
 227
 228 static struct uic * __init uic_init_one(struct device_node *node)
 229 {
 230         struct uic *uic;
 231         const u32 *indexp, *dcrreg;
 232         int len;
 233
 234         BUG_ON(! of_device_is_compatible(node, "ibm,uic"));
 235
 236         uic = kzalloc(sizeof(*uic), GFP_KERNEL);
 237         if (! uic)
 238                 return NULL; /* FIXME: panic? */
 239
 240         raw_spin_lock_init(&uic->lock);
 241         indexp = of_get_property(node, "cell-index", &len);
 242         if (!indexp || (len != sizeof(u32))) {
 243                 printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
 244                        "cell-index property\n", node);
 245                 return NULL;
 246         }
 247         uic->index = *indexp;
 248
 249         dcrreg = of_get_property(node, "dcr-reg", &len);
 250         if (!dcrreg || (len != 2*sizeof(u32))) {
 251                 printk(KERN_ERR "uic: Device node %pOF has missing or invalid "
 252                        "dcr-reg property\n", node);
 253                 return NULL;
 254         }
 255         uic->dcrbase = *dcrreg;
 256
 257         uic->irqhost = irq_domain_add_linear(node, NR_UIC_INTS, &uic_host_ops,
 258                                              uic);
 259         if (! uic->irqhost)
 260                 return NULL; /* FIXME: panic? */
 261
 262         /* Start with all interrupts disabled, level and non-critical */
 263         mtdcr(uic->dcrbase + UIC_ER, 0);
 264         mtdcr(uic->dcrbase + UIC_CR, 0);
 265         mtdcr(uic->dcrbase + UIC_TR, 0);
 266         /* Clear any pending interrupts, in case the firmware left some */
 267         mtdcr(uic->dcrbase + UIC_SR, 0xffffffff);
 268
 269         printk ("UIC%d (%d IRQ sources) at DCR 0x%x\n", uic->index,
 270                 NR_UIC_INTS, uic->dcrbase);
 271
 272         return uic;
 273 }
 274
 275 void __init uic_init_tree(void)
 276 {
 277         struct device_node *np;
 278         struct uic *uic;
 279         const u32 *interrupts;
 280
 281         /* First locate and initialize the top-level UIC */
 282         for_each_compatible_node(np, NULL, "ibm,uic") {
 283                 interrupts = of_get_property(np, "interrupts", NULL);
 284                 if (!interrupts)
 285                         break;
 286         }
 287
 288         BUG_ON(!np); /* uic_init_tree() assumes there's a UIC as the
 289                       * top-level interrupt controller */
 290         primary_uic = uic_init_one(np);
 291         if (!primary_uic)
 292                 panic("Unable to initialize primary UIC %pOF\n", np);
 293
 294         irq_set_default_host(primary_uic->irqhost);
 295         of_node_put(np);
 296
 297         /* The scan again for cascaded UICs */
 298         for_each_compatible_node(np, NULL, "ibm,uic") {
 299                 interrupts = of_get_property(np, "interrupts", NULL);
 300                 if (interrupts) {
 301                         /* Secondary UIC */
 302                         int cascade_virq;
 303
 304                         uic = uic_init_one(np);
 305                         if (! uic)
 306                                 panic("Unable to initialize a secondary UIC %pOF\n",
 307                                       np);
 308
 309                         cascade_virq = irq_of_parse_and_map(np, 0);
 310
 311                         irq_set_handler_data(cascade_virq, uic);
 312                         irq_set_chained_handler(cascade_virq, uic_irq_cascade);
 313
 314                         /* FIXME: setup critical cascade?? */
 315                 }
 316         }
 317 }
 318
 319 /* Return an interrupt vector or 0 if no interrupt is pending. */
 320 unsigned int uic_get_irq(void)
 321 {
 322         u32 msr;
 323         int src;
 324
 325         BUG_ON(! primary_uic);
 326
 327         msr = mfdcr(primary_uic->dcrbase + UIC_MSR);
 328         src = 32 - ffs(msr);
 329
 330         return irq_linear_revmap(primary_uic->irqhost, src);
 331 }