arch/powerpc/platforms/powernv/opal-irqchip.c

   1 /*
   2  * This file implements an irqchip for OPAL events. Whenever there is
   3  * an interrupt that is handled by OPAL we get passed a list of events
   4  * that Linux needs to do something about. These basically look like
   5  * interrupts to Linux so we implement an irqchip to handle them.
   6  *
   7  * Copyright Alistair Popple, IBM Corporation 2014.
   8  *
   9  * This program is free software; you can redistribute  it and/or modify it
  10  * under  the terms of  the GNU General  Public License as published by the
  11  * Free Software Foundation;  either version 2 of the  License, or (at your
  12  * option) any later version.
  13  */
  14 #include <linux/bitops.h>
  15 #include <linux/irq.h>
  16 #include <linux/irqchip.h>
  17 #include <linux/irqdomain.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/kthread.h>
  23 #include <linux/delay.h>
  24 #include <linux/slab.h>
  25 #include <linux/irq_work.h>
  26
  27 #include <asm/machdep.h>
  28 #include <asm/opal.h>
  29
  30 #include "powernv.h"
  31
  32 /* Maximum number of events supported by OPAL firmware */
  33 #define MAX_NUM_EVENTS 64
  34
  35 struct opal_event_irqchip {
  36         struct irq_chip irqchip;
  37         struct irq_domain *domain;
  38         unsigned long mask;
  39 };
  40 static struct opal_event_irqchip opal_event_irqchip;
  41
  42 static unsigned int opal_irq_count;
  43 static unsigned int *opal_irqs;
  44
  45 static void opal_handle_irq_work(struct irq_work *work);
  46 static __be64 last_outstanding_events;
  47 static struct irq_work opal_event_irq_work = {
  48         .func = opal_handle_irq_work,
  49 };
  50
  51 static void opal_event_mask(struct irq_data *d)
  52 {
  53         clear_bit(d->hwirq, &opal_event_irqchip.mask);
  54 }
  55
  56 static void opal_event_unmask(struct irq_data *d)
  57 {
  58         set_bit(d->hwirq, &opal_event_irqchip.mask);
  59
  60         opal_poll_events(&last_outstanding_events);
  61         if (last_outstanding_events & opal_event_irqchip.mask)
  62                 /* Need to retrigger the interrupt */
  63                 irq_work_queue(&opal_event_irq_work);
  64 }
  65
  66 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
  67 {
  68         /*
  69          * For now we only support level triggered events. The irq
  70          * handler will be called continuously until the event has
  71          * been cleared in OPAL.
  72          */
  73         if (flow_type != IRQ_TYPE_LEVEL_HIGH)
  74                 return -EINVAL;
  75
  76         return 0;
  77 }
  78
  79 static struct opal_event_irqchip opal_event_irqchip = {
  80         .irqchip = {
  81                 .name = "OPAL EVT",
  82                 .irq_mask = opal_event_mask,
  83                 .irq_unmask = opal_event_unmask,
  84                 .irq_set_type = opal_event_set_type,
  85         },
  86         .mask = 0,
  87 };
  88
  89 static int opal_event_map(struct irq_domain *d, unsigned int irq,
  90                         irq_hw_number_t hwirq)
  91 {
  92         irq_set_chip_data(irq, &opal_event_irqchip);
  93         irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
  94                                 handle_level_irq);
  95
  96         return 0;
  97 }
  98
  99 void opal_handle_events(uint64_t events)
 100 {
 101         int virq, hwirq = 0;
 102         u64 mask = opal_event_irqchip.mask;
 103         u64 notifier_mask = 0;
 104
 105         if (!in_irq() && (events & mask)) {
 106                 last_outstanding_events = events;
 107                 irq_work_queue(&opal_event_irq_work);
 108                 return;
 109         }
 110
 111         while (events) {
 112                 hwirq = fls64(events) - 1;
 113                 virq = irq_find_mapping(opal_event_irqchip.domain,
 114                                         hwirq);
 115                 if (virq) {
 116                         if (BIT_ULL(hwirq) & mask)
 117                                 generic_handle_irq(virq);
 118                 } else
 119                         notifier_mask |= BIT_ULL(hwirq);
 120                 events &= ~BIT_ULL(hwirq);
 121         }
 122
 123         opal_do_notifier(notifier_mask);
 124 }
 125
 126 static irqreturn_t opal_interrupt(int irq, void *data)
 127 {
 128         __be64 events;
 129
 130         opal_handle_interrupt(virq_to_hw(irq), &events);
 131         opal_handle_events(be64_to_cpu(events));
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static void opal_handle_irq_work(struct irq_work *work)
 137 {
 138         opal_handle_events(be64_to_cpu(last_outstanding_events));
 139 }
 140
 141 static int opal_event_match(struct irq_domain *h, struct device_node *node)
 142 {
 143         return h->of_node == node;
 144 }
 145
 146 static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
 147                            const u32 *intspec, unsigned int intsize,
 148                            irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 149 {
 150         *out_hwirq = intspec[0];
 151         *out_flags = IRQ_TYPE_LEVEL_HIGH;
 152
 153         return 0;
 154 }
 155
 156 static const struct irq_domain_ops opal_event_domain_ops = {
 157         .match  = opal_event_match,
 158         .map    = opal_event_map,
 159         .xlate  = opal_event_xlate,
 160 };
 161
 162 void opal_event_shutdown(void)
 163 {
 164         unsigned int i;
 165
 166         /* First free interrupts, which will also mask them */
 167         for (i = 0; i < opal_irq_count; i++) {
 168                 if (opal_irqs[i])
 169                         free_irq(opal_irqs[i], NULL);
 170                 opal_irqs[i] = 0;
 171         }
 172 }
 173
 174 int __init opal_event_init(void)
 175 {
 176         struct device_node *dn, *opal_node;
 177         const __be32 *irqs;
 178         int i, irqlen, rc = 0;
 179
 180         opal_node = of_find_node_by_path("/ibm,opal");
 181         if (!opal_node) {
 182                 pr_warn("opal: Node not found\n");
 183                 return -ENODEV;
 184         }
 185
 186         /* If dn is NULL it means the domain won't be linked to a DT
 187          * node so therefore irq_of_parse_and_map(...) wont work. But
 188          * that shouldn't be problem because if we're running a
 189          * version of skiboot that doesn't have the dn then the
 190          * devices won't have the correct properties and will have to
 191          * fall back to the legacy method (opal_event_request(...))
 192          * anyway. */
 193         dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
 194         opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
 195                                 &opal_event_domain_ops, &opal_event_irqchip);
 196         of_node_put(dn);
 197         if (!opal_event_irqchip.domain) {
 198                 pr_warn("opal: Unable to create irq domain\n");
 199                 rc = -ENOMEM;
 200                 goto out;
 201         }
 202
 203         /* Get interrupt property */
 204         irqs = of_get_property(opal_node, "opal-interrupts", &irqlen);
 205         opal_irq_count = irqs ? (irqlen / 4) : 0;
 206         pr_debug("Found %d interrupts reserved for OPAL\n", opal_irq_count);
 207
 208         /* Install interrupt handlers */
 209         opal_irqs = kcalloc(opal_irq_count, sizeof(*opal_irqs), GFP_KERNEL);
 210         for (i = 0; irqs && i < opal_irq_count; i++, irqs++) {
 211                 unsigned int irq, virq;
 212
 213                 /* Get hardware and virtual IRQ */
 214                 irq = be32_to_cpup(irqs);
 215                 virq = irq_create_mapping(NULL, irq);
 216                 if (virq == NO_IRQ) {
 217                         pr_warn("Failed to map irq 0x%x\n", irq);
 218                         continue;
 219                 }
 220
 221                 /* Install interrupt handler */
 222                 rc = request_irq(virq, opal_interrupt, 0, "opal", NULL);
 223                 if (rc) {
 224                         irq_dispose_mapping(virq);
 225                         pr_warn("Error %d requesting irq %d (0x%x)\n",
 226                                  rc, virq, irq);
 227                         continue;
 228                 }
 229
 230                 /* Cache IRQ */
 231                 opal_irqs[i] = virq;
 232         }
 233
 234 out:
 235         of_node_put(opal_node);
 236         return rc;
 237 }
 238
 239 /**
 240  * opal_event_request(unsigned int opal_event_nr) - Request an event
 241  * @opal_event_nr: the opal event number to request
 242  *
 243  * This routine can be used to find the linux virq number which can
 244  * then be passed to request_irq to assign a handler for a particular
 245  * opal event. This should only be used by legacy devices which don't
 246  * have proper device tree bindings. Most devices should use
 247  * irq_of_parse_and_map() instead.
 248  */
 249 int opal_event_request(unsigned int opal_event_nr)
 250 {
 251         return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
 252 }
 253 EXPORT_SYMBOL(opal_event_request);