linux/drivers/misc/ocxl/afu_irq.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2// Copyright 2017 IBM Corp.
   3#include <linux/interrupt.h>
   4#include <asm/pnv-ocxl.h>
   5#include "ocxl_internal.h"
   6#include "trace.h"
   7
   8struct afu_irq {
   9        int id;
  10        int hw_irq;
  11        unsigned int virq;
  12        char *name;
  13        u64 trigger_page;
  14        irqreturn_t (*handler)(void *private);
  15        void (*free_private)(void *private);
  16        void *private;
  17};
  18
  19int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset)
  20{
  21        return (offset - ctx->afu->irq_base_offset) >> PAGE_SHIFT;
  22}
  23
  24u64 ocxl_irq_id_to_offset(struct ocxl_context *ctx, int irq_id)
  25{
  26        return ctx->afu->irq_base_offset + (irq_id << PAGE_SHIFT);
  27}
  28
  29int ocxl_irq_set_handler(struct ocxl_context *ctx, int irq_id,
  30                irqreturn_t (*handler)(void *private),
  31                void (*free_private)(void *private),
  32                void *private)
  33{
  34        struct afu_irq *irq;
  35        int rc;
  36
  37        mutex_lock(&ctx->irq_lock);
  38        irq = idr_find(&ctx->irq_idr, irq_id);
  39        if (!irq) {
  40                rc = -EINVAL;
  41                goto unlock;
  42        }
  43
  44        irq->handler = handler;
  45        irq->private = private;
  46        irq->free_private = free_private;
  47
  48        rc = 0;
  49        // Fall through to unlock
  50
  51unlock:
  52        mutex_unlock(&ctx->irq_lock);
  53        return rc;
  54}
  55EXPORT_SYMBOL_GPL(ocxl_irq_set_handler);
  56
  57static irqreturn_t afu_irq_handler(int virq, void *data)
  58{
  59        struct afu_irq *irq = (struct afu_irq *) data;
  60
  61        trace_ocxl_afu_irq_receive(virq);
  62
  63        if (irq->handler)
  64                return irq->handler(irq->private);
  65
  66        return IRQ_HANDLED; // Just drop it on the ground
  67}
  68
  69static int setup_afu_irq(struct ocxl_context *ctx, struct afu_irq *irq)
  70{
  71        int rc;
  72
  73        irq->virq = irq_create_mapping(NULL, irq->hw_irq);
  74        if (!irq->virq) {
  75                pr_err("irq_create_mapping failed\n");
  76                return -ENOMEM;
  77        }
  78        pr_debug("hw_irq %d mapped to virq %u\n", irq->hw_irq, irq->virq);
  79
  80        irq->name = kasprintf(GFP_KERNEL, "ocxl-afu-%u", irq->virq);
  81        if (!irq->name) {
  82                irq_dispose_mapping(irq->virq);
  83                return -ENOMEM;
  84        }
  85
  86        rc = request_irq(irq->virq, afu_irq_handler, 0, irq->name, irq);
  87        if (rc) {
  88                kfree(irq->name);
  89                irq->name = NULL;
  90                irq_dispose_mapping(irq->virq);
  91                pr_err("request_irq failed: %d\n", rc);
  92                return rc;
  93        }
  94        return 0;
  95}
  96
  97static void release_afu_irq(struct afu_irq *irq)
  98{
  99        free_irq(irq->virq, irq);
 100        irq_dispose_mapping(irq->virq);
 101        kfree(irq->name);
 102}
 103
 104int ocxl_afu_irq_alloc(struct ocxl_context *ctx, int *irq_id)
 105{
 106        struct afu_irq *irq;
 107        int rc;
 108
 109        irq = kzalloc(sizeof(struct afu_irq), GFP_KERNEL);
 110        if (!irq)
 111                return -ENOMEM;
 112
 113        /*
 114         * We limit the number of afu irqs per context and per link to
 115         * avoid a single process or user depleting the pool of IPIs
 116         */
 117
 118        mutex_lock(&ctx->irq_lock);
 119
 120        irq->id = idr_alloc(&ctx->irq_idr, irq, 0, MAX_IRQ_PER_CONTEXT,
 121                        GFP_KERNEL);
 122        if (irq->id < 0) {
 123                rc = -ENOSPC;
 124                goto err_unlock;
 125        }
 126
 127        rc = ocxl_link_irq_alloc(ctx->afu->fn->link, &irq->hw_irq,
 128                                &irq->trigger_page);
 129        if (rc)
 130                goto err_idr;
 131
 132        rc = setup_afu_irq(ctx, irq);
 133        if (rc)
 134                goto err_alloc;
 135
 136        trace_ocxl_afu_irq_alloc(ctx->pasid, irq->id, irq->virq, irq->hw_irq);
 137        mutex_unlock(&ctx->irq_lock);
 138
 139        *irq_id = irq->id;
 140
 141        return 0;
 142
 143err_alloc:
 144        ocxl_link_free_irq(ctx->afu->fn->link, irq->hw_irq);
 145err_idr:
 146        idr_remove(&ctx->irq_idr, irq->id);
 147err_unlock:
 148        mutex_unlock(&ctx->irq_lock);
 149        kfree(irq);
 150        return rc;
 151}
 152EXPORT_SYMBOL_GPL(ocxl_afu_irq_alloc);
 153
 154static void afu_irq_free(struct afu_irq *irq, struct ocxl_context *ctx)
 155{
 156        trace_ocxl_afu_irq_free(ctx->pasid, irq->id);
 157        if (ctx->mapping)
 158                unmap_mapping_range(ctx->mapping,
 159                                ocxl_irq_id_to_offset(ctx, irq->id),
 160                                1 << PAGE_SHIFT, 1);
 161        release_afu_irq(irq);
 162        if (irq->free_private)
 163                irq->free_private(irq->private);
 164        ocxl_link_free_irq(ctx->afu->fn->link, irq->hw_irq);
 165        kfree(irq);
 166}
 167
 168int ocxl_afu_irq_free(struct ocxl_context *ctx, int irq_id)
 169{
 170        struct afu_irq *irq;
 171
 172        mutex_lock(&ctx->irq_lock);
 173
 174        irq = idr_find(&ctx->irq_idr, irq_id);
 175        if (!irq) {
 176                mutex_unlock(&ctx->irq_lock);
 177                return -EINVAL;
 178        }
 179        idr_remove(&ctx->irq_idr, irq->id);
 180        afu_irq_free(irq, ctx);
 181        mutex_unlock(&ctx->irq_lock);
 182        return 0;
 183}
 184EXPORT_SYMBOL_GPL(ocxl_afu_irq_free);
 185
 186void ocxl_afu_irq_free_all(struct ocxl_context *ctx)
 187{
 188        struct afu_irq *irq;
 189        int id;
 190
 191        mutex_lock(&ctx->irq_lock);
 192        idr_for_each_entry(&ctx->irq_idr, irq, id)
 193                afu_irq_free(irq, ctx);
 194        mutex_unlock(&ctx->irq_lock);
 195}
 196
 197u64 ocxl_afu_irq_get_addr(struct ocxl_context *ctx, int irq_id)
 198{
 199        struct afu_irq *irq;
 200        u64 addr = 0;
 201
 202        mutex_lock(&ctx->irq_lock);
 203        irq = idr_find(&ctx->irq_idr, irq_id);
 204        if (irq)
 205                addr = irq->trigger_page;
 206        mutex_unlock(&ctx->irq_lock);
 207        return addr;
 208}
 209EXPORT_SYMBOL_GPL(ocxl_afu_irq_get_addr);
 210