drivers/misc/ocxl/afu_irq.c

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