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 <asm/pnv-ocxl.h>
   5 #include "ocxl_internal.h"
   6 #include "trace.h"
   7
   8 struct 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
  19 int ocxl_irq_offset_to_id(struct ocxl_context *ctx, u64 offset)
  20 {
  21         return (offset - ctx->afu->irq_base_offset) >> PAGE_SHIFT;
  22 }
  23
  24 u64 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
  29 int 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
  51 unlock:
  52         mutex_unlock(&ctx->irq_lock);
  53         return rc;
  54 }
  55 EXPORT_SYMBOL_GPL(ocxl_irq_set_handler);
  56
  57 static 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
  69 static 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
  97 static 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
 104 int 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
 143 err_alloc:
 144         ocxl_link_free_irq(ctx->afu->fn->link, irq->hw_irq);
 145 err_idr:
 146         idr_remove(&ctx->irq_idr, irq->id);
 147 err_unlock:
 148         mutex_unlock(&ctx->irq_lock);
 149         kfree(irq);
 150         return rc;
 151 }
 152 EXPORT_SYMBOL_GPL(ocxl_afu_irq_alloc);
 153
 154 static 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
 168 int 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 }
 184 EXPORT_SYMBOL_GPL(ocxl_afu_irq_free);
 185
 186 void 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
 197 u64 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 }
 209 EXPORT_SYMBOL_GPL(ocxl_afu_irq_get_addr);