kernel/irq/irq_sim.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2017-2018 Bartosz Golaszewski <brgl@bgdev.pl>
   4  * Copyright (C) 2020 Bartosz Golaszewski <bgolaszewski@baylibre.com>
   5  */
   6
   7 #include <linux/irq.h>
   8 #include <linux/irq_sim.h>
   9 #include <linux/irq_work.h>
  10 #include <linux/interrupt.h>
  11 #include <linux/slab.h>
  12
  13 struct irq_sim_work_ctx {
  14         struct irq_work         work;
  15         int                     irq_base;
  16         unsigned int            irq_count;
  17         unsigned long           *pending;
  18         struct irq_domain       *domain;
  19 };
  20
  21 struct irq_sim_irq_ctx {
  22         int                     irqnum;
  23         bool                    enabled;
  24         struct irq_sim_work_ctx *work_ctx;
  25 };
  26
  27 static void irq_sim_irqmask(struct irq_data *data)
  28 {
  29         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  30
  31         irq_ctx->enabled = false;
  32 }
  33
  34 static void irq_sim_irqunmask(struct irq_data *data)
  35 {
  36         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  37
  38         irq_ctx->enabled = true;
  39 }
  40
  41 static int irq_sim_set_type(struct irq_data *data, unsigned int type)
  42 {
  43         /* We only support rising and falling edge trigger types. */
  44         if (type & ~IRQ_TYPE_EDGE_BOTH)
  45                 return -EINVAL;
  46
  47         irqd_set_trigger_type(data, type);
  48
  49         return 0;
  50 }
  51
  52 static int irq_sim_get_irqchip_state(struct irq_data *data,
  53                                      enum irqchip_irq_state which, bool *state)
  54 {
  55         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  56         irq_hw_number_t hwirq = irqd_to_hwirq(data);
  57
  58         switch (which) {
  59         case IRQCHIP_STATE_PENDING:
  60                 if (irq_ctx->enabled)
  61                         *state = test_bit(hwirq, irq_ctx->work_ctx->pending);
  62                 break;
  63         default:
  64                 return -EINVAL;
  65         }
  66
  67         return 0;
  68 }
  69
  70 static int irq_sim_set_irqchip_state(struct irq_data *data,
  71                                      enum irqchip_irq_state which, bool state)
  72 {
  73         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  74         irq_hw_number_t hwirq = irqd_to_hwirq(data);
  75
  76         switch (which) {
  77         case IRQCHIP_STATE_PENDING:
  78                 if (irq_ctx->enabled) {
  79                         assign_bit(hwirq, irq_ctx->work_ctx->pending, state);
  80                         if (state)
  81                                 irq_work_queue(&irq_ctx->work_ctx->work);
  82                 }
  83                 break;
  84         default:
  85                 return -EINVAL;
  86         }
  87
  88         return 0;
  89 }
  90
  91 static struct irq_chip irq_sim_irqchip = {
  92         .name                   = "irq_sim",
  93         .irq_mask               = irq_sim_irqmask,
  94         .irq_unmask             = irq_sim_irqunmask,
  95         .irq_set_type           = irq_sim_set_type,
  96         .irq_get_irqchip_state  = irq_sim_get_irqchip_state,
  97         .irq_set_irqchip_state  = irq_sim_set_irqchip_state,
  98 };
  99
 100 static void irq_sim_handle_irq(struct irq_work *work)
 101 {
 102         struct irq_sim_work_ctx *work_ctx;
 103         unsigned int offset = 0;
 104         int irqnum;
 105
 106         work_ctx = container_of(work, struct irq_sim_work_ctx, work);
 107
 108         while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
 109                 offset = find_next_bit(work_ctx->pending,
 110                                        work_ctx->irq_count, offset);
 111                 clear_bit(offset, work_ctx->pending);
 112                 irqnum = irq_find_mapping(work_ctx->domain, offset);
 113                 handle_simple_irq(irq_to_desc(irqnum));
 114         }
 115 }
 116
 117 static int irq_sim_domain_map(struct irq_domain *domain,
 118                               unsigned int virq, irq_hw_number_t hw)
 119 {
 120         struct irq_sim_work_ctx *work_ctx = domain->host_data;
 121         struct irq_sim_irq_ctx *irq_ctx;
 122
 123         irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
 124         if (!irq_ctx)
 125                 return -ENOMEM;
 126
 127         irq_set_chip(virq, &irq_sim_irqchip);
 128         irq_set_chip_data(virq, irq_ctx);
 129         irq_set_handler(virq, handle_simple_irq);
 130         irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
 131         irq_ctx->work_ctx = work_ctx;
 132
 133         return 0;
 134 }
 135
 136 static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
 137 {
 138         struct irq_sim_irq_ctx *irq_ctx;
 139         struct irq_data *irqd;
 140
 141         irqd = irq_domain_get_irq_data(domain, virq);
 142         irq_ctx = irq_data_get_irq_chip_data(irqd);
 143
 144         irq_set_handler(virq, NULL);
 145         irq_domain_reset_irq_data(irqd);
 146         kfree(irq_ctx);
 147 }
 148
 149 static const struct irq_domain_ops irq_sim_domain_ops = {
 150         .map            = irq_sim_domain_map,
 151         .unmap          = irq_sim_domain_unmap,
 152 };
 153
 154 /**
 155  * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
 156  *                         allocate a range of dummy interrupts.
 157  *
 158  * @fwnode:     struct fwnode_handle to be associated with this domain.
 159  * @num_irqs:   Number of interrupts to allocate.
 160  *
 161  * On success: return a new irq_domain object.
 162  * On failure: a negative errno wrapped with ERR_PTR().
 163  */
 164 struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
 165                                          unsigned int num_irqs)
 166 {
 167         struct irq_sim_work_ctx *work_ctx;
 168
 169         work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
 170         if (!work_ctx)
 171                 goto err_out;
 172
 173         work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
 174         if (!work_ctx->pending)
 175                 goto err_free_work_ctx;
 176
 177         work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
 178                                                     &irq_sim_domain_ops,
 179                                                     work_ctx);
 180         if (!work_ctx->domain)
 181                 goto err_free_bitmap;
 182
 183         work_ctx->irq_count = num_irqs;
 184         work_ctx->work = IRQ_WORK_INIT_HARD(irq_sim_handle_irq);
 185
 186         return work_ctx->domain;
 187
 188 err_free_bitmap:
 189         bitmap_free(work_ctx->pending);
 190 err_free_work_ctx:
 191         kfree(work_ctx);
 192 err_out:
 193         return ERR_PTR(-ENOMEM);
 194 }
 195 EXPORT_SYMBOL_GPL(irq_domain_create_sim);
 196
 197 /**
 198  * irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
 199  *                         the interrupt descriptors and allocated memory.
 200  *
 201  * @domain:     The interrupt simulator domain to tear down.
 202  */
 203 void irq_domain_remove_sim(struct irq_domain *domain)
 204 {
 205         struct irq_sim_work_ctx *work_ctx = domain->host_data;
 206
 207         irq_work_sync(&work_ctx->work);
 208         bitmap_free(work_ctx->pending);
 209         kfree(work_ctx);
 210
 211         irq_domain_remove(domain);
 212 }
 213 EXPORT_SYMBOL_GPL(irq_domain_remove_sim);
 214
 215 static void devm_irq_domain_remove_sim(void *data)
 216 {
 217         struct irq_domain *domain = data;
 218
 219         irq_domain_remove_sim(domain);
 220 }
 221
 222 /**
 223  * devm_irq_domain_create_sim - Create a new interrupt simulator for
 224  *                              a managed device.
 225  *
 226  * @dev:        Device to initialize the simulator object for.
 227  * @fwnode:     struct fwnode_handle to be associated with this domain.
 228  * @num_irqs:   Number of interrupts to allocate
 229  *
 230  * On success: return a new irq_domain object.
 231  * On failure: a negative errno wrapped with ERR_PTR().
 232  */
 233 struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
 234                                               struct fwnode_handle *fwnode,
 235                                               unsigned int num_irqs)
 236 {
 237         struct irq_domain *domain;
 238         int ret;
 239
 240         domain = irq_domain_create_sim(fwnode, num_irqs);
 241         if (IS_ERR(domain))
 242                 return domain;
 243
 244         ret = devm_add_action_or_reset(dev, devm_irq_domain_remove_sim, domain);
 245         if (ret)
 246                 return ERR_PTR(ret);
 247
 248         return domain;
 249 }
 250 EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);