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 struct irq_sim_devres {
  28         struct irq_domain       *domain;
  29 };
  30
  31 static void irq_sim_irqmask(struct irq_data *data)
  32 {
  33         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  34
  35         irq_ctx->enabled = false;
  36 }
  37
  38 static void irq_sim_irqunmask(struct irq_data *data)
  39 {
  40         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  41
  42         irq_ctx->enabled = true;
  43 }
  44
  45 static int irq_sim_set_type(struct irq_data *data, unsigned int type)
  46 {
  47         /* We only support rising and falling edge trigger types. */
  48         if (type & ~IRQ_TYPE_EDGE_BOTH)
  49                 return -EINVAL;
  50
  51         irqd_set_trigger_type(data, type);
  52
  53         return 0;
  54 }
  55
  56 static int irq_sim_get_irqchip_state(struct irq_data *data,
  57                                      enum irqchip_irq_state which, bool *state)
  58 {
  59         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  60         irq_hw_number_t hwirq = irqd_to_hwirq(data);
  61
  62         switch (which) {
  63         case IRQCHIP_STATE_PENDING:
  64                 if (irq_ctx->enabled)
  65                         *state = test_bit(hwirq, irq_ctx->work_ctx->pending);
  66                 break;
  67         default:
  68                 return -EINVAL;
  69         }
  70
  71         return 0;
  72 }
  73
  74 static int irq_sim_set_irqchip_state(struct irq_data *data,
  75                                      enum irqchip_irq_state which, bool state)
  76 {
  77         struct irq_sim_irq_ctx *irq_ctx = irq_data_get_irq_chip_data(data);
  78         irq_hw_number_t hwirq = irqd_to_hwirq(data);
  79
  80         switch (which) {
  81         case IRQCHIP_STATE_PENDING:
  82                 if (irq_ctx->enabled) {
  83                         assign_bit(hwirq, irq_ctx->work_ctx->pending, state);
  84                         if (state)
  85                                 irq_work_queue(&irq_ctx->work_ctx->work);
  86                 }
  87                 break;
  88         default:
  89                 return -EINVAL;
  90         }
  91
  92         return 0;
  93 }
  94
  95 static struct irq_chip irq_sim_irqchip = {
  96         .name                   = "irq_sim",
  97         .irq_mask               = irq_sim_irqmask,
  98         .irq_unmask             = irq_sim_irqunmask,
  99         .irq_set_type           = irq_sim_set_type,
 100         .irq_get_irqchip_state  = irq_sim_get_irqchip_state,
 101         .irq_set_irqchip_state  = irq_sim_set_irqchip_state,
 102 };
 103
 104 static void irq_sim_handle_irq(struct irq_work *work)
 105 {
 106         struct irq_sim_work_ctx *work_ctx;
 107         unsigned int offset = 0;
 108         int irqnum;
 109
 110         work_ctx = container_of(work, struct irq_sim_work_ctx, work);
 111
 112         while (!bitmap_empty(work_ctx->pending, work_ctx->irq_count)) {
 113                 offset = find_next_bit(work_ctx->pending,
 114                                        work_ctx->irq_count, offset);
 115                 clear_bit(offset, work_ctx->pending);
 116                 irqnum = irq_find_mapping(work_ctx->domain, offset);
 117                 handle_simple_irq(irq_to_desc(irqnum));
 118         }
 119 }
 120
 121 static int irq_sim_domain_map(struct irq_domain *domain,
 122                               unsigned int virq, irq_hw_number_t hw)
 123 {
 124         struct irq_sim_work_ctx *work_ctx = domain->host_data;
 125         struct irq_sim_irq_ctx *irq_ctx;
 126
 127         irq_ctx = kzalloc(sizeof(*irq_ctx), GFP_KERNEL);
 128         if (!irq_ctx)
 129                 return -ENOMEM;
 130
 131         irq_set_chip(virq, &irq_sim_irqchip);
 132         irq_set_chip_data(virq, irq_ctx);
 133         irq_set_handler(virq, handle_simple_irq);
 134         irq_modify_status(virq, IRQ_NOREQUEST | IRQ_NOAUTOEN, IRQ_NOPROBE);
 135         irq_ctx->work_ctx = work_ctx;
 136
 137         return 0;
 138 }
 139
 140 static void irq_sim_domain_unmap(struct irq_domain *domain, unsigned int virq)
 141 {
 142         struct irq_sim_irq_ctx *irq_ctx;
 143         struct irq_data *irqd;
 144
 145         irqd = irq_domain_get_irq_data(domain, virq);
 146         irq_ctx = irq_data_get_irq_chip_data(irqd);
 147
 148         irq_set_handler(virq, NULL);
 149         irq_domain_reset_irq_data(irqd);
 150         kfree(irq_ctx);
 151 }
 152
 153 static const struct irq_domain_ops irq_sim_domain_ops = {
 154         .map            = irq_sim_domain_map,
 155         .unmap          = irq_sim_domain_unmap,
 156 };
 157
 158 /**
 159  * irq_domain_create_sim - Create a new interrupt simulator irq_domain and
 160  *                         allocate a range of dummy interrupts.
 161  *
 162  * @fwnode:     struct fwnode_handle to be associated with this domain.
 163  * @num_irqs:   Number of interrupts to allocate.
 164  *
 165  * On success: return a new irq_domain object.
 166  * On failure: a negative errno wrapped with ERR_PTR().
 167  */
 168 struct irq_domain *irq_domain_create_sim(struct fwnode_handle *fwnode,
 169                                          unsigned int num_irqs)
 170 {
 171         struct irq_sim_work_ctx *work_ctx;
 172
 173         work_ctx = kmalloc(sizeof(*work_ctx), GFP_KERNEL);
 174         if (!work_ctx)
 175                 goto err_out;
 176
 177         work_ctx->pending = bitmap_zalloc(num_irqs, GFP_KERNEL);
 178         if (!work_ctx->pending)
 179                 goto err_free_work_ctx;
 180
 181         work_ctx->domain = irq_domain_create_linear(fwnode, num_irqs,
 182                                                     &irq_sim_domain_ops,
 183                                                     work_ctx);
 184         if (!work_ctx->domain)
 185                 goto err_free_bitmap;
 186
 187         work_ctx->irq_count = num_irqs;
 188         init_irq_work(&work_ctx->work, irq_sim_handle_irq);
 189
 190         return work_ctx->domain;
 191
 192 err_free_bitmap:
 193         bitmap_free(work_ctx->pending);
 194 err_free_work_ctx:
 195         kfree(work_ctx);
 196 err_out:
 197         return ERR_PTR(-ENOMEM);
 198 }
 199 EXPORT_SYMBOL_GPL(irq_domain_create_sim);
 200
 201 /**
 202  * irq_domain_remove_sim - Deinitialize the interrupt simulator domain: free
 203  *                         the interrupt descriptors and allocated memory.
 204  *
 205  * @domain:     The interrupt simulator domain to tear down.
 206  */
 207 void irq_domain_remove_sim(struct irq_domain *domain)
 208 {
 209         struct irq_sim_work_ctx *work_ctx = domain->host_data;
 210
 211         irq_work_sync(&work_ctx->work);
 212         bitmap_free(work_ctx->pending);
 213         kfree(work_ctx);
 214
 215         irq_domain_remove(domain);
 216 }
 217 EXPORT_SYMBOL_GPL(irq_domain_remove_sim);
 218
 219 static void devm_irq_domain_release_sim(struct device *dev, void *res)
 220 {
 221         struct irq_sim_devres *this = res;
 222
 223         irq_domain_remove_sim(this->domain);
 224 }
 225
 226 /**
 227  * devm_irq_domain_create_sim - Create a new interrupt simulator for
 228  *                              a managed device.
 229  *
 230  * @dev:        Device to initialize the simulator object for.
 231  * @fwnode:     struct fwnode_handle to be associated with this domain.
 232  * @num_irqs:   Number of interrupts to allocate
 233  *
 234  * On success: return a new irq_domain object.
 235  * On failure: a negative errno wrapped with ERR_PTR().
 236  */
 237 struct irq_domain *devm_irq_domain_create_sim(struct device *dev,
 238                                               struct fwnode_handle *fwnode,
 239                                               unsigned int num_irqs)
 240 {
 241         struct irq_sim_devres *dr;
 242
 243         dr = devres_alloc(devm_irq_domain_release_sim,
 244                           sizeof(*dr), GFP_KERNEL);
 245         if (!dr)
 246                 return ERR_PTR(-ENOMEM);
 247
 248         dr->domain = irq_domain_create_sim(fwnode, num_irqs);
 249         if (IS_ERR(dr->domain)) {
 250                 devres_free(dr);
 251                 return dr->domain;
 252         }
 253
 254         devres_add(dev, dr);
 255         return dr->domain;
 256 }
 257 EXPORT_SYMBOL_GPL(devm_irq_domain_create_sim);