drivers/irqchip/irq-al-fic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
   4  */
   5
   6 #include <linux/bitfield.h>
   7 #include <linux/irq.h>
   8 #include <linux/irqchip.h>
   9 #include <linux/irqchip/chained_irq.h>
  10 #include <linux/irqdomain.h>
  11 #include <linux/module.h>
  12 #include <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_irq.h>
  15
  16 /* FIC Registers */
  17 #define AL_FIC_CAUSE            0x00
  18 #define AL_FIC_SET_CAUSE        0x08
  19 #define AL_FIC_MASK             0x10
  20 #define AL_FIC_CONTROL          0x28
  21
  22 #define CONTROL_TRIGGER_RISING  BIT(3)
  23 #define CONTROL_MASK_MSI_X      BIT(5)
  24
  25 #define NR_FIC_IRQS 32
  26
  27 MODULE_AUTHOR("Talel Shenhar");
  28 MODULE_DESCRIPTION("Amazon's Annapurna Labs Interrupt Controller Driver");
  29
  30 enum al_fic_state {
  31         AL_FIC_UNCONFIGURED = 0,
  32         AL_FIC_CONFIGURED_LEVEL,
  33         AL_FIC_CONFIGURED_RISING_EDGE,
  34 };
  35
  36 struct al_fic {
  37         void __iomem *base;
  38         struct irq_domain *domain;
  39         const char *name;
  40         unsigned int parent_irq;
  41         enum al_fic_state state;
  42 };
  43
  44 static void al_fic_set_trigger(struct al_fic *fic,
  45                                struct irq_chip_generic *gc,
  46                                enum al_fic_state new_state)
  47 {
  48         irq_flow_handler_t handler;
  49         u32 control = readl_relaxed(fic->base + AL_FIC_CONTROL);
  50
  51         if (new_state == AL_FIC_CONFIGURED_LEVEL) {
  52                 handler = handle_level_irq;
  53                 control &= ~CONTROL_TRIGGER_RISING;
  54         } else {
  55                 handler = handle_edge_irq;
  56                 control |= CONTROL_TRIGGER_RISING;
  57         }
  58         gc->chip_types->handler = handler;
  59         fic->state = new_state;
  60         writel_relaxed(control, fic->base + AL_FIC_CONTROL);
  61 }
  62
  63 static int al_fic_irq_set_type(struct irq_data *data, unsigned int flow_type)
  64 {
  65         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
  66         struct al_fic *fic = gc->private;
  67         enum al_fic_state new_state;
  68         int ret = 0;
  69
  70         irq_gc_lock(gc);
  71
  72         if (((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH) &&
  73             ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_EDGE_RISING)) {
  74                 pr_debug("fic doesn't support flow type %d\n", flow_type);
  75                 ret = -EINVAL;
  76                 goto err;
  77         }
  78
  79         new_state = (flow_type & IRQ_TYPE_LEVEL_HIGH) ?
  80                 AL_FIC_CONFIGURED_LEVEL : AL_FIC_CONFIGURED_RISING_EDGE;
  81
  82         /*
  83          * A given FIC instance can be either all level or all edge triggered.
  84          * This is generally fixed depending on what pieces of HW it's wired up
  85          * to.
  86          *
  87          * We configure it based on the sensitivity of the first source
  88          * being setup, and reject any subsequent attempt at configuring it in a
  89          * different way.
  90          */
  91         if (fic->state == AL_FIC_UNCONFIGURED) {
  92                 al_fic_set_trigger(fic, gc, new_state);
  93         } else if (fic->state != new_state) {
  94                 pr_debug("fic %s state already configured to %d\n",
  95                          fic->name, fic->state);
  96                 ret = -EINVAL;
  97                 goto err;
  98         }
  99
 100 err:
 101         irq_gc_unlock(gc);
 102
 103         return ret;
 104 }
 105
 106 static void al_fic_irq_handler(struct irq_desc *desc)
 107 {
 108         struct al_fic *fic = irq_desc_get_handler_data(desc);
 109         struct irq_domain *domain = fic->domain;
 110         struct irq_chip *irqchip = irq_desc_get_chip(desc);
 111         struct irq_chip_generic *gc = irq_get_domain_generic_chip(domain, 0);
 112         unsigned long pending;
 113         u32 hwirq;
 114
 115         chained_irq_enter(irqchip, desc);
 116
 117         pending = readl_relaxed(fic->base + AL_FIC_CAUSE);
 118         pending &= ~gc->mask_cache;
 119
 120         for_each_set_bit(hwirq, &pending, NR_FIC_IRQS)
 121                 generic_handle_domain_irq(domain, hwirq);
 122
 123         chained_irq_exit(irqchip, desc);
 124 }
 125
 126 static int al_fic_irq_retrigger(struct irq_data *data)
 127 {
 128         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
 129         struct al_fic *fic = gc->private;
 130
 131         writel_relaxed(BIT(data->hwirq), fic->base + AL_FIC_SET_CAUSE);
 132
 133         return 1;
 134 }
 135
 136 static int al_fic_register(struct device_node *node,
 137                            struct al_fic *fic)
 138 {
 139         struct irq_chip_generic *gc;
 140         int ret;
 141
 142         fic->domain = irq_domain_add_linear(node,
 143                                             NR_FIC_IRQS,
 144                                             &irq_generic_chip_ops,
 145                                             fic);
 146         if (!fic->domain) {
 147                 pr_err("fail to add irq domain\n");
 148                 return -ENOMEM;
 149         }
 150
 151         ret = irq_alloc_domain_generic_chips(fic->domain,
 152                                              NR_FIC_IRQS,
 153                                              1, fic->name,
 154                                              handle_level_irq,
 155                                              0, 0, IRQ_GC_INIT_MASK_CACHE);
 156         if (ret) {
 157                 pr_err("fail to allocate generic chip (%d)\n", ret);
 158                 goto err_domain_remove;
 159         }
 160
 161         gc = irq_get_domain_generic_chip(fic->domain, 0);
 162         gc->reg_base = fic->base;
 163         gc->chip_types->regs.mask = AL_FIC_MASK;
 164         gc->chip_types->regs.ack = AL_FIC_CAUSE;
 165         gc->chip_types->chip.irq_mask = irq_gc_mask_set_bit;
 166         gc->chip_types->chip.irq_unmask = irq_gc_mask_clr_bit;
 167         gc->chip_types->chip.irq_ack = irq_gc_ack_clr_bit;
 168         gc->chip_types->chip.irq_set_type = al_fic_irq_set_type;
 169         gc->chip_types->chip.irq_retrigger = al_fic_irq_retrigger;
 170         gc->chip_types->chip.flags = IRQCHIP_SKIP_SET_WAKE;
 171         gc->private = fic;
 172
 173         irq_set_chained_handler_and_data(fic->parent_irq,
 174                                          al_fic_irq_handler,
 175                                          fic);
 176         return 0;
 177
 178 err_domain_remove:
 179         irq_domain_remove(fic->domain);
 180
 181         return ret;
 182 }
 183
 184 /*
 185  * al_fic_wire_init() - initialize and configure fic in wire mode
 186  * @of_node: optional pointer to interrupt controller's device tree node.
 187  * @base: mmio to fic register
 188  * @name: name of the fic
 189  * @parent_irq: interrupt of parent
 190  *
 191  * This API will configure the fic hardware to to work in wire mode.
 192  * In wire mode, fic hardware is generating a wire ("wired") interrupt.
 193  * Interrupt can be generated based on positive edge or level - configuration is
 194  * to be determined based on connected hardware to this fic.
 195  */
 196 static struct al_fic *al_fic_wire_init(struct device_node *node,
 197                                        void __iomem *base,
 198                                        const char *name,
 199                                        unsigned int parent_irq)
 200 {
 201         struct al_fic *fic;
 202         int ret;
 203         u32 control = CONTROL_MASK_MSI_X;
 204
 205         fic = kzalloc(sizeof(*fic), GFP_KERNEL);
 206         if (!fic)
 207                 return ERR_PTR(-ENOMEM);
 208
 209         fic->base = base;
 210         fic->parent_irq = parent_irq;
 211         fic->name = name;
 212
 213         /* mask out all interrupts */
 214         writel_relaxed(0xFFFFFFFF, fic->base + AL_FIC_MASK);
 215
 216         /* clear any pending interrupt */
 217         writel_relaxed(0, fic->base + AL_FIC_CAUSE);
 218
 219         writel_relaxed(control, fic->base + AL_FIC_CONTROL);
 220
 221         ret = al_fic_register(node, fic);
 222         if (ret) {
 223                 pr_err("fail to register irqchip\n");
 224                 goto err_free;
 225         }
 226
 227         pr_debug("%s initialized successfully in Legacy mode (parent-irq=%u)\n",
 228                  fic->name, parent_irq);
 229
 230         return fic;
 231
 232 err_free:
 233         kfree(fic);
 234         return ERR_PTR(ret);
 235 }
 236
 237 static int __init al_fic_init_dt(struct device_node *node,
 238                                  struct device_node *parent)
 239 {
 240         int ret;
 241         void __iomem *base;
 242         unsigned int parent_irq;
 243         struct al_fic *fic;
 244
 245         if (!parent) {
 246                 pr_err("%s: unsupported - device require a parent\n",
 247                        node->name);
 248                 return -EINVAL;
 249         }
 250
 251         base = of_iomap(node, 0);
 252         if (!base) {
 253                 pr_err("%s: fail to map memory\n", node->name);
 254                 return -ENOMEM;
 255         }
 256
 257         parent_irq = irq_of_parse_and_map(node, 0);
 258         if (!parent_irq) {
 259                 pr_err("%s: fail to map irq\n", node->name);
 260                 ret = -EINVAL;
 261                 goto err_unmap;
 262         }
 263
 264         fic = al_fic_wire_init(node,
 265                                base,
 266                                node->name,
 267                                parent_irq);
 268         if (IS_ERR(fic)) {
 269                 pr_err("%s: fail to initialize irqchip (%lu)\n",
 270                        node->name,
 271                        PTR_ERR(fic));
 272                 ret = PTR_ERR(fic);
 273                 goto err_irq_dispose;
 274         }
 275
 276         return 0;
 277
 278 err_irq_dispose:
 279         irq_dispose_mapping(parent_irq);
 280 err_unmap:
 281         iounmap(base);
 282
 283         return ret;
 284 }
 285
 286 IRQCHIP_DECLARE(al_fic, "amazon,al-fic", al_fic_init_dt);