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_MASK             0x10
  19 #define AL_FIC_CONTROL          0x28
  20
  21 #define CONTROL_TRIGGER_RISING  BIT(3)
  22 #define CONTROL_MASK_MSI_X      BIT(5)
  23
  24 #define NR_FIC_IRQS 32
  25
  26 MODULE_AUTHOR("Talel Shenhar");
  27 MODULE_DESCRIPTION("Amazon's Annapurna Labs Interrupt Controller Driver");
  28 MODULE_LICENSE("GPL v2");
  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         unsigned int irq;
 114         u32 hwirq;
 115
 116         chained_irq_enter(irqchip, desc);
 117
 118         pending = readl_relaxed(fic->base + AL_FIC_CAUSE);
 119         pending &= ~gc->mask_cache;
 120
 121         for_each_set_bit(hwirq, &pending, NR_FIC_IRQS) {
 122                 irq = irq_find_mapping(domain, hwirq);
 123                 generic_handle_irq(irq);
 124         }
 125
 126         chained_irq_exit(irqchip, desc);
 127 }
 128
 129 static int al_fic_register(struct device_node *node,
 130                            struct al_fic *fic)
 131 {
 132         struct irq_chip_generic *gc;
 133         int ret;
 134
 135         fic->domain = irq_domain_add_linear(node,
 136                                             NR_FIC_IRQS,
 137                                             &irq_generic_chip_ops,
 138                                             fic);
 139         if (!fic->domain) {
 140                 pr_err("fail to add irq domain\n");
 141                 return -ENOMEM;
 142         }
 143
 144         ret = irq_alloc_domain_generic_chips(fic->domain,
 145                                              NR_FIC_IRQS,
 146                                              1, fic->name,
 147                                              handle_level_irq,
 148                                              0, 0, IRQ_GC_INIT_MASK_CACHE);
 149         if (ret) {
 150                 pr_err("fail to allocate generic chip (%d)\n", ret);
 151                 goto err_domain_remove;
 152         }
 153
 154         gc = irq_get_domain_generic_chip(fic->domain, 0);
 155         gc->reg_base = fic->base;
 156         gc->chip_types->regs.mask = AL_FIC_MASK;
 157         gc->chip_types->regs.ack = AL_FIC_CAUSE;
 158         gc->chip_types->chip.irq_mask = irq_gc_mask_set_bit;
 159         gc->chip_types->chip.irq_unmask = irq_gc_mask_clr_bit;
 160         gc->chip_types->chip.irq_ack = irq_gc_ack_clr_bit;
 161         gc->chip_types->chip.irq_set_type = al_fic_irq_set_type;
 162         gc->chip_types->chip.flags = IRQCHIP_SKIP_SET_WAKE;
 163         gc->private = fic;
 164
 165         irq_set_chained_handler_and_data(fic->parent_irq,
 166                                          al_fic_irq_handler,
 167                                          fic);
 168         return 0;
 169
 170 err_domain_remove:
 171         irq_domain_remove(fic->domain);
 172
 173         return ret;
 174 }
 175
 176 /*
 177  * al_fic_wire_init() - initialize and configure fic in wire mode
 178  * @of_node: optional pointer to interrupt controller's device tree node.
 179  * @base: mmio to fic register
 180  * @name: name of the fic
 181  * @parent_irq: interrupt of parent
 182  *
 183  * This API will configure the fic hardware to to work in wire mode.
 184  * In wire mode, fic hardware is generating a wire ("wired") interrupt.
 185  * Interrupt can be generated based on positive edge or level - configuration is
 186  * to be determined based on connected hardware to this fic.
 187  */
 188 static struct al_fic *al_fic_wire_init(struct device_node *node,
 189                                        void __iomem *base,
 190                                        const char *name,
 191                                        unsigned int parent_irq)
 192 {
 193         struct al_fic *fic;
 194         int ret;
 195         u32 control = CONTROL_MASK_MSI_X;
 196
 197         fic = kzalloc(sizeof(*fic), GFP_KERNEL);
 198         if (!fic)
 199                 return ERR_PTR(-ENOMEM);
 200
 201         fic->base = base;
 202         fic->parent_irq = parent_irq;
 203         fic->name = name;
 204
 205         /* mask out all interrupts */
 206         writel_relaxed(0xFFFFFFFF, fic->base + AL_FIC_MASK);
 207
 208         /* clear any pending interrupt */
 209         writel_relaxed(0, fic->base + AL_FIC_CAUSE);
 210
 211         writel_relaxed(control, fic->base + AL_FIC_CONTROL);
 212
 213         ret = al_fic_register(node, fic);
 214         if (ret) {
 215                 pr_err("fail to register irqchip\n");
 216                 goto err_free;
 217         }
 218
 219         pr_debug("%s initialized successfully in Legacy mode (parent-irq=%u)\n",
 220                  fic->name, parent_irq);
 221
 222         return fic;
 223
 224 err_free:
 225         kfree(fic);
 226         return ERR_PTR(ret);
 227 }
 228
 229 static int __init al_fic_init_dt(struct device_node *node,
 230                                  struct device_node *parent)
 231 {
 232         int ret;
 233         void __iomem *base;
 234         unsigned int parent_irq;
 235         struct al_fic *fic;
 236
 237         if (!parent) {
 238                 pr_err("%s: unsupported - device require a parent\n",
 239                        node->name);
 240                 return -EINVAL;
 241         }
 242
 243         base = of_iomap(node, 0);
 244         if (!base) {
 245                 pr_err("%s: fail to map memory\n", node->name);
 246                 return -ENOMEM;
 247         }
 248
 249         parent_irq = irq_of_parse_and_map(node, 0);
 250         if (!parent_irq) {
 251                 pr_err("%s: fail to map irq\n", node->name);
 252                 ret = -EINVAL;
 253                 goto err_unmap;
 254         }
 255
 256         fic = al_fic_wire_init(node,
 257                                base,
 258                                node->name,
 259                                parent_irq);
 260         if (IS_ERR(fic)) {
 261                 pr_err("%s: fail to initialize irqchip (%lu)\n",
 262                        node->name,
 263                        PTR_ERR(fic));
 264                 ret = PTR_ERR(fic);
 265                 goto err_irq_dispose;
 266         }
 267
 268         return 0;
 269
 270 err_irq_dispose:
 271         irq_dispose_mapping(parent_irq);
 272 err_unmap:
 273         iounmap(base);
 274
 275         return ret;
 276 }
 277
 278 IRQCHIP_DECLARE(al_fic, "amazon,al-fic", al_fic_init_dt);