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 MODULE_LICENSE("GPL v2");
  30
  31 enum al_fic_state {
  32         AL_FIC_UNCONFIGURED = 0,
  33         AL_FIC_CONFIGURED_LEVEL,
  34         AL_FIC_CONFIGURED_RISING_EDGE,
  35 };
  36
  37 struct al_fic {
  38         void __iomem *base;
  39         struct irq_domain *domain;
  40         const char *name;
  41         unsigned int parent_irq;
  42         enum al_fic_state state;
  43 };
  44
  45 static void al_fic_set_trigger(struct al_fic *fic,
  46                                struct irq_chip_generic *gc,
  47                                enum al_fic_state new_state)
  48 {
  49         irq_flow_handler_t handler;
  50         u32 control = readl_relaxed(fic->base + AL_FIC_CONTROL);
  51
  52         if (new_state == AL_FIC_CONFIGURED_LEVEL) {
  53                 handler = handle_level_irq;
  54                 control &= ~CONTROL_TRIGGER_RISING;
  55         } else {
  56                 handler = handle_edge_irq;
  57                 control |= CONTROL_TRIGGER_RISING;
  58         }
  59         gc->chip_types->handler = handler;
  60         fic->state = new_state;
  61         writel_relaxed(control, fic->base + AL_FIC_CONTROL);
  62 }
  63
  64 static int al_fic_irq_set_type(struct irq_data *data, unsigned int flow_type)
  65 {
  66         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
  67         struct al_fic *fic = gc->private;
  68         enum al_fic_state new_state;
  69         int ret = 0;
  70
  71         irq_gc_lock(gc);
  72
  73         if (((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_HIGH) &&
  74             ((flow_type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_EDGE_RISING)) {
  75                 pr_debug("fic doesn't support flow type %d\n", flow_type);
  76                 ret = -EINVAL;
  77                 goto err;
  78         }
  79
  80         new_state = (flow_type & IRQ_TYPE_LEVEL_HIGH) ?
  81                 AL_FIC_CONFIGURED_LEVEL : AL_FIC_CONFIGURED_RISING_EDGE;
  82
  83         /*
  84          * A given FIC instance can be either all level or all edge triggered.
  85          * This is generally fixed depending on what pieces of HW it's wired up
  86          * to.
  87          *
  88          * We configure it based on the sensitivity of the first source
  89          * being setup, and reject any subsequent attempt at configuring it in a
  90          * different way.
  91          */
  92         if (fic->state == AL_FIC_UNCONFIGURED) {
  93                 al_fic_set_trigger(fic, gc, new_state);
  94         } else if (fic->state != new_state) {
  95                 pr_debug("fic %s state already configured to %d\n",
  96                          fic->name, fic->state);
  97                 ret = -EINVAL;
  98                 goto err;
  99         }
 100
 101 err:
 102         irq_gc_unlock(gc);
 103
 104         return ret;
 105 }
 106
 107 static void al_fic_irq_handler(struct irq_desc *desc)
 108 {
 109         struct al_fic *fic = irq_desc_get_handler_data(desc);
 110         struct irq_domain *domain = fic->domain;
 111         struct irq_chip *irqchip = irq_desc_get_chip(desc);
 112         struct irq_chip_generic *gc = irq_get_domain_generic_chip(domain, 0);
 113         unsigned long pending;
 114         unsigned int irq;
 115         u32 hwirq;
 116
 117         chained_irq_enter(irqchip, desc);
 118
 119         pending = readl_relaxed(fic->base + AL_FIC_CAUSE);
 120         pending &= ~gc->mask_cache;
 121
 122         for_each_set_bit(hwirq, &pending, NR_FIC_IRQS) {
 123                 irq = irq_find_mapping(domain, hwirq);
 124                 generic_handle_irq(irq);
 125         }
 126
 127         chained_irq_exit(irqchip, desc);
 128 }
 129
 130 static int al_fic_irq_retrigger(struct irq_data *data)
 131 {
 132         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
 133         struct al_fic *fic = gc->private;
 134
 135         writel_relaxed(BIT(data->hwirq), fic->base + AL_FIC_SET_CAUSE);
 136
 137         return 1;
 138 }
 139
 140 static int al_fic_register(struct device_node *node,
 141                            struct al_fic *fic)
 142 {
 143         struct irq_chip_generic *gc;
 144         int ret;
 145
 146         fic->domain = irq_domain_add_linear(node,
 147                                             NR_FIC_IRQS,
 148                                             &irq_generic_chip_ops,
 149                                             fic);
 150         if (!fic->domain) {
 151                 pr_err("fail to add irq domain\n");
 152                 return -ENOMEM;
 153         }
 154
 155         ret = irq_alloc_domain_generic_chips(fic->domain,
 156                                              NR_FIC_IRQS,
 157                                              1, fic->name,
 158                                              handle_level_irq,
 159                                              0, 0, IRQ_GC_INIT_MASK_CACHE);
 160         if (ret) {
 161                 pr_err("fail to allocate generic chip (%d)\n", ret);
 162                 goto err_domain_remove;
 163         }
 164
 165         gc = irq_get_domain_generic_chip(fic->domain, 0);
 166         gc->reg_base = fic->base;
 167         gc->chip_types->regs.mask = AL_FIC_MASK;
 168         gc->chip_types->regs.ack = AL_FIC_CAUSE;
 169         gc->chip_types->chip.irq_mask = irq_gc_mask_set_bit;
 170         gc->chip_types->chip.irq_unmask = irq_gc_mask_clr_bit;
 171         gc->chip_types->chip.irq_ack = irq_gc_ack_clr_bit;
 172         gc->chip_types->chip.irq_set_type = al_fic_irq_set_type;
 173         gc->chip_types->chip.irq_retrigger = al_fic_irq_retrigger;
 174         gc->chip_types->chip.flags = IRQCHIP_SKIP_SET_WAKE;
 175         gc->private = fic;
 176
 177         irq_set_chained_handler_and_data(fic->parent_irq,
 178                                          al_fic_irq_handler,
 179                                          fic);
 180         return 0;
 181
 182 err_domain_remove:
 183         irq_domain_remove(fic->domain);
 184
 185         return ret;
 186 }
 187
 188 /*
 189  * al_fic_wire_init() - initialize and configure fic in wire mode
 190  * @of_node: optional pointer to interrupt controller's device tree node.
 191  * @base: mmio to fic register
 192  * @name: name of the fic
 193  * @parent_irq: interrupt of parent
 194  *
 195  * This API will configure the fic hardware to to work in wire mode.
 196  * In wire mode, fic hardware is generating a wire ("wired") interrupt.
 197  * Interrupt can be generated based on positive edge or level - configuration is
 198  * to be determined based on connected hardware to this fic.
 199  */
 200 static struct al_fic *al_fic_wire_init(struct device_node *node,
 201                                        void __iomem *base,
 202                                        const char *name,
 203                                        unsigned int parent_irq)
 204 {
 205         struct al_fic *fic;
 206         int ret;
 207         u32 control = CONTROL_MASK_MSI_X;
 208
 209         fic = kzalloc(sizeof(*fic), GFP_KERNEL);
 210         if (!fic)
 211                 return ERR_PTR(-ENOMEM);
 212
 213         fic->base = base;
 214         fic->parent_irq = parent_irq;
 215         fic->name = name;
 216
 217         /* mask out all interrupts */
 218         writel_relaxed(0xFFFFFFFF, fic->base + AL_FIC_MASK);
 219
 220         /* clear any pending interrupt */
 221         writel_relaxed(0, fic->base + AL_FIC_CAUSE);
 222
 223         writel_relaxed(control, fic->base + AL_FIC_CONTROL);
 224
 225         ret = al_fic_register(node, fic);
 226         if (ret) {
 227                 pr_err("fail to register irqchip\n");
 228                 goto err_free;
 229         }
 230
 231         pr_debug("%s initialized successfully in Legacy mode (parent-irq=%u)\n",
 232                  fic->name, parent_irq);
 233
 234         return fic;
 235
 236 err_free:
 237         kfree(fic);
 238         return ERR_PTR(ret);
 239 }
 240
 241 static int __init al_fic_init_dt(struct device_node *node,
 242                                  struct device_node *parent)
 243 {
 244         int ret;
 245         void __iomem *base;
 246         unsigned int parent_irq;
 247         struct al_fic *fic;
 248
 249         if (!parent) {
 250                 pr_err("%s: unsupported - device require a parent\n",
 251                        node->name);
 252                 return -EINVAL;
 253         }
 254
 255         base = of_iomap(node, 0);
 256         if (!base) {
 257                 pr_err("%s: fail to map memory\n", node->name);
 258                 return -ENOMEM;
 259         }
 260
 261         parent_irq = irq_of_parse_and_map(node, 0);
 262         if (!parent_irq) {
 263                 pr_err("%s: fail to map irq\n", node->name);
 264                 ret = -EINVAL;
 265                 goto err_unmap;
 266         }
 267
 268         fic = al_fic_wire_init(node,
 269                                base,
 270                                node->name,
 271                                parent_irq);
 272         if (IS_ERR(fic)) {
 273                 pr_err("%s: fail to initialize irqchip (%lu)\n",
 274                        node->name,
 275                        PTR_ERR(fic));
 276                 ret = PTR_ERR(fic);
 277                 goto err_irq_dispose;
 278         }
 279
 280         return 0;
 281
 282 err_irq_dispose:
 283         irq_dispose_mapping(parent_irq);
 284 err_unmap:
 285         iounmap(base);
 286
 287         return ret;
 288 }
 289
 290 IRQCHIP_DECLARE(al_fic, "amazon,al-fic", al_fic_init_dt);