drivers/irqchip/irq-nvic.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * drivers/irq/irq-nvic.c
   4  *
   5  * Copyright (C) 2008 ARM Limited, All Rights Reserved.
   6  * Copyright (C) 2013 Pengutronix
   7  *
   8  * Support for the Nested Vectored Interrupt Controller found on the
   9  * ARMv7-M CPUs (Cortex-M3/M4)
  10  */
  11 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/init.h>
  14 #include <linux/kernel.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/io.h>
  18 #include <linux/of.h>
  19 #include <linux/of_address.h>
  20 #include <linux/irq.h>
  21 #include <linux/irqchip.h>
  22 #include <linux/irqdomain.h>
  23
  24 #include <asm/v7m.h>
  25 #include <asm/exception.h>
  26
  27 #define NVIC_ISER               0x000
  28 #define NVIC_ICER               0x080
  29 #define NVIC_IPR                0x400
  30
  31 #define NVIC_MAX_BANKS          16
  32 /*
  33  * Each bank handles 32 irqs. Only the 16th (= last) bank handles only
  34  * 16 irqs.
  35  */
  36 #define NVIC_MAX_IRQ            ((NVIC_MAX_BANKS - 1) * 32 + 16)
  37
  38 static struct irq_domain *nvic_irq_domain;
  39
  40 static void __nvic_handle_irq(irq_hw_number_t hwirq)
  41 {
  42         generic_handle_domain_irq(nvic_irq_domain, hwirq);
  43 }
  44
  45 /*
  46  * TODO: restructure the ARMv7M entry logic so that this entry logic can live
  47  * in arch code.
  48  */
  49 asmlinkage void __exception_irq_entry
  50 nvic_handle_irq(irq_hw_number_t hwirq, struct pt_regs *regs)
  51 {
  52         struct pt_regs *old_regs;
  53
  54         irq_enter();
  55         old_regs = set_irq_regs(regs);
  56         __nvic_handle_irq(hwirq);
  57         set_irq_regs(old_regs);
  58         irq_exit();
  59 }
  60
  61 static int nvic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
  62                                 unsigned int nr_irqs, void *arg)
  63 {
  64         int i, ret;
  65         irq_hw_number_t hwirq;
  66         unsigned int type = IRQ_TYPE_NONE;
  67         struct irq_fwspec *fwspec = arg;
  68
  69         ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
  70         if (ret)
  71                 return ret;
  72
  73         for (i = 0; i < nr_irqs; i++)
  74                 irq_map_generic_chip(domain, virq + i, hwirq + i);
  75
  76         return 0;
  77 }
  78
  79 static const struct irq_domain_ops nvic_irq_domain_ops = {
  80         .translate = irq_domain_translate_onecell,
  81         .alloc = nvic_irq_domain_alloc,
  82         .free = irq_domain_free_irqs_top,
  83 };
  84
  85 static int __init nvic_of_init(struct device_node *node,
  86                                struct device_node *parent)
  87 {
  88         unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
  89         unsigned int irqs, i, ret, numbanks;
  90         void __iomem *nvic_base;
  91
  92         numbanks = (readl_relaxed(V7M_SCS_ICTR) &
  93                     V7M_SCS_ICTR_INTLINESNUM_MASK) + 1;
  94
  95         nvic_base = of_iomap(node, 0);
  96         if (!nvic_base) {
  97                 pr_warn("unable to map nvic registers\n");
  98                 return -ENOMEM;
  99         }
 100
 101         irqs = numbanks * 32;
 102         if (irqs > NVIC_MAX_IRQ)
 103                 irqs = NVIC_MAX_IRQ;
 104
 105         nvic_irq_domain =
 106                 irq_domain_add_linear(node, irqs, &nvic_irq_domain_ops, NULL);
 107
 108         if (!nvic_irq_domain) {
 109                 pr_warn("Failed to allocate irq domain\n");
 110                 return -ENOMEM;
 111         }
 112
 113         ret = irq_alloc_domain_generic_chips(nvic_irq_domain, 32, 1,
 114                                              "nvic_irq", handle_fasteoi_irq,
 115                                              clr, 0, IRQ_GC_INIT_MASK_CACHE);
 116         if (ret) {
 117                 pr_warn("Failed to allocate irq chips\n");
 118                 irq_domain_remove(nvic_irq_domain);
 119                 return ret;
 120         }
 121
 122         for (i = 0; i < numbanks; ++i) {
 123                 struct irq_chip_generic *gc;
 124
 125                 gc = irq_get_domain_generic_chip(nvic_irq_domain, 32 * i);
 126                 gc->reg_base = nvic_base + 4 * i;
 127                 gc->chip_types[0].regs.enable = NVIC_ISER;
 128                 gc->chip_types[0].regs.disable = NVIC_ICER;
 129                 gc->chip_types[0].chip.irq_mask = irq_gc_mask_disable_reg;
 130                 gc->chip_types[0].chip.irq_unmask = irq_gc_unmask_enable_reg;
 131                 /* This is a no-op as end of interrupt is signaled by the
 132                  * exception return sequence.
 133                  */
 134                 gc->chip_types[0].chip.irq_eoi = irq_gc_noop;
 135
 136                 /* disable interrupts */
 137                 writel_relaxed(~0, gc->reg_base + NVIC_ICER);
 138         }
 139
 140         /* Set priority on all interrupts */
 141         for (i = 0; i < irqs; i += 4)
 142                 writel_relaxed(0, nvic_base + NVIC_IPR + i);
 143
 144         return 0;
 145 }
 146 IRQCHIP_DECLARE(armv7m_nvic, "arm,armv7m-nvic", nvic_of_init);