drivers/irqchip/irq-realtek-rtl.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2020 Birger Koblitz <mail@birger-koblitz.de>
   4  * Copyright (C) 2020 Bert Vermeulen <bert@biot.com>
   5  * Copyright (C) 2020 John Crispin <john@phrozen.org>
   6  */
   7
   8 #include <linux/of_irq.h>
   9 #include <linux/irqchip.h>
  10 #include <linux/spinlock.h>
  11 #include <linux/of_address.h>
  12 #include <linux/irqchip/chained_irq.h>
  13
  14 /* Global Interrupt Mask Register */
  15 #define RTL_ICTL_GIMR           0x00
  16 /* Global Interrupt Status Register */
  17 #define RTL_ICTL_GISR           0x04
  18 /* Interrupt Routing Registers */
  19 #define RTL_ICTL_IRR0           0x08
  20 #define RTL_ICTL_IRR1           0x0c
  21 #define RTL_ICTL_IRR2           0x10
  22 #define RTL_ICTL_IRR3           0x14
  23
  24 #define REG(x)          (realtek_ictl_base + x)
  25
  26 static DEFINE_RAW_SPINLOCK(irq_lock);
  27 static void __iomem *realtek_ictl_base;
  28
  29 static void realtek_ictl_unmask_irq(struct irq_data *i)
  30 {
  31         unsigned long flags;
  32         u32 value;
  33
  34         raw_spin_lock_irqsave(&irq_lock, flags);
  35
  36         value = readl(REG(RTL_ICTL_GIMR));
  37         value |= BIT(i->hwirq);
  38         writel(value, REG(RTL_ICTL_GIMR));
  39
  40         raw_spin_unlock_irqrestore(&irq_lock, flags);
  41 }
  42
  43 static void realtek_ictl_mask_irq(struct irq_data *i)
  44 {
  45         unsigned long flags;
  46         u32 value;
  47
  48         raw_spin_lock_irqsave(&irq_lock, flags);
  49
  50         value = readl(REG(RTL_ICTL_GIMR));
  51         value &= ~BIT(i->hwirq);
  52         writel(value, REG(RTL_ICTL_GIMR));
  53
  54         raw_spin_unlock_irqrestore(&irq_lock, flags);
  55 }
  56
  57 static struct irq_chip realtek_ictl_irq = {
  58         .name = "realtek-rtl-intc",
  59         .irq_mask = realtek_ictl_mask_irq,
  60         .irq_unmask = realtek_ictl_unmask_irq,
  61 };
  62
  63 static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
  64 {
  65         irq_set_chip_and_handler(irq, &realtek_ictl_irq, handle_level_irq);
  66
  67         return 0;
  68 }
  69
  70 static const struct irq_domain_ops irq_domain_ops = {
  71         .map = intc_map,
  72         .xlate = irq_domain_xlate_onecell,
  73 };
  74
  75 static void realtek_irq_dispatch(struct irq_desc *desc)
  76 {
  77         struct irq_chip *chip = irq_desc_get_chip(desc);
  78         struct irq_domain *domain;
  79         unsigned int pending;
  80
  81         chained_irq_enter(chip, desc);
  82         pending = readl(REG(RTL_ICTL_GIMR)) & readl(REG(RTL_ICTL_GISR));
  83         if (unlikely(!pending)) {
  84                 spurious_interrupt();
  85                 goto out;
  86         }
  87         domain = irq_desc_get_handler_data(desc);
  88         generic_handle_domain_irq(domain, __ffs(pending));
  89
  90 out:
  91         chained_irq_exit(chip, desc);
  92 }
  93
  94 /*
  95  * SoC interrupts are cascaded to MIPS CPU interrupts according to the
  96  * interrupt-map in the device tree. Each SoC interrupt gets 4 bits for
  97  * the CPU interrupt in an Interrupt Routing Register. Max 32 SoC interrupts
  98  * thus go into 4 IRRs. A routing value of '0' means the interrupt is left
  99  * disconnected. Routing values {1..15} connect to output lines {0..14}.
 100  */
 101 static int __init map_interrupts(struct device_node *node, struct irq_domain *domain)
 102 {
 103         struct device_node *cpu_ictl;
 104         const __be32 *imap;
 105         u32 imaplen, soc_int, cpu_int, tmp, regs[4];
 106         int ret, i, irr_regs[] = {
 107                 RTL_ICTL_IRR3,
 108                 RTL_ICTL_IRR2,
 109                 RTL_ICTL_IRR1,
 110                 RTL_ICTL_IRR0,
 111         };
 112         u8 mips_irqs_set;
 113
 114         ret = of_property_read_u32(node, "#address-cells", &tmp);
 115         if (ret || tmp)
 116                 return -EINVAL;
 117
 118         imap = of_get_property(node, "interrupt-map", &imaplen);
 119         if (!imap || imaplen % 3)
 120                 return -EINVAL;
 121
 122         mips_irqs_set = 0;
 123         memset(regs, 0, sizeof(regs));
 124         for (i = 0; i < imaplen; i += 3 * sizeof(u32)) {
 125                 soc_int = be32_to_cpup(imap);
 126                 if (soc_int > 31)
 127                         return -EINVAL;
 128
 129                 cpu_ictl = of_find_node_by_phandle(be32_to_cpup(imap + 1));
 130                 if (!cpu_ictl)
 131                         return -EINVAL;
 132                 ret = of_property_read_u32(cpu_ictl, "#interrupt-cells", &tmp);
 133                 if (ret || tmp != 1)
 134                         return -EINVAL;
 135                 of_node_put(cpu_ictl);
 136
 137                 cpu_int = be32_to_cpup(imap + 2);
 138                 if (cpu_int > 7 || cpu_int < 2)
 139                         return -EINVAL;
 140
 141                 if (!(mips_irqs_set & BIT(cpu_int))) {
 142                         irq_set_chained_handler_and_data(cpu_int, realtek_irq_dispatch,
 143                                                          domain);
 144                         mips_irqs_set |= BIT(cpu_int);
 145                 }
 146
 147                 /* Use routing values (1..6) for CPU interrupts (2..7) */
 148                 regs[(soc_int * 4) / 32] |= (cpu_int - 1) << (soc_int * 4) % 32;
 149                 imap += 3;
 150         }
 151
 152         for (i = 0; i < 4; i++)
 153                 writel(regs[i], REG(irr_regs[i]));
 154
 155         return 0;
 156 }
 157
 158 static int __init realtek_rtl_of_init(struct device_node *node, struct device_node *parent)
 159 {
 160         struct irq_domain *domain;
 161         int ret;
 162
 163         realtek_ictl_base = of_iomap(node, 0);
 164         if (!realtek_ictl_base)
 165                 return -ENXIO;
 166
 167         /* Disable all cascaded interrupts */
 168         writel(0, REG(RTL_ICTL_GIMR));
 169
 170         domain = irq_domain_add_simple(node, 32, 0,
 171                                        &irq_domain_ops, NULL);
 172
 173         ret = map_interrupts(node, domain);
 174         if (ret) {
 175                 pr_err("invalid interrupt map\n");
 176                 return ret;
 177         }
 178
 179         return 0;
 180 }
 181
 182 IRQCHIP_DECLARE(realtek_rtl_intc, "realtek,rtl-intc", realtek_rtl_of_init);