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 RTL_ICTL_NUM_INPUTS     32
  25
  26 #define REG(x)          (realtek_ictl_base + x)
  27
  28 static DEFINE_RAW_SPINLOCK(irq_lock);
  29 static void __iomem *realtek_ictl_base;
  30
  31 /*
  32  * IRR0-IRR3 store 4 bits per interrupt, but Realtek uses inverted numbering,
  33  * placing IRQ 31 in the first four bits. A routing value of '0' means the
  34  * interrupt is left disconnected. Routing values {1..15} connect to output
  35  * lines {0..14}.
  36  */
  37 #define IRR_OFFSET(idx)         (4 * (3 - (idx * 4) / 32))
  38 #define IRR_SHIFT(idx)          ((idx * 4) % 32)
  39
  40 static void write_irr(void __iomem *irr0, int idx, u32 value)
  41 {
  42         unsigned int offset = IRR_OFFSET(idx);
  43         unsigned int shift = IRR_SHIFT(idx);
  44         u32 irr;
  45
  46         irr = readl(irr0 + offset) & ~(0xf << shift);
  47         irr |= (value & 0xf) << shift;
  48         writel(irr, irr0 + offset);
  49 }
  50
  51 static void realtek_ictl_unmask_irq(struct irq_data *i)
  52 {
  53         unsigned long flags;
  54         u32 value;
  55
  56         raw_spin_lock_irqsave(&irq_lock, flags);
  57
  58         value = readl(REG(RTL_ICTL_GIMR));
  59         value |= BIT(i->hwirq);
  60         writel(value, REG(RTL_ICTL_GIMR));
  61
  62         raw_spin_unlock_irqrestore(&irq_lock, flags);
  63 }
  64
  65 static void realtek_ictl_mask_irq(struct irq_data *i)
  66 {
  67         unsigned long flags;
  68         u32 value;
  69
  70         raw_spin_lock_irqsave(&irq_lock, flags);
  71
  72         value = readl(REG(RTL_ICTL_GIMR));
  73         value &= ~BIT(i->hwirq);
  74         writel(value, REG(RTL_ICTL_GIMR));
  75
  76         raw_spin_unlock_irqrestore(&irq_lock, flags);
  77 }
  78
  79 static struct irq_chip realtek_ictl_irq = {
  80         .name = "realtek-rtl-intc",
  81         .irq_mask = realtek_ictl_mask_irq,
  82         .irq_unmask = realtek_ictl_unmask_irq,
  83 };
  84
  85 static int intc_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
  86 {
  87         unsigned long flags;
  88
  89         irq_set_chip_and_handler(irq, &realtek_ictl_irq, handle_level_irq);
  90
  91         raw_spin_lock_irqsave(&irq_lock, flags);
  92         write_irr(REG(RTL_ICTL_IRR0), hw, 1);
  93         raw_spin_unlock_irqrestore(&irq_lock, flags);
  94
  95         return 0;
  96 }
  97
  98 static const struct irq_domain_ops irq_domain_ops = {
  99         .map = intc_map,
 100         .xlate = irq_domain_xlate_onecell,
 101 };
 102
 103 static void realtek_irq_dispatch(struct irq_desc *desc)
 104 {
 105         struct irq_chip *chip = irq_desc_get_chip(desc);
 106         struct irq_domain *domain;
 107         unsigned long pending;
 108         unsigned int soc_int;
 109
 110         chained_irq_enter(chip, desc);
 111         pending = readl(REG(RTL_ICTL_GIMR)) & readl(REG(RTL_ICTL_GISR));
 112
 113         if (unlikely(!pending)) {
 114                 spurious_interrupt();
 115                 goto out;
 116         }
 117
 118         domain = irq_desc_get_handler_data(desc);
 119         for_each_set_bit(soc_int, &pending, 32)
 120                 generic_handle_domain_irq(domain, soc_int);
 121
 122 out:
 123         chained_irq_exit(chip, desc);
 124 }
 125
 126 static int __init realtek_rtl_of_init(struct device_node *node, struct device_node *parent)
 127 {
 128         struct of_phandle_args oirq;
 129         struct irq_domain *domain;
 130         unsigned int soc_irq;
 131         int parent_irq;
 132
 133         realtek_ictl_base = of_iomap(node, 0);
 134         if (!realtek_ictl_base)
 135                 return -ENXIO;
 136
 137         /* Disable all cascaded interrupts and clear routing */
 138         writel(0, REG(RTL_ICTL_GIMR));
 139         for (soc_irq = 0; soc_irq < RTL_ICTL_NUM_INPUTS; soc_irq++)
 140                 write_irr(REG(RTL_ICTL_IRR0), soc_irq, 0);
 141
 142         if (WARN_ON(!of_irq_count(node))) {
 143                 /*
 144                  * If DT contains no parent interrupts, assume MIPS CPU IRQ 2
 145                  * (HW0) is connected to the first output. This is the case for
 146                  * all known hardware anyway. "interrupt-map" is deprecated, so
 147                  * don't bother trying to parse that.
 148                  */
 149                 oirq.np = of_find_compatible_node(NULL, NULL, "mti,cpu-interrupt-controller");
 150                 oirq.args_count = 1;
 151                 oirq.args[0] = 2;
 152
 153                 parent_irq = irq_create_of_mapping(&oirq);
 154
 155                 of_node_put(oirq.np);
 156         } else {
 157                 parent_irq = of_irq_get(node, 0);
 158         }
 159
 160         if (parent_irq < 0)
 161                 return parent_irq;
 162         else if (!parent_irq)
 163                 return -ENODEV;
 164
 165         domain = irq_domain_add_linear(node, RTL_ICTL_NUM_INPUTS, &irq_domain_ops, NULL);
 166         if (!domain)
 167                 return -ENOMEM;
 168
 169         irq_set_chained_handler_and_data(parent_irq, realtek_irq_dispatch, domain);
 170
 171         return 0;
 172 }
 173
 174 IRQCHIP_DECLARE(realtek_rtl_intc, "realtek,rtl-intc", realtek_rtl_of_init);