drivers/irqchip/irq-or1k-pic.c

   1 /*
   2  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
   3  * Copyright (C) 2014 Stefan Kristansson <stefan.kristiansson@saunalahti.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * as published by the Free Software Foundation; either version
   8  * 2 of the License, or (at your option) any later version.
   9  */
  10
  11 #include <linux/irq.h>
  12 #include <linux/irqchip.h>
  13 #include <linux/of.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/of_address.h>
  16
  17 /* OR1K PIC implementation */
  18
  19 struct or1k_pic_dev {
  20         struct irq_chip chip;
  21         irq_flow_handler_t handle;
  22         unsigned long flags;
  23 };
  24
  25 /*
  26  * We're a couple of cycles faster than the generic implementations with
  27  * these 'fast' versions.
  28  */
  29
  30 static void or1k_pic_mask(struct irq_data *data)
  31 {
  32         mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
  33 }
  34
  35 static void or1k_pic_unmask(struct irq_data *data)
  36 {
  37         mtspr(SPR_PICMR, mfspr(SPR_PICMR) | (1UL << data->hwirq));
  38 }
  39
  40 static void or1k_pic_ack(struct irq_data *data)
  41 {
  42         mtspr(SPR_PICSR, (1UL << data->hwirq));
  43 }
  44
  45 static void or1k_pic_mask_ack(struct irq_data *data)
  46 {
  47         mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
  48         mtspr(SPR_PICSR, (1UL << data->hwirq));
  49 }
  50
  51 /*
  52  * There are two oddities with the OR1200 PIC implementation:
  53  * i)  LEVEL-triggered interrupts are latched and need to be cleared
  54  * ii) the interrupt latch is cleared by writing a 0 to the bit,
  55  *     as opposed to a 1 as mandated by the spec
  56  */
  57 static void or1k_pic_or1200_ack(struct irq_data *data)
  58 {
  59         mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
  60 }
  61
  62 static void or1k_pic_or1200_mask_ack(struct irq_data *data)
  63 {
  64         mtspr(SPR_PICMR, mfspr(SPR_PICMR) & ~(1UL << data->hwirq));
  65         mtspr(SPR_PICSR, mfspr(SPR_PICSR) & ~(1UL << data->hwirq));
  66 }
  67
  68 static struct or1k_pic_dev or1k_pic_level = {
  69         .chip = {
  70                 .name = "or1k-PIC-level",
  71                 .irq_unmask = or1k_pic_unmask,
  72                 .irq_mask = or1k_pic_mask,
  73                 .irq_mask_ack = or1k_pic_mask,
  74         },
  75         .handle = handle_level_irq,
  76         .flags = IRQ_LEVEL | IRQ_NOPROBE,
  77 };
  78
  79 static struct or1k_pic_dev or1k_pic_edge = {
  80         .chip = {
  81                 .name = "or1k-PIC-edge",
  82                 .irq_unmask = or1k_pic_unmask,
  83                 .irq_mask = or1k_pic_mask,
  84                 .irq_ack = or1k_pic_ack,
  85                 .irq_mask_ack = or1k_pic_mask_ack,
  86         },
  87         .handle = handle_edge_irq,
  88         .flags = IRQ_LEVEL | IRQ_NOPROBE,
  89 };
  90
  91 static struct or1k_pic_dev or1k_pic_or1200 = {
  92         .chip = {
  93                 .name = "or1200-PIC",
  94                 .irq_unmask = or1k_pic_unmask,
  95                 .irq_mask = or1k_pic_mask,
  96                 .irq_ack = or1k_pic_or1200_ack,
  97                 .irq_mask_ack = or1k_pic_or1200_mask_ack,
  98         },
  99         .handle = handle_level_irq,
 100         .flags = IRQ_LEVEL | IRQ_NOPROBE,
 101 };
 102
 103 static struct irq_domain *root_domain;
 104
 105 static inline int pic_get_irq(int first)
 106 {
 107         int hwirq;
 108
 109         hwirq = ffs(mfspr(SPR_PICSR) >> first);
 110         if (!hwirq)
 111                 return NO_IRQ;
 112         else
 113                 hwirq = hwirq + first - 1;
 114
 115         return hwirq;
 116 }
 117
 118 static void or1k_pic_handle_irq(struct pt_regs *regs)
 119 {
 120         int irq = -1;
 121
 122         while ((irq = pic_get_irq(irq + 1)) != NO_IRQ)
 123                 handle_domain_irq(root_domain, irq, regs);
 124 }
 125
 126 static int or1k_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
 127 {
 128         struct or1k_pic_dev *pic = d->host_data;
 129
 130         irq_set_chip_and_handler(irq, &pic->chip, pic->handle);
 131         irq_set_status_flags(irq, pic->flags);
 132
 133         return 0;
 134 }
 135
 136 static const struct irq_domain_ops or1k_irq_domain_ops = {
 137         .xlate = irq_domain_xlate_onecell,
 138         .map = or1k_map,
 139 };
 140
 141 /*
 142  * This sets up the IRQ domain for the PIC built in to the OpenRISC
 143  * 1000 CPU.  This is the "root" domain as these are the interrupts
 144  * that directly trigger an exception in the CPU.
 145  */
 146 static int __init or1k_pic_init(struct device_node *node,
 147                                  struct or1k_pic_dev *pic)
 148 {
 149         /* Disable all interrupts until explicitly requested */
 150         mtspr(SPR_PICMR, (0UL));
 151
 152         root_domain = irq_domain_add_linear(node, 32, &or1k_irq_domain_ops,
 153                                             pic);
 154
 155         set_handle_irq(or1k_pic_handle_irq);
 156
 157         return 0;
 158 }
 159
 160 static int __init or1k_pic_or1200_init(struct device_node *node,
 161                                        struct device_node *parent)
 162 {
 163         return or1k_pic_init(node, &or1k_pic_or1200);
 164 }
 165 IRQCHIP_DECLARE(or1k_pic_or1200, "opencores,or1200-pic", or1k_pic_or1200_init);
 166 IRQCHIP_DECLARE(or1k_pic, "opencores,or1k-pic", or1k_pic_or1200_init);
 167
 168 static int __init or1k_pic_level_init(struct device_node *node,
 169                                       struct device_node *parent)
 170 {
 171         return or1k_pic_init(node, &or1k_pic_level);
 172 }
 173 IRQCHIP_DECLARE(or1k_pic_level, "opencores,or1k-pic-level",
 174                 or1k_pic_level_init);
 175
 176 static int __init or1k_pic_edge_init(struct device_node *node,
 177                                      struct device_node *parent)
 178 {
 179         return or1k_pic_init(node, &or1k_pic_edge);
 180 }
 181 IRQCHIP_DECLARE(or1k_pic_edge, "opencores,or1k-pic-edge", or1k_pic_edge_init);