drivers/irqchip/irq-aspeed-scu-ic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Aspeed AST24XX, AST25XX, and AST26XX SCU Interrupt Controller
   4  * Copyright 2019 IBM Corporation
   5  *
   6  * Eddie James <eajames@linux.ibm.com>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/irq.h>
  11 #include <linux/irqchip.h>
  12 #include <linux/irqchip/chained_irq.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/mfd/syscon.h>
  15 #include <linux/of_irq.h>
  16 #include <linux/regmap.h>
  17
  18 #define ASPEED_SCU_IC_REG               0x018
  19 #define ASPEED_SCU_IC_SHIFT             0
  20 #define ASPEED_SCU_IC_ENABLE            GENMASK(6, ASPEED_SCU_IC_SHIFT)
  21 #define ASPEED_SCU_IC_NUM_IRQS          7
  22 #define ASPEED_SCU_IC_STATUS_SHIFT      16
  23
  24 #define ASPEED_AST2600_SCU_IC0_REG      0x560
  25 #define ASPEED_AST2600_SCU_IC0_SHIFT    0
  26 #define ASPEED_AST2600_SCU_IC0_ENABLE   \
  27         GENMASK(5, ASPEED_AST2600_SCU_IC0_SHIFT)
  28 #define ASPEED_AST2600_SCU_IC0_NUM_IRQS 6
  29
  30 #define ASPEED_AST2600_SCU_IC1_REG      0x570
  31 #define ASPEED_AST2600_SCU_IC1_SHIFT    4
  32 #define ASPEED_AST2600_SCU_IC1_ENABLE   \
  33         GENMASK(5, ASPEED_AST2600_SCU_IC1_SHIFT)
  34 #define ASPEED_AST2600_SCU_IC1_NUM_IRQS 2
  35
  36 struct aspeed_scu_ic {
  37         unsigned long irq_enable;
  38         unsigned long irq_shift;
  39         unsigned int num_irqs;
  40         unsigned int reg;
  41         struct regmap *scu;
  42         struct irq_domain *irq_domain;
  43 };
  44
  45 static void aspeed_scu_ic_irq_handler(struct irq_desc *desc)
  46 {
  47         unsigned int irq;
  48         unsigned int sts;
  49         unsigned long bit;
  50         unsigned long enabled;
  51         unsigned long max;
  52         unsigned long status;
  53         struct aspeed_scu_ic *scu_ic = irq_desc_get_handler_data(desc);
  54         struct irq_chip *chip = irq_desc_get_chip(desc);
  55         unsigned int mask = scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT;
  56
  57         chained_irq_enter(chip, desc);
  58
  59         /*
  60          * The SCU IC has just one register to control its operation and read
  61          * status. The interrupt enable bits occupy the lower 16 bits of the
  62          * register, while the interrupt status bits occupy the upper 16 bits.
  63          * The status bit for a given interrupt is always 16 bits shifted from
  64          * the enable bit for the same interrupt.
  65          * Therefore, perform the IRQ operations in the enable bit space by
  66          * shifting the status down to get the mapping and then back up to
  67          * clear the bit.
  68          */
  69         regmap_read(scu_ic->scu, scu_ic->reg, &sts);
  70         enabled = sts & scu_ic->irq_enable;
  71         status = (sts >> ASPEED_SCU_IC_STATUS_SHIFT) & enabled;
  72
  73         bit = scu_ic->irq_shift;
  74         max = scu_ic->num_irqs + bit;
  75
  76         for_each_set_bit_from(bit, &status, max) {
  77                 irq = irq_find_mapping(scu_ic->irq_domain,
  78                                        bit - scu_ic->irq_shift);
  79                 generic_handle_irq(irq);
  80
  81                 regmap_update_bits(scu_ic->scu, scu_ic->reg, mask,
  82                                    BIT(bit + ASPEED_SCU_IC_STATUS_SHIFT));
  83         }
  84
  85         chained_irq_exit(chip, desc);
  86 }
  87
  88 static void aspeed_scu_ic_irq_mask(struct irq_data *data)
  89 {
  90         struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
  91         unsigned int mask = BIT(data->hwirq + scu_ic->irq_shift) |
  92                 (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
  93
  94         /*
  95          * Status bits are cleared by writing 1. In order to prevent the mask
  96          * operation from clearing the status bits, they should be under the
  97          * mask and written with 0.
  98          */
  99         regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, 0);
 100 }
 101
 102 static void aspeed_scu_ic_irq_unmask(struct irq_data *data)
 103 {
 104         struct aspeed_scu_ic *scu_ic = irq_data_get_irq_chip_data(data);
 105         unsigned int bit = BIT(data->hwirq + scu_ic->irq_shift);
 106         unsigned int mask = bit |
 107                 (scu_ic->irq_enable << ASPEED_SCU_IC_STATUS_SHIFT);
 108
 109         /*
 110          * Status bits are cleared by writing 1. In order to prevent the unmask
 111          * operation from clearing the status bits, they should be under the
 112          * mask and written with 0.
 113          */
 114         regmap_update_bits(scu_ic->scu, scu_ic->reg, mask, bit);
 115 }
 116
 117 static int aspeed_scu_ic_irq_set_affinity(struct irq_data *data,
 118                                           const struct cpumask *dest,
 119                                           bool force)
 120 {
 121         return -EINVAL;
 122 }
 123
 124 static struct irq_chip aspeed_scu_ic_chip = {
 125         .name                   = "aspeed-scu-ic",
 126         .irq_mask               = aspeed_scu_ic_irq_mask,
 127         .irq_unmask             = aspeed_scu_ic_irq_unmask,
 128         .irq_set_affinity       = aspeed_scu_ic_irq_set_affinity,
 129 };
 130
 131 static int aspeed_scu_ic_map(struct irq_domain *domain, unsigned int irq,
 132                              irq_hw_number_t hwirq)
 133 {
 134         irq_set_chip_and_handler(irq, &aspeed_scu_ic_chip, handle_level_irq);
 135         irq_set_chip_data(irq, domain->host_data);
 136
 137         return 0;
 138 }
 139
 140 static const struct irq_domain_ops aspeed_scu_ic_domain_ops = {
 141         .map = aspeed_scu_ic_map,
 142 };
 143
 144 static int aspeed_scu_ic_of_init_common(struct aspeed_scu_ic *scu_ic,
 145                                         struct device_node *node)
 146 {
 147         int irq;
 148         int rc = 0;
 149
 150         if (!node->parent) {
 151                 rc = -ENODEV;
 152                 goto err;
 153         }
 154
 155         scu_ic->scu = syscon_node_to_regmap(node->parent);
 156         if (IS_ERR(scu_ic->scu)) {
 157                 rc = PTR_ERR(scu_ic->scu);
 158                 goto err;
 159         }
 160
 161         irq = irq_of_parse_and_map(node, 0);
 162         if (irq < 0) {
 163                 rc = irq;
 164                 goto err;
 165         }
 166
 167         scu_ic->irq_domain = irq_domain_add_linear(node, scu_ic->num_irqs,
 168                                                    &aspeed_scu_ic_domain_ops,
 169                                                    scu_ic);
 170         if (!scu_ic->irq_domain) {
 171                 rc = -ENOMEM;
 172                 goto err;
 173         }
 174
 175         irq_set_chained_handler_and_data(irq, aspeed_scu_ic_irq_handler,
 176                                          scu_ic);
 177
 178         return 0;
 179
 180 err:
 181         kfree(scu_ic);
 182
 183         return rc;
 184 }
 185
 186 static int __init aspeed_scu_ic_of_init(struct device_node *node,
 187                                         struct device_node *parent)
 188 {
 189         struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
 190
 191         if (!scu_ic)
 192                 return -ENOMEM;
 193
 194         scu_ic->irq_enable = ASPEED_SCU_IC_ENABLE;
 195         scu_ic->irq_shift = ASPEED_SCU_IC_SHIFT;
 196         scu_ic->num_irqs = ASPEED_SCU_IC_NUM_IRQS;
 197         scu_ic->reg = ASPEED_SCU_IC_REG;
 198
 199         return aspeed_scu_ic_of_init_common(scu_ic, node);
 200 }
 201
 202 static int __init aspeed_ast2600_scu_ic0_of_init(struct device_node *node,
 203                                                  struct device_node *parent)
 204 {
 205         struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
 206
 207         if (!scu_ic)
 208                 return -ENOMEM;
 209
 210         scu_ic->irq_enable = ASPEED_AST2600_SCU_IC0_ENABLE;
 211         scu_ic->irq_shift = ASPEED_AST2600_SCU_IC0_SHIFT;
 212         scu_ic->num_irqs = ASPEED_AST2600_SCU_IC0_NUM_IRQS;
 213         scu_ic->reg = ASPEED_AST2600_SCU_IC0_REG;
 214
 215         return aspeed_scu_ic_of_init_common(scu_ic, node);
 216 }
 217
 218 static int __init aspeed_ast2600_scu_ic1_of_init(struct device_node *node,
 219                                                  struct device_node *parent)
 220 {
 221         struct aspeed_scu_ic *scu_ic = kzalloc(sizeof(*scu_ic), GFP_KERNEL);
 222
 223         if (!scu_ic)
 224                 return -ENOMEM;
 225
 226         scu_ic->irq_enable = ASPEED_AST2600_SCU_IC1_ENABLE;
 227         scu_ic->irq_shift = ASPEED_AST2600_SCU_IC1_SHIFT;
 228         scu_ic->num_irqs = ASPEED_AST2600_SCU_IC1_NUM_IRQS;
 229         scu_ic->reg = ASPEED_AST2600_SCU_IC1_REG;
 230
 231         return aspeed_scu_ic_of_init_common(scu_ic, node);
 232 }
 233
 234 IRQCHIP_DECLARE(ast2400_scu_ic, "aspeed,ast2400-scu-ic", aspeed_scu_ic_of_init);
 235 IRQCHIP_DECLARE(ast2500_scu_ic, "aspeed,ast2500-scu-ic", aspeed_scu_ic_of_init);
 236 IRQCHIP_DECLARE(ast2600_scu_ic0, "aspeed,ast2600-scu-ic0",
 237                 aspeed_ast2600_scu_ic0_of_init);
 238 IRQCHIP_DECLARE(ast2600_scu_ic1, "aspeed,ast2600-scu-ic1",
 239                 aspeed_ast2600_scu_ic1_of_init);