drivers/irqchip/irq-vf610-mscm-ir.c

   1 /*
   2  * Copyright (C) 2014-2015 Toradex AG
   3  * Author: Stefan Agner <stefan@agner.ch>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  *
  10  * IRQ chip driver for MSCM interrupt router available on Vybrid SoC's.
  11  * The interrupt router is between the CPU's interrupt controller and the
  12  * peripheral. The router allows to route the peripheral interrupts to
  13  * one of the two available CPU's on Vybrid VF6xx SoC's (Cortex-A5 or
  14  * Cortex-M4). The router will be configured transparently on a IRQ
  15  * request.
  16  *
  17  * o All peripheral interrupts of the Vybrid SoC can be routed to
  18  *   CPU 0, CPU 1 or both. The routing is useful for dual-core
  19  *   variants of Vybrid SoC such as VF6xx. This driver routes the
  20  *   requested interrupt to the CPU currently running on.
  21  *
  22  * o It is required to setup the interrupt router even on single-core
  23  *   variants of Vybrid.
  24  */
  25
  26 #include <linux/cpu_pm.h>
  27 #include <linux/io.h>
  28 #include <linux/irq.h>
  29 #include <linux/irqchip.h>
  30 #include <linux/irqdomain.h>
  31 #include <linux/mfd/syscon.h>
  32 #include <dt-bindings/interrupt-controller/arm-gic.h>
  33 #include <linux/of.h>
  34 #include <linux/of_address.h>
  35 #include <linux/slab.h>
  36 #include <linux/regmap.h>
  37
  38 #define MSCM_CPxNUM             0x4
  39
  40 #define MSCM_IRSPRC(n)          (0x80 + 2 * (n))
  41 #define MSCM_IRSPRC_CPEN_MASK   0x3
  42
  43 #define MSCM_IRSPRC_NUM         112
  44
  45 struct vf610_mscm_ir_chip_data {
  46         void __iomem *mscm_ir_base;
  47         u16 cpu_mask;
  48         u16 saved_irsprc[MSCM_IRSPRC_NUM];
  49         bool is_nvic;
  50 };
  51
  52 static struct vf610_mscm_ir_chip_data *mscm_ir_data;
  53
  54 static inline void vf610_mscm_ir_save(struct vf610_mscm_ir_chip_data *data)
  55 {
  56         int i;
  57
  58         for (i = 0; i < MSCM_IRSPRC_NUM; i++)
  59                 data->saved_irsprc[i] = readw_relaxed(data->mscm_ir_base + MSCM_IRSPRC(i));
  60 }
  61
  62 static inline void vf610_mscm_ir_restore(struct vf610_mscm_ir_chip_data *data)
  63 {
  64         int i;
  65
  66         for (i = 0; i < MSCM_IRSPRC_NUM; i++)
  67                 writew_relaxed(data->saved_irsprc[i], data->mscm_ir_base + MSCM_IRSPRC(i));
  68 }
  69
  70 static int vf610_mscm_ir_notifier(struct notifier_block *self,
  71                                   unsigned long cmd, void *v)
  72 {
  73         switch (cmd) {
  74         case CPU_CLUSTER_PM_ENTER:
  75                 vf610_mscm_ir_save(mscm_ir_data);
  76                 break;
  77         case CPU_CLUSTER_PM_ENTER_FAILED:
  78         case CPU_CLUSTER_PM_EXIT:
  79                 vf610_mscm_ir_restore(mscm_ir_data);
  80                 break;
  81         }
  82
  83         return NOTIFY_OK;
  84 }
  85
  86 static struct notifier_block mscm_ir_notifier_block = {
  87         .notifier_call = vf610_mscm_ir_notifier,
  88 };
  89
  90 static void vf610_mscm_ir_enable(struct irq_data *data)
  91 {
  92         irq_hw_number_t hwirq = data->hwirq;
  93         struct vf610_mscm_ir_chip_data *chip_data = data->chip_data;
  94         u16 irsprc;
  95
  96         irsprc = readw_relaxed(chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
  97         irsprc &= MSCM_IRSPRC_CPEN_MASK;
  98
  99         WARN_ON(irsprc & ~chip_data->cpu_mask);
 100
 101         writew_relaxed(chip_data->cpu_mask,
 102                        chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
 103
 104         irq_chip_enable_parent(data);
 105 }
 106
 107 static void vf610_mscm_ir_disable(struct irq_data *data)
 108 {
 109         irq_hw_number_t hwirq = data->hwirq;
 110         struct vf610_mscm_ir_chip_data *chip_data = data->chip_data;
 111
 112         writew_relaxed(0x0, chip_data->mscm_ir_base + MSCM_IRSPRC(hwirq));
 113
 114         irq_chip_disable_parent(data);
 115 }
 116
 117 static struct irq_chip vf610_mscm_ir_irq_chip = {
 118         .name                   = "mscm-ir",
 119         .irq_mask               = irq_chip_mask_parent,
 120         .irq_unmask             = irq_chip_unmask_parent,
 121         .irq_eoi                = irq_chip_eoi_parent,
 122         .irq_enable             = vf610_mscm_ir_enable,
 123         .irq_disable            = vf610_mscm_ir_disable,
 124         .irq_retrigger          = irq_chip_retrigger_hierarchy,
 125         .irq_set_affinity       = irq_chip_set_affinity_parent,
 126 };
 127
 128 static int vf610_mscm_ir_domain_alloc(struct irq_domain *domain, unsigned int virq,
 129                                       unsigned int nr_irqs, void *arg)
 130 {
 131         int i;
 132         irq_hw_number_t hwirq;
 133         struct of_phandle_args *irq_data = arg;
 134         struct of_phandle_args gic_data;
 135
 136         if (irq_data->args_count != 2)
 137                 return -EINVAL;
 138
 139         hwirq = irq_data->args[0];
 140         for (i = 0; i < nr_irqs; i++)
 141                 irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
 142                                               &vf610_mscm_ir_irq_chip,
 143                                               domain->host_data);
 144
 145         gic_data.np = irq_domain_get_of_node(domain->parent);
 146
 147         if (mscm_ir_data->is_nvic) {
 148                 gic_data.args_count = 1;
 149                 gic_data.args[0] = irq_data->args[0];
 150         } else {
 151                 gic_data.args_count = 3;
 152                 gic_data.args[0] = GIC_SPI;
 153                 gic_data.args[1] = irq_data->args[0];
 154                 gic_data.args[2] = irq_data->args[1];
 155         }
 156
 157         return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, &gic_data);
 158 }
 159
 160 static const struct irq_domain_ops mscm_irq_domain_ops = {
 161         .xlate = irq_domain_xlate_twocell,
 162         .alloc = vf610_mscm_ir_domain_alloc,
 163         .free = irq_domain_free_irqs_common,
 164 };
 165
 166 static int __init vf610_mscm_ir_of_init(struct device_node *node,
 167                                struct device_node *parent)
 168 {
 169         struct irq_domain *domain, *domain_parent;
 170         struct regmap *mscm_cp_regmap;
 171         int ret, cpuid;
 172
 173         domain_parent = irq_find_host(parent);
 174         if (!domain_parent) {
 175                 pr_err("vf610_mscm_ir: interrupt-parent not found\n");
 176                 return -EINVAL;
 177         }
 178
 179         mscm_ir_data = kzalloc(sizeof(*mscm_ir_data), GFP_KERNEL);
 180         if (!mscm_ir_data)
 181                 return -ENOMEM;
 182
 183         mscm_ir_data->mscm_ir_base = of_io_request_and_map(node, 0, "mscm-ir");
 184         if (IS_ERR(mscm_ir_data->mscm_ir_base)) {
 185                 pr_err("vf610_mscm_ir: unable to map mscm register\n");
 186                 ret = PTR_ERR(mscm_ir_data->mscm_ir_base);
 187                 goto out_free;
 188         }
 189
 190         mscm_cp_regmap = syscon_regmap_lookup_by_phandle(node, "fsl,cpucfg");
 191         if (IS_ERR(mscm_cp_regmap)) {
 192                 ret = PTR_ERR(mscm_cp_regmap);
 193                 pr_err("vf610_mscm_ir: regmap lookup for cpucfg failed\n");
 194                 goto out_unmap;
 195         }
 196
 197         regmap_read(mscm_cp_regmap, MSCM_CPxNUM, &cpuid);
 198         mscm_ir_data->cpu_mask = 0x1 << cpuid;
 199
 200         domain = irq_domain_add_hierarchy(domain_parent, 0,
 201                                           MSCM_IRSPRC_NUM, node,
 202                                           &mscm_irq_domain_ops, mscm_ir_data);
 203         if (!domain) {
 204                 ret = -ENOMEM;
 205                 goto out_unmap;
 206         }
 207
 208         if (of_device_is_compatible(irq_domain_get_of_node(domain->parent),
 209                                     "arm,armv7m-nvic"))
 210                 mscm_ir_data->is_nvic = true;
 211
 212         cpu_pm_register_notifier(&mscm_ir_notifier_block);
 213
 214         return 0;
 215
 216 out_unmap:
 217         iounmap(mscm_ir_data->mscm_ir_base);
 218 out_free:
 219         kfree(mscm_ir_data);
 220         return ret;
 221 }
 222 IRQCHIP_DECLARE(vf610_mscm_ir, "fsl,vf610-mscm-ir", vf610_mscm_ir_of_init);