drivers/irqchip/irq-gic-v3-its-platform-msi.c

   1 /*
   2  * Copyright (C) 2013-2015 ARM Limited, All Rights Reserved.
   3  * Author: Marc Zyngier <marc.zyngier@arm.com>
   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  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 #include <linux/acpi_iort.h>
  19 #include <linux/device.h>
  20 #include <linux/msi.h>
  21 #include <linux/of.h>
  22 #include <linux/of_irq.h>
  23
  24 static struct irq_chip its_pmsi_irq_chip = {
  25         .name                   = "ITS-pMSI",
  26 };
  27
  28 static int of_pmsi_get_dev_id(struct irq_domain *domain, struct device *dev,
  29                                   u32 *dev_id)
  30 {
  31         int ret, index = 0;
  32
  33         /* Suck the DeviceID out of the msi-parent property */
  34         do {
  35                 struct of_phandle_args args;
  36
  37                 ret = of_parse_phandle_with_args(dev->of_node,
  38                                                  "msi-parent", "#msi-cells",
  39                                                  index, &args);
  40                 if (args.np == irq_domain_get_of_node(domain)) {
  41                         if (WARN_ON(args.args_count != 1))
  42                                 return -EINVAL;
  43                         *dev_id = args.args[0];
  44                         break;
  45                 }
  46                 index++;
  47         } while (!ret);
  48
  49         return ret;
  50 }
  51
  52 int __weak iort_pmsi_get_dev_id(struct device *dev, u32 *dev_id)
  53 {
  54         return -1;
  55 }
  56
  57 static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
  58                             int nvec, msi_alloc_info_t *info)
  59 {
  60         struct msi_domain_info *msi_info;
  61         u32 dev_id;
  62         int ret;
  63
  64         msi_info = msi_get_domain_info(domain->parent);
  65
  66         if (dev->of_node)
  67                 ret = of_pmsi_get_dev_id(domain, dev, &dev_id);
  68         else
  69                 ret = iort_pmsi_get_dev_id(dev, &dev_id);
  70         if (ret)
  71                 return ret;
  72
  73         /* ITS specific DeviceID, as the core ITS ignores dev. */
  74         info->scratchpad[0].ul = dev_id;
  75
  76         /* Allocate at least 32 MSIs, and always as a power of 2 */
  77         nvec = max_t(int, 32, roundup_pow_of_two(nvec));
  78         return msi_info->ops->msi_prepare(domain->parent,
  79                                           dev, nvec, info);
  80 }
  81
  82 static struct msi_domain_ops its_pmsi_ops = {
  83         .msi_prepare    = its_pmsi_prepare,
  84 };
  85
  86 static struct msi_domain_info its_pmsi_domain_info = {
  87         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
  88         .ops    = &its_pmsi_ops,
  89         .chip   = &its_pmsi_irq_chip,
  90 };
  91
  92 static const struct of_device_id its_device_id[] = {
  93         {       .compatible     = "arm,gic-v3-its",     },
  94         {},
  95 };
  96
  97 static int __init its_pmsi_init_one(struct fwnode_handle *fwnode,
  98                                 const char *name)
  99 {
 100         struct irq_domain *parent;
 101
 102         parent = irq_find_matching_fwnode(fwnode, DOMAIN_BUS_NEXUS);
 103         if (!parent || !msi_get_domain_info(parent)) {
 104                 pr_err("%s: unable to locate ITS domain\n", name);
 105                 return -ENXIO;
 106         }
 107
 108         if (!platform_msi_create_irq_domain(fwnode, &its_pmsi_domain_info,
 109                                             parent)) {
 110                 pr_err("%s: unable to create platform domain\n", name);
 111                 return -ENXIO;
 112         }
 113
 114         pr_info("Platform MSI: %s domain created\n", name);
 115         return 0;
 116 }
 117
 118 #ifdef CONFIG_ACPI
 119 static int __init
 120 its_pmsi_parse_madt(union acpi_subtable_headers *header,
 121                         const unsigned long end)
 122 {
 123         struct acpi_madt_generic_translator *its_entry;
 124         struct fwnode_handle *domain_handle;
 125         const char *node_name;
 126         int err = -ENXIO;
 127
 128         its_entry = (struct acpi_madt_generic_translator *)header;
 129         node_name = kasprintf(GFP_KERNEL, "ITS@0x%lx",
 130                               (long)its_entry->base_address);
 131         domain_handle = iort_find_domain_token(its_entry->translation_id);
 132         if (!domain_handle) {
 133                 pr_err("%s: Unable to locate ITS domain handle\n", node_name);
 134                 goto out;
 135         }
 136
 137         err = its_pmsi_init_one(domain_handle, node_name);
 138
 139 out:
 140         kfree(node_name);
 141         return err;
 142 }
 143
 144 static void __init its_pmsi_acpi_init(void)
 145 {
 146         acpi_table_parse_madt(ACPI_MADT_TYPE_GENERIC_TRANSLATOR,
 147                               its_pmsi_parse_madt, 0);
 148 }
 149 #else
 150 static inline void its_pmsi_acpi_init(void) { }
 151 #endif
 152
 153 static void __init its_pmsi_of_init(void)
 154 {
 155         struct device_node *np;
 156
 157         for (np = of_find_matching_node(NULL, its_device_id); np;
 158              np = of_find_matching_node(np, its_device_id)) {
 159                 if (!of_device_is_available(np))
 160                         continue;
 161                 if (!of_property_read_bool(np, "msi-controller"))
 162                         continue;
 163
 164                 its_pmsi_init_one(of_node_to_fwnode(np), np->full_name);
 165         }
 166 }
 167
 168 static int __init its_pmsi_init(void)
 169 {
 170         its_pmsi_of_init();
 171         its_pmsi_acpi_init();
 172         return 0;
 173 }
 174 early_initcall(its_pmsi_init);