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/device.h>
  19 #include <linux/msi.h>
  20 #include <linux/of.h>
  21 #include <linux/of_irq.h>
  22
  23 static struct irq_chip its_pmsi_irq_chip = {
  24         .name                   = "ITS-pMSI",
  25 };
  26
  27 static int its_pmsi_prepare(struct irq_domain *domain, struct device *dev,
  28                             int nvec, msi_alloc_info_t *info)
  29 {
  30         struct msi_domain_info *msi_info;
  31         u32 dev_id;
  32         int ret, index = 0;
  33
  34         msi_info = msi_get_domain_info(domain->parent);
  35
  36         /* Suck the DeviceID out of the msi-parent property */
  37         do {
  38                 struct of_phandle_args args;
  39
  40                 ret = of_parse_phandle_with_args(dev->of_node,
  41                                                  "msi-parent", "#msi-cells",
  42                                                  index, &args);
  43                 if (args.np == irq_domain_get_of_node(domain)) {
  44                         if (WARN_ON(args.args_count != 1))
  45                                 return -EINVAL;
  46                         dev_id = args.args[0];
  47                         break;
  48                 }
  49         } while (!ret);
  50
  51         if (ret)
  52                 return ret;
  53
  54         /* ITS specific DeviceID, as the core ITS ignores dev. */
  55         info->scratchpad[0].ul = dev_id;
  56
  57         return msi_info->ops->msi_prepare(domain->parent,
  58                                           dev, nvec, info);
  59 }
  60
  61 static struct msi_domain_ops its_pmsi_ops = {
  62         .msi_prepare    = its_pmsi_prepare,
  63 };
  64
  65 static struct msi_domain_info its_pmsi_domain_info = {
  66         .flags  = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
  67         .ops    = &its_pmsi_ops,
  68         .chip   = &its_pmsi_irq_chip,
  69 };
  70
  71 static struct of_device_id its_device_id[] = {
  72         {       .compatible     = "arm,gic-v3-its",     },
  73         {},
  74 };
  75
  76 static int __init its_pmsi_init(void)
  77 {
  78         struct device_node *np;
  79         struct irq_domain *parent;
  80
  81         for (np = of_find_matching_node(NULL, its_device_id); np;
  82              np = of_find_matching_node(np, its_device_id)) {
  83                 if (!of_device_is_available(np))
  84                         continue;
  85                 if (!of_property_read_bool(np, "msi-controller"))
  86                         continue;
  87
  88                 parent = irq_find_matching_host(np, DOMAIN_BUS_NEXUS);
  89                 if (!parent || !msi_get_domain_info(parent)) {
  90                         pr_err("%s: unable to locate ITS domain\n",
  91                                np->full_name);
  92                         continue;
  93                 }
  94
  95                 if (!platform_msi_create_irq_domain(of_node_to_fwnode(np),
  96                                                     &its_pmsi_domain_info,
  97                                                     parent)) {
  98                         pr_err("%s: unable to create platform domain\n",
  99                                np->full_name);
 100                         continue;
 101                 }
 102
 103                 pr_info("Platform MSI: %s domain created\n", np->full_name);
 104         }
 105
 106         return 0;
 107 }
 108 early_initcall(its_pmsi_init);