kernel/drivers/bus/vexpress-config.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License version 2 as
   4  * published by the Free Software Foundation.
   5  *
   6  * This program is distributed in the hope that it will be useful,
   7  * but WITHOUT ANY WARRANTY; without even the implied warranty of
   8  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   9  * GNU General Public License for more details.
  10  *
  11  * Copyright (C) 2014 ARM Limited
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/init.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/vexpress.h>
  19
  20
  21 struct vexpress_config_bridge {
  22         struct vexpress_config_bridge_ops *ops;
  23         void *context;
  24 };
  25
  26
  27 static DEFINE_MUTEX(vexpress_config_mutex);
  28 static struct class *vexpress_config_class;
  29 static u32 vexpress_config_site_master = VEXPRESS_SITE_MASTER;
  30
  31
  32 void vexpress_config_set_master(u32 site)
  33 {
  34         vexpress_config_site_master = site;
  35 }
  36
  37 u32 vexpress_config_get_master(void)
  38 {
  39         return vexpress_config_site_master;
  40 }
  41
  42 void vexpress_config_lock(void *arg)
  43 {
  44         mutex_lock(&vexpress_config_mutex);
  45 }
  46
  47 void vexpress_config_unlock(void *arg)
  48 {
  49         mutex_unlock(&vexpress_config_mutex);
  50 }
  51
  52
  53 static void vexpress_config_find_prop(struct device_node *node,
  54                 const char *name, u32 *val)
  55 {
  56         /* Default value */
  57         *val = 0;
  58
  59         of_node_get(node);
  60         while (node) {
  61                 if (of_property_read_u32(node, name, val) == 0) {
  62                         of_node_put(node);
  63                         return;
  64                 }
  65                 node = of_get_next_parent(node);
  66         }
  67 }
  68
  69 int vexpress_config_get_topo(struct device_node *node, u32 *site,
  70                 u32 *position, u32 *dcc)
  71 {
  72         vexpress_config_find_prop(node, "arm,vexpress,site", site);
  73         if (*site == VEXPRESS_SITE_MASTER)
  74                 *site = vexpress_config_site_master;
  75         if (WARN_ON(vexpress_config_site_master == VEXPRESS_SITE_MASTER))
  76                 return -EINVAL;
  77         vexpress_config_find_prop(node, "arm,vexpress,position", position);
  78         vexpress_config_find_prop(node, "arm,vexpress,dcc", dcc);
  79
  80         return 0;
  81 }
  82
  83
  84 static void vexpress_config_devres_release(struct device *dev, void *res)
  85 {
  86         struct vexpress_config_bridge *bridge = dev_get_drvdata(dev->parent);
  87         struct regmap *regmap = res;
  88
  89         bridge->ops->regmap_exit(regmap, bridge->context);
  90 }
  91
  92 struct regmap *devm_regmap_init_vexpress_config(struct device *dev)
  93 {
  94         struct vexpress_config_bridge *bridge;
  95         struct regmap *regmap;
  96         struct regmap **res;
  97
  98         if (WARN_ON(dev->parent->class != vexpress_config_class))
  99                 return ERR_PTR(-ENODEV);
 100
 101         bridge = dev_get_drvdata(dev->parent);
 102         if (WARN_ON(!bridge))
 103                 return ERR_PTR(-EINVAL);
 104
 105         res = devres_alloc(vexpress_config_devres_release, sizeof(*res),
 106                         GFP_KERNEL);
 107         if (!res)
 108                 return ERR_PTR(-ENOMEM);
 109
 110         regmap = bridge->ops->regmap_init(dev, bridge->context);
 111         if (IS_ERR(regmap)) {
 112                 devres_free(res);
 113                 return regmap;
 114         }
 115
 116         *res = regmap;
 117         devres_add(dev, res);
 118
 119         return regmap;
 120 }
 121 EXPORT_SYMBOL_GPL(devm_regmap_init_vexpress_config);
 122
 123 struct device *vexpress_config_bridge_register(struct device *parent,
 124                 struct vexpress_config_bridge_ops *ops, void *context)
 125 {
 126         struct device *dev;
 127         struct vexpress_config_bridge *bridge;
 128
 129         if (!vexpress_config_class) {
 130                 vexpress_config_class = class_create(THIS_MODULE,
 131                                 "vexpress-config");
 132                 if (IS_ERR(vexpress_config_class))
 133                         return (void *)vexpress_config_class;
 134         }
 135
 136         dev = device_create(vexpress_config_class, parent, 0,
 137                         NULL, "%s.bridge", dev_name(parent));
 138
 139         if (IS_ERR(dev))
 140                 return dev;
 141
 142         bridge = devm_kmalloc(dev, sizeof(*bridge), GFP_KERNEL);
 143         if (!bridge) {
 144                 put_device(dev);
 145                 device_unregister(dev);
 146                 return ERR_PTR(-ENOMEM);
 147         }
 148         bridge->ops = ops;
 149         bridge->context = context;
 150
 151         dev_set_drvdata(dev, bridge);
 152
 153         dev_dbg(parent, "Registered bridge '%s', parent node %p\n",
 154                         dev_name(dev), parent->of_node);
 155
 156         return dev;
 157 }
 158
 159
 160 static int vexpress_config_node_match(struct device *dev, const void *data)
 161 {
 162         const struct device_node *node = data;
 163
 164         dev_dbg(dev, "Parent node %p, looking for %p\n",
 165                         dev->parent->of_node, node);
 166
 167         return dev->parent->of_node == node;
 168 }
 169
 170 static int vexpress_config_populate(struct device_node *node)
 171 {
 172         struct device_node *bridge;
 173         struct device *parent;
 174
 175         bridge = of_parse_phandle(node, "arm,vexpress,config-bridge", 0);
 176         if (!bridge)
 177                 return -EINVAL;
 178
 179         parent = class_find_device(vexpress_config_class, NULL, bridge,
 180                         vexpress_config_node_match);
 181         if (WARN_ON(!parent))
 182                 return -ENODEV;
 183
 184         return of_platform_populate(node, NULL, NULL, parent);
 185 }
 186
 187 static int __init vexpress_config_init(void)
 188 {
 189         int err = 0;
 190         struct device_node *node;
 191
 192         /* Need the config devices early, before the "normal" devices... */
 193         for_each_compatible_node(node, NULL, "arm,vexpress,config-bus") {
 194                 err = vexpress_config_populate(node);
 195                 if (err)
 196                         break;
 197         }
 198
 199         return err;
 200 }
 201 postcore_initcall(vexpress_config_init);
 202