powerpc: Add SCOM infrastructure
SCOM is a side-band configuration bus implemented on some processors.
This code provides a way for code to map and operate on devices via
SCOM, while the details of how that is implemented is left up to a
SCOM "controller" in the platform code.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/sysdev/scom.c b/arch/powerpc/sysdev/scom.c
new file mode 100644
index 0000000..b2593ce
--- /dev/null
+++ b/arch/powerpc/sysdev/scom.c
@@ -0,0 +1,192 @@
+/*
+ * Copyright 2010 Benjamin Herrenschmidt, IBM Corp
+ * <benh@kernel.crashing.org>
+ * and David Gibson, IBM Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <asm/prom.h>
+#include <asm/scom.h>
+
+const struct scom_controller *scom_controller;
+EXPORT_SYMBOL_GPL(scom_controller);
+
+struct device_node *scom_find_parent(struct device_node *node)
+{
+ struct device_node *par, *tmp;
+ const u32 *p;
+
+ for (par = of_node_get(node); par;) {
+ if (of_get_property(par, "scom-controller", NULL))
+ break;
+ p = of_get_property(par, "scom-parent", NULL);
+ tmp = par;
+ if (p == NULL)
+ par = of_get_parent(par);
+ else
+ par = of_find_node_by_phandle(*p);
+ of_node_put(tmp);
+ }
+ return par;
+}
+EXPORT_SYMBOL_GPL(scom_find_parent);
+
+scom_map_t scom_map_device(struct device_node *dev, int index)
+{
+ struct device_node *parent;
+ unsigned int cells, size;
+ const u32 *prop;
+ u64 reg, cnt;
+ scom_map_t ret;
+
+ parent = scom_find_parent(dev);
+
+ if (parent == NULL)
+ return 0;
+
+ prop = of_get_property(parent, "#scom-cells", NULL);
+ cells = prop ? *prop : 1;
+
+ prop = of_get_property(dev, "scom-reg", &size);
+ if (!prop)
+ return 0;
+ size >>= 2;
+
+ if (index >= (size / (2*cells)))
+ return 0;
+
+ reg = of_read_number(&prop[index * cells * 2], cells);
+ cnt = of_read_number(&prop[index * cells * 2 + cells], cells);
+
+ ret = scom_map(parent, reg, cnt);
+ of_node_put(parent);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(scom_map_device);
+
+#ifdef CONFIG_SCOM_DEBUGFS
+struct scom_debug_entry {
+ struct device_node *dn;
+ unsigned long addr;
+ scom_map_t map;
+ spinlock_t lock;
+ char name[8];
+ struct debugfs_blob_wrapper blob;
+};
+
+static int scom_addr_set(void *data, u64 val)
+{
+ struct scom_debug_entry *ent = data;
+
+ ent->addr = 0;
+ scom_unmap(ent->map);
+
+ ent->map = scom_map(ent->dn, val, 1);
+ if (scom_map_ok(ent->map))
+ ent->addr = val;
+ else
+ return -EFAULT;
+
+ return 0;
+}
+
+static int scom_addr_get(void *data, u64 *val)
+{
+ struct scom_debug_entry *ent = data;
+ *val = ent->addr;
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(scom_addr_fops, scom_addr_get, scom_addr_set,
+ "0x%llx\n");
+
+static int scom_val_set(void *data, u64 val)
+{
+ struct scom_debug_entry *ent = data;
+
+ if (!scom_map_ok(ent->map))
+ return -EFAULT;
+
+ scom_write(ent->map, 0, val);
+
+ return 0;
+}
+
+static int scom_val_get(void *data, u64 *val)
+{
+ struct scom_debug_entry *ent = data;
+
+ if (!scom_map_ok(ent->map))
+ return -EFAULT;
+
+ *val = scom_read(ent->map, 0);
+ return 0;
+}
+DEFINE_SIMPLE_ATTRIBUTE(scom_val_fops, scom_val_get, scom_val_set,
+ "0x%llx\n");
+
+static int scom_debug_init_one(struct dentry *root, struct device_node *dn,
+ int i)
+{
+ struct scom_debug_entry *ent;
+ struct dentry *dir;
+
+ ent = kzalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+
+ ent->dn = of_node_get(dn);
+ ent->map = SCOM_MAP_INVALID;
+ spin_lock_init(&ent->lock);
+ snprintf(ent->name, 8, "scom%d", i);
+ ent->blob.data = dn->full_name;
+ ent->blob.size = strlen(dn->full_name);
+
+ dir = debugfs_create_dir(ent->name, root);
+ if (!dir) {
+ of_node_put(dn);
+ kfree(ent);
+ return -1;
+ }
+
+ debugfs_create_file("addr", 0600, dir, ent, &scom_addr_fops);
+ debugfs_create_file("value", 0600, dir, ent, &scom_val_fops);
+ debugfs_create_blob("path", 0400, dir, &ent->blob);
+
+ return 0;
+}
+
+static int scom_debug_init(void)
+{
+ struct device_node *dn;
+ struct dentry *root;
+ int i, rc;
+
+ root = debugfs_create_dir("scom", powerpc_debugfs_root);
+ if (!root)
+ return -1;
+
+ i = rc = 0;
+ for_each_node_with_property(dn, "scom-controller")
+ rc |= scom_debug_init_one(root, dn, i++);
+
+ return rc;
+}
+device_initcall(scom_debug_init);
+#endif /* CONFIG_SCOM_DEBUGFS */