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