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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2010 Benjamin Herrenschmidt, IBM Corp
* <benh@kernel.crashing.org>
* and David Gibson, IBM Corporation.
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <asm/debugfs.h>
#include <asm/prom.h>
#include <asm/scom.h>
#include <linux/uaccess.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 __be32 *prop, *sprop;
u64 reg, cnt;
scom_map_t ret;
parent = scom_find_parent(dev);
if (parent == NULL)
return NULL;
/*
* We support "scom-reg" properties for adding scom registers
* to a random device-tree node with an explicit scom-parent
*
* We also support the simple "reg" property if the device is
* a direct child of a scom controller.
*
* In case both exist, "scom-reg" takes precedence.
*/
prop = of_get_property(dev, "scom-reg", &size);
sprop = of_get_property(parent, "#scom-cells", NULL);
if (!prop && parent == dev->parent) {
prop = of_get_property(dev, "reg", &size);
sprop = of_get_property(parent, "#address-cells", NULL);
}
if (!prop)
return NULL;
cells = sprop ? be32_to_cpup(sprop) : 1;
size >>= 2;
if (index >= (size / (2*cells)))
return NULL;
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;
struct debugfs_blob_wrapper path;
char name[16];
};
static ssize_t scom_debug_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct scom_debug_entry *ent = filp->private_data;
u64 __user *ubuf64 = (u64 __user *)ubuf;
loff_t off = *ppos;
ssize_t done = 0;
u64 reg, reg_cnt, val;
scom_map_t map;
int rc;
if (off < 0 || (off & 7) || (count & 7))
return -EINVAL;
reg = off >> 3;
reg_cnt = count >> 3;
map = scom_map(ent->dn, reg, reg_cnt);
if (!scom_map_ok(map))
return -ENXIO;
for (reg = 0; reg < reg_cnt; reg++) {
rc = scom_read(map, reg, &val);
if (!rc)
rc = put_user(val, ubuf64);
if (rc) {
if (!done)
done = rc;
break;
}
ubuf64++;
*ppos += 8;
done += 8;
}
scom_unmap(map);
return done;
}
static ssize_t scom_debug_write(struct file* filp, const char __user *ubuf,
size_t count, loff_t *ppos)
{
struct scom_debug_entry *ent = filp->private_data;
u64 __user *ubuf64 = (u64 __user *)ubuf;
loff_t off = *ppos;
ssize_t done = 0;
u64 reg, reg_cnt, val;
scom_map_t map;
int rc;
if (off < 0 || (off & 7) || (count & 7))
return -EINVAL;
reg = off >> 3;
reg_cnt = count >> 3;
map = scom_map(ent->dn, reg, reg_cnt);
if (!scom_map_ok(map))
return -ENXIO;
for (reg = 0; reg < reg_cnt; reg++) {
rc = get_user(val, ubuf64);
if (!rc)
rc = scom_write(map, reg, val);
if (rc) {
if (!done)
done = rc;
break;
}
ubuf64++;
done += 8;
}
scom_unmap(map);
return done;
}
static const struct file_operations scom_debug_fops = {
.read = scom_debug_read,
.write = scom_debug_write,
.open = simple_open,
.llseek = default_llseek,
};
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);
snprintf(ent->name, 16, "%08x", i);
ent->path.data = (void*)kasprintf(GFP_KERNEL, "%pOF", dn);
ent->path.size = strlen((char *)ent->path.data);
dir = debugfs_create_dir(ent->name, root);
if (!dir) {
of_node_put(dn);
kfree(ent->path.data);
kfree(ent);
return -1;
}
debugfs_create_blob("devspec", 0400, dir, &ent->path);
debugfs_create_file("access", 0600, dir, ent, &scom_debug_fops);
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") {
int id = of_get_ibm_chip_id(dn);
if (id == -1)
id = i;
rc |= scom_debug_init_one(root, dn, id);
i++;
}
return rc;
}
device_initcall(scom_debug_init);
#endif /* CONFIG_SCOM_DEBUGFS */
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