linux/drivers/base/soc.c
Geert Uytterhoeven b0f6807d35 base: soc: Make soc_device_match() simpler and easier to read
The function soc_device_match() is difficult to read for various
reasons:
  - There are two loop conditions using different styles: "while (...)"
    (which is BTW always true) vs. "if ... break",
  - The are two return condition using different logic: "if ... return
    foo" vs. "if ... else return bar".

Make the code easier to read by:
  1. Removing the always-true "!ret" loop condition, and dropping the
     now unneeded pre-initialization of "ret",
  2. Converting "if ... break" to a proper "while (...)" loop condition,
  3. Inverting the logic of the second return condition.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/9f9107c06f7d065ae6581e5290ef5d72f7298fd1.1646132835.git.geert+renesas@glider.be
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-03-18 14:28:07 +01:00

266 lines
6.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) ST-Ericsson SA 2011
*
* Author: Lee Jones <lee.jones@linaro.org> for ST-Ericsson.
*/
#include <linux/sysfs.h>
#include <linux/init.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/spinlock.h>
#include <linux/sys_soc.h>
#include <linux/err.h>
#include <linux/glob.h>
static DEFINE_IDA(soc_ida);
/* Prototype to allow declarations of DEVICE_ATTR(<foo>) before soc_info_show */
static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
char *buf);
struct soc_device {
struct device dev;
struct soc_device_attribute *attr;
int soc_dev_num;
};
static struct bus_type soc_bus_type = {
.name = "soc",
};
static DEVICE_ATTR(machine, 0444, soc_info_show, NULL);
static DEVICE_ATTR(family, 0444, soc_info_show, NULL);
static DEVICE_ATTR(serial_number, 0444, soc_info_show, NULL);
static DEVICE_ATTR(soc_id, 0444, soc_info_show, NULL);
static DEVICE_ATTR(revision, 0444, soc_info_show, NULL);
struct device *soc_device_to_device(struct soc_device *soc_dev)
{
return &soc_dev->dev;
}
static umode_t soc_attribute_mode(struct kobject *kobj,
struct attribute *attr,
int index)
{
struct device *dev = kobj_to_dev(kobj);
struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
if ((attr == &dev_attr_machine.attr) && soc_dev->attr->machine)
return attr->mode;
if ((attr == &dev_attr_family.attr) && soc_dev->attr->family)
return attr->mode;
if ((attr == &dev_attr_revision.attr) && soc_dev->attr->revision)
return attr->mode;
if ((attr == &dev_attr_serial_number.attr) && soc_dev->attr->serial_number)
return attr->mode;
if ((attr == &dev_attr_soc_id.attr) && soc_dev->attr->soc_id)
return attr->mode;
/* Unknown or unfilled attribute */
return 0;
}
static ssize_t soc_info_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
const char *output;
if (attr == &dev_attr_machine)
output = soc_dev->attr->machine;
else if (attr == &dev_attr_family)
output = soc_dev->attr->family;
else if (attr == &dev_attr_revision)
output = soc_dev->attr->revision;
else if (attr == &dev_attr_serial_number)
output = soc_dev->attr->serial_number;
else if (attr == &dev_attr_soc_id)
output = soc_dev->attr->soc_id;
else
return -EINVAL;
return sysfs_emit(buf, "%s\n", output);
}
static struct attribute *soc_attr[] = {
&dev_attr_machine.attr,
&dev_attr_family.attr,
&dev_attr_serial_number.attr,
&dev_attr_soc_id.attr,
&dev_attr_revision.attr,
NULL,
};
static const struct attribute_group soc_attr_group = {
.attrs = soc_attr,
.is_visible = soc_attribute_mode,
};
static void soc_release(struct device *dev)
{
struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
ida_simple_remove(&soc_ida, soc_dev->soc_dev_num);
kfree(soc_dev->dev.groups);
kfree(soc_dev);
}
static struct soc_device_attribute *early_soc_dev_attr;
struct soc_device *soc_device_register(struct soc_device_attribute *soc_dev_attr)
{
struct soc_device *soc_dev;
const struct attribute_group **soc_attr_groups;
int ret;
if (!soc_bus_type.p) {
if (early_soc_dev_attr)
return ERR_PTR(-EBUSY);
early_soc_dev_attr = soc_dev_attr;
return NULL;
}
soc_dev = kzalloc(sizeof(*soc_dev), GFP_KERNEL);
if (!soc_dev) {
ret = -ENOMEM;
goto out1;
}
soc_attr_groups = kcalloc(3, sizeof(*soc_attr_groups), GFP_KERNEL);
if (!soc_attr_groups) {
ret = -ENOMEM;
goto out2;
}
soc_attr_groups[0] = &soc_attr_group;
soc_attr_groups[1] = soc_dev_attr->custom_attr_group;
/* Fetch a unique (reclaimable) SOC ID. */
ret = ida_simple_get(&soc_ida, 0, 0, GFP_KERNEL);
if (ret < 0)
goto out3;
soc_dev->soc_dev_num = ret;
soc_dev->attr = soc_dev_attr;
soc_dev->dev.bus = &soc_bus_type;
soc_dev->dev.groups = soc_attr_groups;
soc_dev->dev.release = soc_release;
dev_set_name(&soc_dev->dev, "soc%d", soc_dev->soc_dev_num);
ret = device_register(&soc_dev->dev);
if (ret) {
put_device(&soc_dev->dev);
return ERR_PTR(ret);
}
return soc_dev;
out3:
kfree(soc_attr_groups);
out2:
kfree(soc_dev);
out1:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(soc_device_register);
/* Ensure soc_dev->attr is freed after calling soc_device_unregister. */
void soc_device_unregister(struct soc_device *soc_dev)
{
device_unregister(&soc_dev->dev);
early_soc_dev_attr = NULL;
}
EXPORT_SYMBOL_GPL(soc_device_unregister);
static int __init soc_bus_register(void)
{
int ret;
ret = bus_register(&soc_bus_type);
if (ret)
return ret;
if (early_soc_dev_attr)
return PTR_ERR(soc_device_register(early_soc_dev_attr));
return 0;
}
core_initcall(soc_bus_register);
static int soc_device_match_attr(const struct soc_device_attribute *attr,
const struct soc_device_attribute *match)
{
if (match->machine &&
(!attr->machine || !glob_match(match->machine, attr->machine)))
return 0;
if (match->family &&
(!attr->family || !glob_match(match->family, attr->family)))
return 0;
if (match->revision &&
(!attr->revision || !glob_match(match->revision, attr->revision)))
return 0;
if (match->soc_id &&
(!attr->soc_id || !glob_match(match->soc_id, attr->soc_id)))
return 0;
return 1;
}
static int soc_device_match_one(struct device *dev, void *arg)
{
struct soc_device *soc_dev = container_of(dev, struct soc_device, dev);
return soc_device_match_attr(soc_dev->attr, arg);
}
/*
* soc_device_match - identify the SoC in the machine
* @matches: zero-terminated array of possible matches
*
* returns the first matching entry of the argument array, or NULL
* if none of them match.
*
* This function is meant as a helper in place of of_match_node()
* in cases where either no device tree is available or the information
* in a device node is insufficient to identify a particular variant
* by its compatible strings or other properties. For new devices,
* the DT binding should always provide unique compatible strings
* that allow the use of of_match_node() instead.
*
* The calling function can use the .data entry of the
* soc_device_attribute to pass a structure or function pointer for
* each entry.
*/
const struct soc_device_attribute *soc_device_match(
const struct soc_device_attribute *matches)
{
int ret;
if (!matches)
return NULL;
while (matches->machine || matches->family || matches->revision ||
matches->soc_id) {
ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
soc_device_match_one);
if (ret < 0 && early_soc_dev_attr)
ret = soc_device_match_attr(early_soc_dev_attr,
matches);
if (ret < 0)
return NULL;
if (ret)
return matches;
matches++;
}
return NULL;
}
EXPORT_SYMBOL_GPL(soc_device_match);