Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/**
 * Copyright (c) ????		Jochen Schäuble <psionic@psionic.de>
 * Copyright (c) 2003-2004	Joern Engel <joern@wh.fh-wedel.de>
 *
 * Usage:
 *
 * one commend line parameter per device, each in the form:
 *   phram=<name>,<start>,<len>
 * <name> may be up to 63 characters.
 * <start> and <len> can be octal, decimal or hexadecimal.  If followed
 * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
 * gigabytes.
 *
 * Example:
 *	phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
 */
 
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
#include <linux/io.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
 
struct phram_mtd_list {
<------>struct mtd_info mtd;
<------>struct list_head list;
};
 
static LIST_HEAD(phram_list);
 
static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
{
<------>u_char *start = mtd->priv;
 
<------>memset(start + instr->addr, 0xff, instr->len);
 
<------>return 0;
}
 
static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
<------><------>size_t *retlen, void **virt, resource_size_t *phys)
{
<------>*virt = mtd->priv + from;
<------>*retlen = len;
<------>return 0;
}
 
static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
<------>return 0;
}
 
static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
<------><------>size_t *retlen, u_char *buf)
{
<------>u_char *start = mtd->priv;
 
<------>memcpy(buf, start + from, len);
<------>*retlen = len;
<------>return 0;
}
 
static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
<------><------>size_t *retlen, const u_char *buf)
{
<------>u_char *start = mtd->priv;
 
<------>memcpy(start + to, buf, len);
<------>*retlen = len;
<------>return 0;
}
 
static void unregister_devices(void)
{
<------>struct phram_mtd_list *this, *safe;
 
<------>list_for_each_entry_safe(this, safe, &phram_list, list) {
<------><------>mtd_device_unregister(&this->mtd);
<------><------>iounmap(this->mtd.priv);
<------><------>kfree(this->mtd.name);
<------><------>kfree(this);
<------>}
}
 
static int register_device(char *name, phys_addr_t start, size_t len)
{
<------>struct phram_mtd_list *new;
<------>int ret = -ENOMEM;
 
<------>new = kzalloc(sizeof(*new), GFP_KERNEL);
<------>if (!new)
<------><------>goto out0;
 
<------>ret = -EIO;
<------>new->mtd.priv = ioremap(start, len);
<------>if (!new->mtd.priv) {
<------><------>pr_err("ioremap failed\n");
<------><------>goto out1;
<------>}
 
 
<------>new->mtd.name = name;
<------>new->mtd.size = len;
<------>new->mtd.flags = MTD_CAP_RAM;
<------>new->mtd._erase = phram_erase;
<------>new->mtd._point = phram_point;
<------>new->mtd._unpoint = phram_unpoint;
<------>new->mtd._read = phram_read;
<------>new->mtd._write = phram_write;
<------>new->mtd.owner = THIS_MODULE;
<------>new->mtd.type = MTD_RAM;
<------>new->mtd.erasesize = PAGE_SIZE;
<------>new->mtd.writesize = 1;
 
<------>ret = -EAGAIN;
<------>if (mtd_device_register(&new->mtd, NULL, 0)) {
<------><------>pr_err("Failed to register new device\n");
<------><------>goto out2;
<------>}
 
<------>list_add_tail(&new->list, &phram_list);
<------>return 0;
 
out2:
<------>iounmap(new->mtd.priv);
out1:
<------>kfree(new);
out0:
<------>return ret;
}
 
static int parse_num64(uint64_t *num64, char *token)
{
<------>size_t len;
<------>int shift = 0;
<------>int ret;
 
<------>len = strlen(token);
<------>/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
<------>if (len > 2) {
<------><------>if (token[len - 1] == 'i') {
<------><------><------>switch (token[len - 2]) {
<------><------><------>case 'G':
<------><------><------><------>shift += 10;
<------><------><------><------>fallthrough;
<------><------><------>case 'M':
<------><------><------><------>shift += 10;
<------><------><------><------>fallthrough;
<------><------><------>case 'k':
<------><------><------><------>shift += 10;
<------><------><------><------>token[len - 2] = 0;
<------><------><------><------>break;
<------><------><------>default:
<------><------><------><------>return -EINVAL;
<------><------><------>}
<------><------>}
<------>}
 
<------>ret = kstrtou64(token, 0, num64);
<------>*num64 <<= shift;
 
<------>return ret;
}
 
static int parse_name(char **pname, const char *token)
{
<------>size_t len;
<------>char *name;
 
<------>len = strlen(token) + 1;
<------>if (len > 64)
<------><------>return -ENOSPC;
 
<------>name = kstrdup(token, GFP_KERNEL);
<------>if (!name)
<------><------>return -ENOMEM;
 
<------>*pname = name;
<------>return 0;
}
 
 
static inline void kill_final_newline(char *str)
{
<------>char *newline = strrchr(str, '\n');
 
<------>if (newline && !newline[1])
<------><------>*newline = 0;
}
 
 
#define parse_err(fmt, args...) do {	\
<------>pr_err(fmt , ## args);	\
<------>return 1;		\
} while (0)
 
#ifndef MODULE
static int phram_init_called;
/*
 * This shall contain the module parameter if any. It is of the form:
 * - phram=<device>,<address>,<size> for module case
 * - phram.phram=<device>,<address>,<size> for built-in case
 * We leave 64 bytes for the device name, 20 for the address and 20 for the
 * size.
 * Example: phram.phram=rootfs,0xa0000000,512Mi
 */
static char phram_paramline[64 + 20 + 20];
#endif
 
static int phram_setup(const char *val)
{
<------>char buf[64 + 20 + 20], *str = buf;
<------>char *token[3];
<------>char *name;
<------>uint64_t start;
<------>uint64_t len;
<------>int i, ret;
 
<------>if (strnlen(val, sizeof(buf)) >= sizeof(buf))
<------><------>parse_err("parameter too long\n");
 
<------>strcpy(str, val);
<------>kill_final_newline(str);
 
<------>for (i = 0; i < 3; i++)
<------><------>token[i] = strsep(&str, ",");
 
<------>if (str)
<------><------>parse_err("too many arguments\n");
 
<------>if (!token[2])
<------><------>parse_err("not enough arguments\n");
 
<------>ret = parse_name(&name, token[0]);
<------>if (ret)
<------><------>return ret;
 
<------>ret = parse_num64(&start, token[1]);
<------>if (ret) {
<------><------>parse_err("illegal start address\n");
<------><------>goto error;
<------>}
 
<------>ret = parse_num64(&len, token[2]);
<------>if (ret) {
<------><------>parse_err("illegal device length\n");
<------><------>goto error;
<------>}
 
<------>ret = register_device(name, start, len);
<------>if (ret)
<------><------>goto error;
 
<------>pr_info("%s device: %#llx at %#llx\n", name, len, start);
<------>return 0;
 
error:
<------>kfree(name);
<------>return ret;
}
 
static int phram_param_call(const char *val, const struct kernel_param *kp)
{
#ifdef MODULE
<------>return phram_setup(val);
#else
<------>/*
<------> * If more parameters are later passed in via
<------> * /sys/module/phram/parameters/phram
<------> * and init_phram() has already been called,
<------> * we can parse the argument now.
<------> */
 
<------>if (phram_init_called)
<------><------>return phram_setup(val);
 
<------>/*
<------> * During early boot stage, we only save the parameters
<------> * here. We must parse them later: if the param passed
<------> * from kernel boot command line, phram_param_call() is
<------> * called so early that it is not possible to resolve
<------> * the device (even kmalloc() fails). Defer that work to
<------> * phram_setup().
<------> */
 
<------>if (strlen(val) >= sizeof(phram_paramline))
<------><------>return -ENOSPC;
<------>strcpy(phram_paramline, val);
 
<------>return 0;
#endif
}
 
module_param_call(phram, phram_param_call, NULL, NULL, 0200);
MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
 
 
static int __init init_phram(void)
{
<------>int ret = 0;
 
#ifndef MODULE
<------>if (phram_paramline[0])
<------><------>ret = phram_setup(phram_paramline);
<------>phram_init_called = 1;
#endif
 
<------>return ret;
}
 
static void __exit cleanup_phram(void)
{
<------>unregister_devices();
}
 
module_init(init_phram);
module_exit(cleanup_phram);
 
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
MODULE_DESCRIPTION("MTD driver for physical RAM");