cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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mmio_nvram.c (3177B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * memory mapped NVRAM
      4 *
      5 * (C) Copyright IBM Corp. 2005
      6 *
      7 * Authors : Utz Bacher <utz.bacher@de.ibm.com>
      8 */
      9
     10#include <linux/fs.h>
     11#include <linux/init.h>
     12#include <linux/kernel.h>
     13#include <linux/of_address.h>
     14#include <linux/spinlock.h>
     15#include <linux/types.h>
     16
     17#include <asm/machdep.h>
     18#include <asm/nvram.h>
     19
     20static void __iomem *mmio_nvram_start;
     21static long mmio_nvram_len;
     22static DEFINE_SPINLOCK(mmio_nvram_lock);
     23
     24static ssize_t mmio_nvram_read(char *buf, size_t count, loff_t *index)
     25{
     26	unsigned long flags;
     27
     28	if (*index >= mmio_nvram_len)
     29		return 0;
     30	if (*index + count > mmio_nvram_len)
     31		count = mmio_nvram_len - *index;
     32
     33	spin_lock_irqsave(&mmio_nvram_lock, flags);
     34
     35	memcpy_fromio(buf, mmio_nvram_start + *index, count);
     36
     37	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
     38	
     39	*index += count;
     40	return count;
     41}
     42
     43static unsigned char mmio_nvram_read_val(int addr)
     44{
     45	unsigned long flags;
     46	unsigned char val;
     47
     48	if (addr >= mmio_nvram_len)
     49		return 0xff;
     50
     51	spin_lock_irqsave(&mmio_nvram_lock, flags);
     52
     53	val = ioread8(mmio_nvram_start + addr);
     54
     55	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
     56
     57	return val;
     58}
     59
     60static ssize_t mmio_nvram_write(char *buf, size_t count, loff_t *index)
     61{
     62	unsigned long flags;
     63
     64	if (*index >= mmio_nvram_len)
     65		return 0;
     66	if (*index + count > mmio_nvram_len)
     67		count = mmio_nvram_len - *index;
     68
     69	spin_lock_irqsave(&mmio_nvram_lock, flags);
     70
     71	memcpy_toio(mmio_nvram_start + *index, buf, count);
     72
     73	spin_unlock_irqrestore(&mmio_nvram_lock, flags);
     74	
     75	*index += count;
     76	return count;
     77}
     78
     79static void mmio_nvram_write_val(int addr, unsigned char val)
     80{
     81	unsigned long flags;
     82
     83	if (addr < mmio_nvram_len) {
     84		spin_lock_irqsave(&mmio_nvram_lock, flags);
     85
     86		iowrite8(val, mmio_nvram_start + addr);
     87
     88		spin_unlock_irqrestore(&mmio_nvram_lock, flags);
     89	}
     90}
     91
     92static ssize_t mmio_nvram_get_size(void)
     93{
     94	return mmio_nvram_len;
     95}
     96
     97int __init mmio_nvram_init(void)
     98{
     99	struct device_node *nvram_node;
    100	unsigned long nvram_addr;
    101	struct resource r;
    102	int ret;
    103
    104	nvram_node = of_find_node_by_type(NULL, "nvram");
    105	if (!nvram_node)
    106		nvram_node = of_find_compatible_node(NULL, NULL, "nvram");
    107	if (!nvram_node) {
    108		printk(KERN_WARNING "nvram: no node found in device-tree\n");
    109		return -ENODEV;
    110	}
    111
    112	ret = of_address_to_resource(nvram_node, 0, &r);
    113	if (ret) {
    114		printk(KERN_WARNING "nvram: failed to get address (err %d)\n",
    115		       ret);
    116		goto out;
    117	}
    118	nvram_addr = r.start;
    119	mmio_nvram_len = resource_size(&r);
    120	if ( (!mmio_nvram_len) || (!nvram_addr) ) {
    121		printk(KERN_WARNING "nvram: address or length is 0\n");
    122		ret = -EIO;
    123		goto out;
    124	}
    125
    126	mmio_nvram_start = ioremap(nvram_addr, mmio_nvram_len);
    127	if (!mmio_nvram_start) {
    128		printk(KERN_WARNING "nvram: failed to ioremap\n");
    129		ret = -ENOMEM;
    130		goto out;
    131	}
    132
    133	printk(KERN_INFO "mmio NVRAM, %luk at 0x%lx mapped to %p\n",
    134	       mmio_nvram_len >> 10, nvram_addr, mmio_nvram_start);
    135
    136	ppc_md.nvram_read_val	= mmio_nvram_read_val;
    137	ppc_md.nvram_write_val	= mmio_nvram_write_val;
    138	ppc_md.nvram_read	= mmio_nvram_read;
    139	ppc_md.nvram_write	= mmio_nvram_write;
    140	ppc_md.nvram_size	= mmio_nvram_get_size;
    141
    142out:
    143	of_node_put(nvram_node);
    144	return ret;
    145}