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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apc.c (4214B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* apc - Driver implementation for power management functions
      3 * of Aurora Personality Chip (APC) on SPARCstation-4/5 and
      4 * derivatives.
      5 *
      6 * Copyright (c) 2002 Eric Brower (ebrower@usa.net)
      7 */
      8
      9#include <linux/kernel.h>
     10#include <linux/fs.h>
     11#include <linux/errno.h>
     12#include <linux/init.h>
     13#include <linux/miscdevice.h>
     14#include <linux/pm.h>
     15#include <linux/of.h>
     16#include <linux/of_device.h>
     17#include <linux/module.h>
     18
     19#include <asm/io.h>
     20#include <asm/oplib.h>
     21#include <linux/uaccess.h>
     22#include <asm/auxio.h>
     23#include <asm/apc.h>
     24#include <asm/processor.h>
     25
     26/* Debugging
     27 * 
     28 * #define APC_DEBUG_LED
     29 */
     30
     31#define APC_MINOR	MISC_DYNAMIC_MINOR
     32#define APC_OBPNAME	"power-management"
     33#define APC_DEVNAME "apc"
     34
     35static u8 __iomem *regs;
     36static int apc_no_idle = 0;
     37
     38#define apc_readb(offs)		(sbus_readb(regs+offs))
     39#define apc_writeb(val, offs) 	(sbus_writeb(val, regs+offs))
     40
     41/* Specify "apc=noidle" on the kernel command line to 
     42 * disable APC CPU standby support.  Certain prototype
     43 * systems (SPARCstation-Fox) do not play well with APC
     44 * CPU idle, so disable this if your system has APC and 
     45 * crashes randomly.
     46 */
     47static int __init apc_setup(char *str) 
     48{
     49	if(!strncmp(str, "noidle", strlen("noidle"))) {
     50		apc_no_idle = 1;
     51		return 1;
     52	}
     53	return 0;
     54}
     55__setup("apc=", apc_setup);
     56
     57/* 
     58 * CPU idle callback function
     59 * See .../arch/sparc/kernel/process.c
     60 */
     61static void apc_swift_idle(void)
     62{
     63#ifdef APC_DEBUG_LED
     64	set_auxio(0x00, AUXIO_LED); 
     65#endif
     66
     67	apc_writeb(apc_readb(APC_IDLE_REG) | APC_IDLE_ON, APC_IDLE_REG);
     68
     69#ifdef APC_DEBUG_LED
     70	set_auxio(AUXIO_LED, 0x00); 
     71#endif
     72} 
     73
     74static inline void apc_free(struct platform_device *op)
     75{
     76	of_iounmap(&op->resource[0], regs, resource_size(&op->resource[0]));
     77}
     78
     79static int apc_open(struct inode *inode, struct file *f)
     80{
     81	return 0;
     82}
     83
     84static int apc_release(struct inode *inode, struct file *f)
     85{
     86	return 0;
     87}
     88
     89static long apc_ioctl(struct file *f, unsigned int cmd, unsigned long __arg)
     90{
     91	__u8 inarg, __user *arg = (__u8 __user *) __arg;
     92
     93	switch (cmd) {
     94	case APCIOCGFANCTL:
     95		if (put_user(apc_readb(APC_FANCTL_REG) & APC_REGMASK, arg))
     96			return -EFAULT;
     97		break;
     98
     99	case APCIOCGCPWR:
    100		if (put_user(apc_readb(APC_CPOWER_REG) & APC_REGMASK, arg))
    101			return -EFAULT;
    102		break;
    103
    104	case APCIOCGBPORT:
    105		if (put_user(apc_readb(APC_BPORT_REG) & APC_BPMASK, arg))
    106			return -EFAULT;
    107		break;
    108
    109	case APCIOCSFANCTL:
    110		if (get_user(inarg, arg))
    111			return -EFAULT;
    112		apc_writeb(inarg & APC_REGMASK, APC_FANCTL_REG);
    113		break;
    114
    115	case APCIOCSCPWR:
    116		if (get_user(inarg, arg))
    117			return -EFAULT;
    118		apc_writeb(inarg & APC_REGMASK, APC_CPOWER_REG);
    119		break;
    120
    121	case APCIOCSBPORT:
    122		if (get_user(inarg, arg))
    123			return -EFAULT;
    124		apc_writeb(inarg & APC_BPMASK, APC_BPORT_REG);
    125		break;
    126
    127	default:
    128		return -EINVAL;
    129	}
    130
    131	return 0;
    132}
    133
    134static const struct file_operations apc_fops = {
    135	.unlocked_ioctl =	apc_ioctl,
    136	.open =			apc_open,
    137	.release =		apc_release,
    138	.llseek =		noop_llseek,
    139};
    140
    141static struct miscdevice apc_miscdev = { APC_MINOR, APC_DEVNAME, &apc_fops };
    142
    143static int apc_probe(struct platform_device *op)
    144{
    145	int err;
    146
    147	regs = of_ioremap(&op->resource[0], 0,
    148			  resource_size(&op->resource[0]), APC_OBPNAME);
    149	if (!regs) {
    150		printk(KERN_ERR "%s: unable to map registers\n", APC_DEVNAME);
    151		return -ENODEV;
    152	}
    153
    154	err = misc_register(&apc_miscdev);
    155	if (err) {
    156		printk(KERN_ERR "%s: unable to register device\n", APC_DEVNAME);
    157		apc_free(op);
    158		return -ENODEV;
    159	}
    160
    161	/* Assign power management IDLE handler */
    162	if (!apc_no_idle)
    163		sparc_idle = apc_swift_idle;
    164
    165	printk(KERN_INFO "%s: power management initialized%s\n", 
    166	       APC_DEVNAME, apc_no_idle ? " (CPU idle disabled)" : "");
    167
    168	return 0;
    169}
    170
    171static const struct of_device_id apc_match[] = {
    172	{
    173		.name = APC_OBPNAME,
    174	},
    175	{},
    176};
    177MODULE_DEVICE_TABLE(of, apc_match);
    178
    179static struct platform_driver apc_driver = {
    180	.driver = {
    181		.name = "apc",
    182		.of_match_table = apc_match,
    183	},
    184	.probe		= apc_probe,
    185};
    186
    187static int __init apc_init(void)
    188{
    189	return platform_driver_register(&apc_driver);
    190}
    191
    192/* This driver is not critical to the boot process
    193 * and is easiest to ioremap when SBus is already
    194 * initialized, so we install ourselves thusly:
    195 */
    196__initcall(apc_init);