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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via-pmu-backlight.c (4536B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Backlight code for via-pmu
      4 *
      5 * Copyright (C) 1998 Paul Mackerras and Fabio Riccardi.
      6 * Copyright (C) 2001-2002 Benjamin Herrenschmidt
      7 * Copyright (C) 2006      Michael Hanselmann <linux-kernel@hansmi.ch>
      8 *
      9 */
     10
     11#include <asm/ptrace.h>
     12#include <linux/adb.h>
     13#include <linux/pmu.h>
     14#include <asm/backlight.h>
     15
     16#define MAX_PMU_LEVEL 0xFF
     17
     18static const struct backlight_ops pmu_backlight_data;
     19static DEFINE_SPINLOCK(pmu_backlight_lock);
     20static int sleeping, uses_pmu_bl;
     21static u8 bl_curve[FB_BACKLIGHT_LEVELS];
     22
     23static void pmu_backlight_init_curve(u8 off, u8 min, u8 max)
     24{
     25	int i, flat, count, range = (max - min);
     26
     27	bl_curve[0] = off;
     28
     29	for (flat = 1; flat < (FB_BACKLIGHT_LEVELS / 16); ++flat)
     30		bl_curve[flat] = min;
     31
     32	count = FB_BACKLIGHT_LEVELS * 15 / 16;
     33	for (i = 0; i < count; ++i)
     34		bl_curve[flat + i] = min + (range * (i + 1) / count);
     35}
     36
     37static int pmu_backlight_curve_lookup(int value)
     38{
     39	int level = (FB_BACKLIGHT_LEVELS - 1);
     40	int i, max = 0;
     41
     42	/* Look for biggest value */
     43	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++)
     44		max = max((int)bl_curve[i], max);
     45
     46	/* Look for nearest value */
     47	for (i = 0; i < FB_BACKLIGHT_LEVELS; i++) {
     48		int diff = abs(bl_curve[i] - value);
     49		if (diff < max) {
     50			max = diff;
     51			level = i;
     52		}
     53	}
     54	return level;
     55}
     56
     57static int pmu_backlight_get_level_brightness(int level)
     58{
     59	int pmulevel;
     60
     61	/* Get and convert the value */
     62	pmulevel = bl_curve[level] * FB_BACKLIGHT_MAX / MAX_PMU_LEVEL;
     63	if (pmulevel < 0)
     64		pmulevel = 0;
     65	else if (pmulevel > MAX_PMU_LEVEL)
     66		pmulevel = MAX_PMU_LEVEL;
     67
     68	return pmulevel;
     69}
     70
     71static int __pmu_backlight_update_status(struct backlight_device *bd)
     72{
     73	struct adb_request req;
     74	int level = bd->props.brightness;
     75
     76
     77	if (bd->props.power != FB_BLANK_UNBLANK ||
     78	    bd->props.fb_blank != FB_BLANK_UNBLANK)
     79		level = 0;
     80
     81	if (level > 0) {
     82		int pmulevel = pmu_backlight_get_level_brightness(level);
     83
     84		pmu_request(&req, NULL, 2, PMU_BACKLIGHT_BRIGHT, pmulevel);
     85		pmu_wait_complete(&req);
     86
     87		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
     88			PMU_POW_BACKLIGHT | PMU_POW_ON);
     89		pmu_wait_complete(&req);
     90	} else {
     91		pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
     92			PMU_POW_BACKLIGHT | PMU_POW_OFF);
     93		pmu_wait_complete(&req);
     94	}
     95
     96	return 0;
     97}
     98
     99static int pmu_backlight_update_status(struct backlight_device *bd)
    100{
    101	unsigned long flags;
    102	int rc = 0;
    103
    104	spin_lock_irqsave(&pmu_backlight_lock, flags);
    105	/* Don't update brightness when sleeping */
    106	if (!sleeping)
    107		rc = __pmu_backlight_update_status(bd);
    108	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
    109	return rc;
    110}
    111
    112
    113static const struct backlight_ops pmu_backlight_data = {
    114	.update_status	= pmu_backlight_update_status,
    115
    116};
    117
    118#ifdef CONFIG_PM
    119void pmu_backlight_set_sleep(int sleep)
    120{
    121	unsigned long flags;
    122
    123	spin_lock_irqsave(&pmu_backlight_lock, flags);
    124	sleeping = sleep;
    125	if (pmac_backlight && uses_pmu_bl) {
    126		if (sleep) {
    127			struct adb_request req;
    128
    129			pmu_request(&req, NULL, 2, PMU_POWER_CTRL,
    130				    PMU_POW_BACKLIGHT | PMU_POW_OFF);
    131			pmu_wait_complete(&req);
    132		} else
    133			__pmu_backlight_update_status(pmac_backlight);
    134	}
    135	spin_unlock_irqrestore(&pmu_backlight_lock, flags);
    136}
    137#endif /* CONFIG_PM */
    138
    139void __init pmu_backlight_init(void)
    140{
    141	struct backlight_properties props;
    142	struct backlight_device *bd;
    143	char name[10];
    144	int level, autosave;
    145
    146	/* Special case for the old PowerBook since I can't test on it */
    147	autosave =
    148		of_machine_is_compatible("AAPL,3400/2400") ||
    149		of_machine_is_compatible("AAPL,3500");
    150
    151	if (!autosave &&
    152	    !pmac_has_backlight_type("pmu") &&
    153	    !of_machine_is_compatible("AAPL,PowerBook1998") &&
    154	    !of_machine_is_compatible("PowerBook1,1"))
    155		return;
    156
    157	snprintf(name, sizeof(name), "pmubl");
    158
    159	memset(&props, 0, sizeof(struct backlight_properties));
    160	props.type = BACKLIGHT_PLATFORM;
    161	props.max_brightness = FB_BACKLIGHT_LEVELS - 1;
    162	bd = backlight_device_register(name, NULL, NULL, &pmu_backlight_data,
    163				       &props);
    164	if (IS_ERR(bd)) {
    165		printk(KERN_ERR "PMU Backlight registration failed\n");
    166		return;
    167	}
    168	uses_pmu_bl = 1;
    169	pmu_backlight_init_curve(0x7F, 0x46, 0x0E);
    170
    171	level = bd->props.max_brightness;
    172
    173	if (autosave) {
    174		/* read autosaved value if available */
    175		struct adb_request req;
    176		pmu_request(&req, NULL, 2, 0xd9, 0);
    177		pmu_wait_complete(&req);
    178
    179		level = pmu_backlight_curve_lookup(
    180				(req.reply[0] >> 4) *
    181				bd->props.max_brightness / 15);
    182	}
    183
    184	bd->props.brightness = level;
    185	bd->props.power = FB_BLANK_UNBLANK;
    186	backlight_update_status(bd);
    187
    188	printk(KERN_INFO "PMU Backlight initialized (%s)\n", name);
    189}