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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rtc-ep93xx.c (4049B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * A driver for the RTC embedded in the Cirrus Logic EP93XX processors
      4 * Copyright (c) 2006 Tower Technologies
      5 *
      6 * Author: Alessandro Zummo <a.zummo@towertech.it>
      7 */
      8
      9#include <linux/module.h>
     10#include <linux/rtc.h>
     11#include <linux/platform_device.h>
     12#include <linux/io.h>
     13#include <linux/gfp.h>
     14
     15#define EP93XX_RTC_DATA			0x000
     16#define EP93XX_RTC_MATCH		0x004
     17#define EP93XX_RTC_STATUS		0x008
     18#define  EP93XX_RTC_STATUS_INTR		 BIT(0)
     19#define EP93XX_RTC_LOAD			0x00C
     20#define EP93XX_RTC_CONTROL		0x010
     21#define  EP93XX_RTC_CONTROL_MIE		 BIT(0)
     22#define EP93XX_RTC_SWCOMP		0x108
     23#define  EP93XX_RTC_SWCOMP_DEL_MASK	 0x001f0000
     24#define  EP93XX_RTC_SWCOMP_DEL_SHIFT	 16
     25#define  EP93XX_RTC_SWCOMP_INT_MASK	 0x0000ffff
     26#define  EP93XX_RTC_SWCOMP_INT_SHIFT	 0
     27
     28struct ep93xx_rtc {
     29	void __iomem	*mmio_base;
     30	struct rtc_device *rtc;
     31};
     32
     33static int ep93xx_rtc_get_swcomp(struct device *dev, unsigned short *preload,
     34				 unsigned short *delete)
     35{
     36	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
     37	unsigned long comp;
     38
     39	comp = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_SWCOMP);
     40
     41	if (preload)
     42		*preload = (comp & EP93XX_RTC_SWCOMP_INT_MASK)
     43				>> EP93XX_RTC_SWCOMP_INT_SHIFT;
     44
     45	if (delete)
     46		*delete = (comp & EP93XX_RTC_SWCOMP_DEL_MASK)
     47				>> EP93XX_RTC_SWCOMP_DEL_SHIFT;
     48
     49	return 0;
     50}
     51
     52static int ep93xx_rtc_read_time(struct device *dev, struct rtc_time *tm)
     53{
     54	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
     55	unsigned long time;
     56
     57	time = readl(ep93xx_rtc->mmio_base + EP93XX_RTC_DATA);
     58
     59	rtc_time64_to_tm(time, tm);
     60	return 0;
     61}
     62
     63static int ep93xx_rtc_set_time(struct device *dev, struct rtc_time *tm)
     64{
     65	struct ep93xx_rtc *ep93xx_rtc = dev_get_drvdata(dev);
     66	unsigned long secs = rtc_tm_to_time64(tm);
     67
     68	writel(secs + 1, ep93xx_rtc->mmio_base + EP93XX_RTC_LOAD);
     69	return 0;
     70}
     71
     72static int ep93xx_rtc_proc(struct device *dev, struct seq_file *seq)
     73{
     74	unsigned short preload, delete;
     75
     76	ep93xx_rtc_get_swcomp(dev, &preload, &delete);
     77
     78	seq_printf(seq, "preload\t\t: %d\n", preload);
     79	seq_printf(seq, "delete\t\t: %d\n", delete);
     80
     81	return 0;
     82}
     83
     84static const struct rtc_class_ops ep93xx_rtc_ops = {
     85	.read_time	= ep93xx_rtc_read_time,
     86	.set_time	= ep93xx_rtc_set_time,
     87	.proc		= ep93xx_rtc_proc,
     88};
     89
     90static ssize_t comp_preload_show(struct device *dev,
     91				 struct device_attribute *attr, char *buf)
     92{
     93	unsigned short preload;
     94
     95	ep93xx_rtc_get_swcomp(dev->parent, &preload, NULL);
     96
     97	return sprintf(buf, "%d\n", preload);
     98}
     99static DEVICE_ATTR_RO(comp_preload);
    100
    101static ssize_t comp_delete_show(struct device *dev,
    102				struct device_attribute *attr, char *buf)
    103{
    104	unsigned short delete;
    105
    106	ep93xx_rtc_get_swcomp(dev->parent, NULL, &delete);
    107
    108	return sprintf(buf, "%d\n", delete);
    109}
    110static DEVICE_ATTR_RO(comp_delete);
    111
    112static struct attribute *ep93xx_rtc_attrs[] = {
    113	&dev_attr_comp_preload.attr,
    114	&dev_attr_comp_delete.attr,
    115	NULL
    116};
    117
    118static const struct attribute_group ep93xx_rtc_sysfs_files = {
    119	.attrs	= ep93xx_rtc_attrs,
    120};
    121
    122static int ep93xx_rtc_probe(struct platform_device *pdev)
    123{
    124	struct ep93xx_rtc *ep93xx_rtc;
    125	int err;
    126
    127	ep93xx_rtc = devm_kzalloc(&pdev->dev, sizeof(*ep93xx_rtc), GFP_KERNEL);
    128	if (!ep93xx_rtc)
    129		return -ENOMEM;
    130
    131	ep93xx_rtc->mmio_base = devm_platform_ioremap_resource(pdev, 0);
    132	if (IS_ERR(ep93xx_rtc->mmio_base))
    133		return PTR_ERR(ep93xx_rtc->mmio_base);
    134
    135	platform_set_drvdata(pdev, ep93xx_rtc);
    136
    137	ep93xx_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
    138	if (IS_ERR(ep93xx_rtc->rtc))
    139		return PTR_ERR(ep93xx_rtc->rtc);
    140
    141	ep93xx_rtc->rtc->ops = &ep93xx_rtc_ops;
    142	ep93xx_rtc->rtc->range_max = U32_MAX;
    143
    144	err = rtc_add_group(ep93xx_rtc->rtc, &ep93xx_rtc_sysfs_files);
    145	if (err)
    146		return err;
    147
    148	return devm_rtc_register_device(ep93xx_rtc->rtc);
    149}
    150
    151static struct platform_driver ep93xx_rtc_driver = {
    152	.driver		= {
    153		.name	= "ep93xx-rtc",
    154	},
    155	.probe		= ep93xx_rtc_probe,
    156};
    157
    158module_platform_driver(ep93xx_rtc_driver);
    159
    160MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
    161MODULE_DESCRIPTION("EP93XX RTC driver");
    162MODULE_LICENSE("GPL");
    163MODULE_ALIAS("platform:ep93xx-rtc");