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-aspeed.c (3185B)

      1// SPDX-License-Identifier: GPL-2.0+
      2// Copyright 2015 IBM Corp.
      3
      4#include <linux/module.h>
      5#include <linux/of.h>
      6#include <linux/platform_device.h>
      7#include <linux/rtc.h>
      8#include <linux/io.h>
      9
     10struct aspeed_rtc {
     11	struct rtc_device *rtc_dev;
     12	void __iomem *base;
     13};
     14
     15#define RTC_TIME	0x00
     16#define RTC_YEAR	0x04
     17#define RTC_CTRL	0x10
     18
     19#define RTC_UNLOCK	BIT(1)
     20#define RTC_ENABLE	BIT(0)
     21
     22static int aspeed_rtc_read_time(struct device *dev, struct rtc_time *tm)
     23{
     24	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
     25	unsigned int cent, year;
     26	u32 reg1, reg2;
     27
     28	if (!(readl(rtc->base + RTC_CTRL) & RTC_ENABLE)) {
     29		dev_dbg(dev, "%s failing as rtc disabled\n", __func__);
     30		return -EINVAL;
     31	}
     32
     33	do {
     34		reg2 = readl(rtc->base + RTC_YEAR);
     35		reg1 = readl(rtc->base + RTC_TIME);
     36	} while (reg2 != readl(rtc->base + RTC_YEAR));
     37
     38	tm->tm_mday = (reg1 >> 24) & 0x1f;
     39	tm->tm_hour = (reg1 >> 16) & 0x1f;
     40	tm->tm_min = (reg1 >> 8) & 0x3f;
     41	tm->tm_sec = (reg1 >> 0) & 0x3f;
     42
     43	cent = (reg2 >> 16) & 0x1f;
     44	year = (reg2 >> 8) & 0x7f;
     45	tm->tm_mon = ((reg2 >>  0) & 0x0f) - 1;
     46	tm->tm_year = year + (cent * 100) - 1900;
     47
     48	dev_dbg(dev, "%s %ptR", __func__, tm);
     49
     50	return 0;
     51}
     52
     53static int aspeed_rtc_set_time(struct device *dev, struct rtc_time *tm)
     54{
     55	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
     56	u32 reg1, reg2, ctrl;
     57	int year, cent;
     58
     59	cent = (tm->tm_year + 1900) / 100;
     60	year = tm->tm_year % 100;
     61
     62	reg1 = (tm->tm_mday << 24) | (tm->tm_hour << 16) | (tm->tm_min << 8) |
     63		tm->tm_sec;
     64
     65	reg2 = ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) |
     66		((tm->tm_mon + 1) & 0xf);
     67
     68	ctrl = readl(rtc->base + RTC_CTRL);
     69	writel(ctrl | RTC_UNLOCK, rtc->base + RTC_CTRL);
     70
     71	writel(reg1, rtc->base + RTC_TIME);
     72	writel(reg2, rtc->base + RTC_YEAR);
     73
     74	/* Re-lock and ensure enable is set now that a time is programmed */
     75	writel(ctrl | RTC_ENABLE, rtc->base + RTC_CTRL);
     76
     77	return 0;
     78}
     79
     80static const struct rtc_class_ops aspeed_rtc_ops = {
     81	.read_time = aspeed_rtc_read_time,
     82	.set_time = aspeed_rtc_set_time,
     83};
     84
     85static int aspeed_rtc_probe(struct platform_device *pdev)
     86{
     87	struct aspeed_rtc *rtc;
     88
     89	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
     90	if (!rtc)
     91		return -ENOMEM;
     92
     93	rtc->base = devm_platform_ioremap_resource(pdev, 0);
     94	if (IS_ERR(rtc->base))
     95		return PTR_ERR(rtc->base);
     96
     97	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
     98	if (IS_ERR(rtc->rtc_dev))
     99		return PTR_ERR(rtc->rtc_dev);
    100
    101	platform_set_drvdata(pdev, rtc);
    102
    103	rtc->rtc_dev->ops = &aspeed_rtc_ops;
    104	rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;
    105	rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */
    106
    107	return devm_rtc_register_device(rtc->rtc_dev);
    108}
    109
    110static const struct of_device_id aspeed_rtc_match[] = {
    111	{ .compatible = "aspeed,ast2400-rtc", },
    112	{ .compatible = "aspeed,ast2500-rtc", },
    113	{ .compatible = "aspeed,ast2600-rtc", },
    114	{}
    115};
    116MODULE_DEVICE_TABLE(of, aspeed_rtc_match);
    117
    118static struct platform_driver aspeed_rtc_driver = {
    119	.driver = {
    120		.name = "aspeed-rtc",
    121		.of_match_table = of_match_ptr(aspeed_rtc_match),
    122	},
    123};
    124
    125module_platform_driver_probe(aspeed_rtc_driver, aspeed_rtc_probe);
    126
    127MODULE_DESCRIPTION("ASPEED RTC driver");
    128MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
    129MODULE_LICENSE("GPL");