rtc.c
1.99 KB
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// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH
*/
#include <common.h>
#include <bootcount.h>
#include <dm.h>
#include <rtc.h>
static const u8 bootcount_magic = 0xbc;
struct bootcount_rtc_priv {
struct udevice *rtc;
u32 offset;
};
static int bootcount_rtc_set(struct udevice *dev, const u32 a)
{
struct bootcount_rtc_priv *priv = dev_get_priv(dev);
const u16 val = bootcount_magic << 8 | (a & 0xff);
if (rtc_write16(priv->rtc, priv->offset, val) < 0) {
debug("%s: rtc_write16 failed\n", __func__);
return -EIO;
}
return 0;
}
static int bootcount_rtc_get(struct udevice *dev, u32 *a)
{
struct bootcount_rtc_priv *priv = dev_get_priv(dev);
u16 val;
if (rtc_read16(priv->rtc, priv->offset, &val) < 0) {
debug("%s: rtc_write16 failed\n", __func__);
return -EIO;
}
if (val >> 8 == bootcount_magic) {
*a = val & 0xff;
return 0;
}
debug("%s: bootcount magic does not match on %04x\n", __func__, val);
return -EIO;
}
static int bootcount_rtc_probe(struct udevice *dev)
{
struct ofnode_phandle_args phandle_args;
struct bootcount_rtc_priv *priv = dev_get_priv(dev);
struct udevice *rtc;
if (dev_read_phandle_with_args(dev, "rtc", NULL, 0, 0, &phandle_args)) {
debug("%s: rtc backing device not specified\n", dev->name);
return -ENOENT;
}
if (uclass_get_device_by_ofnode(UCLASS_RTC, phandle_args.node, &rtc)) {
debug("%s: could not get backing device\n", dev->name);
return -ENODEV;
}
priv->rtc = rtc;
priv->offset = dev_read_u32_default(dev, "offset", 0);
return 0;
}
static const struct bootcount_ops bootcount_rtc_ops = {
.get = bootcount_rtc_get,
.set = bootcount_rtc_set,
};
static const struct udevice_id bootcount_rtc_ids[] = {
{ .compatible = "u-boot,bootcount-rtc" },
{ }
};
U_BOOT_DRIVER(bootcount_rtc) = {
.name = "bootcount-rtc",
.id = UCLASS_BOOTCOUNT,
.priv_auto_alloc_size = sizeof(struct bootcount_rtc_priv),
.probe = bootcount_rtc_probe,
.of_match = bootcount_rtc_ids,
.ops = &bootcount_rtc_ops,
};