1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * (C) Copyright 2018 Theobroma Systems Design und Consulting GmbH 4 */ 5 6 #include <common.h> 7 #include <bootcount.h> 8 #include <dm.h> 9 #include <rtc.h> 10 11 static const u8 bootcount_magic = 0xbc; 12 13 struct bootcount_rtc_priv { 14 struct udevice *rtc; 15 u32 offset; 16 }; 17 18 static int bootcount_rtc_set(struct udevice *dev, const u32 a) 19 { 20 struct bootcount_rtc_priv *priv = dev_get_priv(dev); 21 const u16 val = bootcount_magic << 8 | (a & 0xff); 22 23 if (rtc_write16(priv->rtc, priv->offset, val) < 0) { 24 debug("%s: rtc_write16 failed\n", __func__); 25 return -EIO; 26 } 27 28 return 0; 29 } 30 31 static int bootcount_rtc_get(struct udevice *dev, u32 *a) 32 { 33 struct bootcount_rtc_priv *priv = dev_get_priv(dev); 34 u16 val; 35 36 if (rtc_read16(priv->rtc, priv->offset, &val) < 0) { 37 debug("%s: rtc_write16 failed\n", __func__); 38 return -EIO; 39 } 40 41 if (val >> 8 == bootcount_magic) { 42 *a = val & 0xff; 43 return 0; 44 } 45 46 debug("%s: bootcount magic does not match on %04x\n", __func__, val); 47 return -EIO; 48 } 49 50 static int bootcount_rtc_probe(struct udevice *dev) 51 { 52 struct ofnode_phandle_args phandle_args; 53 struct bootcount_rtc_priv *priv = dev_get_priv(dev); 54 struct udevice *rtc; 55 56 if (dev_read_phandle_with_args(dev, "rtc", NULL, 0, 0, &phandle_args)) { 57 debug("%s: rtc backing device not specified\n", dev->name); 58 return -ENOENT; 59 } 60 61 if (uclass_get_device_by_ofnode(UCLASS_RTC, phandle_args.node, &rtc)) { 62 debug("%s: could not get backing device\n", dev->name); 63 return -ENODEV; 64 } 65 66 priv->rtc = rtc; 67 priv->offset = dev_read_u32_default(dev, "offset", 0); 68 69 return 0; 70 } 71 72 static const struct bootcount_ops bootcount_rtc_ops = { 73 .get = bootcount_rtc_get, 74 .set = bootcount_rtc_set, 75 }; 76 77 static const struct udevice_id bootcount_rtc_ids[] = { 78 { .compatible = "u-boot,bootcount-rtc" }, 79 { } 80 }; 81 82 U_BOOT_DRIVER(bootcount_rtc) = { 83 .name = "bootcount-rtc", 84 .id = UCLASS_BOOTCOUNT, 85 .priv_auto_alloc_size = sizeof(struct bootcount_rtc_priv), 86 .probe = bootcount_rtc_probe, 87 .of_match = bootcount_rtc_ids, 88 .ops = &bootcount_rtc_ops, 89 }; 90