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https://github.com/u-boot/u-boot.git
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e25c34ddb5
Coreboot tables provide information about the CMOS-RAM checksum. Add a command which can check and update this. With this it is possible to adjust CMOS-RAM settings and tidy up the checksum afterwards. Signed-off-by: Simon Glass <sjg@chromium.org>
139 lines
3 KiB
C
139 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Support for booting from coreboot
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*
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* Copyright 2021 Google LLC
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*/
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#define LOG_CATEGORY UCLASS_RTC
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#include <command.h>
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#include <dm.h>
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#include <rtc.h>
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#include <asm/cb_sysinfo.h>
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#include <asm/global_data.h>
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DECLARE_GLOBAL_DATA_PTR;
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const struct sysinfo_t *get_table(void)
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{
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if (!gd->arch.coreboot_table) {
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printf("No coreboot sysinfo table found\n");
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return NULL;
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}
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return &lib_sysinfo;
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}
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static int calc_sum(struct udevice *dev, uint start_bit, uint bit_count)
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{
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uint start_byte = start_bit / 8;
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uint byte_count = bit_count / 8;
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int ret, i;
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uint sum;
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log_debug("Calc sum from %x: %x bytes\n", start_byte, byte_count);
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sum = 0;
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for (i = 0; i < bit_count / 8; i++) {
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ret = rtc_read8(dev, start_bit / 8 + i);
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if (ret < 0)
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return ret;
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sum += ret;
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}
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return (sum & 0xff) << 8 | (sum & 0xff00) >> 8;
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}
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/**
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* prep_cbcmos() - Prepare for a CMOS-RAM command
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*
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* @tab: coreboot table
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* @devnum: RTC device name to use, or NULL for the first one
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* @dep: Returns RTC device on success
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* Return: calculated checksum for CMOS RAM or -ve on error
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*/
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static int prep_cbcmos(const struct sysinfo_t *tab, const char *devname,
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struct udevice **devp)
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{
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struct udevice *dev;
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int ret;
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if (!tab)
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return CMD_RET_FAILURE;
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if (devname)
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ret = uclass_get_device_by_name(UCLASS_RTC, devname, &dev);
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else
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ret = uclass_first_device_err(UCLASS_RTC, &dev);
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if (ret) {
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printf("Failed to get RTC device: %dE\n", ret);
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return ret;
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}
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ret = calc_sum(dev, tab->cmos_range_start,
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tab->cmos_range_end + 1 - tab->cmos_range_start);
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if (ret < 0) {
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printf("Failed to read RTC device: %dE\n", ret);
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return ret;
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}
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*devp = dev;
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return ret;
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}
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static int do_cbcmos_check(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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const struct sysinfo_t *tab = get_table();
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struct udevice *dev;
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u16 cur, sum;
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int ret;
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ret = prep_cbcmos(tab, argv[1], &dev);
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if (ret < 0)
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return CMD_RET_FAILURE;
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sum = ret;
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ret = rtc_read16(dev, tab->cmos_checksum_location / 8, &cur);
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if (ret < 0) {
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printf("Failed to read RTC device: %dE\n", ret);
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return CMD_RET_FAILURE;
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}
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if (sum != cur) {
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printf("Checksum %04x error: calculated %04x\n", cur, sum);
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return CMD_RET_FAILURE;
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}
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return 0;
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}
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static int do_cbcmos_update(struct cmd_tbl *cmdtp, int flag, int argc,
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char *const argv[])
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{
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const struct sysinfo_t *tab = get_table();
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struct udevice *dev;
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u16 sum;
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int ret;
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ret = prep_cbcmos(tab, argv[1], &dev);
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if (ret < 0)
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return CMD_RET_FAILURE;
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sum = ret;
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ret = rtc_write16(dev, tab->cmos_checksum_location / 8, sum);
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if (ret < 0) {
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printf("Failed to read RTC device: %dE\n", ret);
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return CMD_RET_FAILURE;
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}
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printf("Checksum %04x written\n", sum);
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return 0;
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}
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U_BOOT_LONGHELP(cbcmos,
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"check - check CMOS RAM\n"
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"cbcmos update - Update CMOS-RAM checksum";
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);
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U_BOOT_CMD_WITH_SUBCMDS(cbcmos, "coreboot CMOS RAM", cbcmos_help_text,
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U_BOOT_SUBCMD_MKENT(check, 2, 1, do_cbcmos_check),
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U_BOOT_SUBCMD_MKENT(update, 2, 1, do_cbcmos_update));
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