summaryrefslogtreecommitdiffstats
path: root/drivers/rtc/rtc-efi.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /drivers/rtc/rtc-efi.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'drivers/rtc/rtc-efi.c')
-rw-r--r--drivers/rtc/rtc-efi.c224
1 files changed, 224 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
new file mode 100644
index 000000000..b4f44999e
--- /dev/null
+++ b/drivers/rtc/rtc-efi.c
@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * rtc-efi: RTC Class Driver for EFI-based systems
+ *
+ * Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
+ *
+ * Author: dann frazier <dannf@dannf.org>
+ * Based on efirtc.c by Stephane Eranian
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/stringify.h>
+#include <linux/time.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/efi.h>
+
+#define EFI_ISDST (EFI_TIME_ADJUST_DAYLIGHT|EFI_TIME_IN_DAYLIGHT)
+
+/*
+ * returns day of the year [0-365]
+ */
+static inline int
+compute_yday(efi_time_t *eft)
+{
+ /* efi_time_t.month is in the [1-12] so, we need -1 */
+ return rtc_year_days(eft->day, eft->month - 1, eft->year);
+}
+
+/*
+ * returns day of the week [0-6] 0=Sunday
+ */
+static int
+compute_wday(efi_time_t *eft, int yday)
+{
+ int ndays = eft->year * (365 % 7)
+ + (eft->year - 1) / 4
+ - (eft->year - 1) / 100
+ + (eft->year - 1) / 400
+ + yday;
+
+ /*
+ * 1/1/0000 may or may not have been a Sunday (if it ever existed at
+ * all) but assuming it was makes this calculation work correctly.
+ */
+ return ndays % 7;
+}
+
+static void
+convert_to_efi_time(struct rtc_time *wtime, efi_time_t *eft)
+{
+ eft->year = wtime->tm_year + 1900;
+ eft->month = wtime->tm_mon + 1;
+ eft->day = wtime->tm_mday;
+ eft->hour = wtime->tm_hour;
+ eft->minute = wtime->tm_min;
+ eft->second = wtime->tm_sec;
+ eft->nanosecond = 0;
+ eft->daylight = wtime->tm_isdst ? EFI_ISDST : 0;
+ eft->timezone = EFI_UNSPECIFIED_TIMEZONE;
+}
+
+static bool
+convert_from_efi_time(efi_time_t *eft, struct rtc_time *wtime)
+{
+ memset(wtime, 0, sizeof(*wtime));
+
+ if (eft->second >= 60)
+ return false;
+ wtime->tm_sec = eft->second;
+
+ if (eft->minute >= 60)
+ return false;
+ wtime->tm_min = eft->minute;
+
+ if (eft->hour >= 24)
+ return false;
+ wtime->tm_hour = eft->hour;
+
+ if (!eft->day || eft->day > 31)
+ return false;
+ wtime->tm_mday = eft->day;
+
+ if (!eft->month || eft->month > 12)
+ return false;
+ wtime->tm_mon = eft->month - 1;
+
+ if (eft->year < 1900 || eft->year > 9999)
+ return false;
+ wtime->tm_year = eft->year - 1900;
+
+ /* day in the year [1-365]*/
+ wtime->tm_yday = compute_yday(eft);
+
+ /* day of the week [0-6], Sunday=0 */
+ wtime->tm_wday = compute_wday(eft, wtime->tm_yday);
+
+ switch (eft->daylight & EFI_ISDST) {
+ case EFI_ISDST:
+ wtime->tm_isdst = 1;
+ break;
+ case EFI_TIME_ADJUST_DAYLIGHT:
+ wtime->tm_isdst = 0;
+ break;
+ default:
+ wtime->tm_isdst = -1;
+ }
+
+ return true;
+}
+
+static int efi_read_time(struct device *dev, struct rtc_time *tm)
+{
+ efi_status_t status;
+ efi_time_t eft;
+ efi_time_cap_t cap;
+
+ status = efi.get_time(&eft, &cap);
+
+ if (status != EFI_SUCCESS) {
+ /* should never happen */
+ dev_err_once(dev, "can't read time\n");
+ return -EINVAL;
+ }
+
+ if (!convert_from_efi_time(&eft, tm))
+ return -EIO;
+
+ return 0;
+}
+
+static int efi_set_time(struct device *dev, struct rtc_time *tm)
+{
+ efi_status_t status;
+ efi_time_t eft;
+
+ convert_to_efi_time(tm, &eft);
+
+ status = efi.set_time(&eft);
+
+ return status == EFI_SUCCESS ? 0 : -EINVAL;
+}
+
+static int efi_procfs(struct device *dev, struct seq_file *seq)
+{
+ efi_time_t eft;
+ efi_time_cap_t cap;
+
+ memset(&eft, 0, sizeof(eft));
+ memset(&cap, 0, sizeof(cap));
+
+ efi.get_time(&eft, &cap);
+
+ seq_printf(seq,
+ "Time\t\t: %u:%u:%u.%09u\n"
+ "Date\t\t: %u-%u-%u\n"
+ "Daylight\t: %u\n",
+ eft.hour, eft.minute, eft.second, eft.nanosecond,
+ eft.year, eft.month, eft.day,
+ eft.daylight);
+
+ if (eft.timezone == EFI_UNSPECIFIED_TIMEZONE)
+ seq_puts(seq, "Timezone\t: unspecified\n");
+ else
+ /* XXX fixme: convert to string? */
+ seq_printf(seq, "Timezone\t: %u\n", eft.timezone);
+
+ /*
+ * now prints the capabilities
+ */
+ seq_printf(seq,
+ "Resolution\t: %u\n"
+ "Accuracy\t: %u\n"
+ "SetstoZero\t: %u\n",
+ cap.resolution, cap.accuracy, cap.sets_to_zero);
+
+ return 0;
+}
+
+static const struct rtc_class_ops efi_rtc_ops = {
+ .read_time = efi_read_time,
+ .set_time = efi_set_time,
+ .proc = efi_procfs,
+};
+
+static int __init efi_rtc_probe(struct platform_device *dev)
+{
+ struct rtc_device *rtc;
+ efi_time_t eft;
+ efi_time_cap_t cap;
+
+ /* First check if the RTC is usable */
+ if (efi.get_time(&eft, &cap) != EFI_SUCCESS)
+ return -ENODEV;
+
+ rtc = devm_rtc_allocate_device(&dev->dev);
+ if (IS_ERR(rtc))
+ return PTR_ERR(rtc);
+
+ platform_set_drvdata(dev, rtc);
+
+ rtc->ops = &efi_rtc_ops;
+ clear_bit(RTC_FEATURE_ALARM, rtc->features);
+
+ device_init_wakeup(&dev->dev, true);
+
+ return devm_rtc_register_device(rtc);
+}
+
+static struct platform_driver efi_rtc_driver = {
+ .driver = {
+ .name = "rtc-efi",
+ },
+};
+
+module_platform_driver_probe(efi_rtc_driver, efi_rtc_probe);
+
+MODULE_AUTHOR("dann frazier <dannf@dannf.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("EFI RTC driver");
+MODULE_ALIAS("platform:rtc-efi");