[PATCH 1/1] efi: rtc: Enable SET/GET WAKEUP services as optional

Shanker Donthineni
2022-12-27T04:09:54Z

The current implementation of rtc-efi is expecting all the 4
time services GET{SET}_TIME{WAKEUP} must be supported by UEFI
firmware. As per the EFI_RT_PROPERTIES_TABLE, the platform
specific implementations can choose to enable selective time
services based on the RTC device capabilities.

This patch does the following changes to provide GET/SET RTC
services on platforms that do not support the WAKEUP feature.

1) Relax time services cap check when creating a platform device.
2) Clear RTC_FEATURE_ALARM bit in the absence of WAKEUP services.
3) Conditional alarm entries in '/proc/driver/rtc'.

Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
---
drivers/rtc/rtc-efi.c | 48 ++++++++++++++++++++++++-------------------
include/linux/efi.h | 3 ++-
2 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
index e991cccdb6e9c..1e8bc6cc1e12d 100644
--- a/drivers/rtc/rtc-efi.c
+++ b/drivers/rtc/rtc-efi.c
@@ -188,9 +188,10 @@ static int efi_set_time(struct device *dev, struct rtc_time *tm)

static int efi_procfs(struct device *dev, struct seq_file *seq)
{
- efi_time_t eft, alm;
- efi_time_cap_t cap;
- efi_bool_t enabled, pending;
+ efi_time_t eft, alm;
+ efi_time_cap_t cap;
+ efi_bool_t enabled, pending;
+ struct rtc_device *rtc = dev_get_drvdata(dev);

memset(&eft, 0, sizeof(eft));
memset(&alm, 0, sizeof(alm));
@@ -213,23 +214,25 @@ static int efi_procfs(struct device *dev, struct seq_file *seq)
/* XXX fixme: convert to string? */
seq_printf(seq, "Timezone\t: %u\n", eft.timezone);

- seq_printf(seq,
- "Alarm Time\t: %u:%u:%u.%09u\n"
- "Alarm Date\t: %u-%u-%u\n"
- "Alarm Daylight\t: %u\n"
- "Enabled\t\t: %s\n"
- "Pending\t\t: %s\n",
- alm.hour, alm.minute, alm.second, alm.nanosecond,
- alm.year, alm.month, alm.day,
- alm.daylight,
- enabled == 1 ? "yes" : "no",
- pending == 1 ? "yes" : "no");
-
- 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", alm.timezone);
+ if (test_bit(RTC_FEATURE_ALARM, rtc->features)) {
+ seq_printf(seq,
+ "Alarm Time\t: %u:%u:%u.%09u\n"
+ "Alarm Date\t: %u-%u-%u\n"
+ "Alarm Daylight\t: %u\n"
+ "Enabled\t\t: %s\n"
+ "Pending\t\t: %s\n",
+ alm.hour, alm.minute, alm.second, alm.nanosecond,
+ alm.year, alm.month, alm.day,
+ alm.daylight,
+ enabled == 1 ? "yes" : "no",
+ pending == 1 ? "yes" : "no");
+
+ 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", alm.timezone);
+ }

/*
* now prints the capabilities
@@ -269,7 +272,10 @@ static int __init efi_rtc_probe(struct platform_device *dev)

rtc->ops = &efi_rtc_ops;
clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
- set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, rtc->features);
+ if (efi_rt_services_supported(EFI_RT_SUPPORTED_WAKEUP_SERVICES))
+ set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, rtc->features);
+ else
+ clear_bit(RTC_FEATURE_ALARM, rtc->features);

device_init_wakeup(&dev->dev, true);

diff --git a/include/linux/efi.h b/include/linux/efi.h
index 4b27519143f56..98598bd1d2fa5 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -668,7 +668,8 @@ extern struct efi {

#define EFI_RT_SUPPORTED_ALL 0x3fff

-#define EFI_RT_SUPPORTED_TIME_SERVICES 0x000f
+#define EFI_RT_SUPPORTED_TIME_SERVICES 0x0003
+#define EFI_RT_SUPPORTED_WAKEUP_SERVICES 0x000c
#define EFI_RT_SUPPORTED_VARIABLE_SERVICES 0x0070

extern struct mm_struct efi_mm;
--
2.25.1