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

Ard Biesheuvel
2023-01-02T10:47:30Z

On Tue, 27 Dec 2022 at 05:09, Shanker Donthineni <sdonthineni@nvidia.com> wrote:
>
> 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>

Queued as a fix in efi/urgent, thanks.

> ---
> 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
>