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

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Date:   Mon, 2 Jan 2023 11:47:11 +0100
From:   Ard Biesheuvel <ardb@...nel.org>
To:     Shanker Donthineni <sdonthineni@...dia.com>
Cc:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-efi@...r.kernel.org
Subject: Re: [PATCH 1/1] efi: rtc: Enable SET/GET WAKEUP services as optional

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