Re: [RFC PATCH 1/3] efi-rtc: Remove wakeup functionality

[Ard Biesheuvel <ardb@xxxxxxxxxx>]

On Sun, 3 Aug 2025 at 11:05, Alexandre Belloni
<alexandre.belloni@xxxxxxxxxxx> wrote:
>
> Hello,
>
> Apart from the topic that should be "rtc: efi:...", I'm ready to apply
> this patch.
>

Thanks, please go ahead.

> On 14/07/2025 08:08:45+0200, Ard Biesheuvel wrote:
> > From: Ard Biesheuvel <ardb@xxxxxxxxxx>
> >
> > The EFI rtc driver is used by non-x86 architectures only, and exposes
> > the get/set wakeup time functionality provided by the underlying
> > platform. This is usually broken on most platforms, and not widely used
> > to begin with [if at all], so let's just remove it.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> > ---
> >  drivers/rtc/rtc-efi.c | 76 +-------------------
> >  1 file changed, 2 insertions(+), 74 deletions(-)
> >
> > diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
> > index fa8bf82df948..b4f44999ef0f 100644
> > --- a/drivers/rtc/rtc-efi.c
> > +++ b/drivers/rtc/rtc-efi.c
> > @@ -112,48 +112,6 @@ convert_from_efi_time(efi_time_t *eft, struct rtc_time 
> > *wtime)
> >       return true;
> >  }
> >
> > -static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> > -{
> > -     efi_time_t eft;
> > -     efi_status_t status;
> > -
> > -     /*
> > -      * As of EFI v1.10, this call always returns an unsupported status
> > -      */
> > -     status = efi.get_wakeup_time((efi_bool_t *)&wkalrm->enabled,
> > -                                  (efi_bool_t *)&wkalrm->pending, &eft);
> > -
> > -     if (status != EFI_SUCCESS)
> > -             return -EINVAL;
> > -
> > -     if (!convert_from_efi_time(&eft, &wkalrm->time))
> > -             return -EIO;
> > -
> > -     return rtc_valid_tm(&wkalrm->time);
> > -}
> > -
> > -static int efi_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> > -{
> > -     efi_time_t eft;
> > -     efi_status_t status;
> > -
> > -     convert_to_efi_time(&wkalrm->time, &eft);
> > -
> > -     /*
> > -      * XXX Fixme:
> > -      * As of EFI 0.92 with the firmware I have on my
> > -      * machine this call does not seem to work quite
> > -      * right
> > -      *
> > -      * As of v1.10, this call always returns an unsupported status
> > -      */
> > -     status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft);
> > -
> > -     dev_warn(dev, "write status is %d\n", (int)status);
> > -
> > -     return status == EFI_SUCCESS ? 0 : -EINVAL;
> > -}
> > -
> >  static int efi_read_time(struct device *dev, struct rtc_time *tm)
> >  {
> >       efi_status_t status;
> > @@ -188,17 +146,13 @@ 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_t        eft;
> >       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));
> >       memset(&cap, 0, sizeof(cap));
> >
> >       efi.get_time(&eft, &cap);
> > -     efi.get_wakeup_time(&enabled, &pending, &alm);
> >
> >       seq_printf(seq,
> >                  "Time\t\t: %u:%u:%u.%09u\n"
> > @@ -214,26 +168,6 @@ 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);
> >
> > -     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 (alm.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
> >        */
> > @@ -249,8 +183,6 @@ static int efi_procfs(struct device *dev, struct 
> > seq_file *seq)
> >  static const struct rtc_class_ops efi_rtc_ops = {
> >       .read_time      = efi_read_time,
> >       .set_time       = efi_set_time,
> > -     .read_alarm     = efi_read_alarm,
> > -     .set_alarm      = efi_set_alarm,
> >       .proc           = efi_procfs,
> >  };
> >
> > @@ -271,11 +203,7 @@ static int __init efi_rtc_probe(struct platform_device 
> > *dev)
> >       platform_set_drvdata(dev, rtc);
> >
> >       rtc->ops = &efi_rtc_ops;
> > -     clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, 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);
> > +     clear_bit(RTC_FEATURE_ALARM, rtc->features);
> >
> >       device_init_wakeup(&dev->dev, true);
> >
> > --
> > 2.50.0.727.gbf7dc18ff4-goog
> >
>
> --
> Alexandre Belloni, co-owner and COO, Bootlin
> Embedded Linux and Kernel engineering
> https://bootlin.com
>