Message-ID: <DM6PR12MB2619BCAF23BF2A52E97C0D9BE45DA@DM6PR12MB2619.namprd12.prod.outlook.com>
Date:   Wed, 21 Jun 2023 01:24:14 +0000
From:   "Quan, Evan" <Evan.Quan@....com>
To:     "Limonciello, Mario" <Mario.Limonciello@....com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>,
        "rafael@...nel.org" <rafael@...nel.org>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>,
        "Pan, Xinhui" <Xinhui.Pan@....com>,
        "airlied@...il.com" <airlied@...il.com>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "kvalo@...nel.org" <kvalo@...nel.org>,
        "nbd@....name" <nbd@....name>,
        "lorenzo@...nel.org" <lorenzo@...nel.org>,
        "ryder.lee@...iatek.com" <ryder.lee@...iatek.com>,
        "shayne.chen@...iatek.com" <shayne.chen@...iatek.com>,
        "sean.wang@...iatek.com" <sean.wang@...iatek.com>,
        "matthias.bgg@...il.com" <matthias.bgg@...il.com>,
        "angelogioacchino.delregno@...labora.com" 
        <angelogioacchino.delregno@...labora.com>,
        "Lazar, Lijo" <Lijo.Lazar@....com>
Subject: RE: [PATCH V3 2/7] wifi: mac80211: Add support for ACPI WBRF

[AMD Official Use Only - General]

> -----Original Message-----
> From: Limonciello, Mario <Mario.Limonciello@....com>
> Sent: Monday, June 19, 2023 10:17 AM
> To: Quan, Evan <Evan.Quan@....com>
> Cc: linux-kernel@...r.kernel.org; linux-acpi@...r.kernel.org; amd-
> gfx@...ts.freedesktop.org; dri-devel@...ts.freedesktop.org; linux-
> wireless@...r.kernel.org; rafael@...nel.org; lenb@...nel.org; Deucher,
> Alexander <Alexander.Deucher@....com>; Koenig, Christian
> <Christian.Koenig@....com>; Pan, Xinhui <Xinhui.Pan@....com>;
> airlied@...il.com; daniel@...ll.ch; kvalo@...nel.org; nbd@....name;
> lorenzo@...nel.org; ryder.lee@...iatek.com; shayne.chen@...iatek.com;
> sean.wang@...iatek.com; matthias.bgg@...il.com;
> angelogioacchino.delregno@...labora.com; Lazar, Lijo <Lijo.Lazar@....com>
> Subject: Re: [PATCH V3 2/7] wifi: mac80211: Add support for ACPI WBRF
>
> On 6/16/23 01:57, Evan Quan wrote:
> > From: Mario Limonciello <mario.limonciello@....com>
> >
> > To support AMD's WBRF interference mitigation mechanism, Wifi adapters
> > utilized in the system must register the frequencies in use(or
> > unregister those frequencies no longer used) via the dedicated APCI
> > calls. So that, other drivers responding to the frequencies can take
> > proper actions to mitigate possible interference.
> >
> > To make WBRF feature functional, the kernel needs to be configured
> > with CONFIG_ACPI_WBRF and the platform is equipped with WBRF
> > support(from BIOS and drivers).
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> > Co-developed-by: Evan Quan <evan.quan@....com>
> > Signed-off-by: Evan Quan <evan.quan@....com>
> > --
> > v1->v2:
> >    - place the new added member(`wbrf_supported`) in
> >      ieee80211_local(Johannes)
> >    - handle chandefs change scenario properly(Johannes)
> >    - some minor fixes around code sharing and possible invalid input
> >      checks(Johannes)
> > ---
> >   include/net/cfg80211.h     |   8 +++
> >   net/mac80211/Makefile      |   2 +
> >   net/mac80211/chan.c        |  11 +++
> >   net/mac80211/ieee80211_i.h |  19 +++++
> >   net/mac80211/main.c        |   2 +
> >   net/mac80211/wbrf.c        | 137
> +++++++++++++++++++++++++++++++++++++
> >   net/wireless/chan.c        |   3 +-
> >   7 files changed, 181 insertions(+), 1 deletion(-)
> >   create mode 100644 net/mac80211/wbrf.c
> >
> > diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h index
> > 9e04f69712b1..c6dc337eafce 100644
> > --- a/include/net/cfg80211.h
> > +++ b/include/net/cfg80211.h
> > @@ -920,6 +920,14 @@ const struct cfg80211_chan_def *
> >   cfg80211_chandef_compatible(const struct cfg80211_chan_def
> *chandef1,
> >                         const struct cfg80211_chan_def *chandef2);
> >
> > +/**
> > + * nl80211_chan_width_to_mhz - get the channel width in Mhz
> > + * @chan_width: the channel width from &enum nl80211_chan_width
> > + * Return: channel width in Mhz if the chan_width from &enum
> > +nl80211_chan_width
> > + * is valid. -1 otherwise.
> > + */
> > +int nl80211_chan_width_to_mhz(enum nl80211_chan_width
> chan_width);
> > +
>
> It's up to mac80211 maintainers, but I would think that the changes to change
> nl80211_chan_width_to_mhz from static to exported should be separate
> from the patch to introduced WBRF support in the series.
Will do that.
>
> >   /**
> >    * cfg80211_chandef_valid - check if a channel definition is valid
> >    * @chandef: the channel definition to check diff --git
> > a/net/mac80211/Makefile b/net/mac80211/Makefile index
> > b8de44da1fb8..709eb678f42a 100644
> > --- a/net/mac80211/Makefile
> > +++ b/net/mac80211/Makefile
> > @@ -65,4 +65,6 @@ rc80211_minstrel-$(CONFIG_MAC80211_DEBUGFS)
> += \
> >
> >   mac80211-$(CONFIG_MAC80211_RC_MINSTREL) += $(rc80211_minstrel-
> y)
> >
> > +mac80211-$(CONFIG_ACPI_WBRF) += wbrf.o
> > +
> >   ccflags-y += -DDEBUG
> > diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index
> > 77c90ed8f5d7..0c5289a9aa6c 100644
> > --- a/net/mac80211/chan.c
> > +++ b/net/mac80211/chan.c
> > @@ -506,11 +506,16 @@ static void _ieee80211_change_chanctx(struct
> > ieee80211_local *local,
> >
> >     WARN_ON(!cfg80211_chandef_compatible(&ctx->conf.def,
> chandef));
> >
> > +   ieee80211_remove_wbrf(local, &ctx->conf.def);
> > +
> >     ctx->conf.def = *chandef;
> >
> >     /* check if min chanctx also changed */
> >     changed = IEEE80211_CHANCTX_CHANGE_WIDTH |
> >               _ieee80211_recalc_chanctx_min_def(local, ctx, rsvd_for);
> > +
> > +   ieee80211_add_wbrf(local, &ctx->conf.def);
> > +
> >     drv_change_chanctx(local, ctx, changed);
> >
> >     if (!local->use_chanctx) {
> > @@ -668,6 +673,10 @@ static int ieee80211_add_chanctx(struct
> ieee80211_local *local,
> >     lockdep_assert_held(&local->mtx);
> >     lockdep_assert_held(&local->chanctx_mtx);
> >
> > +   err = ieee80211_add_wbrf(local, &ctx->conf.def);
> > +   if (err)
> > +           return err;
> > +
> >     if (!local->use_chanctx)
> >             local->hw.conf.radar_enabled = ctx->conf.radar_enabled;
> >
> > @@ -748,6 +757,8 @@ static void ieee80211_del_chanctx(struct
> ieee80211_local *local,
> >     }
> >
> >     ieee80211_recalc_idle(local);
> > +
> > +   ieee80211_remove_wbrf(local, &ctx->conf.def);
> >   }
> >
> >   static void ieee80211_free_chanctx(struct ieee80211_local *local,
> > diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
> > index b0372e76f373..f832de16073b 100644
> > --- a/net/mac80211/ieee80211_i.h
> > +++ b/net/mac80211/ieee80211_i.h
> > @@ -1591,6 +1591,10 @@ struct ieee80211_local {
> >
> >     /* extended capabilities provided by mac80211 */
> >     u8 ext_capa[8];
> > +
> > +#ifdef CONFIG_ACPI_WBRF
> > +   bool wbrf_supported;
> > +#endif
> >   };
> >
> >   static inline struct ieee80211_sub_if_data * @@ -2615,4 +2619,19 @@
> > ieee80211_eht_cap_ie_to_sta_eht_cap(struct ieee80211_sub_if_data
> *sdata,
> >                                 const struct ieee80211_eht_cap_elem
> *eht_cap_ie_elem,
> >                                 u8 eht_cap_len,
> >                                 struct link_sta_info *link_sta);
> > +
> > +#ifdef CONFIG_ACPI_WBRF
> > +void ieee80211_check_wbrf_support(struct ieee80211_local *local); int
> > +ieee80211_add_wbrf(struct ieee80211_local *local,
> > +                  struct cfg80211_chan_def *chandef); void
> > +ieee80211_remove_wbrf(struct ieee80211_local *local,
> > +                      struct cfg80211_chan_def *chandef); #else static
> inline void
> > +ieee80211_check_wbrf_support(struct ieee80211_local *local) { }
> > +static inline int ieee80211_add_wbrf(struct ieee80211_local *local,
> > +                                struct cfg80211_chan_def *chandef)
> { return 0; } static
> > +inline void ieee80211_remove_wbrf(struct ieee80211_local *local,
> > +                                    struct cfg80211_chan_def *chandef)
> { } #endif /*
> > +CONFIG_ACPI_WBRF */
> > +
> >   #endif /* IEEE80211_I_H */
> > diff --git a/net/mac80211/main.c b/net/mac80211/main.c index
> > 55cdfaef0f5d..0a55626b1546 100644
> > --- a/net/mac80211/main.c
> > +++ b/net/mac80211/main.c
> > @@ -1395,6 +1395,8 @@ int ieee80211_register_hw(struct ieee80211_hw
> *hw)
> >     debugfs_hw_add(local);
> >     rate_control_add_debugfs(local);
> >
> > +   ieee80211_check_wbrf_support(local);
> > +
> >     rtnl_lock();
> >     wiphy_lock(hw->wiphy);
> >
> > diff --git a/net/mac80211/wbrf.c b/net/mac80211/wbrf.c new file mode
> > 100644 index 000000000000..2e1a58cf4dbf
> > --- /dev/null
> > +++ b/net/mac80211/wbrf.c
> > @@ -0,0 +1,137 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * AMD Wifi Band Exclusion Interface
> > + * Copyright (C) 2023 Advanced Micro Devices
> > + *
> > + */
> > +
> > +#include <linux/wbrf.h>
> > +#include <net/cfg80211.h>
> > +#include "ieee80211_i.h"
> > +
> > +#define KHZ_TO_HZ(freq)            ((freq) * 1000ULL)
>
> I think this new macro probably should live in include/linux/ieee80211.h.
Might be better to follow Johannes's suggestion to move this together with MHZ_TO_KHZ().
>
> > +
> > +void ieee80211_check_wbrf_support(struct ieee80211_local *local) {
> > +   struct device *dev = local->hw.wiphy->dev.parent;
> > +   struct acpi_device *acpi_dev;
> > +
> > +   if (!dev)
> > +           return;
> > +
> > +   acpi_dev = ACPI_COMPANION(dev);
> > +   if (!acpi_dev) {
> > +           dev_dbg(dev, "ACPI companion not found\n");
> > +           return;
> > +   }
> > +
> > +   local->wbrf_supported = wbrf_supported_producer(acpi_dev);
> > +   dev_dbg(dev, "WBRF is %s supported\n",
> > +           local->wbrf_supported ? "" : "not"); }
> > +
> > +static void get_chan_freq_boundary(u32 center_freq,
> > +                              u32 bandwidth,
> > +                              u64 *start,
> > +                              u64 *end)
> > +{
> > +   bandwidth = MHZ_TO_KHZ(bandwidth);
> > +   center_freq = MHZ_TO_KHZ(center_freq);
> > +
> > +   *start = center_freq - bandwidth / 2;
> > +   *end = center_freq + bandwidth / 2;
>
> What do you think about using cfg80211_get_start_freq and
> cfg80211_get_end_freq and then converting the result from them to HZ
> instead?
They cannot fit our requirements well. They handle only the peak of the range. What we wanted is the start/end point of the whole range.
The illustration from the link below might give a better view.
https://securityuncorked.com/wordpress/wp-content/uploads/2013/11/graphic-80211-acChannels-all.png
>
> > +
> > +   /* Frequency in HZ is expected */
> > +   *start = KHZ_TO_HZ(*start);
> > +   *end = KHZ_TO_HZ(*end);
> > +}
> > +
> > +static int wbrf_get_ranges_from_chandef(struct cfg80211_chan_def
> *chandef,
> > +                                   struct wbrf_ranges_in *ranges_in) {
> > +   u64 start_freq1, end_freq1;
> > +   u64 start_freq2, end_freq2;
> > +   int bandwidth;
> > +
> > +   bandwidth = nl80211_chan_width_to_mhz(chandef->width);
> > +   if (bandwidth < 0)
> > +           return -EINVAL;
> > +
> > +   get_chan_freq_boundary(chandef->center_freq1,
> > +                          bandwidth,
> > +                          &start_freq1,
> > +                          &end_freq1);
> > +
> > +   ranges_in->band_list[0].start = start_freq1;
> > +   ranges_in->band_list[0].end = end_freq1;
> > +
> > +   if (chandef->width == NL80211_CHAN_WIDTH_80P80) {
> > +           get_chan_freq_boundary(chandef->center_freq2,
> > +                                  bandwidth,
> > +                                  &start_freq2,
> > +                                  &end_freq2);
> > +
> > +           ranges_in->band_list[1].start = start_freq2;
> > +           ranges_in->band_list[1].end = end_freq2;
> > +   }
> > +
> > +   return 0;
> > +}
> > +
> > +static int wbrf_add_exclusion_wlan(struct acpi_device *adev,
> > +                              struct cfg80211_chan_def *chandef) {
> > +   struct wbrf_ranges_in ranges_in = {0};
> > +   int ret;
> > +
> > +   ret = wbrf_get_ranges_from_chandef(chandef, &ranges_in);
> > +   if (ret)
> > +           return ret;
> > +
> > +   return wbrf_add_exclusion(adev, &ranges_in); }
> > +
> > +static int wbrf_remove_exclusion_wlan(struct acpi_device *adev,
> > +                                 struct cfg80211_chan_def *chandef) {
> > +   struct wbrf_ranges_in ranges_in = {0};
> > +   int ret;
> > +
> > +   ret = wbrf_get_ranges_from_chandef(chandef, &ranges_in);
> > +   if (ret)
> > +           return ret;
> > +
> > +   return wbrf_remove_exclusion(adev, &ranges_in); }
>
> I don't really see a good reason for wbrf_remove_exclusion_wlan and
> wbrf_add_exclusion_wlan to be static functions.
> In the earlier verisons they were both in the ACPI file so it made sense as an
> exported symbol.
>
> But they each only have a single calling site now and I think they should
> collapse into those functions.
OK, will update this as suggested.
>
> > +
> > +int ieee80211_add_wbrf(struct ieee80211_local *local,
> > +                  struct cfg80211_chan_def *chandef) {
> > +   struct device *dev = local->hw.wiphy->dev.parent;
> > +   struct acpi_device *acpi_dev;
> > +
> > +   if (!local->wbrf_supported)
> > +           return 0;
> > +
> > +   acpi_dev = ACPI_COMPANION(dev);
> > +   if (!acpi_dev)
> > +           return -ENODEV;
>
> ACPI devices won't go away, this should be an impossible failure.
> When wbrf_supported was populated earlier on the ACPI device was checked.
 Make sense to me. Will update it.
>
> > +
> > +   return wbrf_add_exclusion_wlan(acpi_dev, chandef); > +}
> > +
> > +void ieee80211_remove_wbrf(struct ieee80211_local *local,
> > +                      struct cfg80211_chan_def *chandef) {
> > +   struct device *dev = local->hw.wiphy->dev.parent;
> > +   struct acpi_device *acpi_dev;
> > +
> > +   if (!local->wbrf_supported)
> > +           return;
> > +
> > +   acpi_dev = ACPI_COMPANION(dev);
> > +   if (!acpi_dev)
> > +           return;
> > +
>
> ACPI devices won't go away, this should be an impossible failure.
> When wbrf_supported was populated earlier on the ACPI device was checked.
Will update it.

Evan
>
> > +   wbrf_remove_exclusion_wlan(acpi_dev, chandef); }
> > diff --git a/net/wireless/chan.c b/net/wireless/chan.c index
> > 0b7e81db383d..227db04eac42 100644
> > --- a/net/wireless/chan.c
> > +++ b/net/wireless/chan.c
> > @@ -141,7 +141,7 @@ static bool cfg80211_edmg_chandef_valid(const
> struct cfg80211_chan_def *chandef)
> >     return true;
> >   }
> >
> > -static int nl80211_chan_width_to_mhz(enum nl80211_chan_width
> > chan_width)
> > +int nl80211_chan_width_to_mhz(enum nl80211_chan_width chan_width)
> >   {
> >     int mhz;
> >
> > @@ -190,6 +190,7 @@ static int nl80211_chan_width_to_mhz(enum
> nl80211_chan_width chan_width)
> >     }
> >     return mhz;
> >   }
> > +EXPORT_SYMBOL(nl80211_chan_width_to_mhz);
> >
> >   static int cfg80211_chandef_get_width(const struct cfg80211_chan_def
> *c)
> >   {

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