Re: [PATCH V4 2/2] cfg80211: support ieee80211-freq-limit DT property

On 3 January 2017 at 13:10, Arend Van Spriel
[off-list ref] wrote:

On 3-1-2017 12:03, Rafa=C5=82 Mi=C5=82ecki wrote:

quoted

From: Rafa=C5=82 Mi=C5=82ecki <rafal@milecki.pl>

This patch adds a helper for reading that new property and applying
limitations or supported channels specified this way.
It may be useful for specifying single band devices or devices that
support only some part of the whole band. It's common that tri-band
routers have separated radios for lower and higher part of 5 GHz band.

Signed-off-by: Rafa=C5=82 Mi=C5=82ecki <rafal@milecki.pl>
---
V2: Put main code in core.c as it isn't strictly part of regulatory - po=

inted

quoted

    by Arend.
    Update to support ieee80211-freq-limit (new property).
V3: Introduce separated wiphy_read_of_freq_limits function.
    Add extra sanity checks for DT data.
    Move code back to reg.c as suggested by Johannes.
V4: Move code to of.c
    Use one helper called at init time (no runtime hooks)
    Modify orig_flags
---
 include/net/cfg80211.h |  26 ++++++++++
 net/wireless/Makefile  |   1 +
 net/wireless/of.c      | 137 ++++++++++++++++++++++++++++++++++++++++++=

+++++++

quoted

 net/wireless/reg.c     |   4 +-
 net/wireless/reg.h     |   2 +
 5 files changed, 168 insertions(+), 2 deletions(-)
 create mode 100644 net/wireless/of.c

diff --git a/include/net/cfg80211.h b/include/net/cfg80211.h
index ca2ac1c..d7723a8 100644
--- a/include/net/cfg80211.h
+++ b/include/net/cfg80211.h

@@ -311,6 +311,32 @@ struct ieee80211_supported_band {
      struct ieee80211_sta_vht_cap vht_cap;
 };

+/**
+ * wiphy_read_of_freq_limits - read frequency limits from device tree
+ *
+ * @wiphy: the wireless device to get extra limits for
+ *
+ * Some devices may have extra limitations specified in DT. This may be=

 useful

quoted

+ * for chipsets that normally support more bands but are limited due to=

 board

quoted

+ * design (e.g. by antennas or extermal power amplifier).
+ *
+ * This function reads info from DT and uses it to *modify* channels (d=

isable

quoted

+ * unavailable ones). It's usually a *bad* idea to use it in drivers wi=

th

quoted

+ * shared channel data as DT limitations are device specific.
+ *
+ * As this function access device node it has to be called after set_wi=

phy_dev.

You are aware that you need to modify this description with earlier
patch "cfg80211: allow passing struct device in the wiphy_new call",
right? :-p

I dropped that earlier patch for now as it's no longer a requirement
for this change. If someone find is useful though, I'll be happy to
resume my work on it later. And update this documentation as you
pointed out ;)

quoted

+ * It also modifies channels so they have to be set first.
+ */
+#ifdef CONFIG_OF
+int wiphy_read_of_freq_limits(struct wiphy *wiphy);
+#else /* CONFIG_OF */
+static inline int wiphy_read_of_freq_limits(struct wiphy *wiphy)
+{
+     return 0;
+}
+#endif /* !CONFIG_OF */
+
+

[...]

quoted

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index 5dbac37..bda0e9e 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c

@@ -748,8 +748,8 @@ static bool is_valid_rd(const struct ieee80211_regdo=

main *rd)

quoted

      return true;
 }

-static bool reg_does_bw_fit(const struct ieee80211_freq_range *freq_ran=

ge,

quoted

-                         u32 center_freq_khz, u32 bw_khz)
+bool reg_does_bw_fit(const struct ieee80211_freq_range *freq_range,
+                  u32 center_freq_khz, u32 bw_khz)
 {
      u32 start_freq_khz, end_freq_khz;

would it be more appropriate to move this function to util.c?

I'm OK with moving this function (and maybe struct
ieee80211_freq_range as well). Any objections?

--=20
Rafa=C5=82