From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mailgw1.uni-kl.de ([131.246.120.220]:45077 "EHLO mailgw1.uni-kl.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753768AbbDGNCg (ORCPT ); Tue, 7 Apr 2015 09:02:36 -0400 Received: from itwm2.itwm.fhg.de (itwm2.itwm.fhg.de [131.246.191.3]) by mailgw1.uni-kl.de (8.14.4/8.14.4/Debian-7) with ESMTP id t37D2Y1N024754 for ; Tue, 7 Apr 2015 15:02:34 +0200 Date: Tue, 7 Apr 2015 15:02:32 +0200 From: Phoebe Buckheister Subject: Re: [PATCHv3 bluetooth-next 2/4] nl802154: add set interface cmd Message-ID: <20150407150232.75e3df70@zoidberg> In-Reply-To: <20150407125949.GB16415@omega> References: <1428407393-16005-1-git-send-email-alex.aring@gmail.com> <1428407393-16005-3-git-send-email-alex.aring@gmail.com> <20150407135902.2b885270@zoidberg> <20150407122149.GA16415@omega> <20150407142930.662c0f92@zoidberg> <20150407125949.GB16415@omega> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-wpan-owner@vger.kernel.org List-ID: To: Alexander Aring Cc: linux-wpan@vger.kernel.org, kernel@pengutronix.de, mkl@pengutronix.de On Tue, 7 Apr 2015 14:59:52 +0200 Alexander Aring wrote: > On Tue, Apr 07, 2015 at 02:29:30PM +0200, Phoebe Buckheister wrote: > > On Tue, 7 Apr 2015 14:21:52 +0200 > > Alexander Aring wrote: > > > > > Hi Phoebe, > > > > > > On Tue, Apr 07, 2015 at 01:59:02PM +0200, Phoebe Buckheister > > > wrote: > > > > On Tue, 7 Apr 2015 13:49:51 +0200 > > > > Alexander Aring wrote: > > > > > > > > > This patch introduce the NL802154_CMD_SET_INTERFACE command > > > > > which handles setting of all wpan interface mac attributes. > > > > > his will introduce an easilier wpan mac settings handling in > > > > > userspace application with nl802154. > > > > > > > > > > Signed-off-by: Alexander Aring > > > > > --- > > > > > net/ieee802154/nl802154.c | 110 > > > > > ++++++++++++++++++++++++++++++++++++++++++++++ 1 file > > > > > changed, 110 insertions(+) > > > > > > > > > > diff --git a/net/ieee802154/nl802154.c > > > > > b/net/ieee802154/nl802154.c index c12c07f..e2f50ba 100644 > > > > > --- a/net/ieee802154/nl802154.c > > > > > +++ b/net/ieee802154/nl802154.c > > > > > @@ -603,6 +603,108 @@ static int nl802154_get_interface(struct > > > > > sk_buff *skb, struct genl_info *info) return > > > > > genlmsg_reply(msg, info); } > > > > > > > > > > +static int nl802154_set_interface(struct sk_buff *skb, struct > > > > > genl_info *info) +{ > > > > > + struct cfg802154_registered_device *rdev = > > > > > info->user_ptr[0]; > > > > > + struct net_device *dev = info->user_ptr[1]; > > > > > + struct wpan_dev *wpan_dev = dev->ieee802154_ptr; > > > > > + int ret; > > > > > + > > > > > + if (info->attrs[NL802154_ATTR_PAN_ID]) { > > > > > + __le16 pan_id; > > > > > + > > > > > + if (wpan_dev->iftype == > > > > > NL802154_IFTYPE_MONITOR) > > > > > + return -EINVAL; > > > > > + > > > > > + if (netif_running(dev)) > > > > > + return -EBUSY; > > > > > + > > > > > + pan_id = > > > > > nla_get_le16(info->attrs[NL802154_ATTR_PAN_ID]); > > > > > + ret = rdev_set_pan_id(rdev, wpan_dev, > > > > > pan_id); > > > > > + if (ret < 0) > > > > > + return ret; > > > > > + } > > > > > + > > > > > + if (info->attrs[NL802154_ATTR_SHORT_ADDR]) { > > > > > + __le16 short_addr; > > > > > + > > > > > + if (wpan_dev->iftype == > > > > > NL802154_IFTYPE_MONITOR) > > > > > + return -EINVAL; > > > > > > > > This is not good. You may have partially applied the requested > > > > settings when you return with an error, leaving the device in > > > > some intermediate state that is most likely not useful. It'd be > > > > better to first check whether all settings can be applied, and > > > > then apply them all at once. But even then we have a problem > > > > with rolling back some changes if a command fails :/ > > > > > > > > > > Yes, we need kind of rollback here if the command failed. I also > > > stumble over this issue. [0] Mhh, we don't have it when I do each > > > command in their own CMD SET call. So then I will leave the > > > current behaviour as it is. > > > > > > Some idea: > > > > > > Solution would be on MAC settings that we really check if > > > everything is valid. Then we can set everything in the pib > > > values, after an interface up this values will be "really" set, > > > like address filter settings in phy registers. > > > > > > This works for interface settings (MAC PIB values). But for phy > > > values this is more difficult, because it's directly driver-layer > > > calls. So we can't predigt if an driver layer return some error > > > then. > > > > That sounds good. We could add another driver function that checks a > > PIB/MIB and returns "valid" or "i'm sorry, dave", where "valid" may > > only happen when the driver *knows* that it can load the *IB into > > the hardware. Any possible hardware errors are excluded by these > > checks, > > I think we need such functionality anyway, I wrote in my previous mail > that the not _all_ valid 802.15.4 mac pib values are supported by real > transceivers. Like the mrf24j40 [0] which can set the MIN_BE value > only (I suppose MAX_BE is always 802.15.4 default). But nl802154 > checks only on 802.15.4 constraints only, so you can set everything > which is allowed by 802.15.4. On a "doing interface up" it will fail > because the driver layer will told -EINVAL; then and you don't know > why (okay, experts knows why). > > We need to check this value on the SoftMAC layer in > "net/mac802154/cfg.c". > > Now the design question is "a function" or "a array like > channels_supported which extends the phy pib by us". I would prefer > the array solution and put simple a u32 backoff_exponents_supported in > phy_pib [1] and checking over flags if the transceiver supports it's > or not. > > Then we can add more supported arrays for csma retries, frame retries, > tx_pwr (also design question if all bands or current band only), > etc... > > (For lbt mode, we don't need such functionality... it's only a bool > and the HW flag is enough). > > Currently we don't have this kind of problem, because most settings > can set on an at86rf230 transceiver only which is fully (and beyond) > 802.15.4 complaint. > > Now the question is again: > > It's okay to extend the "supported arrays" in phy pib or we should > introduce a driver_ops function? I prefer the array solution, because > we have already such thing which is described by 802.15.4 pib. Either is fine. The values permitted by the standard are mostly bitmasks and min/max-pairs, so that actually makes more sense than a check() function in each driver (until some driver doesn't fit that model, but we should worry about that then). > > > but we'll only see those on the actual load anyway. Then we can load > > the *IB in bulk and be sure that only the hardware can fail. > > > > Then I would add such functionality to check if valid at first which I > describe above. > > - Alex > > [0] http://ww1.microchip.com/downloads/en/DeviceDoc/39776C.pdf > [1] http://lxr.free-electrons.com/source/include/net/cfg802154.h#L77