From mboxrd@z Thu Jan 1 00:00:00 1970 From: Adrian Hunter Subject: Re: [PATCH v4 5/5] brcmfmac: sdio: Don't tune while the card is off Date: Mon, 17 Jun 2019 11:28:10 +0300 Message-ID: References: <20190613234153.59309-1-dianders@chromium.org> <20190613234153.59309-6-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190613234153.59309-6-dianders@chromium.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Douglas Anderson , Ulf Hansson , Kalle Valo , Arend van Spriel Cc: brcm80211-dev-list.pdl@broadcom.com, linux-rockchip@lists.infradead.org, Double Lo , briannorris@chromium.org, linux-wireless@vger.kernel.org, Naveen Gupta , Madhan Mohan R , mka@chromium.org, Wright Feng , Chi-Hsien Lin , netdev@vger.kernel.org, brcm80211-dev-list@cypress.com, Franky Lin , linux-kernel@vger.kernel.org, Hante Meuleman , YueHaibing , "David S. Miller" List-Id: linux-rockchip.vger.kernel.org On 14/06/19 2:41 AM, Douglas Anderson wrote: > When Broadcom SDIO cards are idled they go to sleep and a whole > separate subsystem takes over their SDIO communication. This is the > Always-On-Subsystem (AOS) and it can't handle tuning requests. > > Specifically, as tested on rk3288-veyron-minnie (which reports having > BCM4354/1 in dmesg), if I force a retune in brcmf_sdio_kso_control() > when "on = 1" (aka we're transition from sleep to wake) by whacking: > bus->sdiodev->func1->card->host->need_retune = 1 > ...then I can often see tuning fail. In this case dw_mmc reports "All > phases bad!"). Note that I don't get 100% failure, presumably because > sometimes the card itself has already transitioned away from the AOS > itself by the time we try to wake it up. If I force retuning when "on > = 0" (AKA force retuning right before sending the command to go to > sleep) then retuning is always OK. > > NOTE: we need _both_ this patch and the patch to avoid triggering > tuning due to CRC errors in the sleep/wake transition, AKA ("brcmfmac: > sdio: Disable auto-tuning around commands expected to fail"). Though > both patches handle issues with Broadcom's AOS, the problems are > distinct: > 1. We want to defer (but not ignore) asynchronous (like > timer-requested) tuning requests till the card is awake. However, > we want to ignore CRC errors during the transition, we don't want > to queue deferred tuning request. > 2. You could imagine that the AOS could implement retuning but we > could still get errors while transitioning in and out of the AOS. > Similarly you could imagine a seamless transition into and out of > the AOS (with no CRC errors) even if the AOS couldn't handle > tuning. > > ALSO NOTE: presumably there is never a desperate need to retune in > order to wake up the card, since doing so is impossible. Luckily the > only way the card can get into sleep state is if we had a good enough > tuning to send it a sleep command, so presumably that "good enough" > tuning is enough to wake us up, at least with a few retries. > > Signed-off-by: Douglas Anderson Acked-by: Adrian Hunter > --- > > Changes in v4: > - Adjust to API rename (Adrian). > > Changes in v3: > - ("brcmfmac: sdio: Don't tune while the card is off") new for v3. > > Changes in v2: None > > drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c > index ee76593259a7..629140b6d7e2 100644 > --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c > +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/sdio.c > @@ -669,6 +669,10 @@ brcmf_sdio_kso_control(struct brcmf_sdio *bus, bool on) > > sdio_retune_crc_disable(bus->sdiodev->func1); > > + /* Cannot re-tune if device is asleep; defer till we're awake */ > + if (on) > + sdio_retune_hold_now(bus->sdiodev->func1); > + > wr_val = (on << SBSDIO_FUNC1_SLEEPCSR_KSO_SHIFT); > /* 1st KSO write goes to AOS wake up core if device is asleep */ > brcmf_sdiod_writeb(bus->sdiodev, SBSDIO_FUNC1_SLEEPCSR, wr_val, &err); > @@ -729,6 +733,9 @@ brcmf_sdio_kso_control(struct brcmf_sdio *bus, bool on) > if (try_cnt > MAX_KSO_ATTEMPTS) > brcmf_err("max tries: rd_val=0x%x err=%d\n", rd_val, err); > > + if (on) > + sdio_retune_release(bus->sdiodev->func1); > + > sdio_retune_crc_enable(bus->sdiodev->func1); > > return err; >