Re: [PATCH V4 01/10] bluetooth: hci_bcm: Fix RTS handling during startup

From: "Ondřej Jirman" <megous@megous.com>
To: Stefan Wahren <wahrenst@gmx.net>
Cc: Marcel Holtmann <marcel@holtmann.org>,
	Johan Hedberg <johan.hedberg@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Ray Jui <rjui@broadcom.com>,
	Scott Branden <sbranden@broadcom.com>,
	Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org, linux-bluetooth@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Eric Anholt <eric@anholt.net>, Rob Herring <robh+dt@kernel.org>,
	bcm-kernel-feedback-list@broadcom.com,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V4 01/10] bluetooth: hci_bcm: Fix RTS handling during startup
Date: Mon, 16 Dec 2019 14:25:09 +0100	[thread overview]
Message-ID: <20191216132509.ofqcdpwxsd7324ql@core.my.home> (raw)
In-Reply-To: <61789264-a4c2-ac85-9d74-d186213ec70a@gmx.net>

Hello,

On Sun, Oct 20, 2019 at 11:17:28PM +0200, Stefan Wahren wrote:
> Hi Marcel,
> hi Johan,
> 
> Am 06.10.19 um 17:28 schrieb Stefan Wahren:
> > The RPi 4 uses the hardware handshake lines for CYW43455, but the chip
> > doesn't react to HCI requests during DT probe. The reason is the inproper
> > handling of the RTS line during startup. According to the startup
> > signaling sequence in the CYW43455 datasheet, the hosts RTS line must
> > be driven after BT_REG_ON and BT_HOST_WAKE.
> >
> > Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
> > ---
> >  drivers/bluetooth/hci_bcm.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> > index 7646636..0f73f6a 100644
> > --- a/drivers/bluetooth/hci_bcm.c
> > +++ b/drivers/bluetooth/hci_bcm.c
> > @@ -445,9 +445,11 @@ static int bcm_open(struct hci_uart *hu)
> >
> >  out:
> >  	if (bcm->dev) {
> > +		hci_uart_set_flow_control(hu, true);
> >  		hu->init_speed = bcm->dev->init_speed;
> >  		hu->oper_speed = bcm->dev->oper_speed;
> >  		err = bcm_gpio_set_power(bcm->dev, true);
> > +		hci_uart_set_flow_control(hu, false);
> >  		if (err)
> >  			goto err_unset_hu;
> >  	}
> > --
> > 2.7.4
> 
> would be nice to get some feedback about this.

I started seeing failures on Orange Pi 3 in 5.5-rc:

[    3.839134] Bluetooth: hci0: command 0xfc18 tx timeout
[   11.999136] Bluetooth: hci0: BCM: failed to write update baudrate (-110)
[   12.004613] Bluetooth: hci0: Failed to set baudrate
[   12.123187] Bluetooth: hci0: BCM: chip id 130
[   12.128398] Bluetooth: hci0: BCM: features 0x0f
[   12.154686] Bluetooth: hci0: BCM4345C5
[   12.157165] Bluetooth: hci0: BCM4345C5 (003.006.006) build 0000
[   15.343684] Bluetooth: hci0: BCM4345C5 (003.006.006) build 0038

Switch to higher baudrate works again after reverting this patch.

That board also uses RTS/CTS signalling.

I guess the patch needs re-thinking/maybe other chips may not need this?

I don't have access to datasheets.

regards,
	o.

> Regards
> Stefan
> 
> 
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