From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [PATCH v2 4/4] usb: Add APIs to access host registers from Tegra PHY Date: Thu, 17 Jan 2013 17:32:29 +0200 Message-ID: <20130117153229.GA21904@arwen.pp.htv.fi> References: <20130117135043.GU18978@arwen.pp.htv.fi> Reply-To: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="4Ckj6UjgE2iN1+kY" Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alan Stern Cc: Felipe Balbi , Venu Byravarasu , "gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org" , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org --4Ckj6UjgE2iN1+kY Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 17, 2013 at 10:21:53AM -0500, Alan Stern wrote: > On Thu, 17 Jan 2013, Felipe Balbi wrote: >=20 > > > Bits 31 & 30 from PORTSC register were allocated by our SOC designers > > > to inform the host controller about the PHY type to be used.=20 > >=20 > > Wow, that's something you should never do. PORTSC register belongs to > > the EHCI controller and those bits are reserved for future use and they > > *MUST* return zero. I wouldn't be surprised if current EHCI driver > > assumes those bits will be zero and/or makes sure they're set to zero > > when writing to PORTSC register. >=20 > In fact, those bits _have_ been assigned an official purpose in the=20 > EHCI-1.1 addendum. Presumably the Tegra hardware only supports=20 > EHCI-1.0. I see, they're used for device addresses now. How can we make sure on Tegra systems we won't use those top two bits ? --=20 balbi --4Ckj6UjgE2iN1+kY Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJQ+BmNAAoJEIaOsuA1yqREP/sQAKubGrk2K+RTsxjb1B8oPdAP H7m5GGzz9mQf0MIS17542fhbahzzTdJpqto36UdPTLE/EPaZJkRdXhXisq1LM/zG 6PniYhLv2IdY3dmhG6SkMZesi7v4OFsAUa5dpSLRXo6mIoI6VtG3DkRQdIyUJSWx Z2UW5x3V9H/f0UCYWPzdEHtjgi7+0IoyRkgH9DzfE0GE0ATLtI/4Jw6/6C8REYO1 gwkyOGe7s60UhXt54pdFDPyLJIap+CrpXos7fg9eapV8NsYoE/C1g+SfpqPpLCAp zcTQUtU7mqITPbW/bbZj5aWbrHYEzfS4JqXYvGZyizr4+Ad1Cne7SMQE2SLArq5Y E9RQOrNI9yjlwAOgv6XCdRFkNogibR9YKcqQLMgTET6ntMyisI7dgTbFPKEEMnde 9x7wNYYdYg4zn5asyAEYlT55rO23fG29Mr9btFIjCzfTW4GYuz/X61iie2YjOljO nhG65oXpbGJy87ftZJJdEeZzH8k97IBBPf/3jqLhmj/eTI3sB5EgRBzCzkgUz0d9 5ZOADfPn3TuS/rRsjepo5NSkBfAnV2IeplCvlXWLTHw27yVnf2tjKupozmDzPEqB QVbDodkm6XFnPVyd0viK9RXu/ioDBed6QtqaXGYCEJwcPJySNWq9yXwhSMQ+ZkhH TGFIqfvbDIyIZ7Ro3iUm =vHn4 -----END PGP SIGNATURE----- --4Ckj6UjgE2iN1+kY--