From mboxrd@z Thu Jan 1 00:00:00 1970 From: Corey Minyard Subject: Re: [PATCH 1/3] misc: Add Aspeed BT IPMI host driver Date: Mon, 12 Sep 2016 17:06:36 -0500 Message-ID: <88ec11d5-3683-7ad3-341e-42d951b6574e@acm.org> References: <1472664259-23933-1-git-send-email-clg@kaod.org> <1ce6c4b4-5938-22fc-7467-d1efc220b772@gmail.com> <4727554.yt7pF8chOH@wuerfel> <7db5ada0-49ea-55eb-089e-d979941ceff5@gmail.com> Reply-To: minyard-HInyCGIudOg@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= , Arnd Bergmann Cc: Mark Rutland , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jeremy Kerr , Andrew Jeffery , Alistair Popple , Russell King , Rob Herring , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Joel Stanley List-Id: devicetree@vger.kernel.org On 09/12/2016 04:23 PM, Cédric Le Goater wrote: > Hello, > > On 09/12/2016 10:33 PM, Corey Minyard wrote: >> On 09/12/2016 02:15 PM, Arnd Bergmann wrote: >>> On Monday, September 12, 2016 1:55:40 PM CEST Corey Minyard wrote: >>>> On 09/02/2016 08:22 AM, Cédric Le Goater wrote: >>>>> Hello, >>>>> >>>>> Adding Corey in cc: . I guess I should have done that in the first place. >>>> Yes, probably so. I've been travelling and didn't see it on the mailing >>>> lists until now. >>>> >>>> There is already a BT driver in the kernel, in drivers/char/ipmi, why >>>> won't that work? >>> The new driver is the host side (running on the BMC), the existing one >>> is the client (running on the PC). >>> >>> Arnd >> Ok, that's not really clear from the documentation or the Kconfig. >> In the IPMI spec the "host" side is the computer side, not the BMC >> side. Like: >> >> 11.6.1 BT Host Interface Registers >> The Host BT interface provides an independent set of registers and >> interrupts to allow the Host driver to >> communicate with the baseboard management controller without >> conflicting with the O/S ACPI driver. >> >> In light of that, this should probably be named the bt-bmc driver. >> >> I haven't reviewed this in detail, but I'm ok with putting it in >> drivers/char/ipmi. The state machine part looks reasonably >> generic. The configuration part isn't, but that could be split >> out later if necessary. >> >> The biggest thing I don't like is the byte at a time interfaces >> from userspace. That seems fairly inefficient if the system >> does extra work for each userspace access. IIRC some >> systems do and some don't. > What about the ioctl to send an SMS ATN event to the host ? Is > that ok for you ? Yeah, that's necessary, there's no way the low-level driver can know when to do that. I have a similar piece of code in the qemu IPMI emulator, even the external IPMI emulator has a message it sends to set ATTN. I did look at similarities between the two pieces of code, but the qemu one has to be register-read/write driven, so it's completely different in design. -corey > Thanks, > > C. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html