From owner-freebsd-current@freebsd.org Fri Apr 28 16:52:13 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 57E24D5486F for ; Fri, 28 Apr 2017 16:52:13 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from mail.baldwin.cx (bigwig.baldwin.cx [96.47.65.170]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 1E792138D; Fri, 28 Apr 2017 16:52:12 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (c-73-231-226-104.hsd1.ca.comcast.net [73.231.226.104]) by mail.baldwin.cx (Postfix) with ESMTPSA id 5749E10A7DB; Fri, 28 Apr 2017 12:52:05 -0400 (EDT) From: John Baldwin To: Sepherosa Ziehau Cc: Dexuan Cui , "freebsd-current@freebsd.org" , Jung-uk Kim , Yanmin Qiao Subject: Re: Add support for ACPI Module Device ACPI0004? Date: Fri, 28 Apr 2017 09:01:41 -0700 Message-ID: <1737882.TJdaAP1hO8@ralph.baldwin.cx> User-Agent: KMail/4.14.10 (FreeBSD/11.0-STABLE; KDE/4.14.10; amd64; ; ) In-Reply-To: References: <3727893.2519smPuKm@ralph.baldwin.cx> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (mail.baldwin.cx); Fri, 28 Apr 2017 12:52:05 -0400 (EDT) X-Virus-Scanned: clamav-milter 0.99.2 at mail.baldwin.cx X-Virus-Status: Clean X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Apr 2017 16:52:13 -0000 On Friday, April 28, 2017 05:38:32 PM Sepherosa Ziehau wrote: > On Thu, Apr 27, 2017 at 12:14 AM, John Baldwin wrote: > > On Wednesday, April 26, 2017 09:18:48 AM Sepherosa Ziehau wrote: > >> On Wed, Apr 26, 2017 at 4:36 AM, John Baldwin wrote: > >> > On Thursday, April 20, 2017 02:29:30 AM Dexuan Cui wrote: > >> >> > From: John Baldwin [mailto:jhb@freebsd.org] > >> >> > Sent: Thursday, April 20, 2017 02:34 > >> >> > > Can we add the support of "ACPI0004" with the below one-line change? > >> >> > > > >> >> > > acpi_sysres_probe(device_t dev) > >> >> > > { > >> >> > > - static char *sysres_ids[] = { "PNP0C01", "PNP0C02", NULL }; > >> >> > > + static char *sysres_ids[] = { "PNP0C01", "PNP0C02", "ACPI0004", NULL }; > >> >> > > > >> >> > Hmm, so the role of C01 and C02 is to reserve system resources, though we > >> >> > in turn allow any child of acpi0 to suballocate those ranges (since historically > >> >> > c01 and c02 tend to allocate I/O ranges that are then used by things like the > >> >> > EC, PS/2 keyboard controller, etc.). From my reading of ACPI0004 in the ACPI > >> >> > 6.1 spec it's not quite clear that ACPI0004 is like that? In particular, it > >> >> > seems that 004 should only allow direct children to suballocate? This > >> >> > change might work, but it will allow more devices to allocate the ranges in > >> >> > _CRS than otherwise. > >> >> > > >> >> > Do you have an acpidump from a guest system that contains an ACPI0004 > >> >> > node that you can share? > >> >> > > >> >> > John Baldwin > >> >> > >> >> Hi John, > >> >> Thanks for the help! > >> >> > >> >> Please see the attached file, which is got by > >> >> "acpidump -dt | gzip -c9 > acpidump.dt.gz" > >> >> > >> >> In the dump, we can see the "ACPI0004" node (VMOD) is the parent of > >> >> "VMBus" (VMBS). > >> >> It looks the _CRS of ACPI0004 is dynamically generated. Though we can't > >> >> see the length of the MMIO range in the dumped asl code, it does have > >> >> a 512MB MMIO range [0xFE0000000, 0xFFFFFFFFF]. > >> >> > >> >> It looks FreeBSD can't detect ACPI0004 automatically. > >> >> With the above one-line change, I can first find the child device > >> >> acpi_sysresource0 of acpi0, then call AcpiWalkResources() to get > >> >> the _CRS of acpi_sysresource0, i.e. the 512MB MMIO range. > >> >> > >> >> If you think we shouldn't touch acpi_sysresource0 here, I guess > >> >> we can add a new small driver for ACPI0004, just like we added VMBus > >> >> driver as a child device of acpi0? > >> > > >> > Hmmm, so looking at this, the "right" thing is probably to have a device > >> > driver for the ACPI0004 device that parses its _CRS and then allows its > >> > child devices to sub-allocate resources from the ranges in _CRS. However, > >> > this would mean make VMBus be a child of the ACPI0004 device. Suppose > >> > we called the ACPI0004 driver 'acpi_module' then the 'acpi_module0' device > >> > would need to create a child device for all of its child devices. Right > >> > now acpi0 also creates devices for them which is somewhat messy (acpi0 > >> > creates child devices anywhere in its namespace that have a valid _HID). > >> > You can find those duplicates and remove them during acpi_module0's attach > >> > routine before creating its own child device_t devices. (We associate > >> > a device_t with each Handle when creating device_t's for ACPI handles > >> > which is how you can find the old device that is a direct child of acpi0 > >> > so that it can be removed). > >> > >> The remove/reassociate vmbus part seems kinda "messy" to me. I'd just > >> hook up a new acpi0004 driver, and let vmbus parse the _CRS like what > >> we did to the hyper-v's pcib0. > > > > The acpi_pci driver used to do the remove/reassociate part. What acpi0 > > should probably be doing is only creating device_t nodes for immediate > > children. This would require an ACPI-aware isa0 for LPC devices below > > the ISA bus in the ACPI namespace. We haven't done that in part because > > BIOS vendors are not always consistent in placing LPC devices under an > > ISA bus. However, you otherwise have no good way to find your parent > > ACPI0004 device. You could perhaps find your ACPI handle, ask for its > > parent handle, then ask for the device_t of that handle to find the > > ACPI0004 device, but then you'd need to have all your bus_alloc_resource > > calls go to that device, not your "real" parent of acpi0, which means > > you can't use any of the standard bus_alloc_resource() methods like > > bus_alloc_resource_any() but would have to manually use BUS_ALLOC_RESOURCE > > with the ACPI0004 device as the explicit first argument. It is primarily > > the ability to let ACPI0004's driver transparently intercept all the > > resource allocation so it can manage that is the reason for "VMBus" > > to be a child of ACPI0004 rather than its sibling. > > Well, there could be more then one ACPI0004 typed devices, which could > not form a device tree for vmbus. Are you saing a vmbus would need resources from multiple ACPI0004 devices? That would seem a bit odd. OTOH, if you can have multiple ACPI0004 devices each with its own VMBus child (in the ACPI namespace) then having the VMBus be a child of ACPI0004 in new-bus would make it easy to find the "right" ACPI0004 parent device. -- John Baldwin