From mboxrd@z Thu Jan 1 00:00:00 1970 From: liviu.dudau@arm.com Subject: Re: [PATCH v1 3/3] ARM64 LPC: update binding doc Date: Tue, 12 Jan 2016 09:07:22 +0000 Message-ID: <20160112090722.GN13633@e106497-lin.cambridge.arm.com> References: <1451396032-23708-1-git-send-email-zourongrong@gmail.com> <568912EE.9030009@huawei.com> <15026471.7nGZ0rWlIf@wuerfel> <20160111161415.GM13633@e106497-lin.cambridge.arm.com> <56946768.7090805@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <56946768.7090805@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Rongrong Zou Cc: Arnd Bergmann , linux-arm-kernel@lists.infradead.org, Rongrong Zou , devicetree@vger.kernel.org, benh@kernel.crashing.org, Corey Minyard , gregkh@linuxfoundation.org, Will Deacon , linux-kernel@vger.kernel.org, linuxarm@huawei.com, Catalin Marinas List-Id: devicetree@vger.kernel.org On Tue, Jan 12, 2016 at 10:39:36AM +0800, Rongrong Zou wrote: > On 2016/1/12 0:14, liviu.dudau@arm.com wrote: > >On Mon, Jan 04, 2016 at 12:13:05PM +0100, Arnd Bergmann wrote: > >>On Sunday 03 January 2016 20:24:14 Rongrong Zou wrote: > >>>=E5=9C=A8 2015/12/31 23:00, Rongrong Zou =E5=86=99=E9=81=93: > >>>>2015-12-31 22:40 GMT+08:00 Arnd Bergmann >: > >>>> > On Thursday 31 December 2015 22:12:19 Rongrong Zou wrote: > >>>> > > =E5=9C=A8 2015/12/30 17:06, Arnd Bergmann =E5=86=99=E9=81=93= : > >>>> > > > On Tuesday 29 December 2015 21:33:52 Rongrong Zou wrote: > >>>> > > >>>> > The DT sample above looks good in principle. I believe what y= ou are missing > >>>> > here is code in your driver to scan the child nodes to create= the platform > >>>> > devices. of_bus_isa_translate() should work with your definit= ion here > >>>> > and create the correct IORESOURCE_IO resources. You don't hav= e any MMIO > >>>> > resources, so the absence of a ranges property is ok. Maybe a= ll you > >>>> > are missing is a call to of_platform_populate() or of_platfor= m_bus_probe()? > >>>> > > >>>> > >>>>You are right. thanks, i'll try on test board . if i get the cor= rect result , the new patch > >>>>will be sent later. By the way, it's my another email account use= when i at home. > >>> > >>>I tried, and there need some additional changes. > >>> > >>>isa@a01b0000 { > >>> > >>>/*the node name should start with "isa", because of below definiti= on > >>>* static int of_bus_isa_match(struct device_node *np) > >>>* { > >>>* return !strcmp(np->name, "isa"); > >>>* } > >> > >>Looks good. It would be nicer to match on device_type than on name, > >>but this is ancient code and it's probably best not to touch it > >>so we don't accidentally break some old SPARC or PPC system. > >> > >>>*/ > >>> compatible =3D "low-pin-count"; > >>> device_type =3D "isa"; > >>> #address-cells =3D <2>; > >>> #size-cells =3D <1>; > >>> reg =3D <0x0 0xa01b0000 0x0 0x10000>; > >>> ranges =3D <0x1 0x0 0x0 0x0 0x1000>; > >>>/* > >>>* ranges is required, then i can get the IORESOURCE_IO <0xe4,4> f= rom "reg =3D <0x1, 0x000000e4, 4>". > >>>* > >>>*/ > >>> ipmi_0:ipmi@000000e4{ > >>> device_type =3D "ipmi"; > >>> compatible =3D "ipmi-bt"; > >>> reg =3D <0x1 0x000000e4 0x4>; > >>>}; > >>> > >> > >>This looks wrong: the property above says that the I/O port range i= s > >>translated to MMIO address 0x00000000 to 0x00010000, which is not > >>true on your hardware. I think this needs to be changed in the code > >>so the ranges property is not required for I/O ports. > >> > >>>drivers\of\address.c > >>>static int __of_address_to_resource(struct device_node *dev, > >>> const __be32 *addrp, u64 size, unsigned int flag= s, > >>> const char *name, struct resource *r) > >>>{ > >>> u64 taddr; > >>> > >>> if ((flags & (IORESOURCE_IO | IORESOURCE_MEM)) =3D=3D 0) > >>> return -EINVAL; > >>> taddr =3D of_translate_address(dev, addrp); > >>> if (taddr =3D=3D OF_BAD_ADDR) > >>> return -EINVAL; > >>> memset(r, 0, sizeof(struct resource)); > >>> if (flags & IORESOURCE_IO) { > >>> unsigned long port; > >>> > >>>/*****************************************************************= / > >>>/*legacy port(< 0x1000) is reserved, and need no translation here*= / > >>>/*****************************************************************= / > >>> if(taddr + size < PCIBIOS_MIN_IO){ > >>> r->start =3D taddr; > >>> r->end =3D taddr + size - 1; > >>> } > >> > >>I don't like having a special case based on the address here, > >>the same kind of hack might be needed for PCI I/O spaces in > >>hardware that uses an indirect method like your LPC bus > >>does, and the code above will not work on any LPC implementation > >>that correctly multiplexes its I/O ports with the first PCI domain. > >> > >>I think it would be better to avoid translating the port into > >>a physical address to start with just to translate it back into > >>a port number, what we need instead is the offset between the > >>bus specific port number and the linux port number. I've added > >>Liviu to Cc, he wrote this code originally and may have some idea > >>of how we could do that. > > > >Hi, >=20 > Hi Liviu, >=20 > Thanks for reviewing this. >=20 > > > >Getting back to work after a longer holiday, my brain might not be r= unning > >at full speed here, so I'm trying to clarify things a bit here. > > > >It looks to me like Rongrong is trying to trap the inb()/outb() call= s that he > >added to arm64 by patch 1/3 and redirect those operations to the mem= ory > >mapped LPC driver. I think the whole redirection and registration of= inb/outb > >ops can be made cleaner, so that the general concept resembles the D= MA ops > >registration? (I have this mental picture that what Rongrong is tryi= ng to do > >is similar to what a DMA engine does, except this is slowing down th= ings to > >byte level). If that is done properly in the parent node, then we sh= ould not > >care what the PCIBIOS_MIN_IO value is as the inb()/outb() calls will= always > >go through the redirection for the children. > > > >As for the ranges property: does he wants the ipmi-bt driver to see = in the > >reg property the legacy ISA I/O ports values or the CPU addresses? I= f the former, > >then I agree that the range property should not be required, but als= o the > >reg values need to be changed (drop the top bit). If the later, then= the > >ranges property is required to do the proper translation. >=20 > The former, thanks. >=20 > > > >Rongrong, removing the ranges property and with a reg =3D <0xe4 0x4>= property > >in the ipmi-bt node, what IO_RESOURCE type resources do you get back= from > >the of_address_to_resource() translation? >=20 > I want to get IORESOURCE_IO type resource, but if the parent node dro= p the > "rangs" property, the of_address_to_resource() translation will retur= n with -EINVAL. Have you tracked what part of the code is sensitive to the presence of = "ranges" property? Does of_get_address() call returns the IO_RESOURCE flag set w= ithout "ranges"? Best regards, Liviu >=20 > > > >Best regards, > >Liviu > > > > > >> > >> Arnd > >> > > > Regards, > Rongrong >=20 --=20 =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- =C2=AF\_(=E3=83=84)_/=C2=AF