Hi Arnd > -----Original Message----- > From: Arnd Bergmann [mailto:arnd@xxxxxxxx] > Sent: 10 November 2016 09:12 > To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > Cc: Yuanzhichang; mark.rutland@xxxxxxx; devicetree@xxxxxxxxxxxxxxx; > lorenzo.pieralisi@xxxxxxx; Gabriele Paoloni; minyard@xxxxxxx; linux- > pci@xxxxxxxxxxxxxxx; benh@xxxxxxxxxxxxxxxxxxx; John Garry; > will.deacon@xxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; xuwei (O); Linuxarm; > zourongrong@xxxxxxxxx; robh+dt@xxxxxxxxxx; kantyzc@xxxxxxx; linux- > serial@xxxxxxxxxxxxxxx; catalin.marinas@xxxxxxx; olof@xxxxxxxxx; > liviu.dudau@xxxxxxx; bhelgaas@xxxxxxxxxx; zhichang.yuan02@xxxxxxxxx > Subject: Re: [PATCH V5 3/3] ARM64 LPC: LPC driver implementation on > Hip06 > > On Thursday, November 10, 2016 2:40:26 PM CET zhichang.yuan wrote: > > On 2016/11/10 5:34, Arnd Bergmann wrote: > > > On Wednesday, November 9, 2016 12:10:43 PM CET Gabriele Paoloni > wrote: > > >>> On Tuesday, November 8, 2016 11:47:09 AM CET zhichang.yuan wrote: > > >>>> + /* > > >>>> + * The first PCIBIOS_MIN_IO is reserved specifically for > > >>> indirectIO. > > >>>> + * It will separate indirectIO range from pci host > bridge to > > >>>> + * avoid the possible PIO conflict. > > >>>> + * Set the indirectIO range directly here. > > >>>> + */ > > >>>> + lpcdev->io_ops.start = 0; > > >>>> + lpcdev->io_ops.end = PCIBIOS_MIN_IO - 1; > > >>>> + lpcdev->io_ops.devpara = lpcdev; > > >>>> + lpcdev->io_ops.pfin = hisilpc_comm_in; > > >>>> + lpcdev->io_ops.pfout = hisilpc_comm_out; > > >>>> + lpcdev->io_ops.pfins = hisilpc_comm_ins; > > >>>> + lpcdev->io_ops.pfouts = hisilpc_comm_outs; > > >>> > > >>> I have to look at patch 2 in more detail again, after missing a > few > > >>> review > > >>> rounds. I'm still a bit skeptical about hardcoding a logical I/O > port > > >>> range here, and would hope that we can just go through the same > > >>> assignment of logical port ranges that we have for PCI buses, > > >>> decoupling > > >>> the bus addresses from the linux-internal ones. > > >> > > >> The point here is that we want to avoid any conflict/overlap > between > > >> the LPC I/O space and the PCI I/O space. With the assignment above > > >> we make sure that LPC never interfere with PCI I/O space. > > > > > > But we already abstract the PCI I/O space using dynamic > registration. > > > There is no need to hardcode the logical address for ISA, though > > > I think we can hardcode the bus address to start at zero here. > > > > Do you means that we can pick up the maximal I/O address from all > children's > > device resources?? > > The driver should not look at the resources of its children, just > register a range of addresses dynamically, as I suggested in an > earlier review. Where should we get the range from? For LPC we know that it is going Work on anything that is not used by PCI I/O space, and this is why we use [0, PCIBIOS_MIN_IO] > > > Your current version has > > if (arm64_extio_ops->pfout) \ > arm64_extio_ops->pfout(arm64_extio_ops->devpara,\ > addr, value, sizeof(type)); \ > > Instead, just subtract the start of the range from the logical > port number to transform it back into a bus-local port number: These accessors do not operate on IO tokens: If (arm64_extio_ops->start > addr || arm64_extio_ops->end < addr) addr is not going to be an I/O token; in fact patch 2/3 imposes that the I/O tokens will start at PCIBIOS_MIN_IO. So from 0 to PCIBIOS_MIN_IO we have free physical addresses that the accessors can operate on. Thanks Gab > > if (arm64_extio_ops->pfout) \ > arm64_extio_ops->pfout(arm64_extio_ops->devpara,\ > addr - arm64_extio_ops->start, value, > sizeof(type)); \ > > We know that the ISA/LPC bus can only have up to 65536 ports, > so you can register all of those, or possibly limit it further to > 1024 or 4096 ports, whichever matches the bus implementation. > > Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
