* Re: Sharing PCIE driver between Microblaze and Arm zynq [not found] <CAHTX3dLxbVxn+D+AV7L0VsGYFOjas3AJ_3M_xncVfxp02FCy=Q@mail.gmail.com> @ 2012-12-06 21:27 ` Bjorn Helgaas 2012-12-07 9:45 ` Michal Simek 0 siblings, 1 reply; 6+ messages in thread From: Bjorn Helgaas @ 2012-12-06 21:27 UTC (permalink / raw) To: Michal Simek Cc: LKML, linux-arm, Arnd Bergmann, Olof Johansson, linux-arch, devicetree-discuss, Grant Likely, John Linn, John Williams, linux-pci [+cc linux-pci] On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: > Hi guys, > > I have a question regarding to sharing generic OF pcie driver between > two architectures MB and ARM Zynq. > Is drivers/pci/pcie location good for it? > Make no sense to have the same driver in two locations. I think you're talking about a PCI host bridge driver. It would definitely be nice to move toward a generic, shared driver. Host bridge drivers are responsible for enumerating the PCI hierarchy below the bridge. Enumeration is not really PCIe-specific, so I wouldn't put it in drivers/pci/pcie. > Is using readl/writel IO functions in this driver the best option > which we can have? > Or is there any other recommendation? I'm not really a driver person, but if you're writing a new driver, wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) rather than readl()? > Also just want to check if it is correct to use pcie device_type. I don't know what you're asking here. Can you elaborate or give a specific example? > The rest should be the same with pci description: > (http://devicetree.org/MPC5200:PCI#PCI_Address_Translation). ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sharing PCIE driver between Microblaze and Arm zynq 2012-12-06 21:27 ` Sharing PCIE driver between Microblaze and Arm zynq Bjorn Helgaas @ 2012-12-07 9:45 ` Michal Simek 2012-12-07 14:11 ` Grant Likely 2012-12-07 19:07 ` Arnd Bergmann 0 siblings, 2 replies; 6+ messages in thread From: Michal Simek @ 2012-12-07 9:45 UTC (permalink / raw) To: Bjorn Helgaas Cc: Michal Simek, LKML, linux-arm, Arnd Bergmann, Olof Johansson, linux-arch, devicetree-discuss, Grant Likely, John Linn, John Williams, linux-pci On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: > [+cc linux-pci] > > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: >> Hi guys, >> >> I have a question regarding to sharing generic OF pcie driver between >> two architectures MB and ARM Zynq. >> Is drivers/pci/pcie location good for it? >> Make no sense to have the same driver in two locations. > > I think you're talking about a PCI host bridge driver. It would > definitely be nice to move toward a generic, shared driver. Host > bridge drivers are responsible for enumerating the PCI hierarchy below > the bridge. Enumeration is not really PCIe-specific, so I wouldn't > put it in drivers/pci/pcie. Not a PCI expert, just trying to find out the proper location for this shared driver. >> Is using readl/writel IO functions in this driver the best option >> which we can have? >> Or is there any other recommendation? > > I'm not really a driver person, but if you're writing a new driver, > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) > rather than readl()? That driver exists but it is not in mainline and it is better to directly add it to proper location with correct io functions. The question is if ioread/iowrite functions are correct one. PowerPC io-defs.h suggests that readl/writel should be used for PCI. >> Also just want to check if it is correct to use pcie device_type. > > I don't know what you're asking here. Can you elaborate or give a > specific example? If node property device_type pcie should be used. device_type = "pcie"; For pci it is device_type = "pci"; For network it is device_type = "network" the same for serial, watchdogs. Do we have any list of device_types which we should use? Thanks, Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sharing PCIE driver between Microblaze and Arm zynq 2012-12-07 9:45 ` Michal Simek @ 2012-12-07 14:11 ` Grant Likely 2012-12-10 7:34 ` Michal Simek 2012-12-07 19:07 ` Arnd Bergmann 1 sibling, 1 reply; 6+ messages in thread From: Grant Likely @ 2012-12-07 14:11 UTC (permalink / raw) To: monstr, Bjorn Helgaas Cc: Michal Simek, LKML, linux-arm, Arnd Bergmann, Olof Johansson, linux-arch, devicetree-discuss, John Linn, John Williams, linux-pci On Fri, 07 Dec 2012 10:45:01 +0100, Michal Simek <monstr@monstr.eu> wrote: > On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: > > [+cc linux-pci] > > > > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: > >> Hi guys, > >> > >> I have a question regarding to sharing generic OF pcie driver between > >> two architectures MB and ARM Zynq. > >> Is drivers/pci/pcie location good for it? > >> Make no sense to have the same driver in two locations. > > > > I think you're talking about a PCI host bridge driver. It would > > definitely be nice to move toward a generic, shared driver. Host > > bridge drivers are responsible for enumerating the PCI hierarchy below > > the bridge. Enumeration is not really PCIe-specific, so I wouldn't > > put it in drivers/pci/pcie. > > Not a PCI expert, just trying to find out the proper location for this shared driver. > > > >> Is using readl/writel IO functions in this driver the best option > >> which we can have? > >> Or is there any other recommendation? > > > > I'm not really a driver person, but if you're writing a new driver, > > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) > > rather than readl()? > > That driver exists but it is not in mainline and it is better to directly > add it to proper location with correct io functions. > The question is if ioread/iowrite functions are correct one. > PowerPC io-defs.h suggests that readl/writel should be used for PCI. > > > >> Also just want to check if it is correct to use pcie device_type. > > > > I don't know what you're asking here. Can you elaborate or give a > > specific example? > > If node property device_type pcie should be used. > device_type = "pcie"; > > For pci it is device_type = "pci"; > For network it is device_type = "network" > the same for serial, watchdogs. > > Do we have any list of device_types which we should use? Don't use them unless a binding requires it. PCI address lookup code uses it, so we put it in those nodes. Otherwise device_type is deprecated and has been for a long time now. You should not be using it in .dts files. g. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sharing PCIE driver between Microblaze and Arm zynq 2012-12-07 14:11 ` Grant Likely @ 2012-12-10 7:34 ` Michal Simek 0 siblings, 0 replies; 6+ messages in thread From: Michal Simek @ 2012-12-10 7:34 UTC (permalink / raw) To: Grant Likely Cc: Bjorn Helgaas, LKML, linux-arm, Arnd Bergmann, Olof Johansson, linux-arch, devicetree-discuss, John Linn, John Williams, linux-pci 2012/12/7 Grant Likely <grant.likely@secretlab.ca>: > On Fri, 07 Dec 2012 10:45:01 +0100, Michal Simek <monstr@monstr.eu> wrote: >> On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: >> > [+cc linux-pci] >> > >> > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: >> >> Hi guys, >> >> >> >> I have a question regarding to sharing generic OF pcie driver between >> >> two architectures MB and ARM Zynq. >> >> Is drivers/pci/pcie location good for it? >> >> Make no sense to have the same driver in two locations. >> > >> > I think you're talking about a PCI host bridge driver. It would >> > definitely be nice to move toward a generic, shared driver. Host >> > bridge drivers are responsible for enumerating the PCI hierarchy below >> > the bridge. Enumeration is not really PCIe-specific, so I wouldn't >> > put it in drivers/pci/pcie. >> >> Not a PCI expert, just trying to find out the proper location for this shared driver. >> >> >> >> Is using readl/writel IO functions in this driver the best option >> >> which we can have? >> >> Or is there any other recommendation? >> > >> > I'm not really a driver person, but if you're writing a new driver, >> > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) >> > rather than readl()? >> >> That driver exists but it is not in mainline and it is better to directly >> add it to proper location with correct io functions. >> The question is if ioread/iowrite functions are correct one. >> PowerPC io-defs.h suggests that readl/writel should be used for PCI. >> >> >> >> Also just want to check if it is correct to use pcie device_type. >> > >> > I don't know what you're asking here. Can you elaborate or give a >> > specific example? >> >> If node property device_type pcie should be used. >> device_type = "pcie"; >> >> For pci it is device_type = "pci"; >> For network it is device_type = "network" >> the same for serial, watchdogs. >> >> Do we have any list of device_types which we should use? > > Don't use them unless a binding requires it. PCI address lookup code > uses it, so we put it in those nodes. Otherwise device_type is > deprecated and has been for a long time now. You should not be using it > in .dts files. Thanks, Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sharing PCIE driver between Microblaze and Arm zynq 2012-12-07 9:45 ` Michal Simek 2012-12-07 14:11 ` Grant Likely @ 2012-12-07 19:07 ` Arnd Bergmann 2012-12-10 7:36 ` Michal Simek 1 sibling, 1 reply; 6+ messages in thread From: Arnd Bergmann @ 2012-12-07 19:07 UTC (permalink / raw) To: monstr Cc: Bjorn Helgaas, Michal Simek, LKML, linux-arm, Olof Johansson, linux-arch, devicetree-discuss, Grant Likely, John Linn, John Williams, linux-pci On Friday 07 December 2012, Michal Simek wrote: > On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: > > [+cc linux-pci] > > > > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: > >> Hi guys, > >> > >> I have a question regarding to sharing generic OF pcie driver between > >> two architectures MB and ARM Zynq. > >> Is drivers/pci/pcie location good for it? > >> Make no sense to have the same driver in two locations. > > > > I think you're talking about a PCI host bridge driver. It would > > definitely be nice to move toward a generic, shared driver. Host > > bridge drivers are responsible for enumerating the PCI hierarchy below > > the bridge. Enumeration is not really PCIe-specific, so I wouldn't > > put it in drivers/pci/pcie. > > Not a PCI expert, just trying to find out the proper location for this shared driver. I'd suggest creating a drivers/pci/host directory. We will have more of these in the future. AFAIK, there is no fully generic (architecture independent) way to interface a PCI host driver to the PCI subsystem, but I think we are getting closer to that. You are probably fairly free to modify the microblaze architecture specific code though if needed. > >> Is using readl/writel IO functions in this driver the best option > >> which we can have? > >> Or is there any other recommendation? > > > > I'm not really a driver person, but if you're writing a new driver, > > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) > > rather than readl()? > > That driver exists but it is not in mainline and it is better to directly > add it to proper location with correct io functions. > The question is if ioread/iowrite functions are correct one. > PowerPC io-defs.h suggests that readl/writel should be used for PCI. ioread32/iowrite32 are defined to behave the same way readl/writel regarding addressing modes and barriers, but also allow operating on __iomem pointers that were returned from ioport_map(). You probably don't need that. Some architectures like powerpc have their own accessors for on-chip MMIO areas, but ARM does not. The PowerPC rule is that you must use either readl/writel or ioread32/iowrite32 to access devices connected to a PCI bus, but you would not necessarily do that for the PCI host controller itself on PowerPC. Arnd Arnd ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: Sharing PCIE driver between Microblaze and Arm zynq 2012-12-07 19:07 ` Arnd Bergmann @ 2012-12-10 7:36 ` Michal Simek 0 siblings, 0 replies; 6+ messages in thread From: Michal Simek @ 2012-12-10 7:36 UTC (permalink / raw) To: Arnd Bergmann Cc: Bjorn Helgaas, LKML, linux-arm, Olof Johansson, linux-arch, devicetree-discuss, Grant Likely, John Linn, John Williams, linux-pci 2012/12/7 Arnd Bergmann <arnd@arndb.de>: > On Friday 07 December 2012, Michal Simek wrote: >> On 12/06/2012 10:27 PM, Bjorn Helgaas wrote: >> > [+cc linux-pci] >> > >> > On Thu, Dec 6, 2012 at 7:23 AM, Michal Simek <michal.simek@xilinx.com> wrote: >> >> Hi guys, >> >> >> >> I have a question regarding to sharing generic OF pcie driver between >> >> two architectures MB and ARM Zynq. >> >> Is drivers/pci/pcie location good for it? >> >> Make no sense to have the same driver in two locations. >> > >> > I think you're talking about a PCI host bridge driver. It would >> > definitely be nice to move toward a generic, shared driver. Host >> > bridge drivers are responsible for enumerating the PCI hierarchy below >> > the bridge. Enumeration is not really PCIe-specific, so I wouldn't >> > put it in drivers/pci/pcie. >> >> Not a PCI expert, just trying to find out the proper location for this shared driver. > > I'd suggest creating a drivers/pci/host directory. We will have more of > these in the future. AFAIK, there is no fully generic (architecture > independent) way to interface a PCI host driver to the PCI subsystem, > but I think we are getting closer to that. You are probably fairly > free to modify the microblaze architecture specific code though if needed. yep. >> >> Is using readl/writel IO functions in this driver the best option >> >> which we can have? >> >> Or is there any other recommendation? >> > >> > I'm not really a driver person, but if you're writing a new driver, >> > wouldn't you use the iomap interfaces (ioremap(), ioread32(), etc) >> > rather than readl()? >> >> That driver exists but it is not in mainline and it is better to directly >> add it to proper location with correct io functions. >> The question is if ioread/iowrite functions are correct one. >> PowerPC io-defs.h suggests that readl/writel should be used for PCI. > > ioread32/iowrite32 are defined to behave the same way readl/writel regarding > addressing modes and barriers, but also allow operating on __iomem pointers > that were returned from ioport_map(). You probably don't need that. > > Some architectures like powerpc have their own accessors for on-chip MMIO > areas, but ARM does not. The PowerPC rule is that you must use either > readl/writel or ioread32/iowrite32 to access devices connected to a PCI > bus, but you would not necessarily do that for the PCI host controller > itself on PowerPC. ok. Thanks, Michal -- Michal Simek, Ing. (M.Eng) w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/ Microblaze U-BOOT custodian ^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <CAHTX3dLxbVxn+D+AV7L0VsGYFOjas3AJ_3M_xncVfxp02FCy=Q@mail.gmail.com>
2012-12-06 21:27 ` Sharing PCIE driver between Microblaze and Arm zynq Bjorn Helgaas
2012-12-07 9:45 ` Michal Simek
2012-12-07 14:11 ` Grant Likely
2012-12-10 7:34 ` Michal Simek
2012-12-07 19:07 ` Arnd Bergmann
2012-12-10 7:36 ` Michal Simek
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