[PATCH] pci: Add support for creating a generic host_bridge from device tree

[jg1.han@samsung.com (Jingoo Han)]

> -----Original Message-----
> From: Tanmay Inamdar [mailto:tinamdar at apm.com]
> Sent: Thursday, February 13, 2014 5:37 PM
> To: Jingoo Han
> Cc: Liviu Dudau; Arnd Bergmann; devicetree at vger.kernel.org; linaro-kernel; linux-pci; Will Deacon;
> LKML; Catalin Marinas; Bjorn Helgaas; LAKML
> Subject: Re: [PATCH] pci: Add support for creating a generic host_bridge from device tree
> 
> On Thu, Feb 13, 2014 at 12:10 AM, Jingoo Han <jg1.han@samsung.com> wrote:
> > On Thursday, February 06, 2014 7:18 PM, Liviu Dudau wrote:
> >> On Wed, Feb 05, 2014 at 10:26:27PM +0000, Tanmay Inamdar wrote:
> >> > Hello Liviu,
> >> >
> >> > I did not get the first email of this particular patch on any of
> >> > subscribed mailing lists (don't know why), hence replying here.
> >>
> >> Strange, it shows in the MARC and GMANE archive for linux-pci, probably
> >> a hickup on your receiving side?
> >>
> >> >
> >> > +struct pci_host_bridge *
> >> > +pci_host_bridge_of_init(struct device *parent, int busno, struct pci_ops *ops,
> >> > + void *host_data, struct list_head *resources)
> >> > +{
> >> > + struct pci_bus *root_bus;
> >> > + struct pci_host_bridge *bridge;
> >> > +
> >> > + /* first parse the host bridge bus ranges */
> >> > + if (pci_host_bridge_of_get_ranges(parent->of_node, resources))
> >> > + return NULL;
> >> > +
> >> > + /* then create the root bus */
> >> > + root_bus = pci_create_root_bus(parent, busno, ops, host_data, resources);
> >> > + if (!root_bus)
> >> > + return NULL;
> >> > +
> >> > + bridge = to_pci_host_bridge(root_bus->bridge);
> >> > +
> >> > + return bridge;
> >> > +}
> >> >
> >> > You are keeping the domain_nr inside pci_host_bridge structure. In
> >> > above API, domain_nr is required in 'pci_find_bus' function called
> >> > from 'pci_create_root_bus'. Since the bridge is allocated after
> >> > creating root bus, 'pci_find_bus' always gets domain_nr as 0. This
> >> > will cause problem for scanning multiple domains.
> >>
> >> Good catch. I was switching between creating a pci_controller in arch/arm64 and
> >> adding the needed bits in pci_host_bridge. After internal review I've decided to
> >> add the domain_nr to pci_host_bridge, but forgot to update the code everywhere.
> >
> > Hi Liviu Dudau,
> >
> > One more thing,
> > I am reviewing and compiling your patch.
> > Would you consider adding 'struct pci_sys_data' and 'struct hw_pci'?
> >
> > Currently, 4 PCIe Host drivers (pci-mvebu.c, pci-tegra.c,
> > pci-rcar-gen2.c, pcie-designware.c) are using 'struct pci_sys_data'
> > and 'struct hw_pci' in their drivers. Without this, it makes build
> > errors.
> >
> > In arm32, 'struct pci_sys_data' and 'struct hw_pci' is defined
> > in "arch/arm/include/asm/mach/pci.h".
> >
> > Tanmay Inamdar,
> > Your 'APM X-Gene PCIe' patch also needs 'struct pci_sys_data' and
> > 'struct hw_pci'. With Liviu Dudau's patch, it will make build
> > errors. Would you check this?
> 
> X-Gene PCIe host driver is dependent on arm64 PCI patch. My previous
> approach was based on 32bit arm PCI support. With Liviu's approach, I
> will have to make changes in host driver to get rid of hw_pci and
> pci_sys_data which are no longer required.

I want to use 'drivers/pci/host/pcie-designware.c' for both arm32
and arm64, without any code changes. However, it looks impossible.

I made 'drivers/pci/host/pcie-designware.c' based on 32bit arm PCI
support. Then, with Liviu's patch, do I have to make new code for arm64,
even though the same HW PCIe IP is used?

- For arm32
  drivers/pci/host/pcie-designware.c

- For arm64
  drivers/pci/host/pcie-designware-arm64.c


> 
> IMO it should not cause build errors for PCI host drivers dependent on
> architectures other than arm64. Can you post the error?
> 

I post the build errors.

  CC      drivers/pci/host/pcie-designware.o
  CHK     kernel/config_data.h
drivers/pci/host/pcie-designware.c:72:52: warning: 'struct pci_sys_data' declared inside parameter list [enabled by default]
 static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
                                                    ^
drivers/pci/host/pcie-designware.c:72:52: warning: its scope is only this definition or declaration, which is probably not what you want [enabled by default]
drivers/pci/host/pcie-designware.c: In function 'sys_to_pcie'
drivers/pci/host/pcie-designware.c:74:12: error: dereferencing pointer to incomplete type
  return sys->private_data;
            ^
drivers/pci/host/pcie-designware.c: In function 'dw_pcie_msi_map'
drivers/pci/host/pcie-designware.c:384:2: error: implicit declaration of function 'set_irq_flags' [-Werror=implicit-function-declaration]
  set_irq_flags(irq, IRQF_VALID);
  ^
drivers/pci/host/pcie-designware.c:384:21: error: 'IRQF_VALID??undeclared (first use in this function)
  set_irq_flags(irq, IRQF_VALID);
                     ^
drivers/pci/host/pcie-designware.c:384:21: note: each undeclared identifier is reported only once for each function it appears in
drivers/pci/host/pcie-designware.c: In function 'dw_pcie_host_init'
drivers/pci/host/pcie-designware.c:492:2: error: invalid use of undefined type 'struct hw_pci'
  dw_pci.nr_controllers = 1;
  ^
drivers/pci/host/pcie-designware.c:493:2: error: invalid use of undefined type 'struct hw_pci'
  dw_pci.private_data = (void **)&pp;
  ^
drivers/pci/host/pcie-designware.c:495:2: error: implicit declaration of function 'pci_common_init' [-Werror=implicit-function-declaration]
  pci_common_init(&dw_pci);
  ^
drivers/pci/host/pcie-designware.c:498:2: error: invalid use of undefined type 'struct hw_pci'
  dw_pci.domain++;
  ^
drivers/pci/host/pcie-designware.c: At top level:
drivers/pci/host/pcie-designware.c:698:41: warning: 'struct pci_sys_data??declared inside parameter list [enabled by default]
 static int dw_pcie_setup(int nr, struct pci_sys_data *sys)
                                         ^
drivers/pci/host/pcie-designware.c: In function 'dw_pcie_setup'
drivers/pci/host/pcie-designware.c:702:2: warning: passing argument 1 of 'sys_to_pcie' from incompatible pointer type [enabled by default]
  pp = sys_to_pcie(sys);
  ^
drivers/pci/host/pcie-designware.c:72:33: note: expected 'struct pci_sys_data *' but argument is of type 'struct pci_sys_data *'
 static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
                                 ^
drivers/pci/host/pcie-designware.c:708:6: error: dereferencing pointer to incomplete type
   sys->io_offset = global_io_offset - pp->config.io_bus_addr;
      ^
drivers/pci/host/pcie-designware.c:711:31: error: dereferencing pointer to incomplete type
   pci_add_resource_offset(&sys->resources, &pp->io,
                               ^
drivers/pci/host/pcie-designware.c:712:9: error: dereferencing pointer to incomplete type
      sys->io_offset);
         ^
drivers/pci/host/pcie-designware.c:715:5: error: dereferencing pointer to incomplete type
  sys->mem_offset = pp->mem.start - pp->config.mem_bus_addr;
     ^
drivers/pci/host/pcie-designware.c:716:30: error: dereferencing pointer to incomplete type
  pci_add_resource_offset(&sys->resources, &pp->mem, sys->mem_offset);
                              ^
drivers/pci/host/pcie-designware.c:716:56: error: dereferencing pointer to incomplete type
  pci_add_resource_offset(&sys->resources, &pp->mem, sys->mem_offset);
                                                        ^
drivers/pci/host/pcie-designware.c: At top level:
drivers/pci/host/pcie-designware.c:721:56: warning: 'struct pci_sys_data' declared inside parameter list [enabled by default]
 static struct pci_bus *dw_pcie_scan_bus(int nr, struct pci_sys_data *sys)
                                                        ^
drivers/pci/host/pcie-designware.c: In function 'dw_pcie_scan_bus'
drivers/pci/host/pcie-designware.c:724:9: warning: passing argument 1 of 'sys_to_pcie' from incompatible pointer type [enabled by default]
  struct pcie_port *pp = sys_to_pcie(sys);
         ^
drivers/pci/host/pcie-designware.c:72:33: note: expected 'struct pci_sys_data *' but argument is of type 'sruct pci_sys_data *'
 static inline struct pcie_port *sys_to_pcie(struct pci_sys_data *sys)
                                 ^
drivers/pci/host/pcie-designware.c:727:24: error: dereferencing pointer to incomplete type
   pp->root_bus_nr = sys->busnr;
                        ^
drivers/pci/host/pcie-designware.c:728:36: error: dereferencing pointer to incomplete type
   bus = pci_scan_root_bus(NULL, sys->busnr, &dw_pcie_ops,
                                    ^
drivers/pci/host/pcie-designware.c:729:15: error: dereferencing pointer to incomplete type
      sys, &sys->resources);
               ^
drivers/pci/host/pcie-designware.c: At top level:
drivers/pci/host/pcie-designware.c:755:15: error: variable 'dw_pci' has initializer but incomplete type
 static struct hw_pci dw_pci = {
               ^
drivers/pci/host/pcie-designware.c:756:2: error: unknown field 'setup' specified in initializer
  .setup  = dw_pcie_setup,
  ^
drivers/pci/host/pcie-designware.c:756:2: warning: excess elements in struct initializer [enabled by default]
drivers/pci/host/pcie-designware.c:756:2: warning: (near initialization for 'dw_pci' [enabled by default]
drivers/pci/host/pcie-designware.c:757:2: error: unknown field 'scan' specified in initializer
  .scan  = dw_pcie_scan_bus,
  ^
drivers/pci/host/pcie-designware.c:757:2: warning: excess elements in struct initializer [enabled by default]
drivers/pci/host/pcie-designware.c:757:2: warning: (near initialization for 'dw_pci' [enabled by default]
drivers/pci/host/pcie-designware.c:758:2: error: unknown field 'map_irq' specified in initializer
  .map_irq = dw_pcie_map_irq,
  ^
drivers/pci/host/pcie-designware.c:758:2: warning: excess elements in struct initializer [enabled by default]
drivers/pci/host/pcie-designware.c:758:2: warning: (near initialization for 'dw_pci' [enabled by default]
drivers/pci/host/pcie-designware.c:759:2: error: unknown field 'add_bus' specified in initializer
  .add_bus = dw_pcie_add_bus,
  ^
drivers/pci/host/pcie-designware.c:759:2: warning: excess elements in struct initializer [enabled by default]
drivers/pci/host/pcie-designware.c:759:2: warning: (near initialization for 'dw_pci' [enabled by default]
cc1: some warnings being treated as errors
make[3]: *** [drivers/pci/host/pcie-designware.o] Error 1


> >
> >>
> >> Thanks for reviewing this, will fix in v2.
> >>
> >> Do you find porting to the new API straight forward?
> >>
> >