On Fri, Jul 22, 2022 at 9:27 AM Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote: > > On Thu, 21 Jul 2022 16:06:52 PDT (-0700), Rob Herring wrote: > > On Tue, Jul 19, 2022 at 9:59 AM Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote: > >> > >> On Sun, 17 Jul 2022 17:41:14 PDT (-0700), shorne@xxxxxxxxx wrote: > >> > The asm/pci.h used for many newer architectures share similar > >> > definitions. Move the common parts to asm-generic/pci.h to allow for > >> > sharing code. > >> > > >> > Two things to note are: > >> > > >> > - isa_dma_bridge_buggy, traditionally this is defined in asm/dma.h but > >> > these architectures avoid creating that file and add the definition > >> > to asm/pci.h. > >> > - ARCH_GENERIC_PCI_MMAP_RESOURCE, csky does not define this so we > >> > undefine it after including asm-generic/pci.h. Why doesn't csky > >> > define it? > >> > - pci_get_legacy_ide_irq, This function is only used on architectures > >> > that support PNP. It is only maintained for arm64, in other > >> > architectures it is removed. > >> > > >> > Suggested-by: Arnd Bergmann <arnd@xxxxxxxx> > >> > Link: https://lore.kernel.org/lkml/CAK8P3a0JmPeczfmMBE__vn=Jbvf=nkbpVaZCycyv40pZNCJJXQ@xxxxxxxxxxxxxx/ > >> > Signed-off-by: Stafford Horne <shorne@xxxxxxxxx> > >> > --- > >> > Second note on isa_dma_bridge_buggy, this is set on x86 but it it also set in > >> > pci/quirks.c. We discussed limiting it only to x86 though as its a general > >> > quick triggered by pci ids I think it will be more tricky than we thought so I > >> > will leave as is. It might be nice to move it out of asm/dma.h and into > >> > asm/pci.h though. > >> > > >> > Since v2: > >> > - Nothing > >> > Since v1: > >> > - Remove definition of pci_get_legacy_ide_irq > >> > > >> > arch/arm64/include/asm/pci.h | 12 +++--------- > >> > arch/csky/include/asm/pci.h | 24 ++++-------------------- > >> > arch/riscv/include/asm/pci.h | 25 +++---------------------- > >> > arch/um/include/asm/pci.h | 24 ++---------------------- > >> > include/asm-generic/pci.h | 36 ++++++++++++++++++++++++++++++++++++ > >> > 5 files changed, 48 insertions(+), 73 deletions(-) > >> > create mode 100644 include/asm-generic/pci.h > >> > > >> > diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h > >> > index b33ca260e3c9..1180e83712f5 100644 > >> > --- a/arch/arm64/include/asm/pci.h > >> > +++ b/arch/arm64/include/asm/pci.h > >> > @@ -9,7 +9,6 @@ > >> > #include <asm/io.h> > >> > > >> > #define PCIBIOS_MIN_IO 0x1000 > >> > -#define PCIBIOS_MIN_MEM 0 > >> > > >> > /* > >> > * Set to 1 if the kernel should re-assign all PCI bus numbers > >> > @@ -18,9 +17,6 @@ > >> > (pci_has_flag(PCI_REASSIGN_ALL_BUS)) > >> > > >> > #define arch_can_pci_mmap_wc() 1 > >> > -#define ARCH_GENERIC_PCI_MMAP_RESOURCE 1 > >> > - > >> > -extern int isa_dma_bridge_buggy; > >> > > >> > #ifdef CONFIG_PCI > >> > static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) > >> > @@ -28,11 +24,9 @@ static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) > >> > /* no legacy IRQ on arm64 */ > >> > return -ENODEV; > >> > } > >> > - > >> > -static inline int pci_proc_domain(struct pci_bus *bus) > >> > -{ > >> > - return 1; > >> > -} > >> > #endif /* CONFIG_PCI */ > >> > > >> > +/* Generic PCI */ > >> > +#include <asm-generic/pci.h> > >> > + > >> > #endif /* __ASM_PCI_H */ > >> > diff --git a/arch/csky/include/asm/pci.h b/arch/csky/include/asm/pci.h > >> > index ebc765b1f78b..44866c1ad461 100644 > >> > --- a/arch/csky/include/asm/pci.h > >> > +++ b/arch/csky/include/asm/pci.h > >> > @@ -9,26 +9,10 @@ > >> > > >> > #include <asm/io.h> > >> > > >> > -#define PCIBIOS_MIN_IO 0 > >> > -#define PCIBIOS_MIN_MEM 0 > >> > +/* Generic PCI */ > >> > +#include <asm-generic/pci.h> > >> > > >> > -/* C-SKY shim does not initialize PCI bus */ > >> > -#define pcibios_assign_all_busses() 1 > >> > - > >> > -extern int isa_dma_bridge_buggy; > >> > - > >> > -#ifdef CONFIG_PCI > >> > -static inline int pci_get_legacy_ide_irq(struct pci_dev *dev, int channel) > >> > -{ > >> > - /* no legacy IRQ on csky */ > >> > - return -ENODEV; > >> > -} > >> > - > >> > -static inline int pci_proc_domain(struct pci_bus *bus) > >> > -{ > >> > - /* always show the domain in /proc */ > >> > - return 1; > >> > -} > >> > -#endif /* CONFIG_PCI */ > >> > +/* csky doesn't use generic pci resource mapping */ > >> > +#undef ARCH_GENERIC_PCI_MMAP_RESOURCE > >> > > >> > #endif /* __ASM_CSKY_PCI_H */ > >> > diff --git a/arch/riscv/include/asm/pci.h b/arch/riscv/include/asm/pci.h > >> > index 7fd52a30e605..12ce8150cfb0 100644 > >> > --- a/arch/riscv/include/asm/pci.h > >> > +++ b/arch/riscv/include/asm/pci.h > >> > @@ -12,29 +12,7 @@ > >> > > >> > #include <asm/io.h> > >> > > >> > -#define PCIBIOS_MIN_IO 0 > >> > -#define PCIBIOS_MIN_MEM 0 > >> > >> My for-next changes these in bb356ddb78b2 ("RISC-V: PCI: Avoid handing > >> out address 0 to devices"). Do you mind either splitting out the > >> arch/riscv bits or having this in via some sort of shared tag? > > > > Shouldn't the values not matter here if the IO and mem resources are > > described in the DT (and don't use 0)? The values of 4 and 16 look > > odd. > > The linked thread has a fairly long discussion > <https://lore.kernel.org/all/alpine.DEB.2.21.2202260044180.25061@xxxxxxxxxxxxxxxxx/>. > I agree it's odd to have this in arch code: "don't hand out address 0" > isn't really a RISC-V constraint (ie, we don't have architecture-defined > limitations on these address spaces) but a constraint that comes from > the generic port I/O functions and some other related PCI/resource code > where the value 0 is a sentinel. If you look at arm32, we have a variable for PCIBIOS_MIN_MEM because pre-DT what platforms required was all over the place. Nothing using DT needs to set that variable. And arm64 uses 0 without problems. In all those platforms, none of them have the same restrictions? So it is still curious to me how PCIBIOS_MIN_MEM matters for Risc-V. I/O is different as Arnd said, but I'd imagine we could just set the min to 4 in the generic header and be done with it. > Maybe the right thing to do here is actually to make the default > definitions of these macros non-zero, or to add some sort of ARCH_ > flavor of them and move that non-zero requirement closer to where it > comes from? From the look of it any port that uses the generic port I/O > functions and has 0 for these will be broken in the same way. > > That said, I'm not really a PCI guy so maybe Bjorn or Maciej has a > better idea? >From fu740: ranges = <0x81000000 0x0 0x60080000 0x0 0x60080000 0x0 0x10000>, /* I/O */ <0x82000000 0x0 0x60090000 0x0 0x60090000 0x0 0xff70000>, /* mem */ <0x82000000 0x0 0x70000000 0x0 0x70000000 0x0 0x1000000>, /* mem */ <0xc3000000 0x20 0x00000000 0x20 0x00000000 0x20 0x00000000>; /* mem prefetchable */ So again, how does one get a 0 address handed out when that's not even a valid region according to DT? Is there some legacy stuff that ignores the bridge windows? Rob
