On 2013-12-9 19:50, Catalin Marinas wrote:
On Mon, Dec 09, 2013 at 04:12:24AM +0000, Hanjun Guo wrote:
On 2013-12-7 1:23, Arnd Bergmann wrote:
On Friday 06 December 2013, Tomasz Nowicki wrote:
On 05.12.2013 23:04, Arnd Bergmann wrote:
On Wednesday 04 December 2013, Hanjun Guo wrote:
On 2013年12月04日 00:41, Matthew Garrett wrote: > Given the number of #ifdefs you're adding, wouldn't it make more sense > to just add stub functions to include/linux/pci.h?
Thanks for the suggestion :)
I can add stub functions in include/linux/pci.h for raw_pci_read()/ raw_pci_write(), then can remove #ifdefs for acpi_os_read/write_pci_configuration().
Actually I wonder about the usefulness of this patch in either form: Since ACPI on ARM64 is only for servers, I would very much expect them to always come with PCI, either physical host bridges with attached devices, or logical PCI functions used to describe the on-SoC I/O devices. Even in case of virtual machines, you'd normally use PCI as the method to communicate data about the virtio channels.
Can you name a realistic use-case where you'd want ACPI but not PCI?
Yes you can describe SoC I/O devices using logical PCI functions only if they are on PCI, correct me if I am wrong. Also, devices can be placed only on IOMEM (like for ARM SoC) and it is hard to predict which way vendors chose. So way don't let it be configurable? ACPI spec says nothing like PCI is needed for ACPI, AFAIK.
You are right that today's ARM SoCs basically never use PCI to describe internal devices (IIRC VIA VT8500 is an exception, but their PCI was just a software fabrication).
However, when we're talking about ACPI on ARM64, that is nothing like classic ARM SoCs: As Jon Masters mentioned, this is about new server hardware following a (still secret, but hopefully not much longer) hardware specification that is explicitly designed to allow interoperability between vendors, so they must have put some thought into how to make the hardware discoverable. It seems that they are modeling things after how it's done on x86, and the only sensible way to have discoverable hardware there is PCI. This is also what all x86 SoCs do.
I think the concern here is that ACPI is only for server platform or not.
Since ACPI has lots of content related to power management, I think ACPI can be used for mobile devices and other platform too, not only for ARM servers, and with this patch, we can support both requirement.
'Can be used' is one thing, will it really be used is another? I don't think so, it was (well, is) difficult enough to make the transition to FDT, I don't see how ACPI would solve the current issues.
I see ACPI as a server distro requirement and there are indeed benefits in abstracting the hardware behind standard description, AML. Of course, this would work even better with probe-able buses like PCIe and I'm pretty sure this would be the case on high-end servers. But even if a server distro like RHEL supports a SoC without PCIe, I would expect them to only provide a single binary Image with CONFIG_PCI enabled.
This patch is small enough and allows ACPI build with !CONFIG_PCI for the time being but longer term I would expect such SoCs without PCI to be able to run on a kernel with CONFIG_PCI enabled.
Yes, we will support PCI in ACPI in the long run, and we just make PCI optional for ACPI in this patch.
Actually, I had reworked this patch and make the code with minimal changes to ACPI code:
Not all the ARM64 targets that are using ACPI have PCI, so introduce some stub functions to make ACPI core run without CONFIG_PCI on ARM64.
pcibios_penalize_isa_irq() is arch dependent, introduce asm/pci.h to include it.
Since ACPI on X86 and IA64 depends on PCI, it will not break X86 and IA64 with this patch.
Signed-off-by: Graeme Gregory graeme.gregory@linaro.org Signed-off-by: Al Stone al.stone@linaro.org Signed-off-by: Hanjun Guo hanjun.guo@linaro.org --- arch/arm64/include/asm/pci.h | 13 +++++++++++++ drivers/acpi/Makefile | 2 +- drivers/acpi/internal.h | 5 +++++ include/linux/pci.h | 32 +++++++++++++++++++++++--------- 4 files changed, 42 insertions(+), 10 deletions(-) create mode 100644 arch/arm64/include/asm/pci.h
diff --git a/arch/arm64/include/asm/pci.h b/arch/arm64/include/asm/pci.h new file mode 100644 index 0000000..e682c25 --- /dev/null +++ b/arch/arm64/include/asm/pci.h @@ -0,0 +1,13 @@ +#ifndef ASMARM_PCI_H +#define ASMARM_PCI_H + +#ifdef __KERNEL__ + +static inline void pcibios_penalize_isa_irq(int irq, int active) +{ + /* We don't do dynamic PCI IRQ allocation */ +} + +#endif /* __KERNEL__ */ + +#endif diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 0331f91..d8cebe3 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -38,7 +38,7 @@ acpi-y += acpi_processor.o acpi-y += processor_core.o acpi-y += ec.o acpi-$(CONFIG_ACPI_DOCK) += dock.o -acpi-y += pci_root.o pci_link.o pci_irq.o +acpi-$(CONFIG_PCI) += pci_root.o pci_link.o pci_irq.o acpi-$(CONFIG_X86_INTEL_LPSS) += acpi_lpss.o acpi-y += acpi_platform.o acpi-y += power.o diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index b125fdb..b1ef8fa 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -26,8 +26,13 @@ acpi_status acpi_os_initialize1(void); int init_acpi_device_notify(void); int acpi_scan_init(void); +#ifdef CONFIG_PCI void acpi_pci_root_init(void); void acpi_pci_link_init(void); +#else +static inline void acpi_pci_root_init(void) {} +static inline void acpi_pci_link_init(void) {} +#endif /* CONFIG_PCI */ void acpi_processor_init(void); void acpi_platform_init(void); int acpi_sysfs_init(void); diff --git a/include/linux/pci.h b/include/linux/pci.h index 1084a15..28334dd 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -541,15 +541,6 @@ struct pci_ops { int (*write)(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val); };
-/* - * ACPI needs to be able to access PCI config space before we've done a - * PCI bus scan and created pci_bus structures. - */ -int raw_pci_read(unsigned int domain, unsigned int bus, unsigned int devfn, - int reg, int len, u32 *val); -int raw_pci_write(unsigned int domain, unsigned int bus, unsigned int devfn, - int reg, int len, u32 val); - struct pci_bus_region { resource_size_t start; resource_size_t end; @@ -1280,6 +1271,15 @@ typedef int (*arch_set_vga_state_t)(struct pci_dev *pdev, bool decode, unsigned int command_bits, u32 flags); void pci_register_set_vga_state(arch_set_vga_state_t func);
+/* + * ACPI needs to be able to access PCI config space before we've done a + * PCI bus scan and created pci_bus structures. + */ +int raw_pci_read(unsigned int domain, unsigned int bus, unsigned int devfn, + int reg, int len, u32 *val); +int raw_pci_write(unsigned int domain, unsigned int bus, unsigned int devfn, + int reg, int len, u32 val); + #else /* CONFIG_PCI is not enabled */
/* @@ -1476,6 +1476,20 @@ static inline int pci_domain_nr(struct pci_bus *bus) static inline struct pci_dev *pci_dev_get(struct pci_dev *dev) { return NULL; }
+static inline struct pci_bus *pci_find_bus(int domain, int busnr) +{ return NULL; } + +static inline int pci_bus_write_config_byte(struct pci_bus *bus, + unsigned int devfn, int where, u8 val); +{ return -ENODEV; } + +static inline int raw_pci_read(unsigned int domain, unsigned int bus, + unsigned int devfn, int reg, int len, u32 *val); +{ return -EINVAL; } +static inline int raw_pci_write(unsigned int domain, unsigned int bus, + unsigned int devfn, int reg, int len, u32 val); +{return -EINVAL; } + #define dev_is_pci(d) (false) #define dev_is_pf(d) (false) #define dev_num_vf(d) (0)
-- Hanjun