Messages in this thread | | | Date | Tue, 20 Jan 2015 10:39:16 +0800 | From | Hanjun Guo <> | Subject | Re: [PATCH v7 06/17] ARM64 / ACPI: Make PCI optional for ACPI on ARM64 |
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On 2015年01月19日 18:42, Catalin Marinas wrote: > On Sun, Jan 18, 2015 at 06:25:53AM +0000, Hanjun Guo wrote: >> On 2015年01月16日 17:49, Catalin Marinas wrote: >>> On Wed, Jan 14, 2015 at 03:04:54PM +0000, Hanjun Guo wrote: >>>> --- a/arch/arm64/kernel/pci.c >>>> +++ b/arch/arm64/kernel/pci.c >>>> @@ -10,6 +10,7 @@ >>>> * >>>> */ >>>> >>>> +#include <linux/acpi.h> >>>> #include <linux/init.h> >>>> #include <linux/io.h> >>>> #include <linux/kernel.h> >>>> @@ -68,3 +69,30 @@ void pci_bus_assign_domain_nr(struct pci_bus *bus, struct device *parent) >>>> bus->domain_nr = domain; >>>> } >>>> #endif >>>> + >>>> +/* >>>> + * raw_pci_read/write - Platform-specific PCI config space access. >>>> + * >>>> + * Default empty implementation. Replace with an architecture-specific setup >>>> + * routine, if necessary. >>>> + */ >>>> +int raw_pci_read(unsigned int domain, unsigned int bus, >>>> + unsigned int devfn, int reg, int len, u32 *val) >>>> +{ >>>> + return -EINVAL; >>>> +} >>>> + >>>> +int raw_pci_write(unsigned int domain, unsigned int bus, >>>> + unsigned int devfn, int reg, int len, u32 val) >>>> +{ >>>> + return -EINVAL; >>>> +} >>>> + >>>> +#ifdef CONFIG_ACPI >>>> +/* Root bridge scanning */ >>>> +struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) >>>> +{ >>>> + /* TODO: Should be revisited when implementing PCI on ACPI */ >>>> + return NULL; >>>> +} >>>> +#endif > [...] >>> When PCI is enabled and the above functions are compiled in, do they >>> need to return any useful data or just -EINVAL. Are they ever called? >> >> They will be called if PCI root bridge is defined in DSDT, should I >> print some warning message before it is implemented? > > My point: do they need to return real data when a PCI root bridge is > defined in DSDT or you always expect them to always return some -E*? Can > you explain why?
Not always return -E* or NULL;
For raw_pci_read/write(), they are needed to access the PCI config space before the PCI root bus is created. so they will return 0 if access to PCI config space is ok; pci_acpi_scan_root() will return root bus pointer if it is successfully created.
Thanks Hanjun
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