Subject: [RFC PATCH V2 1/2] ACPI/PCI: Match PCI config space accessors against platfrom specific ECAM quirks

From: [email-masked] (Dongdong Liu)
Date: Tue, 14 Jun 2016 13:51:09 +0800

Hi Duc

? 2016/6/14 4:57, Duc Dang ??:
> On Mon, Jun 13, 2016 at 8:47 AM, Christopher Covington
> <[email-masked]> wrote:
>> Hi Dongdong,
>>
>> On 06/13/2016 09:02 AM, Dongdong Liu wrote:
>>> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
>>> index d3c3e85..49612b3 100644
>>> --- a/drivers/acpi/pci_mcfg.c
>>> +++ b/drivers/acpi/pci_mcfg.c
>>> @@ -22,6 +22,10 @@
>>>   #include <linux/kernel.h>
>>>   #include <linux/pci.h>
>>>   #include <linux/pci-acpi.h>
>>> +#include <linux/pci-ecam.h>
>>> +
>>> +/* Root pointer to the mapped MCFG table */
>>> +static struct acpi_table_mcfg *mcfg_table;
>>>
>>>   /* Structure to hold entries from the MCFG table */
>>>   struct mcfg_entry {
>>> @@ -35,6 +39,38 @@ struct mcfg_entry {
>>>   /* List to save mcfg entries */
>>>   static LIST_HEAD(pci_mcfg_list);
>>>
>>> +extern struct pci_cfg_fixup __start_acpi_mcfg_fixups[];
>>> +extern struct pci_cfg_fixup __end_acpi_mcfg_fixups[];
>>> +
>>> +struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
>>> +{
>>> +     int bus_num = root->secondary.start;
>>> +     int domain = root->segment;
>>> +     struct pci_cfg_fixup *f;
>>> +
>>> +     if (!mcfg_table)
>>> +             return &pci_generic_ecam_ops;
>>> +
>>> +     /*
>>> +      * Match against platform specific quirks and return corresponding
>>> +      * CAM ops.
>>> +      *
>>> +      * First match against PCI topology <domain:bus> then use OEM ID and
>>> +      * OEM revision from MCFG table standard header.
>>> +      */
>>> +     for (f = __start_acpi_mcfg_fixups; f < __end_acpi_mcfg_fixups; f++) {
>>> +             if ((f->domain == domain || f->domain == PCI_MCFG_DOMAIN_ANY) &&
>>> +                 (f->bus_num == bus_num || f->bus_num == PCI_MCFG_BUS_ANY) &&
>>> +                 (!strncmp(f->oem_id, mcfg_table->header.oem_id,
>>> +                           ACPI_OEM_ID_SIZE)) &&
>>> +                 (!strncmp(f->oem_table_id, mcfg_table->header.oem_table_id,
>>> +                           ACPI_OEM_TABLE_ID_SIZE)))
>>
>> This would just be a small convenience, but if the character count used here were
>>
>> min(strlen(f->oem_id), ACPI_OEM_ID_SIZE)
>>
>> then the parameters to DECLARE_ACPI_MCFG_FIXUP macro could be substrings and
>> wouldn't need to be padded out to the full length.
>>
>>> +                     return f->ops;
>>> +     }
>>> +     /* No quirks, use ECAM */
>>> +     return &pci_generic_ecam_ops;
>>> +}
>>
>>> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
>>> index 7d63a66..088a1da 100644
>>> --- a/include/linux/pci-acpi.h
>>> +++ b/include/linux/pci-acpi.h
>>> @@ -25,6 +25,7 @@ static inline acpi_status pci_acpi_remove_pm_notifier(struct acpi_device *dev)
>>>   extern phys_addr_t acpi_pci_root_get_mcfg_addr(acpi_handle handle);
>>>
>>>   extern phys_addr_t pci_mcfg_lookup(u16 domain, struct resource *bus_res);
>>> +extern struct pci_ecam_ops *pci_mcfg_get_ops(struct acpi_pci_root *root);
>>>
>>>   static inline acpi_handle acpi_find_root_bridge_handle(struct pci_dev *pdev)
>>>   {
>>> @@ -72,6 +73,25 @@ struct acpi_pci_root_ops {
>>>        int (*prepare_resources)(struct acpi_pci_root_info *info);
>>>   };
>>>
>>> +struct pci_cfg_fixup {
>>> +     struct pci_ecam_ops *ops;
>>> +     char *oem_id;
>>> +     char *oem_table_id;
>>> +     int domain;
>>> +     int bus_num;
>>> +};
>>> +
>>> +#define PCI_MCFG_DOMAIN_ANY  -1
>>> +#define PCI_MCFG_BUS_ANY     -1
>>> +
>>> +/* Designate a routine to fix up buggy MCFG */
>>> +#define DECLARE_ACPI_MCFG_FIXUP(ops, oem_id, oem_table_id, dom, bus) \
>>> +     static const struct pci_cfg_fixup                               \
>>> +     __mcfg_fixup_##oem_id##oem_table_id##dom##bus                   \
>>
>> I'm not entirely sure that this is the right fix--I'm pretty blindly
>> following a GCC documentation suggestion [1]--but removing the first two
>> preprocessor concatenation operators "##" solved the following build error
>> for me.
>>
>> include/linux/pci-acpi.h:90:2: error: pasting "__mcfg_fixup_" and ""QCOM"" does not give a valid preprocessing token
>>    __mcfg_fixup_##oem_id##oem_table_id##dom##bus   \
>
> I think the problem is gcc is not happy with quoted string when
> processing these tokens
> (""QCOM"", the extra "" are added by gcc). So should we not concat
> string tokens and
> use the fixup definition in v1 of this RFC:
> /* Designate a routine to fix up buggy MCFG */
> #define DECLARE_ACPI_MCFG_FIXUP(ops, oem_id, rev, dom, bus)             \
>          static const struct pci_cfg_fixup __mcfg_fixup_##system##dom##bus\
>           __used __attribute__((__section__(".acpi_fixup_mcfg"),         \
>                                  aligned((sizeof(void *))))) =           \
>          { ops, oem_id, rev, dom, bus };

V1 fixup exist the redefinition error when compiling mutiple DECLARE_ACPI_MCFG_FIXUP
with the same PCI_MCFG_DOMAIN_ANY and PCI_MCFG_BUS_ANY.

#define EFI_ACPI_HISI_OEM_ID "HISI"
#define EFI_ACPI_HISI_D02_OEM_TABLE_ID "HISI-D02"
#define EFI_ACPI_HISI_D03_OEM_TABLE_ID "HISI-D03"

DECLARE_ACPI_MCFG_FIXUP(&hisi_pcie_ecam_ops, EFI_ACPI_HISI_OEM_ID,
        EFI_ACPI_HISI_D02_OEM_TABLE_ID, PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);

DECLARE_ACPI_MCFG_FIXUP(&hisi_pcie_ecam_ops, EFI_ACPI_HISI_OEM_ID,
        EFI_ACPI_HISI_D03_OEM_TABLE_ID, PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);

In file included from drivers/pci/host/pcie-hisi-acpi.c:15:0:
include/linux/pci-acpi.h:98:43: error: redefinition of '__mcfg_fixup_systemPCI_MCFG_DOMAIN_ANYPCI_MCFG_BUS_ANY'
          static const struct pci_cfg_fixup __mcfg_fixup_##system##dom##bus\
                                            ^
drivers/pci/host/pcie-hisi-acpi.c:215:1: note: in expansion of macro 'DECLARE_ACPI_MCFG_FIXUP'
  DECLARE_ACPI_MCFG_FIXUP(&hisi_pcie_ecam_ops, EFI_ACPI_HISI_OEM_ID,
  ^
include/linux/pci-acpi.h:98:43: note: previous definition of '__mcfg_fixup_systemPCI_MCFG_DOMAIN_ANYPCI_MCFG_BUS_ANY' was here
          static const struct pci_cfg_fixup __mcfg_fixup_##system##dom##bus\
                                            ^
drivers/pci/host/pcie-hisi-acpi.c:212:1: note: in expansion of macro 'DECLARE_ACPI_MCFG_FIXUP'

V2 fixup can resolve the redefinition error, but need to use macro.
We can see that the name of macro is not replace with it's value in
"__mcfg_fixup_EFI_ACPI_HISI_OEM_IDEFI_ACPI_HISI_D03_OEM_TABLE_IDPCI_MCFG_DOMAIN_ANYPCI_MCFG_BUS_ANY".

Any good idea is appreciated.

Thanks
Dongdong

>
> Regards,
> Duc Dang.
>
>
>>    ^
>> arch/arm64/kernel/pci.c:225:1: note: in expansion of macro ?DECLARE_ACPI_MCFG_FIXUP?
>>   DECLARE_ACPI_MCFG_FIXUP(&pci_32b_ecam_ops, "QCOM", "QDF2432", PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);
>>   ^
>> arch/arm64/kernel/pci.c:225:44: error: pasting ""QCOM"" and ""QDF2432"" does not give a valid preprocessing token
>>   DECLARE_ACPI_MCFG_FIXUP(&pci_32b_ecam_ops, "QCOM", "QDF2432", PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);
>>                                              ^
>> include/linux/pci-acpi.h:90:17: note: in definition of macro ?DECLARE_ACPI_MCFG_FIXUP?
>>    __mcfg_fixup_##oem_id##oem_table_id##dom##bus   \
>>                   ^
>> arch/arm64/kernel/pci.c:225:52: error: pasting ""QDF2432"" and "PCI_MCFG_DOMAIN_ANY" does not give a valid preprocessi
>> ng token
>>   DECLARE_ACPI_MCFG_FIXUP(&pci_32b_ecam_ops, "QCOM", "QDF2432", PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);
>>                                                      ^
>> include/linux/pci-acpi.h:90:25: note: in definition of macro ?DECLARE_ACPI_MCFG_FIXUP?
>>    __mcfg_fixup_##oem_id##oem_table_id##dom##bus   \
>>                           ^
>> arch/arm64/kernel/pci.c:225:44: error: expected ?=?, ?,?, ?;?, ?asm? or ?__attribute__? before string constant
>>   DECLARE_ACPI_MCFG_FIXUP(&pci_32b_ecam_ops, "QCOM", "QDF2432", PCI_MCFG_DOMAIN_ANY, PCI_MCFG_BUS_ANY);
>>                                              ^
>> include/linux/pci-acpi.h:90:17: note: in definition of macro ?DECLARE_ACPI_MCFG_FIXUP?
>>    __mcfg_fixup_##oem_id##oem_table_id##dom##bus   \
>>                   ^
>> make[1]: *** [arch/arm64/kernel/pci.o] Error 1
>> make: *** [arch/arm64/kernel] Error 2
>>
>> 1. https://gcc.gnu.org/onlinedocs/cpp/Concatenation.html#Concatenation
>>
>>> +     __used  __attribute__((__section__(".acpi_fixup_mcfg"),         \
>>> +                             aligned((sizeof(void *))))) =           \
>>> +     { ops, oem_id, oem_table_id, dom, bus };
>>> +
>>>   extern int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info);
>>>   extern struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
>>>                                            struct acpi_pci_root_ops *ops,
>>>
>>
>> Thanks,
>> Cov
>>
>> --
>> Qualcomm Innovation Center, Inc.
>> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
>> a Linux Foundation Collaborative Project
>
> .
>