Re: [PATCH V6 2/5] PCI/ACPI: Check platform specific ECAM quirks

[Duc Dang]

On Fri, Sep 9, 2016 at 12:24 PM, Tomasz Nowicki <tn@xxxxxxxxxxxx> wrote:
>
> Some platforms may not be fully compliant with generic set of PCI config
> accessors. For these cases we implement the way to overwrite CFG accessors
> set and configuration space range.
>
> In first place pci_mcfg_parse() saves machine's IDs and revision number
> (these come from MCFG header) in order to match against known quirk entries.
> Then the algorithm traverses available quirk list (static array),
> matches against <oem_id, oem_table_id, rev, domain, bus number range> and
> returns custom PCI config ops and/or CFG resource structure.
>
> When adding new quirk there are two possibilities:
> 1. Override default pci_generic_ecam_ops ops but CFG resource comes from MCFG
> { "OEM_ID", "OEM_TABLE_ID", <REV>, <DOMAIN>, <BUS_NR>, &foo_ops, MCFG_RES_EMPTY },
> 2. Override default pci_generic_ecam_ops ops and CFG resource. For this case
> it is also allowed get CFG resource from quirk entry w/o having it in MCFG.
> { "OEM_ID", "OEM_TABLE_ID", <REV>, <DOMAIN>, <BUS_NR>, &boo_ops,
>   DEFINE_RES_MEM(START, SIZE) },
>
> pci_generic_ecam_ops and MCFG entries will be used for platforms
> free from quirks.
>
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> Signed-off-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> Signed-off-by: Christopher Covington <cov@xxxxxxxxxxxxxx>
> ---
>  drivers/acpi/pci_mcfg.c | 80 +++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 74 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> index ffcc651..2b8acc7 100644
> --- a/drivers/acpi/pci_mcfg.c
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -32,6 +32,59 @@ struct mcfg_entry {
>         u8                      bus_start;
>         u8                      bus_end;
>  };
> +struct mcfg_fixup {
> +       char oem_id[ACPI_OEM_ID_SIZE + 1];
> +       char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
> +       u32 oem_revision;
> +       u16 seg;
> +       struct resource bus_range;
> +       struct pci_ecam_ops *ops;
> +       struct resource cfgres;
> +};
> +
> +#define MCFG_DOM_ANY                   (-1)
> +#define MCFG_BUS_RANGE(start, end)     DEFINE_RES_NAMED((start),       \
> +                                               ((end) - (start) + 1),  \
> +                                               NULL, IORESOURCE_BUS)
> +#define MCFG_BUS_ANY           MCFG_BUS_RANGE(0x0, 0xff)
> +#define MCFG_RES_EMPTY         DEFINE_RES_NAMED(0, 0, NULL, 0)
> +
> +static struct mcfg_fixup mcfg_quirks[] = {
> +/*     { OEM_ID, OEM_TABLE_ID, REV, DOMAIN, BUS_RANGE, cfgres, ops }, */
> +};
> +
> +static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
> +static char mcfg_oem_table_id[ACPI_OEM_TABLE_ID_SIZE];
> +static u32 mcfg_oem_revision;
> +
> +static void pci_mcfg_match_quirks(struct acpi_pci_root *root,
> +                                 struct resource *cfgres,
> +                                 struct pci_ecam_ops **ecam_ops)
> +{
> +       struct mcfg_fixup *f;
> +       int i;
> +
> +       /*
> +        * First match against PCI topology <domain:bus> then use OEM ID, OEM
> +        * table ID, and OEM revision from MCFG table standard header.
> +        */
> +       for (i = 0, f = mcfg_quirks; i < ARRAY_SIZE(mcfg_quirks); i++, f++) {
> +               if (f->seg == root->segment &&

Is dropping the comparison with MCFG_DOM_ANY intended? It is useful if
all the controllers (segs) can use the same quirk (X-Gene case).
If you decide to drop it, then we can remove MCFG_DOM_ANY definition as well.

> +                   resource_contains(&f->bus_range, &root->secondary) &&
> +                   !memcmp(f->oem_id, mcfg_oem_id, ACPI_OEM_ID_SIZE) &&
> +                   !memcmp(f->oem_table_id, mcfg_oem_table_id,
> +                           ACPI_OEM_TABLE_ID_SIZE) &&
> +                   f->oem_revision == mcfg_oem_revision) {
> +                       if (f->cfgres.start)
> +                               *cfgres = f->cfgres;
> +                       if (f->ops)
> +                               *ecam_ops =  f->ops;
> +                       dev_info(&root->device->dev, "Applying PCI MCFG quirks for %s %s rev: %d\n",
> +                                f->oem_id, f->oem_table_id, f->oem_revision);
> +                       return;
> +               }
> +       }
> +}
>
>  /* List to save MCFG entries */
>  static LIST_HEAD(pci_mcfg_list);
> @@ -61,14 +114,24 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
>
>         }
>
> -       if (!root->mcfg_addr)
> -               return -ENXIO;
> -
>  skip_lookup:
>         memset(&res, 0, sizeof(res));
> -       res.start = root->mcfg_addr + (bus_res->start << 20);
> -       res.end = res.start + (resource_size(bus_res) << 20) - 1;
> -       res.flags = IORESOURCE_MEM;
> +       if (root->mcfg_addr) {
> +               res.start = root->mcfg_addr + (bus_res->start << 20);
> +               res.end = res.start + (resource_size(bus_res) << 20) - 1;
> +               res.flags = IORESOURCE_MEM;
> +       }
> +
> +       /*
> +        * Let to override default ECAM ops and CFG resource range.
> +        * Also, this might even retrieve CFG resource range in case MCFG
> +        * does not have it. Invalid CFG start address means MCFG firmware bug
> +        * or we need another quirk in array.
> +        */
> +       pci_mcfg_match_quirks(root, &res, &ops);
> +       if (!res.start)
> +               return -ENXIO;
> +
>         *cfgres = res;
>         *ecam_ops = ops;
>         return 0;
> @@ -101,6 +164,11 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
>                 list_add(&e->list, &pci_mcfg_list);
>         }
>
> +       /* Save MCFG IDs and revision for quirks matching */
> +       memcpy(mcfg_oem_id, header->oem_id, ACPI_OEM_ID_SIZE);
> +       memcpy(mcfg_oem_table_id, header->oem_table_id, ACPI_OEM_TABLE_ID_SIZE);
> +       mcfg_oem_revision = header->revision;
> +
>         pr_info("MCFG table detected, %d entries\n", n);
>         return 0;
>  }
> --
> 1.9.1
Regards,
Duc Dang.