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    SubjectRe: [PATCH V6 2/5] PCI/ACPI: Check platform specific ECAM quirks
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    On 13.09.2016 00:47, Duc Dang wrote:
    > On Mon, Sep 12, 2016 at 3:24 PM, Duc Dang <dhdang@apm.com> wrote:
    >> On Fri, Sep 9, 2016 at 12:24 PM, Tomasz Nowicki <tn@semihalf.com> 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@semihalf.com>
    >>> Signed-off-by: Dongdong Liu <liudongdong3@huawei.com>
    >>> Signed-off-by: Christopher Covington <cov@codeaurora.org>
    >>> ---
    >>> 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;
    >
    > I think this is a typo, it should be:
    > mcfg_oem_revision = header->oem_revision;

    You are right, header->oem_revision should be assigned.

    Thanks!
    Tomasz

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