On Wed, 2016-01-13 at 14:21 +0100, Tomasz Nowicki wrote:
> Some platforms may not be fully compliant with generic set of PCI config
> accessors. For these cases we implement the way to overwrite accessors
> set prior to PCI buses enumeration. Algorithm traverses available quirk
> list, matches against <platform ID (DMI), domain, bus number> tuple and
> returns corresponding accessors. All quirks can be defined using:
> DECLARE_ACPI_MCFG_FIXUP() and keep self contained. Example,
>
> static const struct dmi_system_id foo_dmi[] = {
> {
> .ident = "<Platform ident string>",
> .callback = <handler>,
> .matches = {
> DMI_MATCH(DMI_SYS_VENDOR, "<system vendor>"),
> DMI_MATCH(DMI_PRODUCT_NAME, "<product name>"),
> DMI_MATCH(DMI_PRODUCT_VERSION, "product version"),
> },
> },
> { }
> };
>
> static struct pci_ops foo_ecam_pci_ops = {
> .map_bus = pci_mcfg_dev_base,
> .read = foo_ecam_config_read,
> .write = foo_ecam_config_write,
> };
> DECLARE_ACPI_MCFG_FIXUP(foo_dmi, NULL, &foo_ecam_pci_ops, <domain_nr>, <bus_nr>);
>
> More custom (non-DMI) matching can be done via an alternative call.
> Note that there is possibility to assign quirk related private data to
> root->sysdata which will be available along read/wriate accessor, example:
>
> static int boo_match(struct pci_mcfg_fixup *fixup, struct acpi_pci_root *root)
> {
> return [condition] ? 1 : 0;
> }
>
> int boo_ecam_config_read(struct pci_bus *bus, unsigned int devfn,
> int where, int size, u32 *val)
> {
> struct acpi_pci_root *root = bus->sysdata;
> struct boo_priv_data *boo_data = root->sysdata;
>
> [..]
> }
>
> static struct pci_ops boo_ecam_pci_ops = {
> .map_bus = pci_mcfg_dev_base,
> .read = boo_ecam_config_read,
> .write = boo_ecam_config_write,
> };
> DECLARE_ACPI_MCFG_FIXUP(NULL, boo_match, &boo_ecam_pci_ops, <domain_nr>, <bus_nr>);
>
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> ---
> drivers/acpi/mcfg.c | 33 +++++++++++++++++++++++++++++++--
> include/acpi/acpi_bus.h | 1 +
> include/asm-generic/vmlinux.lds.h | 7 +++++++
> include/linux/ecam.h | 18 ++++++++++++++++++
> 4 files changed, 57 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/acpi/mcfg.c b/drivers/acpi/mcfg.c
> index dfc2d14..ec5fe7b 100644
> --- a/drivers/acpi/mcfg.c
> +++ b/drivers/acpi/mcfg.c
> @@ -8,6 +8,7 @@
> */
>
> #include <linux/acpi.h>
> +#include <linux/dmi.h>
> #include <linux/ecam.h>
> #include <linux/pci.h>
> #include <linux/pci-acpi.h>
> @@ -34,6 +35,29 @@ int __weak raw_pci_write(unsigned int domain, unsigned int bus,
> return PCIBIOS_DEVICE_NOT_FOUND;
> }
>
> +extern struct pci_mcfg_fixup __start_acpi_mcfg_fixups[];
> +extern struct pci_mcfg_fixup __end_acpi_mcfg_fixups[];
> +
> +static struct pci_ops *pci_mcfg_check_quirks(struct acpi_pci_root *root)
> +{
> + struct pci_mcfg_fixup *f;
> + int bus_num = root->secondary.start;
> + int domain = root->segment;
> +
> + /*
> + * First match against PCI topology <domain:bus> then use DMI or
> + * custom match handler.
> + */
> + 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) &&
> + (f->system ? dmi_check_system(f->system) : 0 ||
> + f->match ? f->match(f, root) : 0))
> + return f->ops;
I think this would be better as:
(f->system ? dmi_check_system(f->system) : 1 &&
f->match ? f->match(f, root) : 1))
return f->ops;
Otherwise, one has to call dmi_check_system() from f->match() if
access to root is needed.
> + }
> + return NULL;
> +}
> +
> void __iomem *
> pci_mcfg_dev_base(struct pci_bus *bus, unsigned int devfn, int offset)
> {
> @@ -56,10 +80,15 @@ static struct pci_ops default_pci_mcfg_ops = {
>
> struct pci_ops *pci_mcfg_get_ops(struct acpi_pci_root *root)
> {
> + struct pci_ops *pci_mcfg_ops_quirk;
> +
> /*
> - * TODO: Match against platform specific quirks and return
> - * corresponding PCI config space accessor set.
> + * Match against platform specific quirks and return corresponding
> + * PCI config space accessor set.
> */
> + pci_mcfg_ops_quirk = pci_mcfg_check_quirks(root);
> + if (pci_mcfg_ops_quirk)
> + return pci_mcfg_ops_quirk;
>
> return &default_pci_mcfg_ops;
> }
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index ad0a5ff..ea4d2b5 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -554,6 +554,7 @@ struct acpi_pci_root {
> struct pci_bus *bus;
> u16 segment;
> struct resource secondary; /* downstream bus range */
> + void *sysdata;
>
> u32 osc_support_set; /* _OSC state of support bits */
> u32 osc_control_set; /* _OSC state of control bits */
> diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
> index c4bd0e2..c93fc97 100644
> --- a/include/asm-generic/vmlinux.lds.h
> +++ b/include/asm-generic/vmlinux.lds.h
> @@ -298,6 +298,13 @@
> VMLINUX_SYMBOL(__end_pci_fixups_suspend_late) = .; \
> } \
> \
> + /* ACPI MCFG quirks */ \
> + .acpi_fixup : AT(ADDR(.acpi_fixup) - LOAD_OFFSET) { \
> + VMLINUX_SYMBOL(__start_acpi_mcfg_fixups) = .; \
> + *(.acpi_fixup_mcfg) \
> + VMLINUX_SYMBOL(__end_acpi_mcfg_fixups) = .; \
> + } \
> + \
> /* Built-in firmware blobs */ \
> .builtin_fw : AT(ADDR(.builtin_fw) - LOAD_OFFSET) { \
> VMLINUX_SYMBOL(__start_builtin_fw) = .; \
> diff --git a/include/linux/ecam.h b/include/linux/ecam.h
> index e0f322e..21215be 100644
> --- a/include/linux/ecam.h
> +++ b/include/linux/ecam.h
> @@ -20,6 +20,24 @@ struct pci_mmcfg_region {
> bool hot_added;
> };
>
> +struct pci_mcfg_fixup {
> + const struct dmi_system_id *system;
> + int (*match)(struct pci_mcfg_fixup *, struct acpi_pci_root *);
> + struct pci_ops *ops;
> + 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(system, match, ops, dom, bus) \
> + static const struct pci_mcfg_fixup __mcfg_fixup_##system##dom##bus\
> + __used __attribute__((__section__(".acpi_fixup_mcfg"), \
> + aligned((sizeof(void *))))) = \
> + { system, match, ops, dom, bus };
> +
> struct pci_mmcfg_region *pci_mmconfig_lookup(int segment, int bus);
> struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> int end, u64 addr);
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