[RFC PATCH V5 3/5] PCI: Check platform specific ECAM quirks
Bjorn Helgaas
helgaas at kernel.org
Sun Sep 4 19:59:08 PDT 2016
On Mon, Aug 08, 2016 at 03:05:39PM +0200, 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. Algorithm traverses available quirk list (static array),
> matches against <oem_id, oem_table_id, rev, domain, bus number range> and
> returns pci_config_window structure with fancy PCI config ops.
> oem_id, oem_table_id and rev come from MCFG table standard header.
>
> It is possible to define custom init call which is responsible for
> setting up PCI configuration access accordingly to quirk requirements.
> If custom init call is not defined, use standard pci_acpi_setup_ecam_mapping().
>
> pci_generic_ecam_ops will be used for platforms free from quirks.
>
> Signed-off-by: Tomasz Nowicki <tn at semihalf.com>
> Signed-off-by: Dongdong Liu <liudongdong3 at huawei.com>
> Signed-off-by: Christopher Covington <cov at codeaurora.org>
> ---
> drivers/pci/host/Makefile | 1 +
> drivers/pci/host/mcfg-quirks.c | 86 ++++++++++++++++++++++++++++++++++++++++++
> drivers/pci/host/mcfg-quirks.h | 20 ++++++++++
> include/linux/pci-acpi.h | 2 +
> 4 files changed, 109 insertions(+)
> create mode 100644 drivers/pci/host/mcfg-quirks.c
> create mode 100644 drivers/pci/host/mcfg-quirks.h
>
> diff --git a/drivers/pci/host/Makefile b/drivers/pci/host/Makefile
> index 8843410..500cf78 100644
> --- a/drivers/pci/host/Makefile
> +++ b/drivers/pci/host/Makefile
> @@ -31,3 +31,4 @@ obj-$(CONFIG_PCI_HOST_THUNDER_ECAM) += pci-thunder-ecam.o
> obj-$(CONFIG_PCI_HOST_THUNDER_PEM) += pci-thunder-pem.o
> obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
> obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
> +obj-$(CONFIG_ACPI_MCFG) += mcfg-quirks.o
> diff --git a/drivers/pci/host/mcfg-quirks.c b/drivers/pci/host/mcfg-quirks.c
> new file mode 100644
> index 0000000..aa9907b
> --- /dev/null
> +++ b/drivers/pci/host/mcfg-quirks.c
> @@ -0,0 +1,86 @@
> +/*
> + * Copyright (C) 2016 Semihalf
> + * Author: Tomasz Nowicki <tn at semihalf.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation (the "GPL").
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License version 2 (GPLv2) for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * version 2 (GPLv2) along with this source code.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/ioport.h>
> +#include <linux/pci.h>
> +#include <linux/pci-acpi.h>
> +#include <linux/pci-ecam.h>
> +
> +#include "mcfg-quirks.h"
> +
> +struct pci_cfg_fixup {
> + char oem_id[ACPI_OEM_ID_SIZE + 1];
> + char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1];
> + u32 oem_revision;
> + struct resource domain_range;
> + struct resource bus_range;
> + struct pci_ops *ops;
> + struct pci_config_window *(*init)(struct acpi_pci_root *root,
> + struct pci_ops *ops);
> +};
> +
> +#define MCFG_DOM_RANGE(start, end) DEFINE_RES_NAMED((start), \
> + ((end) - (start) + 1), NULL, 0)
> +#define MCFG_DOM_ANY MCFG_DOM_RANGE(0x0, 0xffff)
> +#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)
> +
> +static struct pci_cfg_fixup mcfg_quirks[] __initconst = {
> +/* { OEM_ID, OEM_TABLE_ID, REV, DOMAIN, BUS_RANGE, pci_ops, init_hook }, */
> +};
> +
> +static bool pci_mcfg_fixup_match(struct pci_cfg_fixup *f,
> + struct acpi_table_header *mcfg_header)
> +{
> + return (!memcmp(f->oem_id, mcfg_header->oem_id, ACPI_OEM_ID_SIZE) &&
> + !memcmp(f->oem_table_id, mcfg_header->oem_table_id,
> + ACPI_OEM_TABLE_ID_SIZE) &&
> + f->oem_revision == mcfg_header->oem_revision);
> +}
> +
> +struct pci_config_window *pci_mcfg_match_quirks(struct acpi_pci_root *root)
> +{
> + struct resource dom_res = MCFG_DOM_RANGE(root->segment, root->segment);
> + struct resource *bus_res = &root->secondary;
> + struct pci_cfg_fixup *f = mcfg_quirks;
> + struct acpi_table_header *mcfg_header;
> + acpi_status status;
> + int i;
> +
> + status = acpi_get_table(ACPI_SIG_MCFG, 0, &mcfg_header);
> + if (ACPI_FAILURE(status))
> + return NULL;
I remember working out why pci_mcfg_parse() has to cache the data from
MCFG, but I don't remember the actual reason... a comment there would
have been helpful. Anyway, now I wonder why it's OK to call
acpi_get_table(ACPI_SIG_MCFG) again here. I guess I'd be inclined to
just cache the OEM info along with the rest of the data so you don't
have to get the table again here.
> + /*
> + * 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; i < ARRAY_SIZE(mcfg_quirks); i++, f++) {
> + if (resource_contains(&f->domain_range, &dom_res) &&
> + resource_contains(&f->bus_range, bus_res) &&
> + pci_mcfg_fixup_match(f, mcfg_header)) {
> + 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 f->init ? f->init(root, f->ops) :
> + pci_acpi_setup_ecam_mapping(root, f->ops);
> + }
> + }
> + return pci_acpi_setup_ecam_mapping(root, &pci_generic_ecam_ops.pci_ops);
I think the scope of these MCFG quirks is to:
1) Override (or even fabricate) a MEM resource to be used as ECAM
space, and
2) Supply a pci_ecam_ops structure if we need something other than
pci_generic_ecam_ops
Today, pci_mcfg_lookup() merely returns a physical address. I didn't
chase down where (or whether) that is turned into a struct resource
that we put in the iomem tree. I wonder if pci_mcfg_lookup() could be
extended to return a resource and a pci_ecam_ops pointer, and handle
the quirk application internally, e.g.,
int pci_mcfg_lookup(u16 seg, struct resource *bus_res,
struct resource *cfgres, struct pci_ecam_ops **ecam_ops)
{
struct resource res;
struct pci_ecam_ops *ops;
struct mcfg_entry *e;
memset(&res, 0, sizeof(res));
res.flags = IORESOURCE_MEM;
e = pci_mcfg_list_search(seg, bus_res);
if (e) {
res.start = e->addr;
res.end = res.start + ...;
}
ops = &pci_generic_ecam_ops;
ret = pci_mcfg_match_quirks(seg, bus_res, &res, &ops);
if (ret)
return ret;
*cfgres = res;
*ecam_ops = ops;
return 0;
}
Then the quirks would see any mem resource we discovered via MCFG, and
they would see the default pci_ecam_ops, and they could override
whatever they needed to.
That would make pci_acpi_setup_ecam_mapping() look something like this:
pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root)
{
struct resource cfgres;
struct pci_ecam_ops *ecam_ops;
ret = pci_mcfg_lookup(root->segment, &root->secondary, &cfgres, &ecam_ops);
if (ret) {
dev_err(..., "ECAM region not found\n");
return ret;
}
cfg = pci_ecam_create(&root->device->dev, &cfgres, bus_res,
ecam_ops);
}
> +}
> diff --git a/drivers/pci/host/mcfg-quirks.h b/drivers/pci/host/mcfg-quirks.h
> new file mode 100644
> index 0000000..45cbd16
> --- /dev/null
> +++ b/drivers/pci/host/mcfg-quirks.h
> @@ -0,0 +1,20 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License, version 2, as
> + * published by the Free Software Foundation (the "GPL").
> + *
> + * This program is distributed in the hope that it will be useful, but
> + * WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * General Public License version 2 (GPLv2) for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * version 2 (GPLv2) along with this source code.
> + */
> +
> +#ifndef __MCFG_QUIRKS_H__
> +#define __MCFG_QUIRKS_H__
> +
> +/* MCFG quirks initialize call list */
> +
> +#endif /* __MCFG_QUIRKS_H__ */
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index e9bfe00..28cdce4 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -25,6 +25,8 @@ 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_config_window *
> +pci_mcfg_match_quirks(struct acpi_pci_root *root);
>
> extern struct pci_config_window *
> pci_acpi_setup_ecam_mapping(struct acpi_pci_root *root, struct pci_ops *ops);
> --
> 1.9.1
>
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