On Tue, Feb 16, 2016 at 02:53:34PM +0100, Tomasz Nowicki wrote:
> There are two ways we can get ECAM (aka MCFG) regions using ACPI,
> first from MCFG static table and second from _CBA method. We cannot remove
> static regions, however regions coming from _CBA should be removed while
> removing bridge device.
>
> In the light of above we need flag to mark hot added ECAM entries
> and user to call pci_mmconfig_insert while adding regions from _CBA method.
> Similarly pci_mmconfig_delete while removing hot added regions.
"According to the PCI firmware specification, ACPI provides two standard
mechanisms to retrieve ECAM memory mapped configuration regions (aka MCFG).
For non-hot-removable bridges, ECAM bridge configurations are retrieved from
the static MCFG table and have to be considered non-hot-removable for the
current boot; hot-removable PCI host bridges configurations are retrieved
through bridges _CBA methods.
When ECAM regions are added through _CBA methods, they can be marked
as hot-added so that, upon respective PCI host bridge hot-removal, they can
be unmapped and deleted in that no longer needed.
This patch adds a flag to MCFG regions allowing to mark them as hot-added,
so that upon corresponding PCI bridge hot-removal they can be deleted since
no longer needed."
> Signed-off-by: Tomasz Nowicki <tn@xxxxxxxxxxxx>
> Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> Tested-by: Jeremy Linton <jeremy.linton@xxxxxxx>
> Tested-by: Duc Dang <dhdang@xxxxxxx>
> Tested-by: Dongdong Liu <liudongdong3@xxxxxxxxxx>
> Tested-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
> Tested-by: Graeme Gregory <graeme.gregory@xxxxxxxxxx>
> Tested-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
> ---
> drivers/acpi/pci_mcfg.c | 4 +++-
> include/linux/pci-acpi.h | 1 +
> 2 files changed, 4 insertions(+), 1 deletion(-)
It would be great if x86 people can have a look, we no longer
associate a MCFG region to a bridge structure, the end result
should be equivalent though, so:
Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
>
> diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> index 0467b00..3282f2a 100644
> --- a/drivers/acpi/pci_mcfg.c
> +++ b/drivers/acpi/pci_mcfg.c
> @@ -74,6 +74,7 @@ static struct pci_mmcfg_region *pci_mmconfig_alloc(int segment, int start,
> new->segment = segment;
> new->start_bus = start;
> new->end_bus = end;
> + new->hot_added = false;
>
> res = &new->res;
> res->start = addr + PCI_MMCFG_BUS_OFFSET(start);
> @@ -205,6 +206,7 @@ int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
> }
> rc = pci_mmconfig_map_resource(dev, cfg);
> if (!rc) {
> + cfg->hot_added = true;
> list_add_sorted(cfg);
> dev_info(dev, "MMCONFIG at %pR (base %#lx)\n",
> &cfg->res, (unsigned long)addr);
> @@ -228,7 +230,7 @@ int pci_mmconfig_delete(u16 seg, u8 start, u8 end)
> mutex_lock(&pci_mmcfg_lock);
> list_for_each_entry_rcu(cfg, &pci_mmcfg_list, list)
> if (cfg->segment == seg && cfg->start_bus == start &&
> - cfg->end_bus == end) {
> + cfg->end_bus == end && cfg->hot_added) {
> list_del_rcu(&cfg->list);
> synchronize_rcu();
> pci_mmconfig_unmap_resource(cfg);
> diff --git a/include/linux/pci-acpi.h b/include/linux/pci-acpi.h
> index e9450ef..94d8f38 100644
> --- a/include/linux/pci-acpi.h
> +++ b/include/linux/pci-acpi.h
> @@ -119,6 +119,7 @@ struct pci_mmcfg_region {
> u8 start_bus;
> u8 end_bus;
> char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> + bool hot_added;
> };
>
> extern int pci_mmconfig_insert(struct device *dev, u16 seg, u8 start, u8 end,
> --
> 1.9.1
>
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