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@semihalf.com Tested-by: Suravee Suthikulpanit Suravee.Suthikulpanit@amd.com Tested-by: Jeremy Linton jeremy.linton@arm.com Tested-by: Duc Dang dhdang@apm.com Tested-by: Dongdong Liu liudongdong3@huawei.com Tested-by: Hanjun Guo hanjun.guo@linaro.org Tested-by: Graeme Gregory graeme.gregory@linaro.org Tested-by: Sinan Kaya okaya@codeaurora.org
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@arm.com
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;@@ -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