On Thu, Jun 19, 2014 at 04:52:17PM +0300, Marcel Apfelbaum wrote:
> commit c6e298e1f12e0f4ca02b6da5e42919ae055f6830
> hw/pci: reserve IO and mem for pci-2-pci bridges with no devices attached
>
> introduced support for hot-plugging devices behind pci-2-pci bridges.
> Extend hotplug support also for pci express downstream ports.
>
> Signed-off-by: Marcel Apfelbaum <marce...@redhat.com>
> ---
> src/fw/pciinit.c | 23 +++++++++++++++++++++--
> src/hw/pci_regs.h | 2 ++
> 2 files changed, 23 insertions(+), 2 deletions(-)
>
> diff --git a/src/fw/pciinit.c b/src/fw/pciinit.c
> index 0ad548f..edb3fe9 100644
> --- a/src/fw/pciinit.c
> +++ b/src/fw/pciinit.c
> @@ -636,6 +636,25 @@ pci_region_create_entry(struct pci_bus *bus, struct
> pci_device *dev,
> return entry;
> }
>
> +static int pci_bus_hotplug_support(struct pci_bus *bus)
> +{
> + u8 shpc_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_SHPC);
> + u8 pcie_cap = pci_find_capability(bus->bus_dev, PCI_CAP_ID_EXP);
> + int downstream_port = 0;
> + int slot_implemented = 0;
> +
> + if (pcie_cap) {
> + u16 pcie_flags = pci_config_readw(bus->bus_dev->bdf,
> + pcie_cap + PCI_EXP_FLAGS);
> + u16 port_type = ((pcie_flags & PCI_EXP_FLAGS_TYPE) >>
> + PCI_EXP_FLAGS_TYPE_SHIFT) & 0xf;
0xf is not needed here: PCI_EXP_FLAGS_TYPE is enough.
Also should be u8.
> + downstream_port = (port_type == PCI_EXP_TYPE_DOWNSTREAM) ||
> + (port_type == PCI_EXP_TYPE_ROOT_PORT);
This is correct, the spec says:
Configuration Space, and other capabilities.
8 Slot Implemented – When Set, this bit indicates that the Link
HwInit associated with this Port is connected to a slot (as compared to
being connected to a system-integrated device or being
disabled).
This bit is valid for Downstream Ports. This bit is undefined for
Upstream Ports.
Maybe add a comment in case people will wonder.
> + slot_implemented = !!(pcie_flags & PCI_EXP_FLAGS_SLOT);
I would do
return downstream_port && slot_implemented;
here, avoid testing shpc for express devices.
Also allows moving downstream_port && slot_implemented here.
> + }
> + return shpc_cap || (downstream_port && slot_implemented);
> +}
> +
> static int pci_bios_check_devices(struct pci_bus *busses)
> {
> dprintf(1, "PCI: check devices\n");
> @@ -678,7 +697,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
> continue;
> struct pci_bus *parent = &busses[pci_bdf_to_bus(s->bus_dev->bdf)];
> int type;
> - u8 shpc_cap = pci_find_capability(s->bus_dev, PCI_CAP_ID_SHPC);
> + int hotplug_support = pci_bus_hotplug_support(s);
> for (type = 0; type < PCI_REGION_TYPE_COUNT; type++) {
> u64 align = (type == PCI_REGION_TYPE_IO) ?
> PCI_BRIDGE_IO_MIN : PCI_BRIDGE_MEM_MIN;
> @@ -687,7 +706,7 @@ static int pci_bios_check_devices(struct pci_bus *busses)
> if (pci_region_align(&s->r[type]) > align)
> align = pci_region_align(&s->r[type]);
> u64 sum = pci_region_sum(&s->r[type]);
> - if (!sum && shpc_cap)
> + if (!sum && hotplug_support)
> sum = align; /* reserve min size for hot-plug */
> u64 size = ALIGN(sum, align);
> int is64 = pci_bios_bridge_region_is64(&s->r[type],
> diff --git a/src/hw/pci_regs.h b/src/hw/pci_regs.h
> index e5effd4..6a71569 100644
> --- a/src/hw/pci_regs.h
> +++ b/src/hw/pci_regs.h
> @@ -426,6 +426,8 @@
> #define PCI_EXP_DEVCTL2 40 /* Device Control 2 */
> #define PCI_EXP_DEVCTL2_ARI 0x20 /* Alternative Routing-ID */
>
> +#define PCI_EXP_FLAGS_TYPE_SHIFT 4
> +
It's generally not a good idea to randomly add macros
in random places.
In this case this is not needed. Just call __ffs on
PCI_EXP_FLAGS_TYPE.
> /* Extended Capabilities (PCI-X 2.0 and Express) */
> #define PCI_EXT_CAP_ID(header) (header & 0x0000ffff)
> #define PCI_EXT_CAP_VER(header) ((header >> 16) & 0xf)
> --
> 1.8.3.1
