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OvmfPkg: PciHostBridgeLib: convert main loop from PciHostBridgeDxe 

In this patch we import the scan for extra root buses from the
InitializePciHostBridge() function, in file
"OvmfPkg/PciHostBridgeDxe/PciHostBridge.c".

For the time being, the InitRootBridge() and UninitRootBridge() functions
are just placeholders.

The PciHostBridgeGetRootBridges() API expects us to return the
PCI_ROOT_BRIDGE structures in a contiguous array, instead of a linked
list. Therefore the following bits have to be converted manually:

(1) The array is allocated in advance, in a single step.

(2) The calculation of the array size depends on an explicit
    multiplication, which we must check against overflow. Since more than
    255 extra root bridges make no sense anyway, we use (1 + 255) as the
    limit on the main plus all extra root bridges. This also ensures that
    the UINTN multiplication doesn't overflow.

(3) The PciHostBridgeDxe code decrements "ExtraRootBridgesLeft" to
    terminate the scanning early. Here we need track the increasing count
    of used array elements as well, so we employ "ExtraRootBridges" as a
    constant limit, and increment the new local variable "Initialized".

(4) The prototypes of InitRootBridge() and UninitRootBridge() reflect that
    the PCI_ROOT_BRIDGE structure is allocated by the caller; only
    in-place initialization is necessary.

Additionally, macros are employed for standard PCI quantities, from
"MdePkg/Include/IndustryStandard/Pci22.h":

- MAX_PCI_DEVICE_NUMBER (31) is replaced with PCI_MAX_DEVICE (same),
- the constant 255 is replaced with PCI_MAX_BUS,
- the (RootBridgeNumber < 256) condition is replaced with
  (RootBridgeNumber <= PCI_MAX_BUS).

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
This commit is contained in:
Laszlo Ersek 2016-01-25 22:47:00 +01:00
parent d85861d718
commit 46e46eaf62
2 changed files with 170 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

163
OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.c
View File

@ -14,14 +14,75 @@
**/
#include <PiDxe.h>
#include <Library/PciHostBridgeLib.h>
#include <IndustryStandard/Pci.h>
#include <Library/DebugLib.h>
#include <Library/MemoryAllocationLib.h>
#include <Library/PciHostBridgeLib.h>
#include <Library/PciLib.h>
#include <Library/QemuFwCfgLib.h>
GLOBAL_REMOVE_IF_UNREFERENCED
CHAR16 *mPciHostBridgeLibAcpiAddressSpaceTypeStr[] = {
L"Mem", L"I/O", L"Bus"
};
/**
Initialize a PCI_ROOT_BRIDGE structure.
param[in] RootBusNumber The bus number to store in RootBus.
param[in] MaxSubBusNumber The inclusive maximum bus number that can be
assigned to any subordinate bus found behind any
PCI bridge hanging off this root bus.
The caller is repsonsible for ensuring that
RootBusNumber <= MaxSubBusNumber. If
RootBusNumber equals MaxSubBusNumber, then the
root bus has no room for subordinate buses.
param[out] RootBus The PCI_ROOT_BRIDGE structure (allocated by the
caller) that should be filled in by this
function.
@retval EFI_SUCCESS Initialization successful. A device path
consisting of an ACPI device path node, with
UID = RootBusNumber, has been allocated and
linked into RootBus.
@retval EFI_OUT_OF_RESOURCES Memory allocation failed.
**/
STATIC
EFI_STATUS
InitRootBridge (
IN UINT8 RootBusNumber,
IN UINT8 MaxSubBusNumber,
OUT PCI_ROOT_BRIDGE *RootBus
)
{
return EFI_OUT_OF_RESOURCES;
}
/**
Uninitialize a PCI_ROOT_BRIDGE structure set up with InitRootBridge().
param[in] RootBus The PCI_ROOT_BRIDGE structure, allocated by the caller and
initialized with InitRootBridge(), that should be
uninitialized. This function doesn't free RootBus.
**/
STATIC
VOID
UninitRootBridge (
IN PCI_ROOT_BRIDGE *RootBus
)
{
}
/**
Return all the root bridge instances in an array.
@ -37,10 +98,109 @@ PciHostBridgeGetRootBridges (
UINTN *Count
)
{
EFI_STATUS Status;
FIRMWARE_CONFIG_ITEM FwCfgItem;
UINTN FwCfgSize;
UINT64 ExtraRootBridges;
PCI_ROOT_BRIDGE *Bridges;
UINTN Initialized;
UINTN LastRootBridgeNumber;
UINTN RootBridgeNumber;
*Count = 0;
//
// QEMU provides the number of extra root buses, shortening the exhaustive
// search below. If there is no hint, the feature is missing.
//
Status = QemuFwCfgFindFile ("etc/extra-pci-roots", &FwCfgItem, &FwCfgSize);
if (EFI_ERROR (Status) || FwCfgSize != sizeof ExtraRootBridges) {
ExtraRootBridges = 0;
} else {
QemuFwCfgSelectItem (FwCfgItem);
QemuFwCfgReadBytes (FwCfgSize, &ExtraRootBridges);
if (ExtraRootBridges > PCI_MAX_BUS) {
DEBUG ((EFI_D_ERROR, "%a: invalid count of extra root buses (%Lu) "
"reported by QEMU\n", __FUNCTION__, ExtraRootBridges));
return NULL;
}
DEBUG ((EFI_D_INFO, "%a: %Lu extra root buses reported by QEMU\n",
__FUNCTION__, ExtraRootBridges));
}
//
// Allocate the "main" root bridge, and any extra root bridges.
//
Bridges = AllocatePool ((1 + (UINTN)ExtraRootBridges) * sizeof *Bridges);
if (Bridges == NULL) {
DEBUG ((EFI_D_ERROR, "%a: %r\n", __FUNCTION__, EFI_OUT_OF_RESOURCES));
return NULL;
}
Initialized = 0;
//
// The "main" root bus is always there.
//
LastRootBridgeNumber = 0;
//
// Scan all other root buses. If function 0 of any device on a bus returns a
// VendorId register value different from all-bits-one, then that bus is
// alive.
//
for (RootBridgeNumber = 1;
RootBridgeNumber <= PCI_MAX_BUS && Initialized < ExtraRootBridges;
++RootBridgeNumber) {
UINTN Device;
for (Device = 0; Device <= PCI_MAX_DEVICE; ++Device) {
if (PciRead16 (PCI_LIB_ADDRESS (RootBridgeNumber, Device, 0,
PCI_VENDOR_ID_OFFSET)) != MAX_UINT16) {
break;
}
}
if (Device <= PCI_MAX_DEVICE) {
//
// Found the next root bus. We can now install the *previous* one,
// because now we know how big a bus number range *that* one has, for any
// subordinate buses that might exist behind PCI bridges hanging off it.
//
Status = InitRootBridge ((UINT8)LastRootBridgeNumber,
(UINT8)(RootBridgeNumber - 1), &Bridges[Initialized]);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
++Initialized;
LastRootBridgeNumber = RootBridgeNumber;
}
}
//
// Install the last root bus (which might be the only, ie. main, root bus, if
// we've found no extra root buses).
//
Status = InitRootBridge ((UINT8)LastRootBridgeNumber, PCI_MAX_BUS,
&Bridges[Initialized]);
if (EFI_ERROR (Status)) {
goto FreeBridges;
}
++Initialized;
*Count = Initialized;
return Bridges;
FreeBridges:
while (Initialized > 0) {
--Initialized;
UninitRootBridge (&Bridges[Initialized]);
}
FreePool (Bridges);
return NULL;
}
/**
Free the root bridge instances array returned from
PciHostBridgeGetRootBridges().
@ -58,6 +218,7 @@ PciHostBridgeFreeRootBridges (
return;
}
/**
Inform the platform that the resource conflict happens.

9
OvmfPkg/Library/PciHostBridgeLib/PciHostBridgeLib.inf
View File

@ -34,5 +34,12 @@
PciHostBridgeLib.c
[Packages]
MdePkg/MdePkg.dec
MdeModulePkg/MdeModulePkg.dec
MdePkg/MdePkg.dec
OvmfPkg/OvmfPkg.dec
[LibraryClasses]
DebugLib
MemoryAllocationLib
PciLib
QemuFwCfgLib