From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/firmware/efi/libstub/pci.c | 114 +++++++++++++++++++++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 drivers/firmware/efi/libstub/pci.c (limited to 'drivers/firmware/efi/libstub/pci.c') diff --git a/drivers/firmware/efi/libstub/pci.c b/drivers/firmware/efi/libstub/pci.c new file mode 100644 index 000000000..99fb25d2b --- /dev/null +++ b/drivers/firmware/efi/libstub/pci.c @@ -0,0 +1,114 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * PCI-related functions used by the EFI stub on multiple + * architectures. + * + * Copyright 2019 Google, LLC + */ + +#include +#include + +#include + +#include "efistub.h" + +void efi_pci_disable_bridge_busmaster(void) +{ + efi_guid_t pci_proto = EFI_PCI_IO_PROTOCOL_GUID; + unsigned long pci_handle_size = 0; + efi_handle_t *pci_handle = NULL; + efi_handle_t handle; + efi_status_t status; + u16 class, command; + int i; + + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, &pci_proto, + NULL, &pci_handle_size, NULL); + + if (status != EFI_BUFFER_TOO_SMALL) { + if (status != EFI_SUCCESS && status != EFI_NOT_FOUND) + efi_err("Failed to locate PCI I/O handles'\n"); + return; + } + + status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, pci_handle_size, + (void **)&pci_handle); + if (status != EFI_SUCCESS) { + efi_err("Failed to allocate memory for 'pci_handle'\n"); + return; + } + + status = efi_bs_call(locate_handle, EFI_LOCATE_BY_PROTOCOL, &pci_proto, + NULL, &pci_handle_size, pci_handle); + if (status != EFI_SUCCESS) { + efi_err("Failed to locate PCI I/O handles'\n"); + goto free_handle; + } + + for_each_efi_handle(handle, pci_handle, pci_handle_size, i) { + efi_pci_io_protocol_t *pci; + unsigned long segment_nr, bus_nr, device_nr, func_nr; + + status = efi_bs_call(handle_protocol, handle, &pci_proto, + (void **)&pci); + if (status != EFI_SUCCESS) + continue; + + /* + * Disregard devices living on bus 0 - these are not behind a + * bridge so no point in disconnecting them from their drivers. + */ + status = efi_call_proto(pci, get_location, &segment_nr, &bus_nr, + &device_nr, &func_nr); + if (status != EFI_SUCCESS || bus_nr == 0) + continue; + + /* + * Don't disconnect VGA controllers so we don't risk losing + * access to the framebuffer. Drivers for true PCIe graphics + * controllers that are behind a PCIe root port do not use + * DMA to implement the GOP framebuffer anyway [although they + * may use it in their implementation of Gop->Blt()], and so + * disabling DMA in the PCI bridge should not interfere with + * normal operation of the device. + */ + status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16, + PCI_CLASS_DEVICE, 1, &class); + if (status != EFI_SUCCESS || class == PCI_CLASS_DISPLAY_VGA) + continue; + + /* Disconnect this handle from all its drivers */ + efi_bs_call(disconnect_controller, handle, NULL, NULL); + } + + for_each_efi_handle(handle, pci_handle, pci_handle_size, i) { + efi_pci_io_protocol_t *pci; + + status = efi_bs_call(handle_protocol, handle, &pci_proto, + (void **)&pci); + if (status != EFI_SUCCESS || !pci) + continue; + + status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16, + PCI_CLASS_DEVICE, 1, &class); + + if (status != EFI_SUCCESS || class != PCI_CLASS_BRIDGE_PCI) + continue; + + /* Disable busmastering */ + status = efi_call_proto(pci, pci.read, EfiPciIoWidthUint16, + PCI_COMMAND, 1, &command); + if (status != EFI_SUCCESS || !(command & PCI_COMMAND_MASTER)) + continue; + + command &= ~PCI_COMMAND_MASTER; + status = efi_call_proto(pci, pci.write, EfiPciIoWidthUint16, + PCI_COMMAND, 1, &command); + if (status != EFI_SUCCESS) + efi_err("Failed to disable PCI busmastering\n"); + } + +free_handle: + efi_bs_call(free_pool, pci_handle); +} -- cgit v1.2.3