Hi Michael et. al
Gentle ping.
Regards,
Pankaj Bansal
> -----Original Message-----
> From: Pankaj Bansal (OSS)
> Sent: Tuesday, May 12, 2020 6:29 PM
> To: Michael Brown <mc...@ipxe.org>
> Cc: ipxe-devel@lists.ipxe.org
> Subject: [PATCH] [efi] implement api to convert pci address to host address
>
> From: Pankaj Bansal <pankaj.ban...@nxp.com>
>
> The PCI device address may not be same as host address (CPU view address)
> To read/write directly to PCI device's BARs (without using
> EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Mem.Read() and
> EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Mem.Write()) we need to convert PCI
> device address to host address.
>
> The UEFI specifications 2.7 provide a method to translate the PCI device
> address to host address and vice versa.
>
> device address = host address + translation offset
>
> EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.Configuration() method can provide us
> with
> the translation offset and host address range.
>
> Using this we can convert the PCI device address to host address.
>
> Signed-off-by: Pankaj Bansal <pankaj.ban...@nxp.com>
> ---
> src/include/ipxe/pci_io.h | 10 ++++
> src/interface/efi/efi_pci.c | 60 ++++++++++++++++++++
> 2 files changed, 70 insertions(+)
>
> diff --git a/src/include/ipxe/pci_io.h b/src/include/ipxe/pci_io.h
> index 10e69763..5806390d 100644
> --- a/src/include/ipxe/pci_io.h
> +++ b/src/include/ipxe/pci_io.h
> @@ -122,4 +122,14 @@ int pci_write_config_word ( struct pci_device *pci,
> unsigned int where,
> int pci_write_config_dword ( struct pci_device *pci, unsigned int where,
> uint32_t value );
>
> +/**
> + * retrieve Host Address corresponding to pci bus address
> + *
> + * @v pci PCI device
> + * @v bus_addr PCI Bus address
> + * @v len Length of region
> + * @ret io_addr Host address
> + */
> +uint64_t pci_ioremap ( struct pci_device *pci, uint64_t bus_addr, size_t len
> );
> +
> #endif /* _IPXE_PCI_IO_H */
> diff --git a/src/interface/efi/efi_pci.c b/src/interface/efi/efi_pci.c
> index c1f451c9..b688210e 100644
> --- a/src/interface/efi/efi_pci.c
> +++ b/src/interface/efi/efi_pci.c
> @@ -215,6 +215,66 @@ int efipci_write ( struct pci_device *pci, unsigned long
> location,
> return rc;
> }
>
> +/**
> + * retrieve Host Address corresponding to pci bus address
> + *
> + * @v pci PCI device
> + * @v bus_addr PCI Bus address
> + * @v len Length of region
> + * @ret io_addr Host address
> + */
> +static uint64_t efi_pci_ioremap ( struct pci_device *pci, uint64_t bus_addr,
> + size_t len ) {
> + EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
> + EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL *root;
> + EFI_ACPI_ADDRESS_SPACE_DESCRIPTOR *config;
> + EFI_HANDLE handle;
> + EFI_STATUS efirc;
> + uint64_t bus_addr_start;
> + int rc;
> +
> + /* Identify root bridge */
> + if ( ( rc = efipci_root ( pci, &handle, &root ) ) != 0 )
> + goto err_root;
> +
> + /* Retrieves the current resource settings of this PCI root bridge */
> + efirc = root->Configuration ( root, (void **) &config);
> + if (efirc != 0) {
> + rc = -EEFI ( efirc );
> + DBGC ( pci, "EFIPCI " PCI_FMT "Retrieval of current resource "
> + "settings of PCI root bridge failed: %s\n",
> + PCI_ARGS ( pci ), strerror ( rc ) );
> + goto err_configuration;
> + }
> +
> + /* According to UEFI 2.7,
> + * EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL::Configuration()
> + * returns host address instead of device address,
> + * while AddrTranslationOffset is not zero, and
> + * device address = host address + AddrTranslationOffset, so
> + * we convert host address to device address for range compare.
> + */
> + while ( config->Desc == ACPI_ADDRESS_SPACE_DESCRIPTOR ) {
> + bus_addr_start = config->AddrRangeMin +
> + config->AddrTranslationOffset;
> + if ( ( config->ResType == ACPI_ADDRESS_SPACE_TYPE_MEM )
> &&
> + ( bus_addr_start <= bus_addr ) &&
> + ( bus_addr_start + config->AddrLen >= bus_addr + len ) ) {
> + return ( bus_addr - config->AddrTranslationOffset );
> + }
> + config++;
> + }
> +
> + return bus_addr;
> +
> +err_configuration:
> + bs->CloseProtocol ( handle, &efi_pci_root_bridge_io_protocol_guid,
> + efi_image_handle, handle );
> +err_root:
> + return rc;
> +}
> +
> +PROVIDE_PCIAPI (efi, pci_ioremap, efi_pci_ioremap);
> PROVIDE_PCIAPI_INLINE ( efi, pci_num_bus );
> PROVIDE_PCIAPI_INLINE ( efi, pci_read_config_byte );
> PROVIDE_PCIAPI_INLINE ( efi, pci_read_config_word );
> --
> 2.17.1
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