implement api to convert pci address to host address

[pankajbansalnxp]

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.bansal@nxp.com

[mcb30]

So, this looks like a generally good idea to have. However:

• there would also need to be implementations for each of the other PCI APIs (pcibios and pcidirect)
• something would need to actually use the API; at the moment it's purely unused code

[pankajbansalnxp]

@mcb30 : i have used this patch to create an intel e1000 PCIE NIC efi driver. like this:

commit c32de21f035e57c56824fef5dac036a22a2f3e2a (HEAD -> github/master)
Author: Pankaj Bansal pankaj.bansal@nxp.com
Date: Fri Jul 3 12:00:45 2020 -0500

use pci_ioremap

Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>

diff --git a/src/drivers/net/intel.c b/src/drivers/net/intel.c
index d9b8b46b..17be5f63 100644
--- a/src/drivers/net/intel.c
+++ b/src/drivers/net/intel.c
@@ -959,7 +959,8 @@ static int intel_probe ( struct pci_device *pci ) {
adjust_pci_device ( pci );

    /* Map registers */

•   intel->regs = ioremap ( pci->membase, INTEL_BAR_SIZE );
  

•   intel->regs = ioremap ( pci_ioremap ( pci, pci->membase, INTEL_BAR_SIZE ),
  

•                           INTEL_BAR_SIZE );
    if ( ! intel->regs ) {
            rc = -ENODEV;
            goto err_ioremap;
  

I did not submit this patch because i did not know if this would cause any issues with any existing functionality or not?
I am fairly new to ipxe code and still not familiar with many of it's features and functions.

[mcb30]

@pankajbansalnxp Thank you for contributing this. I have implemented equivalent functionality in #146 and updated all PCI drivers to use it. Please let me know if this does not work for you.