On 9/4/24 15:20, Bjorn Helgaas wrote:

To me, this series would make more sense if we squashed these
together:

  PCI: Introduce PCIe TPH support framework
  PCI: Add TPH related register definition
  PCI/TPH: Add pcie_enable_tph() to enable TPH
  PCI/TPH: Add pcie_disable_tph() to disable TPH
  PCI/TPH: Add save/restore support for TPH

These would add the "minimum viable functionality", e.g., enable TPH
just for Processing Hints, with no Steering Tag support at all.  Would
also include "pci=notph".

Will do

  PCI/TPH: Add pcie_tph_set_st_entry() to set ST tag
  PCI/TPH: Add pcie_tph_get_cpu_st() to get ST tag

And squash these also to add Steering Tag support in a single commit,
including enhancing the save/restore.

Can you elaborate on save/restore enhancement? Assuming that the first
combined patch will have save/restore support as suggested. Are you
talking about the ST entries save/restore as the enhancements (see
below), because the second combined patch deals with ST?

        st_entry = (u16 *)cap;
        offset = PCI_TPH_BASE_SIZEOF;
	num_entries = get_st_table_size(pdev);
        for (i = 0; i < num_entries; i++) {
                pci_write_config_word(pdev, pdev->tph_cap + offset,
 	                              *st_entry++);
                offset += sizeof(u16);
	}

  PCI/TPH: Add pcie_tph_modes() to query TPH modes
  PCI/TPH: Add pcie_tph_enabled() to check TPH state

And maybe we can get away without these altogether.  I mentioned
pcie_tph_modes() elsewhere; seems possibly unnecessary since drivers
can just request the mode they want and we'll fail if it's not
supported.

Drivers should also be able to remember whether they enabled TPH
successfully without us having to remind them.