On Thu, Sep 05, 2024 at 10:45:57AM -0500, Wei Huang wrote:

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

quoted

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".

quoted

  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);
	}

I meant that since the first patch knows nothing about ST, it would
save/restore TPH control but not the ST entries.

The second patch would add ST support and also add save/restore of the
ST entries.