PCI: Add managed partial-BAR request and map infrastructure

The pcim_iomap_devres table tracks entire-BAR mappings, so we can't use it
to build a managed version of pci_iomap_range(), which maps partial BARs.

Add struct pcim_addr_devres, which can track request and mapping of both
entire BARs and partial BARs.

Add the following internal devres functions based on struct
pcim_addr_devres:

  pcim_iomap_region()               # request & map entire BAR
  pcim_iounmap_region()             # unmap & release entire BAR
  pcim_request_region()             # request entire BAR
  pcim_release_region()             # release entire BAR
  pcim_request_all_regions()        # request all entire BARs
  pcim_release_all_regions()        # release all entire BARs

Rework the following public interfaces using the new infrastructure
listed above:

  pcim_iomap()                      # map partial BAR
  pcim_iounmap()                    # unmap partial BAR
  pcim_iomap_regions()              # request & map specified BARs
  pcim_iomap_regions_request_all()  # request all BARs, map specified BARs
  pcim_iounmap_regions()            # unmap & release specified BARs

Link: https://lore.kernel.org/r/20240613115032.29098-4-pstanner@redhat.com
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index fd44565c4756..c09487f5550c 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -826,6 +826,11 @@ struct pci_devres {
 	unsigned int orig_intx:1;
 	unsigned int restore_intx:1;
 	unsigned int mwi:1;
+
+	/*
+	 * TODO: remove the region_mask once everyone calling
+	 * pcim_enable_device() + pci_*region*() is ported to pcim_ functions.
+	 */
 	u32 region_mask;
 };