Re: [PATCH v19 04/10] PCI: endpoint: Add pci_epf_align_inbound_addr() helper for address alignment

On Mon, Jun 09, 2025 at 12:34:16PM GMT, Frank Li wrote:

Introduce the helper function pci_epf_align_inbound_addr() to adjust addresses according to PCI BAR alignment requirements, converting addresses into base and offset values.

Signed-off-by: Frank Li Frank.Li@nxp.com

Change from v15 to v16

• none

Change from v14 to v15

• change out address type to dma_addr_t to fix below build issue

| Reported-by: kernel test robot lkp@intel.com | Closes: https://lore.kernel.org/oe-kbuild-all/202502082311.G1hWGggF-lkp@intel.com/

All errors (new ones prefixed by >>):

drivers/pci/endpoint/functions/pci-epf-test.c: In function 'pci_epf_test_enable_doorbell':

...

...

drivers/pci/endpoint/functions/pci-epf-test.c:726:42: error: passing argument 4 of 'pci_epf_align_inbound_addr' from incompatible pointer type [-Werror=incompatible-pointer-types]

 726 |                                          &epf_test->db_bar.phys_addr, &offset);
     |                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~
     |                                          |
     |                                          dma_addr_t * {aka unsigned int *}

In file included from include/linux/pci-epc.h:12,

Change form v9 to v14

• none

change from v8 to v9

• pci_epf_align_inbound_addr(), base and off must be not NULL
• rm pci_epf_align_inbound_addr_lo_hi()

change from v7 to v8

• change name to pci_epf_align_inbound_addr()
• update comment said only need for memory, which not allocated by

pci_epf_alloc_space().

change from v6 to v7

• new patch

---

drivers/pci/endpoint/pci-epf-core.c | 44 +++++++++++++++++++++++++++++++++++++ include/linux/pci-epf.h | 3 +++ 2 files changed, 47 insertions(+)

diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c index 95fb3d7c1d45e..33e14a6b1549a 100644 --- a/drivers/pci/endpoint/pci-epf-core.c +++ b/drivers/pci/endpoint/pci-epf-core.c @@ -481,6 +481,50 @@ struct pci_epf *pci_epf_create(const char *name) } EXPORT_SYMBOL_GPL(pci_epf_create); +/**

• • pci_epf_align_inbound_addr() - Get base address and offset that match BAR's

• • 	  alignment requirement
    

'Align the given address based on the BAR alignment requirement'

• • @epf: the EPF device
• • @addr: the address of the memory

'inbound address to be aligned'

• • @bar: the BAR number corresponding to map addr

s/map addr/the given addr

• • @base: return base address, which match BAR's alignment requirement.

'base address matching the @bar alignment requirement'

• • @off: return offset.

'offset to be added to the @base address'

• • Helper function to convert input 'addr' to base and offset, which match

s/convert/align

• • BAR's alignment requirement.
• • The pci_epf_alloc_space() function already accounts for alignment. This is
• • primarily intended for use with other memory regions not allocated by
• • pci_epf_alloc_space(), such as peripheral register spaces or the trigger
• • address for a platform MSI controller.
• */

+int pci_epf_align_inbound_addr(struct pci_epf *epf, enum pci_barno bar,

• 	       u64 addr, dma_addr_t *base, size_t *off)
  

+{

• const struct pci_epc_features *epc_features;
• u64 align;
• if (!base || !off)

• return -EINVAL;
  

• epc_features = pci_epc_get_features(epf->epc, epf->func_no, epf->vfunc_no);
• if (!epc_features) {

• dev_err(&epf->dev, "epc_features not implemented\n");
  

• return -EOPNOTSUPP;
  

• }
• align = epc_features->align;
• align = align ? align : 128;

From where this 128 byte alignment comes from?

- Mani