[PATCH v14 08/15] PCI: endpoint: Add pci_epf_align_inbound_addr() helper for address alignment

[Frank Li]

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...@nxp.com>
---
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 f728ee2660a4e..04facefc70423 100644
--- a/drivers/pci/endpoint/pci-epf-core.c
+++ b/drivers/pci/endpoint/pci-epf-core.c
@@ -469,6 +469,50 @@ 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
+ * @epf: the EPF device
+ * @addr: the address of the memory
+ * @bar: the BAR number corresponding to map addr
+ * @base: return base address, which match BAR's alignment requirement.
+ * @off: return offset.
+ *
+ * Helper function to convert input 'addr' to base and offset, which match
+ * 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, u64 *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;
+       if (epc_features->bar[bar].type == BAR_FIXED)
+               align = max(epc_features->bar[bar].fixed_size, align);
+
+       *base = round_down(addr, align);
+       *off = addr & (align - 1);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(pci_epf_align_inbound_addr);
+
 static void pci_epf_dev_release(struct device *dev)
 {
        struct pci_epf *epf = to_pci_epf(dev);
diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
index 518bc4171285e..1a5cc4d4ae362 100644
--- a/include/linux/pci-epf.h
+++ b/include/linux/pci-epf.h
@@ -240,6 +240,9 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, 
enum pci_barno bar,
                          enum pci_epc_interface_type type);
 void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar,
                        enum pci_epc_interface_type type);
+
+int pci_epf_align_inbound_addr(struct pci_epf *epf, enum pci_barno bar,
+                              u64 addr, u64 *base, size_t *off);
 int pci_epf_bind(struct pci_epf *epf);
 void pci_epf_unbind(struct pci_epf *epf);
 int pci_epf_add_vepf(struct pci_epf *epf_pf, struct pci_epf *epf_vf);

-- 
2.34.1