On 10/12/24 20:57, Manivannan Sadhasivam wrote: > On Sat, Oct 12, 2024 at 08:32:40PM +0900, Damien Le Moal wrote: >> This series introduces the new functions pci_epc_mem_map() and >> pci_epc_mem_unmap() to improve handling of the PCI address mapping >> alignment constraints of endpoint controllers in a controller >> independent manner. >> >> The issue fixed is that the fixed alignment defined by the "align" field >> of struct pci_epc_features is defined for inbound ATU entries (e.g. >> BARs) and is a fixed value, whereas some controllers need a PCI address >> alignment that depends on the PCI address itself. For instance, the >> rk3399 SoC controller in endpoint mode uses the lower bits of the local >> endpoint memory address as the lower bits for the PCI addresses for data >> transfers. That is, when mapping local memory, one must take into >> account the number of bits of the RC PCI address that change from the >> start address of the mapping. >> >> To fix this, the new endpoint controller method .align_addr is >> introduced and called from the new pci_epc_mem_map() function. This >> method is optional and for controllers that do not define it, it is >> assumed that the controller has no PCI address constraint. >> >> The functions pci_epc_mem_map() is a helper function which obtains >> the mapping information, allocates endpoint controller memory according >> to the mapping size obtained and maps the memory. pci_epc_mem_unmap() >> unmaps and frees the endpoint memory. >> >> This series is organized as follows: >> - Patch 1 introduces a small helper to clean up the epc core code >> - Patch 2 improves pci_epc_mem_alloc_addr() >> - Patch 3 introduce the new align_addr() endpoint controller method >> and the epc functions pci_epc_mem_map() and pci_epc_mem_unmap(). >> - Patch 4 documents these new functions. >> - Patch 5 modifies the test endpoint function driver to use >> pci_epc_mem_map() and pci_epc_mem_unmap() to illustrate the use of >> these functions. >> - Finally, patch 6 implements the RK3588 endpoint controller driver >> .align_addr() operation to satisfy that controller PCI address >> alignment constraint. >> >> This patch series was tested using the pci endpoint test driver (as-is >> and a modified version removing memory allocation alignment on the host >> side) as well as with a prototype NVMe endpoint function driver (where >> data transfers use addresses that are never aligned to any specific >> boundary). >> > > Applied to pci/endpoint! Awesome ! Thanks a lot ! -- Damien Le Moal Western Digital Research
