Hi Alex, I love your patch! Perhaps something to improve:

[auto build test WARNING on net/master] url: https://github.com/0day-ci/linux/commits/Alex-Elder/net-ipa-endpoint-conf... base: https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git 89dc68533b190117e1a2fb4298d88b96b3580abf config: arm64-allyesconfig (attached as .config) compiler: aarch64-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm64 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>, old ones prefixed by <<): << from drivers/net/ipa/ipa_endpoint.c:8: >> drivers/net/ipa/ipa_endpoint.c:457:6: warning: no previous prototype for 'ipa_endpoint_init_hdr' [-Wmissing-prototypes] 457 | void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint) | ^~~~~~~~~~~~~~~~~~~~~ In file included from include/linux/bits.h:23, from include/linux/bitops.h:5, from include/linux/kernel.h:12, from include/linux/list.h:9, from include/linux/rculist.h:10, from include/linux/pid.h:5, from include/linux/sched.h:14, from include/linux/ratelimit.h:6, from include/linux/dev_printk.h:16, from include/linux/device.h:15, from drivers/net/ipa/ipa_endpoint.c:8: drivers/net/ipa/ipa_endpoint.c: In function 'ipa_endpoint_config': include/linux/bits.h:26:28: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 26 | __builtin_constant_p((l) > (h)), (l) > (h), 0))) | ^ include/linux/build_bug.h:16:62: notkke: in definition of macro 'BUILD_BUG_ON_ZERO' 16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) | ^ include/linux/bits.h:39:3: note: in expansion of macro 'GENMASK_INPUT_CHECK' 39 | (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l)) | ^~~~~~~~~~~~~~~~~~~ drivers/net/ipa/ipa_endpoint.c:1546:12: note: in expansion of macro 'GENMASK' 1546 | tx_mask = GENMASK(max - 1, 0); | ^~~~~~~ include/linux/bits.h:26:40: warning: comparison of unsigned expression < 0 is always false [-Wtype-limits] 26 | __builtin_constant_p((l) > (h)), (l) > (h), 0))) | ^ include/linux/build_bug.h:16:62: note: in definition of macro 'BUILD_BUG_ON_ZERO' 16 | #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); }))) | ^ include/linux/bits.h:39:3: note: in expansion of macro 'GENMASK_INPUT_CHECK' 39 | (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l)) | ^~~~~~~~~~~~~~~~~~~ drivers/net/ipa/ipa_endpoint.c:1546:12: note: in expansion of macro 'GENMASK' 1546 | tx_mask = GENMASK(max - 1, 0); | ^~~~~~~ vim +/ipa_endpoint_init_hdr +457 drivers/net/ipa/ipa_endpoint.c 438 439 /** 440 * We program QMAP endpoints so each packet received is preceded by a QMAP 441 * header structure. The QMAP header contains a 1-byte mux_id and 2-byte 442 * packet size field, and we have the IPA hardware populate both for each 443 * received packet. The header is configured (in the HDR_EXT register) 444 * to use big endian format. 445 * 446 * The packet size is written into the QMAP header's pkt_len field. That 447 * location is defined here using the HDR_OFST_PKT_SIZE field. 448 * 449 * The mux_id comes from a 4-byte metadata value supplied with each packet 450 * by the modem. It is *not* a QMAP header, but it does contain the mux_id 451 * value that we want, in its low-order byte. A bitmask defined in the 452 * endpoint's METADATA_MASK register defines which byte within the modem 453 * metadata contains the mux_id. And the OFST_METADATA field programmed 454 * here indicates where the extracted byte should be placed within the QMAP 455 * header. 456 */ > 457 void ipa_endpoint_init_hdr(struct ipa_endpoint *endpoint) 458 { 459 u32 offset = IPA_REG_ENDP_INIT_HDR_N_OFFSET(endpoint->endpoint_id); 460 u32 val = 0; 461 462 if (endpoint->data->qmap) { 463 size_t header_size = sizeof(struct rmnet_map_header); 464 465 /* We might supply a checksum header after the QMAP header */ 466 if (endpoint->toward_ipa && endpoint->data->checksum) 467 header_size += sizeof(struct rmnet_map_ul_csum_header); 468 val |= u32_encode_bits(header_size, HDR_LEN_FMASK); 469 470 /* Define how to fill mux_id in a received QMAP header */ 471 if (!endpoint->toward_ipa) { 472 u32 off; /* Field offset within header */ 473 474 /* Where IPA will write the metadata value */ 475 off = offsetof(struct rmnet_map_header, mux_id); 476 val |= u32_encode_bits(off, HDR_OFST_METADATA_FMASK); 477 478 /* Where IPA will write the length */ 479 off = offsetof(struct rmnet_map_header, pkt_len); 480 val |= HDR_OFST_PKT_SIZE_VALID_FMASK; 481 val |= u32_encode_bits(off, HDR_OFST_PKT_SIZE_FMASK); 482 } 483 /* For QMAP TX, metadata offset is 0 (modem assumes this) */ 484 val |= HDR_OFST_METADATA_VALID_FMASK; 485 486 /* HDR_ADDITIONAL_CONST_LEN is 0; (RX only) */ 487 /* HDR_A5_MUX is 0 */ 488 /* HDR_LEN_INC_DEAGG_HDR is 0 */ 489 /* HDR_METADATA_REG_VALID is 0 (TX only) */ 490 } 491 492 iowrite32(val, endpoint->ipa->reg_virt + offset); 493 } 494 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org