From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> To: Alex Elder <elder@linaro.org> Cc: arnd@arndb.de, david.brown@linaro.org, agross@kernel.org, davem@davemloft.net, bjorn.andersson@linaro.org, ilias.apalodimas@linaro.org, cpratapa@codeaurora.org, syadagir@codeaurora.org, evgreen@chromium.org, benchan@google.com, ejcaruso@google.com, netdev@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Date: Mon, 20 May 2019 19:32:29 -0600 [thread overview] Message-ID: <d90f8ccdc1f76f9166f269eb71a14f7f@codeaurora.org> (raw) In-Reply-To: <81fd1e01-b8e3-f86a-fcc9-2bcbc51bd679@linaro.org> >> If the above illustration is supposed to be in network byte order, >> then it is wrong. The documentation has the definition for the MAP >> packet. > > Network *bit* order is irrelevant to the host. Host memory is > byte addressable only, and bit 0 is the low-order bit. > >> Packet format - >> >> Bit 0 1 2-7 8 - 15 16 >> - 31 >> Function Command / Data Reserved Pad Multiplexer ID >> Payload length >> Bit 32 - x >> Function Raw Bytes > > I don't know how to interpret this. Are you saying that the low- > order bit of the first byte is the command/data flag? Or is it > the high-order bit of the first byte? > > I'm saying that what I observed when building the code was that > as originally defined, the cd_bit field was the high-order bit > (bit 7) of the first byte, which I understand to be wrong. > > If you are telling me that the command/data flag resides at bit > 7 of the first byte, I will update the field masks in a later > patch in this series to reflect that. > Higher order bit is Command / Data. >> The driver was written assuming that the host was running ARM64, so >> the structs are little endian. (I should have made it compatible >> with big and little endian earlier so that is my fault). > > Little endian and big endian have no bearing on the host's > interpretation of bits within a byte. > > Please clarify. I want the patches to be correct, and what > you're explaining doesn't really straighten things out for me. > > -Alex Can't this bitfields just be used similar to how struct tcphdr & iphdr are currently defined. That way, you dont have to make these many changes. diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h index 884f1f5..302d1db 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h @@ -40,9 +40,17 @@ enum rmnet_map_commands { }; struct rmnet_map_header { +#if defined(__LITTLE_ENDIAN_BITFIELD) u8 pad_len:6; u8 reserved_bit:1; u8 cd_bit:1; +#elif defined (__BIG_ENDIAN_BITFIELD) + u8 cd_bit:1; + u8 reserved_bit:1; + u8 pad_len:6; +#else +#error "Please fix <asm/byteorder.h>" +#endif u8 mux_id; __be16 pkt_len; } __aligned(1); -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project
WARNING: multiple messages have this Message-ID (diff)
From: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org> To: Alex Elder <elder@linaro.org> Cc: syadagir@codeaurora.org, ejcaruso@google.com, arnd@arndb.de, netdev@vger.kernel.org, ilias.apalodimas@linaro.org, linux-kernel@vger.kernel.org, evgreen@chromium.org, bjorn.andersson@linaro.org, david.brown@linaro.org, agross@kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, davem@davemloft.net, cpratapa@codeaurora.org, benchan@google.com Subject: Re: [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Date: Mon, 20 May 2019 19:32:29 -0600 [thread overview] Message-ID: <d90f8ccdc1f76f9166f269eb71a14f7f@codeaurora.org> (raw) In-Reply-To: <81fd1e01-b8e3-f86a-fcc9-2bcbc51bd679@linaro.org> >> If the above illustration is supposed to be in network byte order, >> then it is wrong. The documentation has the definition for the MAP >> packet. > > Network *bit* order is irrelevant to the host. Host memory is > byte addressable only, and bit 0 is the low-order bit. > >> Packet format - >> >> Bit 0 1 2-7 8 - 15 16 >> - 31 >> Function Command / Data Reserved Pad Multiplexer ID >> Payload length >> Bit 32 - x >> Function Raw Bytes > > I don't know how to interpret this. Are you saying that the low- > order bit of the first byte is the command/data flag? Or is it > the high-order bit of the first byte? > > I'm saying that what I observed when building the code was that > as originally defined, the cd_bit field was the high-order bit > (bit 7) of the first byte, which I understand to be wrong. > > If you are telling me that the command/data flag resides at bit > 7 of the first byte, I will update the field masks in a later > patch in this series to reflect that. > Higher order bit is Command / Data. >> The driver was written assuming that the host was running ARM64, so >> the structs are little endian. (I should have made it compatible >> with big and little endian earlier so that is my fault). > > Little endian and big endian have no bearing on the host's > interpretation of bits within a byte. > > Please clarify. I want the patches to be correct, and what > you're explaining doesn't really straighten things out for me. > > -Alex Can't this bitfields just be used similar to how struct tcphdr & iphdr are currently defined. That way, you dont have to make these many changes. diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h index 884f1f5..302d1db 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map.h @@ -40,9 +40,17 @@ enum rmnet_map_commands { }; struct rmnet_map_header { +#if defined(__LITTLE_ENDIAN_BITFIELD) u8 pad_len:6; u8 reserved_bit:1; u8 cd_bit:1; +#elif defined (__BIG_ENDIAN_BITFIELD) + u8 cd_bit:1; + u8 reserved_bit:1; + u8 pad_len:6; +#else +#error "Please fix <asm/byteorder.h>" +#endif u8 mux_id; __be16 pkt_len; } __aligned(1); -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-05-21 1:32 UTC|newest] Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-05-20 13:53 [PATCH 0/8] net: introduce "include/linux/if_rmnet.h" Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 13:53 ` [PATCH 1/8] net: qualcomm: rmnet: fix struct rmnet_map_header Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:38 ` Bjorn Andersson 2019-05-20 15:38 ` Bjorn Andersson 2019-05-20 20:11 ` Subash Abhinov Kasiviswanathan 2019-05-20 20:11 ` Subash Abhinov Kasiviswanathan 2019-05-20 21:23 ` Alex Elder 2019-05-20 21:23 ` Alex Elder 2019-05-21 1:32 ` Subash Abhinov Kasiviswanathan [this message] 2019-05-21 1:32 ` Subash Abhinov Kasiviswanathan 2019-05-21 2:30 ` Alex Elder 2019-05-21 2:30 ` Alex Elder 2019-05-21 3:07 ` Bjorn Andersson 2019-05-21 3:07 ` Bjorn Andersson 2019-05-21 11:03 ` Alex Elder 2019-05-21 11:03 ` Alex Elder 2019-05-20 13:53 ` [PATCH 2/8] net: qualcomm: rmnet: kill RMNET_MAP_GET_*() accessor macros Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:41 ` Bjorn Andersson 2019-05-20 15:41 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 3/8] net: qualcomm: rmnet: use field masks instead of C bit-fields Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:43 ` Bjorn Andersson 2019-05-20 15:43 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 4/8] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum header Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 15:49 ` Bjorn Andersson 2019-05-20 15:49 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 5/8] net: qualcomm: rmnet: don't use C bit-fields in rmnet checksum trailer Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 6/8] net: qualcomm: rmnet: get rid of a variable in rmnet_map_ipv4_ul_csum_header() Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 7/8] net: qualcomm: rmnet: mark endianness of struct rmnet_map_dl_csum_trailer fields Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 17:17 ` Bjorn Andersson 2019-05-20 13:53 ` [PATCH 8/8] net: introduce "include/linux/if_rmnet.h" Alex Elder 2019-05-20 13:53 ` Alex Elder 2019-05-20 17:18 ` Bjorn Andersson 2019-05-20 17:18 ` Bjorn Andersson 2019-05-20 18:00 ` [PATCH 0/8] " Alex Elder 2019-05-20 18:00 ` Alex Elder
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