Hello, LoRa is a long-range, low-power wireless technology by Semtech. Unlike other LPWAN technologies, users don't need to rely on infrastructure providers and SIM cards and expensive subscription plans, they can set up their own gateways. Modules, adapters and evaluation boards are available from a large number of vendors. Many vendors also make available Open Source software examples on GitHub. But when taking a closer look, many of them combine licenses in ways that are not redistributable. My reports have remained without response or solution. https://github.com/ernstdevreede/lmic_pi/issues/2 https://github.com/Snootlab/lmic_chisterapi/issues/2 https://github.com/Snootlab/lora_chisterapi/issues/2 Another issue was that most such projects around the Raspberry Pi make use of spidev to communicate with the Semtech chipsets from userspace. The Linux spi maintainers have chosen to greet any such users of spidev with a friendly WARN_ON(), preferring in-kernel spi drivers and white-listing individual devices only. https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/spi/spidev.c?h=v4.17#n722 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/spi/spidev.c?h=v4.17#n667 Also I don't quite see the point in having userspace probe what SPI devices are connected to a generic spidev driver when we have an easy Device Tree hardware description on arm/arm64 that could give us that info. I raised the topic during Q&A of a FOSDEM 2017 talk (cut off at the end of the video) but unfortunately found no one to collaborate on this. https://archive.fosdem.org/2017/schedule/event/lorawan/ Instead of porting from wiringPi to a differently licensed GPIO library and dealing with seemingly unmaintained LoRaWAN code dumps, I started a spi kernel driver for SX1276 back in 2016. But obviously a kernel driver isn't too helpful without a userspace API to send and receive packets. This patchset, updated from 2017 and extended, is implementing kernel drivers for various LoRa chipsets and modules. As API I'm proposing a PF_LORA socket implementation. Why? LoRa uses data packets with headers and checksums and differing MTUs and multiple protocols layered on top of it. Apart from simple headers for addressing used by RadioHead library and IMST's LoRa P2P protocol, the main use case (not implemented in this patchset) is expected to be LoRaWAN. And LoRaWAN has competing proprietary protocols, such as Link Labs' Symphony Link or GlobalSat M.O.S.T. or RadioShuttle, that might at some point want to adopt a standard API for their implementations, too. Ready-made LoRa hardware modules come in three flavors, a) with SPI access to the underlying Semtech chipsets, needing a software implementation of e.g. LoRaWAN protocol stack (i.e., a soft MAC), b) with a custom, often UART based interface and a pre-certified LoRaWAN protocol stack already integrated (i.e., hard/full MAC), and c) with a microcontroller that serves not only for the protocol stack but also as application processor, not offering a ready-made interface. This patchset focuses on option a). An SX1276 based LoRaWAN stack appeared to be the project of Jian-Hong Pan and is not included here. This patchset also includes drivers for b), from text based AT commands to a binary SLIP based HCI protocol. Hardware examples for c) are Murata CMWX1ZZABZ-078 and RAK813. This patchset is clearly not ready for merging, but is being submitted for discussion, as requested by Jiri, in particular of the design choices: 1) PF_LORA/AF_LORA and associated identifiers are proposed to represent this technology. While for an SX1276 - case a) above - it might work to layer LoRaWAN as a protocol option for PF_LORA and add LoRaWAN address fields to the union in my sockaddr_lora, how would that work for devices that only support LoRaWAN but not pure LoRa? Do we need both AF_LORA and AF_LORAWAN, or just a separate ETH_P_LORAWAN or ARPHRD_LORAWAN? 2) PF_LORA is used with SOCK_DGRAM here. The assumption is that RAW mode would be DGRAM plus preamble plus optional checksum. 3) Only the transmit path is partially implemented already. The assumption is that the devices should go into receive mode by default and only interrupt that when asked to transmit. 4) Some hardware settings need to be supplied externally, such as the radio frequency for some modules, but many others can be runtime-configured, such as Spreading Factor, Bandwidth, Sync Word, or which antenna to use. What settings should be implemented as socket option vs. netlink layer vs. ioctl vs. sysfs? What are the criteria to apply? 5) Many of the modules support multiple modes, such as LoRa, LoRaWAN and FSK. Lacking a LoRaWAN implementation, I am currently switching them into LoRa mode at probe time wherever possible. How do we deal with that properly? a) Is there any precedence from the Wifi world for dynamically selecting between our own trusted Open Source implementation vs. hardware/firmware accelerated and/or certified implementations? b) Would a proof of concept for FSK (non-LoRa) modes be required for merging any LoRa driver for chipsets that support both? Or is there any facility or design guidelines that would allow us to focus on LoRa and LoRaWAN and leave non-LoRa radio modes to later contributors? As evident by the many questions, this is my first deep dive into the Linux net subsystem. It's also my first experiments with the new serdev subsystem, so in particular the receive paths will need some review and optimizations. This patchset was developed and tested mainly as KMP, originally at https://github.com/afaerber/lora-modules. It was recently transformed into a linux-next based tree, still mostly tested on our openSUSE Tumbleweed kernel with a differing AF_LORA value below current AF_MAX limit. Some corresponding Device Tree Overlays have been collected here: https://github.com/afaerber/dt-overlays Only European models for 868 MHz and 433 MHz could be tested when available. Thanks to all companies and people that have supported this project so far. Have a lot of fun! Cheers, Andreas Cc: Jian-Hong Pan <starnight@xxxxxxxxxxxx> Cc: Jiri Pirko <jiri@xxxxxxxxxxx> Cc: Marcel Holtmann <marcel@xxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Matthias Brugger <mbrugger@xxxxxxxx> Cc: Konstantin Böhm <konstantin.boehm@xxxxxxxx> Cc: Jan Jongboom <jan.jongboom@xxxxxxx> Cc: Janus Piwek <jpiwek@xxxxxxxxxxxxxxx> Cc: Michael Röder <michael.roeder@xxxxxxxx> Cc: Dollar Chen (陳義元) <dollar.chen@xxxxxxxxx> Cc: Ken Yu (禹凯) <ken.yu@xxxxxxxxxxxxxxx> Cc: Jon Ortego <Jon.Ortego@xxxxxxx> Cc: contact@xxxxxxxxxxxx Cc: Ben Whitten <ben.whitten@xxxxxxxxxxxxx> Cc: Brian Ray <brian.ray@xxxxxxxxxxxxx> Cc: lora@xxxxxxxxxxxxxxxx Cc: lora@xxxxxxxxxxxxxxx Cc: Alexander Graf <agraf@xxxxxxx> Cc: Michal Kubeček <mkubecek@xxxxxxx> Cc: Rob Herring <robh@xxxxxxxxxx> Cc: devicetree@xxxxxxxxxxxxxxx Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Cc: Steve deRosier <derosier@xxxxxxxxx> Cc: Mark Brown <broonie@xxxxxxxxxx> Cc: linux-spi@xxxxxxxxxxxxxxx Andreas Färber (15): net: Reserve protocol numbers for LoRa net: lora: Define sockaddr_lora net: lora: Add protocol numbers net: Add lora subsystem HACK: net: lora: Deal with .poll_mask in 4.18-rc2 net: lora: Prepare for device drivers net: lora: Add Semtech SX1276 net: lora: sx1276: Add debugfs net: lora: Prepare EUI helpers net: lora: Add Microchip RN2483 net: lora: Add IMST WiMOD net: lora: Add USI WM-SG-SM-42 net: lora: Prepare RAK RAK811 net: lora: Prepare Semtech SX1257 net: lora: Add Semtech SX1301 drivers/net/Makefile | 1 + drivers/net/lora/Kconfig | 72 ++++ drivers/net/lora/Makefile | 32 ++ drivers/net/lora/dev.c | 125 ++++++ drivers/net/lora/rak811.c | 219 +++++++++++ drivers/net/lora/rn2483.c | 344 +++++++++++++++++ drivers/net/lora/rn2483.h | 40 ++ drivers/net/lora/rn2483_cmd.c | 130 +++++++ drivers/net/lora/sx1257.c | 96 +++++ drivers/net/lora/sx1276.c | 740 ++++++++++++++++++++++++++++++++++++ drivers/net/lora/sx1301.c | 446 ++++++++++++++++++++++ drivers/net/lora/usi.c | 411 ++++++++++++++++++++ drivers/net/lora/wimod.c | 597 +++++++++++++++++++++++++++++ include/linux/lora/dev.h | 44 +++ include/linux/lora/skb.h | 29 ++ include/linux/socket.h | 4 +- include/uapi/linux/if_arp.h | 1 + include/uapi/linux/if_ether.h | 1 + include/uapi/linux/lora.h | 24 ++ net/Kconfig | 1 + net/Makefile | 1 + net/lora/Kconfig | 15 + net/lora/Makefile | 8 + net/lora/af_lora.c | 152 ++++++++ net/lora/af_lora.h | 13 + net/lora/dgram.c | 297 +++++++++++++++ security/selinux/hooks.c | 4 +- security/selinux/include/classmap.h | 4 +- 28 files changed, 3848 insertions(+), 3 deletions(-) create mode 100644 drivers/net/lora/Kconfig create mode 100644 drivers/net/lora/Makefile create mode 100644 drivers/net/lora/dev.c create mode 100644 drivers/net/lora/rak811.c create mode 100644 drivers/net/lora/rn2483.c create mode 100644 drivers/net/lora/rn2483.h create mode 100644 drivers/net/lora/rn2483_cmd.c create mode 100644 drivers/net/lora/sx1257.c create mode 100644 drivers/net/lora/sx1276.c create mode 100644 drivers/net/lora/sx1301.c create mode 100644 drivers/net/lora/usi.c create mode 100644 drivers/net/lora/wimod.c create mode 100644 include/linux/lora/dev.h create mode 100644 include/linux/lora/skb.h create mode 100644 include/uapi/linux/lora.h create mode 100644 net/lora/Kconfig create mode 100644 net/lora/Makefile create mode 100644 net/lora/af_lora.c create mode 100644 net/lora/af_lora.h create mode 100644 net/lora/dgram.c -- 2.16.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
