135 lines
3.6 KiB
Lua
Executable File
135 lines
3.6 KiB
Lua
Executable File
#! /usr/bin/env lua
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--[[
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spid.lua - Lua part of the Flukso daemon
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Copyright (C) 2011 Bart Van Der Meerssche <bart.vandermeerssche@flukso.net>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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]]--
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local dbg = require 'dbg'
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local spi = require 'flukso.spi'
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local nixio = require 'nixio'
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nixio.fs = require 'nixio.fs'
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local arg = arg or {} -- needed when this code is not loaded via the interpreter
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local DEBUG = (arg[1] == '-d')
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local SPI_DEV = '/dev/spidev0.0'
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local SPI_MAX_CLK_SPEED_HZ = 1e6
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local SPI_MIN_BYTE_DELAY_US = 250
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local SPI_TX_RX_DELAY_NS = 1e7
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local SPI_CT_DELAY_NS = 5e8
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local POLL_TIMEOUT_MS = 100
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local TIMERFD_ENABLE = 1
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local TIMERFD_SEC = 1
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local TIMERFD_NS = 0
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local GET_DELTA = 'gd'
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local DAEMON = os.getenv('DAEMON') or 'spid'
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local DAEMON_PATH = os.getenv('DAEMON_PATH') or '/var/run/' .. DAEMON
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local O_RDWR_NONBLOCK = nixio.open_flags('rdwr', 'nonblock')
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local POLLIN = nixio.poll_flags('in')
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function mkfifos(input)
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local path = string.format('%s/%s/', DAEMON_PATH, input)
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nixio.fs.mkdirr(path)
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-- nixio.fs.unlink(path .. 'in') -- clean up mess from previous run
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-- nixio.fs.unlink(path .. 'out') -- idem
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nixio.fs.mkfifo(path .. 'in', '644')
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nixio.fs.mkfifo(path .. 'out', '644')
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local fdin = nixio.open(path .. 'in', O_RDWR_NONBLOCK)
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local fdout = nixio.open(path .. 'out', O_RDWR_NONBLOCK)
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return { fd = fdin, -- need this entry for nixio.poll
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fdin = fdin,
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fdout = fdout,
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events = POLLIN,
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revents = 0,
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line = fdin:linesource() }
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end
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local uart = mkfifos('uart')
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local ctrl = mkfifos('ctrl')
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local delta = mkfifos('delta')
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if TIMERFD_ENABLE == 1 then
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delta.fd = nixio.timerfd(TIMERFD_SEC, TIMERFD_NS, TIMERFD_SEC, TIMERFD_NS)
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end
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local fds = { uart, ctrl, delta }
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local spidev = nixio.open(SPI_DEV, O_RDWR_NONBLOCK)
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nixio.spi.setspeed(spidev, SPI_MAX_CLK_SPEED_HZ, SPI_MIN_BYTE_DELAY_US)
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spidev:lock('lock') -- blocks until it can place a write lock on the spidev device
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while true do
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local msg
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local poll = nixio.poll(fds, POLL_TIMEOUT_MS)
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if poll == 0 then -- poll timed out, so time to 'poll' the spi bus
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msg = spi.new_msg('', '')
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elseif poll > 0 then
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if ctrl.revents == POLLIN then
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msg = spi.new_msg('ctrl', ctrl.line())
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msg:parse()
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elseif delta.revents == POLLIN then
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if TIMERFD_ENABLE == 1 then
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delta.fd:numexp() -- reset the numexp counter
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else
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delta.line()
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end
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msg = spi.new_msg('delta', GET_DELTA)
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msg:parse()
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elseif uart.revents == POLLIN then
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msg = spi.new_msg('uart', uart.line())
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end
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msg:encode()
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msg:tx(spidev)
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msg:wait(SPI_TX_RX_DELAY_NS, SPI_CT_DELAY_NS)
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end
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if poll >= 0 then
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msg:rx(spidev)
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local dispatch = msg:decode()
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if DEBUG then dbg.vardump(msg) end
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if dispatch.ctrl then
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ctrl.fdout:write(dispatch.ctrl .. '\n')
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end
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if dispatch.delta then
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delta.fdout:write(dispatch.delta .. '\n')
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end
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if dispatch.uart then
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uart.fdout:write(dispatch.uart .. '\n')
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end
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end
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end
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