/* * soclib_tty.c - soclib_tty driver definition (used in the TSAR_IOB architecture). * * Author Alain Greiner (2016,2017,2018) * * Copyright (c) UPMC Sorbonne Universites * * This file is part of ALMOS-MKH. * * ALMOS-MKH is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License as published by * the Free Software Foundation; version 2.0 of the License. * * ALMOS-MKH is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with ALMOS-kernel; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include #include /**************************************************************************************** * This driver supports the vci_tty_tsar component. * * 1) This hardware component handles several hardware channels, supporting directly * several kernel TXT channels. * 2) For received characters, the hardware support one RX_IRQ, and one bit * in the STATUS register to signal that the READ register is full. * 3) For transmitted characters, the hardware supports one RX_IRQ, and one bit * in STATUS register to signal that the WRITE register is empty. * * It implements the generic TXT device API: * - transfer one single character from TTY to command "buffer" if to_mem is non-zero. * - transfer "count" characters from command "buffer" to TTY if to_mem is zero. * * It handles asynchronous control characters (^C / ^Z), that are translated to signals * transmited to the TXT owner process (foreground process). * * This driver implements one TX_FIFO for the transmited characters, writen by the "cmd" * function, and read by the "isr" function). * This driver implements one RX_FIFO for the received characters, writen by the "isr" * function, and read by the "cmd" function). ***************************************************************************************/ /**************************************************************************************** * SOCLIB_TTY registers offsets ***************************************************************************************/ #define TTY_WRITE 0 #define TTY_STATUS 1 #define TTY_READ 2 #define TTY_RX_IRQ_ENABLE 3 #define TTY_TX_IRQ_ENABLE 4 #define TTY_SPAN 8 // number of registers per channel /**************************************************************************************** * masks for TTY_STATUS_REG ***************************************************************************************/ #define TTY_STATUS_RX_FULL 1 // TTY_READ_REG full if 1 #define TTY_STATUS_TX_FULL 2 // TTY_WRITE_REG full if 1 /**************************************************************************************** * This structure is used for both the RX_FIFO and the TX_FIFO. ***************************************************************************************/ #define TTY_FIFO_DEPTH 128 typedef struct tty_fifo_s { char data[TTY_FIFO_DEPTH]; // one char per slot unsigned int ptr; // next free slot index unsigned int ptw; // next full slot index unsigned int sts; // number of full slots } tty_fifo_t; /**************************************************************************************** * This function masks both the TTY_RX and TTY_TX IRQs. * These IRQs are unmasked by the soclib_tty_cmd() function. **************************************************************************************** * @ chdev : pointer on the TXT chdev descriptor. ***************************************************************************************/ void soclib_tty_init( chdev_t * chdev ); /**************************************************************************************** * This function implements both the TXT_READ & TXT_WRITE commands registered in the * client thread descriptor (in the txt_cmd field), even if ALMOS-MKH defines two * different chdevs (and consequently two diffeerent server threads) for the RX and TX * directions. The client thread is identified by the argument. * These functions are supposed to be called by the server thread associated at a * given TXT channel for a given direction (TX or RX). * Depending on the command type, it access the TX_FIFO or RX_FIFO, and blocks the TXT * device server thread on the THREAD_BLOCKED_DEV_ISR, if the RX_FIFO is empty (for a * READ), or if the TX_FIFO is full for a WRITE). * The actual transfer between the FIFOs and the TTY device registers is done by the ISR. * **************************************************************************************** * @ thread_xp : extended pointer on client thread descriptor. ***************************************************************************************/ void soclib_tty_cmd( xptr_t thread_xp ); /**************************************************************************************** * This function implements the TXT_SYNC_WRITE command registered in the txt_aux_t * structure, using a busy waiting policy, without using the TTY IRQ. * It is used by the kernel do display debug messages on TXT0 terminal, without * interference with another TXT access to another terminal done by the same thread. **************************************************************************************** * @ thread_xp : pointer on the txt_aux_t structure containing the arguments. ***************************************************************************************/ void soclib_tty_aux( void * args ); /**************************************************************************************** * This ISR is executed to handle both the TTY_TX_IRQ and the TTY_RX_IRQ, even if * there is two different channel devices for TX and RX transfers. * * As the argument is a local pointer, this ISR is always executed by a core * that is in the same cluster as the core running the DEV server thread. * * - The RX_IRQ is activated as soon as the TTY_STATUS_RX_FULL bit is 1 in the * TTY_STATUS register, when the TTY_RX_IRQ_ENABLE is non zero, indicating that * the TTY_READ buffer is full and can be read. * - The TX_IRQ is activated as soon as the TTY_STATUS_TX_FULL bit is 0 in the * TTY_STATUS register, when the TTY_TX_IRQ_ENABLE is non zero, indicating that * the TTY_WRITE buffer is empty, and can be written. * * The RX_IRQ is always enabled to catch the control characters (^Z / ^C), * but the TX_IRQ is dynamically enabled by the TXT_WRITE command, and disabled when * the command is completed. * * For normal characters The ISR uses two private TTY_RX and TTY_TX software FIFOs * (two FIFOs per channel) to communicates with the DEV server thread executing the * soclib_tty_cmd() function. * For an RX transfer, this ISR executes a while loop moving bytes until the source * TTY_READ buffer is empty: * 1) The ISR read one byte from the TTY_READ register and acknowledge the RX_IRQ. * 2) if the byte is a ^Z character, it uses a multicast RPC to block all treads of * the TXT owner process, and transfer TXT ownership to another process of the group. * 3) if the byte is a ^C character, it removes the process from the TXT group, and send * a multicast RPC to delete all threads of the TXT owner process. * 4) if the byte is a normal character and the destination TTY_RX_FIFO is not full, * it writes the byte to this FIFO, unblock the TXT_RX server thread, and send an IPI * to this server thread (only if it is running on another core than the ISR). * 5) It discards the byte if the TTY_RX_FIFO is full, with a warning message on TXT0. * * For a TX transfer, this ISR executes a while loop moving bytes until the source * TTY_TX_FIFO is empty: * 1) if the destination TTY_WRITE register is not full, it moves the byte from the * TTY_TX_FIFO to the TTY_WRITE register. * 2) if the TTY_WRITE register is full, it polls (busy waiting) the TTY_STATUS register, * until the TTY_WRITE register is empty. * 3) when the source TTY_TX_FIFO is empty, this ISR disable the TTY_TX_IRQ, unblock * the TXT_TX server thread, and send an IPI to this server thread (only if it is * running on another core than the ISR). **************************************************************************************** * @ chdev : local pointer on TXT chdev descriptor. ***************************************************************************************/ void soclib_tty_isr( chdev_t * chdev );