[75] | 1 | /* |
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| 2 | * soclib_tty.c - soclib tty driver definition. |
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| 3 | * |
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| 4 | * Author Alain Greiner (2016) |
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| 5 | * |
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| 6 | * Copyright (c) UPMC Sorbonne Universites |
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| 7 | * |
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| 8 | * This file is part of ALMOS-MKH. |
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| 9 | * |
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| 10 | * ALMOS-MKH is free software; you can redistribute it and/or modify it |
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| 11 | * under the terms of the GNU General Public License as published by |
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| 12 | * the Free Software Foundation; version 2.0 of the License. |
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| 13 | * |
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| 14 | * ALMOS-MKH is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 17 | * General Public License for more details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License |
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| 20 | * along with ALMOS-kernel; if not, write to the Free Software Foundation, |
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| 21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
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| 22 | */ |
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| 23 | |
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| 24 | #include <dev_txt.h> |
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| 25 | #include <chdev.h> |
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| 26 | #include <spinlock.h> |
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| 27 | |
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| 28 | |
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| 29 | /**************************************************************************************** |
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[435] | 30 | * This driver supports the vci_tty_tsar component. |
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[75] | 31 | * It implements the generic TXT device API: |
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| 32 | * - transfer one single character from TTY to command "buffer" if to_mem is non-zero. |
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| 33 | * - transfer "count" characters from command "buffer" to TTY if "to_mem is zero. |
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| 34 | ***************************************************************************************/ |
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| 35 | |
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| 36 | /**************************************************************************************** |
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| 37 | * SOCLIB_TTY registers offsets |
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| 38 | ***************************************************************************************/ |
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| 39 | |
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[407] | 40 | #define TTY_WRITE 0 |
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| 41 | #define TTY_STATUS 1 |
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| 42 | #define TTY_READ 2 |
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| 43 | #define TTY_RX_IRQ_ENABLE 3 |
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| 44 | #define TTY_TX_IRQ_ENABLE 4 |
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[75] | 45 | |
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[407] | 46 | #define TTY_SPAN 8 // number of registers per channel |
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[75] | 47 | |
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| 48 | /**************************************************************************************** |
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| 49 | * masks for TTY_STATUS_REG |
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| 50 | ***************************************************************************************/ |
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| 51 | |
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| 52 | #define TTY_STATUS_RX_FULL 1 // TTY_READ_REG full if 1 |
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| 53 | #define TTY_STATUS_TX_FULL 2 // TTY_WRITE_REG full if 1 |
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| 54 | |
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| 55 | /**************************************************************************************** |
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| 56 | * This function masks both the TTY_RX and TTY_TX IRQs. |
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| 57 | * These IRQs are unmasked by the soclib_tty_cmd() function. |
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| 58 | **************************************************************************************** |
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| 59 | * @ chdev : pointer on the TXT chdev descriptor. |
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| 60 | ***************************************************************************************/ |
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| 61 | void soclib_tty_init( chdev_t * chdev ); |
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| 62 | |
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| 63 | /**************************************************************************************** |
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[435] | 64 | * This function implements both the TXT_READ & TXT_WRITE commands registered in the |
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| 65 | * client thread descriptor (in the txt_cmd field), even if ALMOS-MKH defines two |
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| 66 | * different chdevs (and consequently two diffeerent server threads) for the RX and TX |
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| 67 | * directions. The client thread is identified by the <thread_xp> argument. |
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| 68 | * Depending on the command type, it unmasks the relevant TTY_RX / TTY_TX IRQ, |
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[407] | 69 | * and blocks the TXT device server thread on the THREAD_BLOCKED_DEV_ISR, as the data |
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| 70 | * transfer is done by the ISR. |
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| 71 | * **************************************************************************************** |
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[75] | 72 | * @ thread_xp : extended pointer on client thread descriptor. |
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| 73 | ***************************************************************************************/ |
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| 74 | void soclib_tty_cmd( xptr_t thread_xp ); |
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| 75 | |
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| 76 | /**************************************************************************************** |
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[407] | 77 | * This function implements the TXT_SYNC_WRITE command registered in the txt_aux_t |
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| 78 | * structure, using a busy waiting policy, without using the TTY IRQ. |
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| 79 | * It is used by the kernel do display debug messages on TXT0 terminal, without |
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| 80 | * interference with another TXT access to another terminal done by the same thread. |
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| 81 | **************************************************************************************** |
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| 82 | * @ thread_xp : pointer on the txt_aux_t structure containing the arguments. |
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| 83 | ***************************************************************************************/ |
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| 84 | void soclib_tty_aux( void * args ); |
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| 85 | |
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| 86 | /**************************************************************************************** |
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[435] | 87 | * This ISR is executed to handle both the TTY_TX_IRQ and the TTY_RX_IRQ, even if |
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| 88 | * The RX_IRQ is activated as soon as the TTY_STATUS_RX_FULL bit is 1 in the |
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| 89 | * TTY_STATUS register, when the TTY_RX_IRQ_ENABLE is non zero, indicating that |
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| 90 | * the TTY_READ buffer is full and can be read. |
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| 91 | * The TX_IRQ is activated as soon as the TTY_STATUS_TX_FULL bit is 0 in the |
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| 92 | * TTY_STATUS register, when the TTY_TX_IRQ_ENABLE is non zero, indicating that |
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| 93 | * the TTY_WRITE buffer is empty, and can be written. |
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| 94 | * WARNING : In ALMOS-MKH, the RX_IRQ is always enabled to catch the control signals, |
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| 95 | * but the TX_IRQ is dynamically enabled by the TXT_WRITE command, and disabled when |
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| 96 | * the command is completed. |
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[424] | 97 | * |
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[435] | 98 | * 1) The ISR first read the TTY_STATUS to get the current state of the TTY_READ and |
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| 99 | * the TTY_WRITE buffers. |
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| 100 | * |
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| 101 | * 2) It try to read the first command registered in the server thread queue associated |
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| 102 | * to the TTY channel |
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| 103 | * |
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| 104 | * 2) The ISR handles the RX when the TTY_READ buffer is full : |
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| 105 | * . it read the available character from the TTY_READ buffer, and this |
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| 106 | * acknowledges the RX_IRQ. |
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| 107 | * . if it is a control character ( ^C / ^D / ^Z ) it translate it to the proper |
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| 108 | * signal and execute the relevant sigaction for the foreground process. |
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| 109 | * . if it is a normal character, it try to get the first command registered in the |
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| 110 | * server thread queue. If it is a TXT_READ, it returns this character to the |
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| 111 | * command buffer in the client thread. |
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| 112 | * |
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| 113 | * 3) The ISR handles the TX when the TTY_WRITE buffer is empty and a TXT_WRITE |
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| 114 | * . it try to get it copies the |
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[424] | 115 | * character to the command buffer, acknowledges the TTY_RX_IRQ, and unblock the |
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| 116 | * associated server thread. |
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| 117 | |
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[435] | 118 | * . the control characters ^C / ^D / ^Z are directly handled by the ISR and |
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| 119 | * translated to the foreground process. |
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| 120 | |
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| 121 | * - the |
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[424] | 122 | the TXT_READ and TXT_WRITE commands. |
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[75] | 123 | * It gets the command arguments from the first client thread in the TXT chdev queue: |
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| 124 | * - if TXT_READ, it transfers one byte from the TTY_READ_REG to the command buffer. |
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| 125 | * It simply returns for retry if TTY_READ_REG is empty. |
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| 126 | * - if TXT_WRITE, it tries to transfer several bytes from the command buffer to the |
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| 127 | * TTY_WRITE_REG. If the TTY_WRITE_REG is full, it updates the "count" and "buffer" |
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| 128 | * command arguments and returns for retry. |
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| 129 | * When the I/O operation is completed, it sets the status field in the command, unblocks |
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| 130 | * the server thread, and unblocks the client thread. |
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| 131 | **************************************************************************************** |
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| 132 | * @ chdev : local pointer on TXT chdev descriptor. |
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| 133 | ***************************************************************************************/ |
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| 134 | void soclib_tty_isr( chdev_t * chdev ); |
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| 135 | |
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