source: trunk/hal/tsar_mips32/drivers/soclib_tty.h @ 425

Last change on this file since 425 was 424, checked in by alain, 5 years ago

cosmetic.

File size: 5.5 KB
Line 
1/*
2 * soclib_tty.c - soclib tty driver definition.
3 *
4 * Author  Alain Greiner (2016)
5 *
6 * Copyright (c)  UPMC Sorbonne Universites
7 *
8 * This file is part of ALMOS-MKH.
9 *
10 * ALMOS-MKH is free software; you can redistribute it and/or modify it
11 * under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; version 2.0 of the License.
13 *
14 * ALMOS-MKH is distributed in the hope that it will be useful, but
15 * WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
17 * General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with ALMOS-kernel; if not, write to the Free Software Foundation,
21 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22 */
23
24#include <dev_txt.h>
25#include <chdev.h>
26#include <spinlock.h>
27
28
29/****************************************************************************************
30 * This driver supports the soclib_multi_tty component.
31 * It implements the generic TXT device API:
32 * - transfer one single character from TTY to command "buffer" if to_mem is non-zero.
33 * - transfer "count" characters from command "buffer" to TTY if "to_mem is zero.
34 ***************************************************************************************/
35
36/****************************************************************************************
37 *     SOCLIB_TTY registers offsets
38 ***************************************************************************************/
39
40#define TTY_WRITE              0
41#define TTY_STATUS             1
42#define TTY_READ               2
43#define TTY_RX_IRQ_ENABLE      3
44#define TTY_TX_IRQ_ENABLE      4
45
46#define TTY_SPAN               8       // number of registers per channel
47
48/****************************************************************************************
49 * masks for TTY_STATUS_REG
50 ***************************************************************************************/
51
52#define TTY_STATUS_RX_FULL     1       // TTY_READ_REG full if 1
53#define TTY_STATUS_TX_FULL     2       // TTY_WRITE_REG full if 1
54
55/****************************************************************************************
56 * This function masks both the TTY_RX and TTY_TX IRQs.
57 * These IRQs are unmasked by the soclib_tty_cmd() function.
58 ****************************************************************************************
59 * @ chdev     : pointer on the TXT chdev descriptor.
60 ***************************************************************************************/
61void soclib_tty_init( chdev_t * chdev );
62
63/****************************************************************************************
64 * This function implements the TXT_READ & TXT_WRITE commands registered in the client
65 * thread descriptor (in the txt_cmd field), identified by the <xp_thread> argument.
66 * Depending on the command type, it only unmasks the relevant TTY_RX / TTY_TX IRQ,
67 * and blocks the TXT device server thread on the THREAD_BLOCKED_DEV_ISR, as the data
68 * transfer is done by the ISR.
69 * ****************************************************************************************
70 * @ thread_xp : extended pointer on client thread descriptor.
71 ***************************************************************************************/
72void soclib_tty_cmd( xptr_t thread_xp );
73
74/****************************************************************************************
75 * This function implements the TXT_SYNC_WRITE command registered in the txt_aux_t
76 * structure, using a busy waiting policy, without using the TTY IRQ.
77 * It is used by the kernel do display debug messages on TXT0 terminal, without
78 * interference with another TXT access to another terminal done by the same thread.
79 ****************************************************************************************
80 * @ thread_xp : pointer on the txt_aux_t structure containing the arguments.
81 ***************************************************************************************/
82void soclib_tty_aux( void * args );
83
84/****************************************************************************************
85 * This ISR is executed to handle both the TTY_TX_IRQ and the TTY_RX_IRQ.
86 * - the TTY_RX_IRQ is activated as soon as the TTY_STATUS_RX_FULL bit is set in the
87 *   TTY status register, indicating a character registered in the TTY_READ register.
88 *
89 *   . if it exist a TXT_READ command registered in the command queue, and thit copies the
90 *     character to the command buffer, acknowledges the TTY_RX_IRQ, and unblock the
91 *     associated server thread.
92     
93 *   . the control characters are directly handled by the txt ^C / ^D /  and the this IRQ ca
94 *
95 the TXT_READ and TXT_WRITE commands.
96 * It gets the command arguments from the first client thread in the TXT chdev queue:
97 * - if TXT_READ, it transfers one byte from the TTY_READ_REG to the command buffer.
98 *   It simply returns for retry if TTY_READ_REG is empty.
99 * - if TXT_WRITE, it tries to transfer several bytes from the command buffer to the
100 *   TTY_WRITE_REG. If the TTY_WRITE_REG is full, it updates the "count" and "buffer"
101 *   command arguments and returns for retry.
102 * When the I/O operation is completed, it sets the status field in the command, unblocks
103 * the server thread, and unblocks the client thread.
104 ****************************************************************************************
105 * @ chdev     : local pointer on TXT chdev descriptor.
106 ***************************************************************************************/
107void soclib_tty_isr( chdev_t * chdev );
108
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