src/target/firmware/comm/sercomm_cons.c

   1 /* Serial console layer, layered on top of sercomm HDLC */
   2
   3 /* (C) 2010 by Harald Welte <laforge@gnumonks.org>
   4  *
   5  * All Rights Reserved
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  */
  18
  19 #include <stdint.h>
  20 #include <errno.h>
  21 #include <string.h>
  22
  23 #include <asm/system.h>
  24
  25 #include <uart.h>
  26
  27 #include <console.h>
  28 #include <osmocom/core/msgb.h>
  29 #include <comm/sercomm.h>
  30 #include <comm/sercomm_cons.h>
  31
  32 static struct {
  33         struct msgb *cur_msg;
  34 } scons;
  35
  36 static void raw_puts(const char *s)
  37 {
  38         int i = strlen(s);
  39         int uart_id = sercomm_get_uart();
  40         while (i--)
  41                 uart_putchar_wait(uart_id, *s++);
  42 }
  43
  44 #ifdef DEBUG
  45 #define raw_putd(x)     raw_puts(x)
  46 #else
  47 #define raw_putd(x)
  48 #endif
  49
  50 int sercomm_puts(const char *s)
  51 {
  52         unsigned long flags;
  53         const int len = strlen(s);
  54         unsigned int bytes_left = len;
  55
  56         if (!sercomm_initialized()) {
  57                 raw_putd("sercomm not initialized: ");
  58                 raw_puts(s);
  59                 return len - 1;
  60         }
  61
  62         /* This function is called from any context: Supervisor, IRQ, FIQ, ...
  63          * as such, we need to ensure re-entrant calls are either supported or
  64          * avoided. */
  65         local_irq_save(flags);
  66         local_fiq_disable();
  67
  68         while (bytes_left > 0) {
  69                 unsigned int write_num, space_left, flush;
  70                 uint8_t *data;
  71
  72                 if (!scons.cur_msg)
  73                         scons.cur_msg = sercomm_alloc_msgb(SERCOMM_CONS_ALLOC);
  74
  75                 if (!scons.cur_msg) {
  76                         raw_putd("cannot allocate sercomm msgb: ");
  77                         raw_puts(s);
  78                         return -ENOMEM;
  79                 }
  80
  81                 /* space left in the current msgb */
  82                 space_left = msgb_tailroom(scons.cur_msg);
  83
  84                 if (space_left <= bytes_left) {
  85                         write_num = space_left;
  86                         /* flush buffer when it is full */
  87                         flush = 1;
  88                 } else {
  89                         write_num = bytes_left;
  90                         flush = 0;
  91                 }
  92
  93                 /* obtain pointer where to copy the data */
  94                 data = msgb_put(scons.cur_msg, write_num);
  95
  96                 /* copy data while looking for \n line termination */
  97                 {
  98                         unsigned int i;
  99                         for (i = 0; i < write_num; i++) {
 100                                 /* flush buffer at end of line, but skip
 101                                  * flushing if we have a backlog in order to
 102                                  * increase efficiency of msgb filling */
 103                                 if (*s == '\n' &&
 104                                     sercomm_tx_queue_depth(SC_DLCI_CONSOLE) < 4)
 105                                         flush = 1;
 106                                 *data++ = *s++;
 107                         }
 108                 }
 109                 bytes_left -= write_num;
 110
 111                 if (flush) {
 112                         sercomm_sendmsg(SC_DLCI_CONSOLE, scons.cur_msg);
 113                         /* reset scons.cur_msg pointer to ensure we allocate
 114                          * a new one next round */
 115                         scons.cur_msg = NULL;
 116                 }
 117         }
 118
 119         local_irq_restore(flags);
 120
 121         return len - 1;
 122 }
 123
 124 int sercomm_putchar(int c)
 125 {
 126         char s[2];
 127         int rc;
 128
 129         s[0] = c & 0xff;
 130         s[1] = '\0';
 131
 132         rc = sercomm_puts(s);
 133         if (rc < 0)
 134                 return rc;
 135
 136         return c;
 137 }