drivers/serial/serial_semihosting.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
   4  */
   5
   6 #include <common.h>
   7 #include <dm.h>
   8 #include <serial.h>
   9 #include <semihosting.h>
  10
  11 /**
  12  * struct smh_serial_priv - Semihosting serial private data
  13  * @infd: stdin file descriptor (or error)
  14  */
  15 struct smh_serial_priv {
  16         int infd;
  17         int outfd;
  18 };
  19
  20 #if CONFIG_IS_ENABLED(DM_SERIAL)
  21 static int smh_serial_getc(struct udevice *dev)
  22 {
  23         char ch = 0;
  24         struct smh_serial_priv *priv = dev_get_priv(dev);
  25
  26         if (priv->infd < 0)
  27                 return smh_getc();
  28
  29         smh_read(priv->infd, &ch, sizeof(ch));
  30         return ch;
  31 }
  32
  33 static int smh_serial_putc(struct udevice *dev, const char ch)
  34 {
  35         smh_putc(ch);
  36         return 0;
  37 }
  38
  39 static const struct dm_serial_ops smh_serial_ops = {
  40         .putc = smh_serial_putc,
  41         .getc = smh_serial_getc,
  42 };
  43
  44 static int smh_serial_probe(struct udevice *dev)
  45 {
  46         struct smh_serial_priv *priv = dev_get_priv(dev);
  47
  48         priv->infd = smh_open(":tt", MODE_READ);
  49         return 0;
  50 }
  51
  52 U_BOOT_DRIVER(smh_serial) = {
  53         .name   = "serial_semihosting",
  54         .id     = UCLASS_SERIAL,
  55         .probe  = smh_serial_probe,
  56         .priv_auto = sizeof(struct smh_serial_priv),
  57         .ops    = &smh_serial_ops,
  58         .flags  = DM_FLAG_PRE_RELOC,
  59 };
  60
  61 U_BOOT_DRVINFO(smh_serial) = {
  62         .name = "serial_semihosting",
  63 };
  64 #else /* DM_SERIAL */
  65 static int infd = -ENODEV;
  66 static int outfd = -ENODEV;
  67
  68 static int smh_serial_start(void)
  69 {
  70         infd = smh_open(":tt", MODE_READ);
  71         outfd = smh_open(":tt", MODE_WRITE);
  72         return 0;
  73 }
  74
  75 static int smh_serial_stop(void)
  76 {
  77         if (outfd >= 0)
  78                 smh_close(outfd);
  79         return 0;
  80 }
  81
  82 static void smh_serial_setbrg(void)
  83 {
  84 }
  85
  86 static int smh_serial_getc(void)
  87 {
  88         char ch = 0;
  89
  90         if (infd < 0)
  91                 return smh_getc();
  92
  93         smh_read(infd, &ch, sizeof(ch));
  94         return ch;
  95 }
  96
  97 static int smh_serial_tstc(void)
  98 {
  99         return 1;
 100 }
 101
 102 static void smh_serial_puts(const char *s)
 103 {
 104         ulong unused;
 105
 106         if (outfd < 0)
 107                 smh_puts(s);
 108         else
 109                 smh_write(outfd, s, strlen(s), &unused);
 110 }
 111
 112 struct serial_device serial_smh_device = {
 113         .name   = "serial_smh",
 114         .start  = smh_serial_start,
 115         .stop   = smh_serial_stop,
 116         .setbrg = smh_serial_setbrg,
 117         .getc   = smh_serial_getc,
 118         .tstc   = smh_serial_tstc,
 119         .putc   = smh_putc,
 120         .puts   = smh_serial_puts,
 121 };
 122
 123 void smh_serial_initialize(void)
 124 {
 125         serial_register(&serial_smh_device);
 126 }
 127
 128 __weak struct serial_device *default_serial_console(void)
 129 {
 130         return &serial_smh_device;
 131 }
 132 #endif
 133
 134 #ifdef CONFIG_DEBUG_UART_SEMIHOSTING
 135 #include <debug_uart.h>
 136
 137 static inline void _debug_uart_init(void)
 138 {
 139 }
 140
 141 static inline void _debug_uart_putc(int c)
 142 {
 143         smh_putc(c);
 144 }
 145
 146 DEBUG_UART_FUNCS
 147 #endif