2 * jtag-console.c - console driver over Blackfin JTAG
4 * Copyright (c) 2008-2010 Analog Devices Inc.
6 * Licensed under the GPL-2 or later.
10 #include <stdio_dev.h>
11 #include <asm/blackfin.h>
13 static inline uint32_t bfin_write_emudat(uint32_t emudat)
15 __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
19 static inline uint32_t bfin_read_emudat(void)
22 __asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
26 #ifndef CONFIG_JTAG_CONSOLE_TIMEOUT
27 # define CONFIG_JTAG_CONSOLE_TIMEOUT 500
30 /* The Blackfin tends to be much much faster than the JTAG hardware. */
31 static bool jtag_write_emudat(uint32_t emudat)
33 static bool overflowed = false;
34 ulong timeout = get_timer(0) + CONFIG_JTAG_CONSOLE_TIMEOUT;
35 while (bfin_read_DBGSTAT() & 0x1) {
38 if (timeout < get_timer(0))
42 bfin_write_emudat(emudat);
45 /* Transmit a buffer. The format is:
46 * [32bit length][actual data]
48 static void jtag_send(const char *c, uint32_t len)
55 /* First send the length */
56 if (jtag_write_emudat(len))
59 /* Then send the data */
60 for (i = 0; i < len; i += 4) {
66 if (jtag_write_emudat(emudat)) {
72 static void jtag_putc(const char c)
76 static void jtag_puts(const char *s)
78 jtag_send(s, strlen(s));
81 static size_t inbound_len, leftovers_len;
83 /* Lower layers want to know when jtag has data */
84 static int jtag_tstc_dbg(void)
86 return (bfin_read_DBGSTAT() & 0x2);
89 /* Higher layers want to know when any data is available */
90 static int jtag_tstc(void)
92 return jtag_tstc_dbg() || leftovers_len;
95 /* Receive a buffer. The format is:
96 * [32bit length][actual data]
98 static uint32_t leftovers;
99 static int jtag_getc(void)
104 /* see if any data is left over */
107 ret = leftovers & 0xff;
112 /* wait for new data ! */
113 while (!jtag_tstc_dbg())
115 emudat = bfin_read_emudat();
117 if (inbound_len == 0) {
118 /* grab the length */
119 inbound_len = emudat;
121 /* store the bytes */
122 leftovers_len = min(4, inbound_len);
123 inbound_len -= leftovers_len;
130 int drv_jtag_console_init(void)
132 struct stdio_dev dev;
135 memset(&dev, 0x00, sizeof(dev));
136 strcpy(dev.name, "jtag");
137 dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
138 dev.putc = jtag_putc;
139 dev.puts = jtag_puts;
140 dev.tstc = jtag_tstc;
141 dev.getc = jtag_getc;
143 ret = stdio_register(&dev);
144 return (ret == 0 ? 1 : ret);
147 #ifdef CONFIG_UART_CONSOLE_IS_JTAG
148 /* Since the JTAG is always available (at power on), allow it to fake a UART */
149 void serial_set_baud(uint32_t baud) {}
150 void serial_setbrg(void) {}
151 int serial_init(void) { return 0; }
152 void serial_putc(const char c) __attribute__((alias("jtag_putc")));
153 void serial_puts(const char *s) __attribute__((alias("jtag_puts")));
154 int serial_tstc(void) __attribute__((alias("jtag_tstc")));
155 int serial_getc(void) __attribute__((alias("jtag_getc")));