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>
14 # define dprintf(...) serial_printf(__VA_ARGS__)
16 # define dprintf(...) do { if (0) printf(__VA_ARGS__); } while (0)
19 static inline void dprintf_decode(const char *s, uint32_t len)
22 for (i = 0; i < len; ++i)
23 if (s[i] < 0x20 || s[i] >= 0x7f)
24 dprintf("\\%o", s[i]);
29 static inline uint32_t bfin_write_emudat(uint32_t emudat)
31 __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
35 static inline uint32_t bfin_read_emudat(void)
38 __asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
42 #ifndef CONFIG_JTAG_CONSOLE_TIMEOUT
43 # define CONFIG_JTAG_CONSOLE_TIMEOUT 500
46 /* The Blackfin tends to be much much faster than the JTAG hardware. */
47 static bool jtag_write_emudat(uint32_t emudat)
49 static bool overflowed = false;
50 ulong timeout = get_timer(0) + CONFIG_JTAG_CONSOLE_TIMEOUT;
51 while (bfin_read_DBGSTAT() & 0x1) {
54 if (timeout < get_timer(0))
58 bfin_write_emudat(emudat);
61 /* Transmit a buffer. The format is:
62 * [32bit length][actual data]
64 static void jtag_send(const char *c, uint32_t len)
71 dprintf("%s(\"", __func__);
72 dprintf_decode(c, len);
73 dprintf("\", %i)\n", len);
75 /* First send the length */
76 if (jtag_write_emudat(len))
79 /* Then send the data */
80 for (i = 0; i < len; i += 4) {
86 if (jtag_write_emudat(emudat)) {
92 static void jtag_putc(const char c)
96 static void jtag_puts(const char *s)
98 jtag_send(s, strlen(s));
101 static size_t inbound_len, leftovers_len;
103 /* Lower layers want to know when jtag has data */
104 static int jtag_tstc_dbg(void)
106 int ret = (bfin_read_DBGSTAT() & 0x2);
108 dprintf("%s: ret:%i\n", __func__, ret);
112 /* Higher layers want to know when any data is available */
113 static int jtag_tstc(void)
115 return jtag_tstc_dbg() || leftovers_len;
118 /* Receive a buffer. The format is:
119 * [32bit length][actual data]
121 static uint32_t leftovers;
122 static int jtag_getc(void)
127 dprintf("%s: inlen:%zu leftlen:%zu left:%x\n", __func__,
128 inbound_len, leftovers_len, leftovers);
130 /* see if any data is left over */
133 ret = leftovers & 0xff;
138 /* wait for new data ! */
139 while (!jtag_tstc_dbg())
141 emudat = bfin_read_emudat();
143 if (inbound_len == 0) {
144 /* grab the length */
145 inbound_len = emudat;
147 /* store the bytes */
148 leftovers_len = min(4, inbound_len);
149 inbound_len -= leftovers_len;
156 int drv_jtag_console_init(void)
158 struct stdio_dev dev;
161 memset(&dev, 0x00, sizeof(dev));
162 strcpy(dev.name, "jtag");
163 dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
164 dev.putc = jtag_putc;
165 dev.puts = jtag_puts;
166 dev.tstc = jtag_tstc;
167 dev.getc = jtag_getc;
169 ret = stdio_register(&dev);
170 return (ret == 0 ? 1 : ret);
173 #ifdef CONFIG_UART_CONSOLE_IS_JTAG
174 /* Since the JTAG is always available (at power on), allow it to fake a UART */
175 void serial_set_baud(uint32_t baud) {}
176 void serial_setbrg(void) {}
177 int serial_init(void) { return 0; }
178 void serial_putc(const char c) __attribute__((alias("jtag_putc")));
179 void serial_puts(const char *s) __attribute__((alias("jtag_puts")));
180 int serial_tstc(void) __attribute__((alias("jtag_tstc")));
181 int serial_getc(void) __attribute__((alias("jtag_getc")));