jtag-console.c
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/*
* jtag-console.c - console driver over Blackfin JTAG
*
* Copyright (c) 2008-2010 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <malloc.h>
#include <stdio_dev.h>
#include <asm/blackfin.h>
#ifdef DEBUG
# define dprintf(...) serial_printf(__VA_ARGS__)
#else
# define dprintf(...) do { if (0) printf(__VA_ARGS__); } while (0)
#endif
static inline void dprintf_decode(const char *s, uint32_t len)
{
uint32_t i;
for (i = 0; i < len; ++i)
if (s[i] < 0x20 || s[i] >= 0x7f)
dprintf("\\%o", s[i]);
else
dprintf("%c", s[i]);
}
static inline uint32_t bfin_write_emudat(uint32_t emudat)
{
__asm__ __volatile__("emudat = %0;" : : "d"(emudat));
return emudat;
}
static inline uint32_t bfin_read_emudat(void)
{
uint32_t emudat;
__asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
return emudat;
}
#ifndef CONFIG_JTAG_CONSOLE_TIMEOUT
# define CONFIG_JTAG_CONSOLE_TIMEOUT 500
#endif
/* The Blackfin tends to be much much faster than the JTAG hardware. */
static bool jtag_write_emudat(uint32_t emudat)
{
static bool overflowed = false;
ulong timeout = get_timer(0) + CONFIG_JTAG_CONSOLE_TIMEOUT;
while (bfin_read_DBGSTAT() & 0x1) {
if (overflowed)
return overflowed;
if (timeout < get_timer(0))
overflowed = true;
}
overflowed = false;
bfin_write_emudat(emudat);
return overflowed;
}
/* Transmit a buffer. The format is:
* [32bit length][actual data]
*/
static void jtag_send(const char *raw_str, uint32_t len)
{
const char *cooked_str;
uint32_t i, ex;
if (len == 0)
return;
/* Ugh, need to output \r after \n */
ex = 0;
for (i = 0; i < len; ++i)
if (raw_str[i] == '\n')
++ex;
if (ex) {
char *c = malloc(len + ex);
cooked_str = c;
for (i = 0; i < len; ++i) {
*c++ = raw_str[i];
if (raw_str[i] == '\n')
*c++ = '\r';
}
len += ex;
} else
cooked_str = raw_str;
dprintf("%s(\"", __func__);
dprintf_decode(cooked_str, len);
dprintf("\", %i)\n", len);
/* First send the length */
if (jtag_write_emudat(len))
goto done;
/* Then send the data */
for (i = 0; i < len; i += 4) {
uint32_t emudat =
(cooked_str[i + 0] << 0) |
(cooked_str[i + 1] << 8) |
(cooked_str[i + 2] << 16) |
(cooked_str[i + 3] << 24);
if (jtag_write_emudat(emudat)) {
bfin_write_emudat(0);
goto done;
}
}
done:
if (cooked_str != raw_str)
free((char *)cooked_str);
}
static void jtag_putc(const char c)
{
jtag_send(&c, 1);
}
static void jtag_puts(const char *s)
{
jtag_send(s, strlen(s));
}
static size_t inbound_len, leftovers_len;
/* Lower layers want to know when jtag has data */
static int jtag_tstc_dbg(void)
{
int ret = (bfin_read_DBGSTAT() & 0x2);
if (ret)
dprintf("%s: ret:%i\n", __func__, ret);
return ret;
}
/* Higher layers want to know when any data is available */
static int jtag_tstc(void)
{
return jtag_tstc_dbg() || leftovers_len;
}
/* Receive a buffer. The format is:
* [32bit length][actual data]
*/
static uint32_t leftovers;
static int jtag_getc(void)
{
int ret;
uint32_t emudat;
dprintf("%s: inlen:%zu leftlen:%zu left:%x\n", __func__,
inbound_len, leftovers_len, leftovers);
/* see if any data is left over */
if (leftovers_len) {
--leftovers_len;
ret = leftovers & 0xff;
leftovers >>= 8;
return ret;
}
/* wait for new data ! */
while (!jtag_tstc_dbg())
continue;
emudat = bfin_read_emudat();
if (inbound_len == 0) {
/* grab the length */
inbound_len = emudat;
} else {
/* store the bytes */
leftovers_len = min(4, inbound_len);
inbound_len -= leftovers_len;
leftovers = emudat;
}
return jtag_getc();
}
int drv_jtag_console_init(void)
{
struct stdio_dev dev;
int ret;
memset(&dev, 0x00, sizeof(dev));
strcpy(dev.name, "jtag");
dev.flags = DEV_FLAGS_OUTPUT | DEV_FLAGS_INPUT | DEV_FLAGS_SYSTEM;
dev.putc = jtag_putc;
dev.puts = jtag_puts;
dev.tstc = jtag_tstc;
dev.getc = jtag_getc;
ret = stdio_register(&dev);
return (ret == 0 ? 1 : ret);
}
#ifdef CONFIG_UART_CONSOLE_IS_JTAG
/* Since the JTAG is always available (at power on), allow it to fake a UART */
void serial_set_baud(uint32_t baud) {}
void serial_setbrg(void) {}
int serial_init(void) { return 0; }
void serial_putc(const char c) __attribute__((alias("jtag_putc")));
void serial_puts(const char *s) __attribute__((alias("jtag_puts")));
int serial_tstc(void) __attribute__((alias("jtag_tstc")));
int serial_getc(void) __attribute__((alias("jtag_getc")));
#endif