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-rw-r--r--arch/blackfin/cpu/jtag-console.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/arch/blackfin/cpu/jtag-console.c b/arch/blackfin/cpu/jtag-console.c
new file mode 100644
index 000000000..1cd619f10
--- /dev/null
+++ b/arch/blackfin/cpu/jtag-console.c
@@ -0,0 +1,132 @@
+/*
+ * jtag-console.c - console driver over Blackfin JTAG
+ *
+ * Copyright (c) 2008 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <common.h>
+#include <stdio_dev.h>
+#include <asm/blackfin.h>
+
+#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 void 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;
+ if (timeout < get_timer(0))
+ overflowed = true;
+ }
+ overflowed = false;
+ __asm__ __volatile__("emudat = %0;" : : "d"(emudat));
+}
+/* Transmit a buffer. The format is:
+ * [32bit length][actual data]
+ */
+static void jtag_send(const char *c, uint32_t len)
+{
+ uint32_t i;
+
+ if (len == 0)
+ return;
+
+ /* First send the length */
+ jtag_write_emudat(len);
+
+ /* Then send the data */
+ for (i = 0; i < len; i += 4)
+ jtag_write_emudat((c[i] << 0) | (c[i+1] << 8) | (c[i+2] << 16) | (c[i+3] << 24));
+}
+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)
+{
+ return (bfin_read_DBGSTAT() & 0x2);
+}
+
+/* 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;
+
+ /* 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;
+ __asm__("%0 = emudat;" : "=d"(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