drivers/console: Reimplement MUTLI_CONSOLE_API framework in C

Now that we have switched to using the stack in MULTI_CONSOLE_API
framework functions and have factored all code involved in crash
reporting out into a separate file, there's really no reason to keep the
main framework code in assembly anymore. This patch rewrites it in C
which allows us to have a single implementation across aarch32/64 and
should be much easier to maintain going forward.

Change-Id: I6c85a01e89a79e8b233f3f8bee812f0dbd026221
Signed-off-by: Julius Werner <jwerner@chromium.org>

1 files changed, 122 insertions, 0 deletions

diff --git a/drivers/console/multi_console.c b/drivers/console/multi_console.c
new file mode 100644
index 000000000..c678de098
--- /dev/null
+++ b/drivers/console/multi_console.c
@@ -0,0 +1,122 @@
+/*
+ * Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#if MULTI_CONSOLE_API
+
+#include <assert.h>
+#include <drivers/console.h>
+
+console_t *console_list;
+uint8_t console_state = CONSOLE_FLAG_BOOT;
+
+int console_register(console_t *console)
+{
+	IMPORT_SYM(console_t *, __STACKS_START__, stacks_start)
+	IMPORT_SYM(console_t *, __STACKS_END__, stacks_end)
+
+	/* Assert that the struct is not on the stack (common mistake). */
+	assert((console < stacks_start) || (console >= stacks_end));
+	/* Assert that we won't make a circle in the list. */
+	assert(!console_is_registered(console));
+
+	console->next = console_list;
+	console_list = console;
+
+	/* Return 1 for convenient tail-calling from console_xxx_register(). */
+	return 1;
+}
+
+console_t *console_unregister(console_t *to_be_deleted)
+{
+	console_t **ptr;
+
+	assert(to_be_deleted != NULL);
+
+	for (ptr = &console_list; *ptr != NULL; ptr = &(*ptr)->next)
+		if (*ptr == to_be_deleted) {
+			*ptr = (*ptr)->next;
+			return to_be_deleted;
+		}
+
+	return NULL;
+}
+
+int console_is_registered(console_t *to_find)
+{
+	console_t *console;
+
+	assert(to_find != NULL);
+
+	for (console = console_list; console != NULL; console = console->next)
+		if (console == to_find)
+			return 1;
+
+	return 0;
+}
+
+void console_switch_state(unsigned int new_state)
+{
+	console_state = new_state;
+}
+
+void console_set_scope(console_t *console, unsigned int scope)
+{
+	assert(console != NULL);
+
+	console->flags = (console->flags & ~CONSOLE_FLAG_SCOPE_MASK) | scope;
+}
+
+int console_putc(int c)
+{
+	int err = ERROR_NO_VALID_CONSOLE;
+	console_t *console;
+
+	for (console = console_list; console != NULL; console = console->next)
+		if (console->flags & console_state) {
+			int ret = console->putc(c, console);
+			if ((err == ERROR_NO_VALID_CONSOLE) || (ret < err))
+				err = ret;
+		}
+
+	return err;
+}
+
+int console_getc(void)
+{
+	int err = ERROR_NO_VALID_CONSOLE;
+	console_t *console;
+
+	do {	/* Keep polling while at least one console works correctly. */
+		for (console = console_list; console != NULL;
+		     console = console->next)
+			if (console->flags & console_state) {
+				int ret = console->getc(console);
+				if (ret >= 0)
+					return ret;
+				if (err != ERROR_NO_PENDING_CHAR)
+					err = ret;
+			}
+	} while (err == ERROR_NO_PENDING_CHAR);
+
+	return err;
+}
+
+int console_flush(void)
+{
+	int err = ERROR_NO_VALID_CONSOLE;
+	console_t *console;
+
+	for (console = console_list; console != NULL; console = console->next)
+		if (console->flags & console_state) {
+			int ret = console->flush(console);
+			if ((err == ERROR_NO_VALID_CONSOLE) || (ret < err))
+				err = ret;
+		}
+
+	return err;
+}
+
+#endif	/* MULTI_CONSOLE_API */