common: uart: split off printf and like functions into separate module

This separates the high-level uart output functions like uart_printf
and uart_putc from the uart buffering module, allowing the buffering
to be implemented separately from the output functions.

The contract between this module and the uart_buffering layer is to
implement uart_tx_char_raw and uart_tx_start.

BUG=b:178033156
BRANCH=none
TEST=buildall

Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Change-Id: I5fb62ca2be1fea04654eaadd7a3806ac0c586929
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2685411
Reviewed-by: Simon Glass <sjg@chromium.org>

4 files changed, 107 insertions, 90 deletions

diff --git a/common/build.mk b/common/build.mk
index e86fc1eb01..3ca7a0fa56 100644
--- a/common/build.mk
+++ b/common/build.mk
@@ -187,7 +187,7 @@ common-$(CONFIG_WEBUSB_URL)+=webusb_desc.o
 common-$(CONFIG_WIRELESS)+=wireless.o
 common-$(HAS_TASK_CHIPSET)+=chipset.o
 common-$(HAS_TASK_CONSOLE)+=console.o console_output.o
-common-$(HAS_TASK_CONSOLE)+=uart_buffering.o uart_hostcmd.o
+common-$(HAS_TASK_CONSOLE)+=uart_buffering.o uart_hostcmd.o uart_printf.o
 common-$(CONFIG_CMD_MEM)+=memory_commands.o
 common-$(HAS_TASK_HOSTCMD)+=host_command.o ec_features.o
 common-$(HAS_TASK_PDCMD)+=host_command_pd.o
diff --git a/common/uart_buffering.c b/common/uart_buffering.c
index 38bbd67d2d..78dc06e5f4 100644
--- a/common/uart_buffering.c
+++ b/common/uart_buffering.c
@@ -71,16 +71,7 @@ void uart_init_buffer(void)
 	}
 }
 
-/**
- * Put a single character into the transmit buffer.
- *
- * Does not enable the transmit interrupt; assumes that happens elsewhere.
- *
- * @param context	Context; ignored.
- * @param c		Character to write.
- * @return 0 if the character was transmitted, 1 if it was dropped.
- */
-static int __tx_char_raw(void *context, int c)
+int uart_tx_char_raw(void *context, int c)
 {
 	int tx_buf_next, tx_buf_new_tail;
 
@@ -118,14 +109,6 @@ static int __tx_char_raw(void *context, int c)
 	return 0;
 }
 
-static int __tx_char(void *context, int c)
-{
-	/* Translate '\n' to '\r\n' */
-	if (c == '\n' && __tx_char_raw(NULL, '\r'))
-		return 1;
-	return __tx_char_raw(context, c);
-}
-
 #ifdef CONFIG_UART_TX_DMA
 
 /**
@@ -265,77 +248,6 @@ void uart_clear_input(void)
 
 #endif /* !CONFIG_UART_RX_DMA */
 
-int uart_putc(int c)
-{
-	int rv = __tx_char(NULL, c);
-
-	uart_tx_start();
-
-	return rv ? EC_ERROR_OVERFLOW : EC_SUCCESS;
-}
-
-int uart_puts(const char *outstr)
-{
-	/* Put all characters in the output buffer */
-	while (*outstr) {
-		if (__tx_char(NULL, *outstr++) != 0)
-			break;
-	}
-
-	uart_tx_start();
-
-	/* Successful if we consumed all output */
-	return *outstr ? EC_ERROR_OVERFLOW : EC_SUCCESS;
-}
-
-int uart_put(const char *out, int len)
-{
-	/* Put all characters in the output buffer */
-	while (len--) {
-		if (__tx_char(NULL, *out++) != 0)
-			break;
-	}
-
-	uart_tx_start();
-
-	/* Successful if we consumed all output */
-	return len ? EC_ERROR_OVERFLOW : EC_SUCCESS;
-}
-
-int uart_put_raw(const char *out, int len)
-{
-	/* Put all characters in the output buffer */
-	while (len--) {
-		if (__tx_char_raw(NULL, *out++) != 0)
-			break;
-	}
-
-	uart_tx_start();
-
-	/* Successful if we consumed all output */
-	return len ? EC_ERROR_OVERFLOW : EC_SUCCESS;
-}
-
-int uart_vprintf(const char *format, va_list args)
-{
-	int rv = vfnprintf(__tx_char, NULL, format, args);
-
-	uart_tx_start();
-
-	return rv;
-}
-
-int uart_printf(const char *format, ...)
-{
-	int rv;
-	va_list args;
-
-	va_start(args, format);
-	rv = uart_vprintf(format, args);
-	va_end(args);
-	return rv;
-}
-
 void uart_flush_output(void)
 {
 	/* If UART not initialized ignore flush request. */
diff --git a/common/uart_printf.c b/common/uart_printf.c
new file mode 100644
index 0000000000..80a72065b3
--- /dev/null
+++ b/common/uart_printf.c
@@ -0,0 +1,89 @@
+/* Copyright 2021 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include <stddef.h>
+
+#include "common.h"
+#include "printf.h"
+#include "uart.h"
+
+static int __tx_char(void *context, int c)
+{
+	/* Translate '\n' to '\r\n' */
+	if (c == '\n' && uart_tx_char_raw(context, '\r'))
+		return 1;
+	return uart_tx_char_raw(context, c);
+}
+
+int uart_putc(int c)
+{
+	int rv = __tx_char(NULL, c);
+
+	uart_tx_start();
+
+	return rv ? EC_ERROR_OVERFLOW : EC_SUCCESS;
+}
+
+int uart_puts(const char *outstr)
+{
+	/* Put all characters in the output buffer */
+	while (*outstr) {
+		if (__tx_char(NULL, *outstr++) != 0)
+			break;
+	}
+
+	uart_tx_start();
+
+	/* Successful if we consumed all output */
+	return *outstr ? EC_ERROR_OVERFLOW : EC_SUCCESS;
+}
+
+int uart_put(const char *out, int len)
+{
+	/* Put all characters in the output buffer */
+	while (len--) {
+		if (__tx_char(NULL, *out++) != 0)
+			break;
+	}
+
+	uart_tx_start();
+
+	/* Successful if we consumed all output */
+	return len ? EC_ERROR_OVERFLOW : EC_SUCCESS;
+}
+
+int uart_put_raw(const char *out, int len)
+{
+	/* Put all characters in the output buffer */
+	while (len--) {
+		if (uart_tx_char_raw(NULL, *out++) != 0)
+			break;
+	}
+
+	uart_tx_start();
+
+	/* Successful if we consumed all output */
+	return len ? EC_ERROR_OVERFLOW : EC_SUCCESS;
+}
+
+int uart_vprintf(const char *format, va_list args)
+{
+	int rv = vfnprintf(__tx_char, NULL, format, args);
+
+	uart_tx_start();
+
+	return rv;
+}
+
+int uart_printf(const char *format, ...)
+{
+	int rv;
+	va_list args;
+
+	va_start(args, format);
+	rv = uart_vprintf(format, args);
+	va_end(args);
+	return rv;
+}
diff --git a/include/uart.h b/include/uart.h
index b6dce4f21f..95df22d5bd 100644
--- a/include/uart.h
+++ b/include/uart.h
@@ -85,6 +85,22 @@ int uart_printf(const char *format, ...);
 int uart_vprintf(const char *format, va_list args);
 
 /**
+ * Put a single character into the transmit buffer.
+ *
+ * Does not enable the transmit interrupt; assumes that happens elsewhere.
+ *
+ * @param context	Context; ignored.
+ * @param c		Character to write.
+ * @return 0 if the character was transmitted, 1 if it was dropped.
+ *
+ * Note: This is intended to be implemented by the UART buffering
+ * module, and called only by the implementations of the uart_*
+ * functions.  You should stick to the higher level functions, such as
+ * uart_putc, outside of the UART implementation.
+ */
+int uart_tx_char_raw(void *context, int c);
+
+/**
  * Flush output.  Blocks until UART has transmitted all output.
  */
 void uart_flush_output(void);