Prepare for transitioning to packet mode console

A very few changes are needed to support the packet mode:

 - provide functions to report how much room is left in USB/UART
   transmit buffers;

 - compile out cprintf/cprints/cputs just in case to be able to catch
   cases where util_precompile.py fails to convert them for whatever
   reason;

 - do not add CR to every LF, this messes up packet transmissions, and
   the terminal is doing the right thing anyways

 - there is a problem with the USB channel in packet mode: the device
   reboots as soon as an attempt to send something to the host is
   undertaken. The problem can be rectified by disabling the deferred
   function path in the Cr50 console USB channel. A bug was open to
   track it down, but in packet mode using deferred function in this
   path is less critical, as the amount of sent data always is at
   least as much as the packet header size

BUG=b:149964350, b:152116489
TEST=with the rest of the patches applied packet mode console works
     fine. When packet mode is disabled the conventional mode console
     works fine.

Change-Id: Ib010cede36adc87cf80f49e5d76ec9e274d9e608
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2114238
Reviewed-by: Randall Spangler <rspangler@chromium.org>
Reviewed-by: Namyoon Woo <namyoon@chromium.org>

7 files changed, 54 insertions, 9 deletions

diff --git a/chip/g/usb-stream.h b/chip/g/usb-stream.h
index 49048a6d9c..f051e0c093 100644
--- a/chip/g/usb-stream.h
+++ b/chip/g/usb-stream.h
@@ -75,6 +75,20 @@ extern struct producer_ops const usb_stream_producer_ops;
 #endif
 
 /*
+ * When in packet mode, the terminal application (Acroterm) constantly times
+ * out if the deferred function is used in the USB transmit path.
+ *
+ * The below allows to exclude the console channel from the set using the
+ * deferred function when in packet console mode.
+ */
+#ifdef CONFIG_EXTRACT_PRINTF_STRINGS
+#define UART_CONSOLE_CHANNEL(x)  (((x) == USB_EP_AP) || ((x) == USB_EP_EC))
+#else
+#define UART_CONSOLE_CHANNEL(x)  (((x) == USB_EP_AP) || ((x) == USB_EP_EC) || \
+				  ((x) == USB_EP_CONSOLE))
+#endif
+
+/*
  * Convenience macro for defining USB streams and their associated state and
  * buffers.
  *
@@ -136,9 +150,7 @@ extern struct producer_ops const usb_stream_producer_ops;
 	static size_t CONCAT2(NAME, _tx_handled);			\
 	struct usb_stream_config const NAME = {				\
 		.endpoint     = ENDPOINT,				\
-		.is_uart_console = ((ENDPOINT == USB_EP_EC) ||		\
-				    (ENDPOINT == USB_EP_CONSOLE) ||	\
-				    (ENDPOINT == USB_EP_AP)),		\
+		.is_uart_console = UART_CONSOLE_CHANNEL(ENDPOINT),	\
 		.tx_in_progress = &CONCAT2(NAME, _tx_in_progress_),	\
 		.kicker_running = &CONCAT2(NAME, _kicker_running_),	\
 		.is_reset     = &CONCAT2(NAME, _is_reset_),		\
diff --git a/common/console.c b/common/console.c
index 8f42dffbf5..9ee3dc5b13 100644
--- a/common/console.c
+++ b/common/console.c
@@ -279,10 +279,7 @@ static void console_init(void)
 
 static int console_putc(int c)
 {
-	int rv1 = uart_putc(c);
-	int rv2 = usb_putc(c);
-
-	return rv1 == EC_SUCCESS ? rv2 : rv1;
+	return ccprintf("%c", c);
 }
 
 #ifndef CONFIG_EXPERIMENTAL_CONSOLE
diff --git a/common/console_output.c b/common/console_output.c
index 2fe1ac99a9..6d883f7030 100644
--- a/common/console_output.c
+++ b/common/console_output.c
@@ -37,6 +37,8 @@ BUILD_ASSERT(ARRAY_SIZE(channel_names) == CC_CHANNEL_COUNT);
 BUILD_ASSERT(CC_CHANNEL_COUNT <= 8*sizeof(uint32_t));
 #endif /* CONFIG_CONSOLE_CHANNEL */
 
+#ifndef CONFIG_EXTRACT_PRINTF_STRINGS
+
 /*****************************************************************************/
 /* Channel-based console output */
 
@@ -106,6 +108,7 @@ int cprints(enum console_channel channel, const char *format, ...)
 	r = cputs(channel, "]\n");
 	return r ? r : rv;
 }
+#endif /* ^^^^^^^^ CONFIG_EXTRACT_PRINTF_STRINGS NOT defined. */
 
 void cflush(void)
 {
diff --git a/common/uart_buffering.c b/common/uart_buffering.c
index e3b7e73fbd..c54cbf98dd 100644
--- a/common/uart_buffering.c
+++ b/common/uart_buffering.c
@@ -84,9 +84,11 @@ static int __tx_char(void *context, int c)
 {
 	int tx_buf_next, tx_buf_new_tail;
 
+#ifndef CONFIG_EXTRACT_PRINTF_STRINGS
 	/* Do newline to CRLF translation */
 	if (c == '\n' && __tx_char(NULL, '\r'))
 		return 1;
+#endif
 
 #if defined CONFIG_POLLING_UART
 	(void) tx_buf_next;
@@ -122,6 +124,11 @@ static int __tx_char(void *context, int c)
 	return 0;
 }
 
+size_t uart_buffer_room(void)
+{
+	return (tx_buf_tail - tx_buf_head - 1) & (CONFIG_UART_TX_BUF_SIZE - 1);
+}
+
 #ifdef CONFIG_UART_TX_DMA
 
 /**
diff --git a/common/usb_console_stream.c b/common/usb_console_stream.c
index 40bbc07e3c..6ba1f484a4 100644
--- a/common/usb_console_stream.c
+++ b/common/usb_console_stream.c
@@ -162,6 +162,21 @@ static int __tx_char(void *context, int c)
 #endif
 }
 
+size_t usb_buffer_room(void)
+{
+	if (!is_enabled)
+		return 0;
+
+	return queue_space(&tx_q);
+}
+
+int usb_put(const char *s, int len)
+{
+	QUEUE_ADD_UNITS(&tx_q, s, len);
+	handle_output();
+	return EC_SUCCESS;
+}
+
 /*
  * Public USB console implementation below.
  */
diff --git a/include/uart.h b/include/uart.h
index e333196d4a..3b798140ae 100644
--- a/include/uart.h
+++ b/include/uart.h
@@ -9,8 +9,10 @@
 #define __CROS_EC_UART_H
 
 #include <stdarg.h>  /* For va_list */
+
 #include "common.h"
 #include "gpio.h"
+#include "stddef.h"
 
 /**
  * Initialize the UART module.
@@ -352,9 +354,12 @@ int uart_console_read_buffer(uint8_t type,
 			     uint16_t dest_size,
 			     uint16_t *write_count);
 
-#endif  /* __CROS_EC_UART_H */
-
 /**
  * Initialize tx buffer head and tail
  */
 void uart_init_buffer(void);
+
+/* Return the size of the free room in the UART TX circular buffer. */
+size_t uart_buffer_room(void);
+
+#endif  /* __CROS_EC_UART_H */
diff --git a/include/usb_console.h b/include/usb_console.h
index 296829ff9c..cac8fde093 100644
--- a/include/usb_console.h
+++ b/include/usb_console.h
@@ -62,6 +62,12 @@ uint32_t usb_console_crc(void);
  */
 void usb_console_enable(int enabled, int readonly);
 
+/* Return the size of the free room in the USB TX circular buffer. */
+size_t usb_buffer_room(void);
+
+/* Send characters to the USB channel. */
+int usb_put(const char *str, int count);
+
 #define usb_va_start va_start
 #define usb_va_end va_end
 #else