efi_loader: console: Correctly report modes

Add support for EFI console modes.
Mode 0 is always 80x25 and present by EFI specification.
Mode 1 is always 80x50 and not mandatory.
Mode 2 and above is freely usable.

If the terminal can handle mode 1, we mark it as supported.
If the terminal size is greater than mode 0 and different than mode 1,
we install it as mode 2.

Modes can be switch with cout_set_mode.

Changes in V5:
 Correctly detect mode before enabling mode 2.

Changes in V4:
 Reset cursor positon on mode switch
 Use local variables in console query code

Changes in V3:
 Valid mode are 0 to EFIMode-1
 Fix style

Changes in V2:
 Add mode switch
 Report only the modes that we support

Signed-off-by: Emmanuel Vadot <manu@bidouilliste.com>
Signed-off-by: Alexander Graf <agraf@suse.de>

lib/efi_loader/efi_console.c

@@ -9,11 +9,38 @@
 #include <common.h>
 #include <efi_loader.h>
 
-/* If we can't determine the console size, default to 80x24 */
-static int console_columns = 80;
-static int console_rows = 24;
 static bool console_size_queried;
 
+#define EFI_COUT_MODE_2 2
+#define EFI_MAX_COUT_MODE 3
+
+struct cout_mode {
+	unsigned long columns;
+	unsigned long rows;
+	int present;
+};
+
+static struct cout_mode efi_cout_modes[] = {
+	/* EFI Mode 0 is 80x25 and always present */
+	{
+		.columns = 80,
+		.rows = 25,
+		.present = 1,
+	},
+	/* EFI Mode 1 is always 80x50 */
+	{
+		.columns = 80,
+		.rows = 50,
+		.present = 0,
+	},
+	/* Value are unknown until we query the console */
+	{
+		.columns = 0,
+		.rows = 0,
+		.present = 0,
+	},
+};
+
 const efi_guid_t efi_guid_console_control = CONSOLE_CONTROL_GUID;
 
 #define cESC '\x1b'
@@ -56,8 +83,9 @@ const struct efi_console_control_protocol efi_console_control = {
 	.lock_std_in = efi_cin_lock_std_in,
 };
 
+/* Default to mode 0 */
 static struct simple_text_output_mode efi_con_mode = {
-	.max_mode = 0,
+	.max_mode = 1,
 	.mode = 0,
 	.attribute = 0,
 	.cursor_column = 0,
@@ -131,8 +159,10 @@ static efi_status_t EFIAPI efi_cout_output_string(
 			struct efi_simple_text_output_protocol *this,
 			const unsigned short *string)
 {
+	struct cout_mode *mode;
 	u16 ch;
 
+	mode = &efi_cout_modes[efi_con_mode.mode];
 	EFI_ENTRY("%p, %p", this, string);
 	for (;(ch = *string); string++) {
 		print_unicode_in_utf8(ch);
@@ -140,13 +170,12 @@ static efi_status_t EFIAPI efi_cout_output_string(
 		if (ch == '\n') {
 			efi_con_mode.cursor_column = 1;
 			efi_con_mode.cursor_row++;
-		} else if (efi_con_mode.cursor_column > console_columns) {
+		} else if (efi_con_mode.cursor_column > mode->columns) {
 			efi_con_mode.cursor_column = 1;
 			efi_con_mode.cursor_row++;
 		}
-		if (efi_con_mode.cursor_row > console_rows) {
+		if (efi_con_mode.cursor_row > mode->rows)
-			efi_con_mode.cursor_row = console_rows;
+			efi_con_mode.cursor_row = mode->rows;
-		}
 	}
 
 	return EFI_EXIT(EFI_SUCCESS);
@@ -160,6 +189,14 @@ static efi_status_t EFIAPI efi_cout_test_string(
 	return EFI_EXIT(EFI_SUCCESS);
 }
 
+static bool cout_mode_matches(struct cout_mode *mode, int rows, int cols)
+{
+	if (!mode->present)
+		return false;
+
+	return (mode->rows == rows) && (mode->columns == cols);
+}
+
 static efi_status_t EFIAPI efi_cout_query_mode(
 			struct efi_simple_text_output_protocol *this,
 			unsigned long mode_number, unsigned long *columns,
@@ -170,6 +207,8 @@ static efi_status_t EFIAPI efi_cout_query_mode(
 	if (!console_size_queried) {
 		/* Ask the terminal about its size */
 		int n[3];
+		int cols;
+		int rows;
 		u64 timeout;
 
 		console_size_queried = true;
@@ -191,15 +230,40 @@ static efi_status_t EFIAPI efi_cout_query_mode(
 			goto out;
 		}
 
-		console_columns = n[2];
+		cols = n[2];
-		console_rows = n[1];
+		rows = n[1];
+
+		/* Test if we can have Mode 1 */
+		if (cols >= 80 && rows >= 50) {
+			efi_cout_modes[1].present = 1;
+			efi_con_mode.max_mode = 2;
 		}
 
+		/*
+		 * Install our mode as mode 2 if it is different
+		 * than mode 0 or 1 and set it  as the currently selected mode
+		 */
+		if (!cout_mode_matches(&efi_cout_modes[0], rows, cols) &&
+		    !cout_mode_matches(&efi_cout_modes[1], rows, cols)) {
+			efi_cout_modes[EFI_COUT_MODE_2].columns = cols;
+			efi_cout_modes[EFI_COUT_MODE_2].rows = rows;
+			efi_cout_modes[EFI_COUT_MODE_2].present = 1;
+			efi_con_mode.max_mode = EFI_MAX_COUT_MODE;
+			efi_con_mode.mode = EFI_COUT_MODE_2;
+		}
+	}
+
+	if (mode_number >= efi_con_mode.max_mode)
+		return EFI_EXIT(EFI_UNSUPPORTED);
+
+	if (efi_cout_modes[mode_number].present != 1)
+		return EFI_EXIT(EFI_UNSUPPORTED);
+
 out:
 	if (columns)
-		*columns = console_columns;
+		*columns = efi_cout_modes[mode_number].columns;
 	if (rows)
-		*rows = console_rows;
+		*rows = efi_cout_modes[mode_number].rows;
 
 	return EFI_EXIT(EFI_SUCCESS);
 }
@@ -210,11 +274,15 @@ static efi_status_t EFIAPI efi_cout_set_mode(
 {
 	EFI_ENTRY("%p, %ld", this, mode_number);
 
-	/* We only support text output for now */
-	if (mode_number == EFI_CONSOLE_MODE_TEXT)
-		return EFI_EXIT(EFI_SUCCESS);
 
+	if (mode_number > efi_con_mode.max_mode)
 		return EFI_EXIT(EFI_UNSUPPORTED);
+
+	efi_con_mode.mode = mode_number;
+	efi_con_mode.cursor_column = 0;
+	efi_con_mode.cursor_row = 0;
+
+	return EFI_EXIT(EFI_SUCCESS);
 }
 
 static efi_status_t EFIAPI efi_cout_set_attribute(