fastboot: add oem console command support

"oem console" serves to read console record buffer.

Signed-off-by: Ion Agorria <ion@agorria.com>
Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>
Reviewed-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>
Link: https://lore.kernel.org/r/20240105072212.6615-7-clamor95@gmail.com
Signed-off-by: Mattijs Korpershoek <mkorpershoek@baylibre.com>

doc/android/fastboot.rst

@@ -29,6 +29,7 @@ The following OEM commands are supported (if enabled):
   with <arg> = boot_ack boot_partition
 - ``oem bootbus``  - this executes ``mmc bootbus %x %s`` to configure eMMC
 - ``oem run`` - this executes an arbitrary U-Boot command
+- ``oem console`` - this dumps U-Boot console record buffer
 
 Support for both eMMC and NAND devices is included.
 

drivers/fastboot/Kconfig

@@ -242,6 +242,13 @@ config FASTBOOT_OEM_RUN
 	  this feature if you are using verified boot, as it will allow an
 	  attacker to bypass any restrictions you have in place.
 
+config FASTBOOT_CMD_OEM_CONSOLE
+	bool "Enable the 'oem console' command"
+	depends on CONSOLE_RECORD
+	help
+	  Add support for the "oem console" command to input and read console
+	  record buffer.
+
 endif # FASTBOOT
 
 endmenu

drivers/fastboot/fb_command.c

@@ -41,6 +41,7 @@ static void reboot_recovery(char *, char *);
 static void oem_format(char *, char *);
 static void oem_partconf(char *, char *);
 static void oem_bootbus(char *, char *);
+static void oem_console(char *, char *);
 static void run_ucmd(char *, char *);
 static void run_acmd(char *, char *);
 
@@ -108,6 +109,10 @@ static const struct {
 		.command = "oem run",
 		.dispatch = CONFIG_IS_ENABLED(FASTBOOT_OEM_RUN, (run_ucmd), (NULL))
 	},
+	[FASTBOOT_COMMAND_OEM_CONSOLE] = {
+		.command = "oem console",
+		.dispatch = CONFIG_IS_ENABLED(FASTBOOT_CMD_OEM_CONSOLE, (oem_console), (NULL))
+	},
 	[FASTBOOT_COMMAND_UCMD] = {
 		.command = "UCmd",
 		.dispatch = CONFIG_IS_ENABLED(FASTBOOT_UUU_SUPPORT, (run_ucmd), (NULL))
@@ -159,6 +164,23 @@ void fastboot_multiresponse(int cmd, char *response)
 	case FASTBOOT_COMMAND_GETVAR:
 		fastboot_getvar_all(response);
 		break;
+	case FASTBOOT_COMMAND_OEM_CONSOLE:
+		if (CONFIG_IS_ENABLED(FASTBOOT_CMD_OEM_CONSOLE)) {
+			char buf[FASTBOOT_RESPONSE_LEN] = { 0 };
+
+			if (console_record_isempty()) {
+				console_record_reset();
+				fastboot_okay(NULL, response);
+			} else {
+				int ret = console_record_readline(buf, sizeof(buf) - 5);
+
+				if (ret < 0)
+					fastboot_fail("Error reading console", response);
+				else
+					fastboot_response("INFO", response, "%s", buf);
+			}
+			break;
+		}
 	default:
 		fastboot_fail("Unknown multiresponse command", response);
 		break;
@@ -503,3 +525,20 @@ static void __maybe_unused oem_bootbus(char *cmd_parameter, char *response)
 	else
 		fastboot_okay(NULL, response);
 }
+
+/**
+ * oem_console() - Execute the OEM console command
+ *
+ * @cmd_parameter: Pointer to command parameter
+ * @response: Pointer to fastboot response buffer
+ */
+static void __maybe_unused oem_console(char *cmd_parameter, char *response)
+{
+	if (cmd_parameter)
+		console_in_puts(cmd_parameter);
+
+	if (console_record_isempty())
+		fastboot_fail("Empty console", response);
+	else
+		fastboot_response(FASTBOOT_MULTIRESPONSE_START, response, NULL);
+}

include/fastboot.h

@@ -47,6 +47,7 @@ enum {
 	FASTBOOT_COMMAND_OEM_PARTCONF,
 	FASTBOOT_COMMAND_OEM_BOOTBUS,
 	FASTBOOT_COMMAND_OEM_RUN,
+	FASTBOOT_COMMAND_OEM_CONSOLE,
 	FASTBOOT_COMMAND_ACMD,
 	FASTBOOT_COMMAND_UCMD,
 	FASTBOOT_COMMAND_COUNT