[U-Boot] [PATCH] fastboot: add support for 'getvar platform'

[Eugeniu Rosca]

Our R-Car3 Android userspace relies on the output of 'fastboot
getvar platform' and U-Boot currently is not able to handle it:

host $> fastboot getvar platform
getvar:platform FAILED (remote: Variable not implemented)
finished. total time: 0.001s

We either have the option of adding 'fastboot.platform' variable
to the default/saved environment as a workaround or add proper
'fastboot getvar platform' support in U-Boot via this patch.
In the latter case, other platforms can benefit from it too.

Note that R-Car3 already exports 'platform' environment variable via
v2019.01 commit 00e4b57e9e71c3 ("ARM: rmobile: Set environment variable
containing CPU type").

Signed-off-by: Eugeniu Rosca <erosca at de.adit-jv.com>
---
 drivers/fastboot/fb_getvar.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/fastboot/fb_getvar.c b/drivers/fastboot/fb_getvar.c
index 4d264c985d7e..bc2481b57d73 100644
--- a/drivers/fastboot/fb_getvar.c
+++ b/drivers/fastboot/fb_getvar.c
@@ -17,6 +17,7 @@ static void getvar_downloadsize(char *var_parameter, char *response);
 static void getvar_serialno(char *var_parameter, char *response);
 static void getvar_version_baseband(char *var_parameter, char *response);
 static void getvar_product(char *var_parameter, char *response);
+static void getvar_platform(char *var_parameter, char *response);
 static void getvar_current_slot(char *var_parameter, char *response);
 static void getvar_slot_suffixes(char *var_parameter, char *response);
 static void getvar_has_slot(char *var_parameter, char *response);
@@ -55,6 +56,9 @@ static const struct {
 	}, {
 		.variable = "product",
 		.dispatch = getvar_product
+	}, {
+		.variable = "platform",
+		.dispatch = getvar_platform
 	}, {
 		.variable = "current-slot",
 		.dispatch = getvar_current_slot
@@ -117,6 +121,16 @@ static void getvar_product(char *var_parameter, char *response)
 		fastboot_fail("Board not set", response);
 }
 
+static void getvar_platform(char *var_parameter, char *response)
+{
+	const char *p = env_get("platform");
+
+	if (p)
+		fastboot_okay(p, response);
+	else
+		fastboot_fail("platform not set", response);
+}
+
 static void getvar_current_slot(char *var_parameter, char *response)
 {
 	/* A/B not implemented, for now always return _a */
-- 
2.21.0