[RFC PATCH 2/4] cmd: fuse: Add fuse writebuff sub-system command

[Harsha Vardhan V M <h-vm@ti.com>]

Add CMD_FUSE_WRITEBUFF config option to add and enable fuse writebuff
sub-system command. Add fuse_writebuff function to be invoked on
writebuff command.

Signed-off-by: Harsha Vardhan V M <h-vm@ti.com>
---
 cmd/Kconfig    |  8 ++++++++
 cmd/fuse.c     | 26 ++++++++++++++++++++++----
 include/fuse.h |  9 +++++++++
 3 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/cmd/Kconfig b/cmd/Kconfig
index cd391d422ae..81c59becc2d 100644
--- a/cmd/Kconfig
+++ b/cmd/Kconfig
@@ -1236,6 +1236,14 @@ config CMD_FUSE
 	  which control the behaviour of the device. The command uses the
 	  fuse_...() API.
 
+config CMD_FUSE_WRITEBUFF
+	bool "Support for the fuse writebuff"
+	depends on CMD_FUSE
+	help
+	  This allows programming fuses, which control the behaviour of
+	  the device, using a structured buffer in memory. The command
+	  uses the fuse_writebuff() API.
+
 config CMD_GPIO
 	bool "gpio"
 	help
diff --git a/cmd/fuse.c b/cmd/fuse.c
index 9f489570634..2d53e6bf2c4 100644
--- a/cmd/fuse.c
+++ b/cmd/fuse.c
@@ -43,9 +43,14 @@ static int do_fuse(struct cmd_tbl *cmdtp, int flag, int argc,
 	argc -= 2 + confirmed;
 	argv += 2 + confirmed;
 
-	if (argc < 2 || !(str2long(argv[0], (ulong *)&bank)) ||
-			!(str2long(argv[1], (ulong *)&word)))
-		return CMD_RET_USAGE;
+	if (IS_ENABLED(CONFIG_CMD_FUSE_WRITEBUFF) && !strcmp(op, "writebuff")) {
+		if (argc != 1 || !(str2long(argv[0], &addr)))
+			return CMD_RET_USAGE;
+	} else {
+		if (argc < 2 || !(str2long(argv[0], (ulong *)&bank)) ||
+				!(str2long(argv[1], (ulong *)&word)))
+			return CMD_RET_USAGE;
+	}
 
 	if (!strcmp(op, "read")) {
 		if (argc == 2)
@@ -153,6 +158,15 @@ static int do_fuse(struct cmd_tbl *cmdtp, int flag, int argc,
 			if (ret)
 				goto err;
 		}
+	} else if (IS_ENABLED(CONFIG_CMD_FUSE_WRITEBUFF) && !strcmp(op, "writebuff")) {
+		printf("Programming fuses using a structured buffer in memory "
+				"starting at addr 0x%lx\n", addr);
+		if (!confirmed && !confirm_prog())
+			return CMD_RET_FAILURE;
+
+		ret = fuse_writebuff(addr);
+		if (ret)
+			goto err;
 	} else {
 		return CMD_RET_USAGE;
 	}
@@ -178,5 +192,9 @@ U_BOOT_CMD(
 	"fuse prog [-y] <bank> <word> <hexval> [<hexval>...] - program 1 or\n"
 	"    several fuse words, starting at 'word' (PERMANENT)\n"
 	"fuse override <bank> <word> <hexval> [<hexval>...] - override 1 or\n"
-	"    several fuse words, starting at 'word'"
+	"    several fuse words, starting at 'word'\n"
+#ifdef CONFIG_CMD_FUSE_WRITEBUFF
+	"fuse writebuff [-y] <addr> - program fuse data\n"
+	"    using a structured buffer in memory starting at 'addr'\n"
+#endif /* CONFIG_CMD_FUSE_WRITEBUFF */
 );
diff --git a/include/fuse.h b/include/fuse.h
index 4519821af7e..902b5f56a74 100644
--- a/include/fuse.h
+++ b/include/fuse.h
@@ -12,6 +12,7 @@
 #define _FUSE_H_
 
 #include <linux/types.h>
+#include <linux/errno.h>
 
 /*
  * Read/Sense/Program/Override interface:
@@ -25,5 +26,13 @@ int fuse_read(u32 bank, u32 word, u32 *val);
 int fuse_sense(u32 bank, u32 word, u32 *val);
 int fuse_prog(u32 bank, u32 word, u32 val);
 int fuse_override(u32 bank, u32 word, u32 val);
+#ifdef CONFIG_CMD_FUSE_WRITEBUFF
+int fuse_writebuff(ulong addr);
+#else
+static inline int fuse_writebuff(ulong addr)
+{
+	return -EPERM;
+}
+#endif	/* CONFIG_CMD_FUSE_WRITEBUFF */
 
 #endif	/* _FUSE_H_ */
-- 
2.34.1