dfu: rename dfu_tftp_write() to dfu_write_by_name()

This function is essentially independent from tftp, and will also be
utilised in implementing UEFI capsule update in a later commit.
So just give it a more generic name.
In addition, a new configuration option, CONFIG_DFU_WRITE_ALT, was
introduced so that the file will be compiled with different options,
particularly one added in a later commit.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
diff --git a/drivers/dfu/Kconfig b/drivers/dfu/Kconfig
index 0eec00b..10196f3 100644
--- a/drivers/dfu/Kconfig
+++ b/drivers/dfu/Kconfig
@@ -14,8 +14,13 @@
 	depends on NET
 
 if DFU
+config DFU_WRITE_ALT
+	bool
+	default n
+
 config DFU_TFTP
 	bool "DFU via TFTP"
+	select DFU_WRITE_ALT
 	select DFU_OVER_TFTP
 	help
 	  This option allows performing update of DFU-managed medium with data
diff --git a/drivers/dfu/Makefile b/drivers/dfu/Makefile
index 0d7925c..dfbf64d 100644
--- a/drivers/dfu/Makefile
+++ b/drivers/dfu/Makefile
@@ -9,5 +9,5 @@
 obj-$(CONFIG_$(SPL_)DFU_NAND) += dfu_nand.o
 obj-$(CONFIG_$(SPL_)DFU_RAM) += dfu_ram.o
 obj-$(CONFIG_$(SPL_)DFU_SF) += dfu_sf.o
-obj-$(CONFIG_$(SPL_)DFU_TFTP) += dfu_tftp.o
+obj-$(CONFIG_$(SPL_)DFU_WRITE_ALT) += dfu_alt.o
 obj-$(CONFIG_$(SPL_)DFU_VIRT) += dfu_virt.o
diff --git a/drivers/dfu/dfu_tftp.c b/drivers/dfu/dfu_alt.c
similarity index 66%
rename from drivers/dfu/dfu_tftp.c
rename to drivers/dfu/dfu_alt.c
index ffae4bb..8870967 100644
--- a/drivers/dfu/dfu_tftp.c
+++ b/drivers/dfu/dfu_alt.c
@@ -10,8 +10,21 @@
 #include <errno.h>
 #include <dfu.h>
 
-int dfu_tftp_write(char *dfu_entity_name, unsigned int addr, unsigned int len,
-		   char *interface, char *devstring)
+/**
+ * dfu_write_by_name() - write data to DFU medium
+ * @dfu_entity_name:    Name of DFU entity to write
+ * @addr:               Address of data buffer to write
+ * @len:                Number of bytes
+ * @interface:          Destination DFU medium (e.g. "mmc")
+ * @devstring:          Instance number of destination DFU medium (e.g. "1")
+ *
+ * This function is storing data received on DFU supported medium which
+ * is specified by @dfu_entity_name.
+ *
+ * Return:              0 - on success, error code - otherwise
+ */
+int dfu_write_by_name(char *dfu_entity_name, unsigned int addr,
+		      unsigned int len, char *interface, char *devstring)
 {
 	char *s, *sb;
 	int alt_setting_num, ret;
@@ -44,7 +57,7 @@
 	free(sb);
 	if (alt_setting_num < 0) {
 		pr_err("Alt setting [%d] to write not found!",
-		      alt_setting_num);
+		       alt_setting_num);
 		ret = -ENODEV;
 		goto done;
 	}