dfu: ram support

DFU spec mentions it as a method to upgrade firmware (software stored
in writable non-volatile memory). It also says other potential uses of
DFU is beyond scope of the spec.

Here such a beyond the scope use is being attempted - directly pumping
binary images from host via USB to RAM. This facility is a developer
centric one in that it gives advantage over upgrading non-volatile
memory for testing new images every time during development and/or
testing.

Directly putting image onto RAM would speed up upgrade process. This and
convenience was the initial thoughts that led to doing this, speed
improvement over MMC was only 1 second though - 6 sec on RAM as opposed
to 7 sec on MMC in beagle bone, perhaps enabling cache and/or optimizing
DFU framework to avoid multiple copy for ram (if worth) may help, and
on other platforms and other boot media like NAND maybe improvement
would be higher.

And for a platform that doesn't yet have proper DFU suppport for
non-volatile media's, DFU to RAM can be used.

Another minor advantage would be to increase life of mmc/nand as it
would be less used during development/testing.

usage: <image name> ram <start address> <size>
eg. kernel ram 0x81000000 0x1000000

Downloading images to RAM using DFU is not something new, this is
acheived in openmoko also.

DFU on RAM can be used for extracting RAM contents to host using dfu
upload. Perhaps this can be extended to io for squeezing out register
dump through usb, if it is worth.

Signed-off-by: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Cc: Heiko Schocher <hs@denx.de>
Cc: Marek Vasut <marex@denx.de>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Pantelis Antoniou <panto@antoniou-consulting.com>
Cc: Gerhard Sittig <gsi@denx.de>
Acked-by: Marek Vasut <marex@denx.de>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Heiko Schocher <hs@denx.de>

README

@@ -1409,6 +1409,12 @@ The following options need to be configured:
 		CONFIG_DFU_NAND
 		This enables support for exposing NAND devices via DFU.
 
+		CONFIG_DFU_RAM
+		This enables support for exposing RAM via DFU.
+		Note: DFU spec refer to non-volatile memory usage, but
+		allow usages beyond the scope of spec - here RAM usage,
+		one that would help mostly the developer.
+
 		CONFIG_SYS_DFU_DATA_BUF_SIZE
 		Dfu transfer uses a buffer before writing data to the
 		raw storage device. Make the size (in bytes) of this buffer

drivers/dfu/Makefile

@@ -12,6 +12,7 @@ LIB	= $(obj)libdfu.o
 COBJS-$(CONFIG_DFU_FUNCTION) += dfu.o
 COBJS-$(CONFIG_DFU_MMC) += dfu_mmc.o
 COBJS-$(CONFIG_DFU_NAND) += dfu_nand.o
+COBJS-$(CONFIG_DFU_RAM) += dfu_ram.o
 
 SRCS    := $(COBJS-y:.o=.c)
 OBJS	:= $(addprefix $(obj),$(COBJS-y))

drivers/dfu/dfu.c

@@ -348,6 +348,9 @@ static int dfu_fill_entity(struct dfu_entity *dfu, char *s, int alt,
 	} else if (strcmp(interface, "nand") == 0) {
 		if (dfu_fill_entity_nand(dfu, s))
 			return -1;
+	} else if (strcmp(interface, "ram") == 0) {
+		if (dfu_fill_entity_ram(dfu, s))
+			return -1;
 	} else {
 		printf("%s: Device %s not (yet) supported!\n",
 		       __func__,  interface);
@@ -397,14 +400,14 @@ int dfu_config_entities(char *env, char *interface, int num)
 
 const char *dfu_get_dev_type(enum dfu_device_type t)
 {
-	const char *dev_t[] = {NULL, "eMMC", "OneNAND", "NAND" };
+	const char *dev_t[] = {NULL, "eMMC", "OneNAND", "NAND", "RAM" };
 	return dev_t[t];
 }
 
 const char *dfu_get_layout(enum dfu_layout l)
 {
 	const char *dfu_layout[] = {NULL, "RAW_ADDR", "FAT", "EXT2",
-					   "EXT3", "EXT4" };
+					   "EXT3", "EXT4", "RAM_ADDR" };
 	return dfu_layout[l];
 }
 

drivers/dfu/dfu_ram.c

@@ -0,0 +1,77 @@
+/*
+ * (C) Copyright 2013
+ * Afzal Mohammed <afzal.mohd.ma@gmail.com>
+ *
+ * Reference: dfu_mmc.c
+ * Copyright (C) 2012 Samsung Electronics
+ * author: Lukasz Majewski <l.majewski@samsung.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <malloc.h>
+#include <errno.h>
+#include <dfu.h>
+
+static int dfu_transfer_medium_ram(enum dfu_op op, struct dfu_entity *dfu,
+				   u64 offset, void *buf, long *len)
+{
+	if (dfu->layout != DFU_RAM_ADDR) {
+		error("unsupported layout: %s\n", dfu_get_layout(dfu->layout));
+		return  -EINVAL;
+	}
+
+	if (offset > dfu->data.ram.size) {
+		error("request exceeds allowed area\n");
+		return -EINVAL;
+	}
+
+	if (op == DFU_OP_WRITE)
+		memcpy(dfu->data.ram.start + offset, buf, *len);
+	else
+		memcpy(buf, dfu->data.ram.start + offset, *len);
+
+	return 0;
+}
+
+static int dfu_write_medium_ram(struct dfu_entity *dfu, u64 offset,
+				void *buf, long *len)
+{
+	return dfu_transfer_medium_ram(DFU_OP_WRITE, dfu, offset, buf, len);
+}
+
+static int dfu_read_medium_ram(struct dfu_entity *dfu, u64 offset,
+			       void *buf, long *len)
+{
+	if (!*len) {
+		*len = dfu->data.ram.size;
+		return 0;
+	}
+
+	return dfu_transfer_medium_ram(DFU_OP_READ, dfu, offset, buf, len);
+}
+
+int dfu_fill_entity_ram(struct dfu_entity *dfu, char *s)
+{
+	char *st;
+
+	dfu->dev_type = DFU_DEV_RAM;
+	st = strsep(&s, " ");
+	if (strcmp(st, "ram")) {
+		error("unsupported device: %s\n", st);
+		return -ENODEV;
+	}
+
+	dfu->layout = DFU_RAM_ADDR;
+	dfu->data.ram.start = (void *)simple_strtoul(s, &s, 16);
+	s++;
+	dfu->data.ram.size = simple_strtoul(s, &s, 16);
+
+	dfu->write_medium = dfu_write_medium_ram;
+	dfu->read_medium = dfu_read_medium_ram;
+
+	dfu->inited = 0;
+
+	return 0;
+}

include/dfu.h

@@ -19,6 +19,7 @@ enum dfu_device_type {
 	DFU_DEV_MMC = 1,
 	DFU_DEV_ONENAND,
 	DFU_DEV_NAND,
+	DFU_DEV_RAM,
 };
 
 enum dfu_layout {
@@ -27,6 +28,7 @@ enum dfu_layout {
 	DFU_FS_EXT2,
 	DFU_FS_EXT3,
 	DFU_FS_EXT4,
+	DFU_RAM_ADDR,
 };
 
 enum dfu_op {
@@ -56,6 +58,11 @@ struct nand_internal_data {
 	unsigned int ubi;
 };
 
+struct ram_internal_data {
+	void		*start;
+	unsigned int	size;
+};
+
 static inline unsigned int get_mmc_blk_size(int dev)
 {
 	return find_mmc_device(dev)->read_bl_len;
@@ -81,6 +88,7 @@ struct dfu_entity {
 	union {
 		struct mmc_internal_data mmc;
 		struct nand_internal_data nand;
+		struct ram_internal_data ram;
 	} data;
 
 	int (*read_medium)(struct dfu_entity *dfu,
@@ -143,4 +151,14 @@ static inline int dfu_fill_entity_nand(struct dfu_entity *dfu, char *s)
 }
 #endif
 
+#ifdef CONFIG_DFU_RAM
+extern int dfu_fill_entity_ram(struct dfu_entity *dfu, char *s);
+#else
+static inline int dfu_fill_entity_ram(struct dfu_entity *dfu, char *s)
+{
+	puts("RAM support not available!\n");
+	return -1;
+}
+#endif
+
 #endif /* __DFU_ENTITY_H_ */