dfu: fix some issues with reads/uploads

DFU read support appears to rely upon dfu->read_medium() updating the
passed-by-reference len parameter to indicate the remaining size
available for reading.

dfu_read_medium_mmc() never does this, and the implementation of
dfu_read_medium_nand() will only work if called just once; it hard-codes
the value to the total size of the NAND device irrespective of read
offset.

I believe that overloading dfu->read_medium() is confusing. As such,
this patch introduces a new function dfu->get_medium_size() which can
be used to explicitly find out the medium size, and nothing else.
dfu_read() is modified to use this function to set the initial value for
dfu->r_left, rather than attempting to use the side-effects of
dfu->read_medium() for this purpose.

Due to this change, dfu_read() must initially set dfu->b_left to 0, since
no data has been read.

dfu_read_buffer_fill() must also be modified not to adjust dfu->r_left
when simply copying data from dfu->i_buf_start to the upload request
buffer. r_left represents the amount of data left to be read from HW.
That value is not affected by the memcpy(), but only by calls to
dfu->read_medium().

After this change, I can read from either a 4MB or 1.5MB chunk of a 4MB
eMMC boot partion with CONFIG_SYS_DFU_DATA_BUF_SIZE==1MB. Without this
change, attempting to do that would result in DFU read returning no data
at all due to r_left never being set.

Signed-off-by: Stephen Warren <swarren@nvidia.com>

drivers/dfu/dfu.c

@@ -267,7 +267,6 @@ static int dfu_read_buffer_fill(struct dfu_entity *dfu, void *buf, int size)
 
 			dfu->i_buf += chunk;
 			dfu->b_left -= chunk;
-			dfu->r_left -= chunk;
 			size -= chunk;
 			buf += chunk;
 			readn += chunk;
@@ -313,10 +312,19 @@ int dfu_read(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 		if (dfu->i_buf_start == NULL)
 			return -ENOMEM;
 
-		ret = dfu->read_medium(dfu, 0, dfu->i_buf_start, &dfu->r_left);
+		dfu->r_left = dfu->get_medium_size(dfu);
-		if (ret != 0) {
+		if (dfu->r_left < 0)
-			debug("%s: failed to get r_left\n", __func__);
+			return dfu->r_left;
-			return ret;
+		switch (dfu->layout) {
+		case DFU_RAW_ADDR:
+		case DFU_RAM_ADDR:
+			break;
+		default:
+			if (dfu->r_left >= dfu_buf_size) {
+				printf("%s: File too big for buffer\n",
+				       __func__);
+				return -EOVERFLOW;
+			}
 		}
 
 		debug("%s: %s %ld [B]\n", __func__, dfu->name, dfu->r_left);
@@ -326,7 +334,7 @@ int dfu_read(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
 		dfu->offset = 0;
 		dfu->i_buf_end = dfu_get_buf() + dfu_buf_size;
 		dfu->i_buf = dfu->i_buf_start;
-		dfu->b_left = min(dfu_buf_size, dfu->r_left);
+		dfu->b_left = 0;
 
 		dfu->bad_skip = 0;
 

drivers/dfu/dfu_mmc.c

@@ -12,6 +12,8 @@
 #include <errno.h>
 #include <div64.h>
 #include <dfu.h>
+#include <ext4fs.h>
+#include <fat.h>
 #include <mmc.h>
 
 static unsigned char __aligned(CONFIG_SYS_CACHELINE_SIZE)
@@ -113,22 +115,17 @@ static int mmc_file_buffer(struct dfu_entity *dfu, void *buf, long *len)
 static int mmc_file_op(enum dfu_op op, struct dfu_entity *dfu,
 			void *buf, long *len)
 {
+	const char *fsname, *opname;
 	char cmd_buf[DFU_CMD_BUF_SIZE];
 	char *str_env;
 	int ret;
 
 	switch (dfu->layout) {
 	case DFU_FS_FAT:
-		sprintf(cmd_buf, "fat%s mmc %d:%d 0x%x %s",
+		fsname = "fat";
-			op == DFU_OP_READ ? "load" : "write",
-			dfu->data.mmc.dev, dfu->data.mmc.part,
-			(unsigned int) buf, dfu->name);
 		break;
 	case DFU_FS_EXT4:
-		sprintf(cmd_buf, "ext4%s mmc %d:%d 0x%x /%s",
+		fsname = "ext4";
-			op == DFU_OP_READ ? "load" : "write",
-			dfu->data.mmc.dev, dfu->data.mmc.part,
-			(unsigned int) buf, dfu->name);
 		break;
 	default:
 		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
@@ -136,6 +133,28 @@ static int mmc_file_op(enum dfu_op op, struct dfu_entity *dfu,
 		return -1;
 	}
 
+	switch (op) {
+	case DFU_OP_READ:
+		opname = "load";
+		break;
+	case DFU_OP_WRITE:
+		opname = "write";
+		break;
+	case DFU_OP_SIZE:
+		opname = "size";
+		break;
+	default:
+		return -1;
+	}
+
+	sprintf(cmd_buf, "%s%s mmc %d:%d", fsname, opname,
+		dfu->data.mmc.dev, dfu->data.mmc.part);
+
+	if (op != DFU_OP_SIZE)
+		sprintf(cmd_buf + strlen(cmd_buf), " 0x%x", (unsigned int)buf);
+
+	sprintf(cmd_buf + strlen(cmd_buf), " %s", dfu->name);
+
 	if (op == DFU_OP_WRITE)
 		sprintf(cmd_buf + strlen(cmd_buf), " %lx", *len);
 
@@ -147,7 +166,7 @@ static int mmc_file_op(enum dfu_op op, struct dfu_entity *dfu,
 		return ret;
 	}
 
-	if (dfu->layout != DFU_RAW_ADDR && op == DFU_OP_READ) {
+	if (op != DFU_OP_WRITE) {
 		str_env = getenv("filesize");
 		if (str_env == NULL) {
 			puts("dfu: Wrong file size!\n");
@@ -196,6 +215,27 @@ int dfu_flush_medium_mmc(struct dfu_entity *dfu)
 	return ret;
 }
 
+long dfu_get_medium_size_mmc(struct dfu_entity *dfu)
+{
+	int ret;
+	long len;
+
+	switch (dfu->layout) {
+	case DFU_RAW_ADDR:
+		return dfu->data.mmc.lba_size * dfu->data.mmc.lba_blk_size;
+	case DFU_FS_FAT:
+	case DFU_FS_EXT4:
+		ret = mmc_file_op(DFU_OP_SIZE, dfu, NULL, &len);
+		if (ret < 0)
+			return ret;
+		return len;
+	default:
+		printf("%s: Layout (%s) not (yet) supported!\n", __func__,
+		       dfu_get_layout(dfu->layout));
+		return -1;
+	}
+}
+
 int dfu_read_medium_mmc(struct dfu_entity *dfu, u64 offset, void *buf,
 		long *len)
 {
@@ -316,6 +356,7 @@ int dfu_fill_entity_mmc(struct dfu_entity *dfu, char *s)
 	}
 
 	dfu->dev_type = DFU_DEV_MMC;
+	dfu->get_medium_size = dfu_get_medium_size_mmc;
 	dfu->read_medium = dfu_read_medium_mmc;
 	dfu->write_medium = dfu_write_medium_mmc;
 	dfu->flush_medium = dfu_flush_medium_mmc;

drivers/dfu/dfu_nand.c

@@ -114,6 +114,11 @@ static int dfu_write_medium_nand(struct dfu_entity *dfu,
 	return ret;
 }
 
+long dfu_get_medium_size_nand(struct dfu_entity *dfu)
+{
+	return dfu->data.nand.size;
+}
+
 static int dfu_read_medium_nand(struct dfu_entity *dfu, u64 offset, void *buf,
 		long *len)
 {
@@ -121,7 +126,6 @@ static int dfu_read_medium_nand(struct dfu_entity *dfu, u64 offset, void *buf,
 
 	switch (dfu->layout) {
 	case DFU_RAW_ADDR:
-		*len = dfu->data.nand.size;
 		ret = nand_block_read(dfu, offset, buf, len);
 		break;
 	default:
@@ -220,6 +224,7 @@ int dfu_fill_entity_nand(struct dfu_entity *dfu, char *s)
 		return -1;
 	}
 
+	dfu->get_medium_size = dfu_get_medium_size_nand;
 	dfu->read_medium = dfu_read_medium_nand;
 	dfu->write_medium = dfu_write_medium_nand;
 	dfu->flush_medium = dfu_flush_medium_nand;

drivers/dfu/dfu_ram.c

@@ -41,14 +41,14 @@ static int dfu_write_medium_ram(struct dfu_entity *dfu, u64 offset,
 	return dfu_transfer_medium_ram(DFU_OP_WRITE, dfu, offset, buf, len);
 }
 
+long dfu_get_medium_size_ram(struct dfu_entity *dfu)
+{
+	return dfu->data.ram.size;
+}
+
 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);
 }
 
@@ -69,6 +69,7 @@ int dfu_fill_entity_ram(struct dfu_entity *dfu, char *s)
 	dfu->data.ram.size = simple_strtoul(s, &s, 16);
 
 	dfu->write_medium = dfu_write_medium_ram;
+	dfu->get_medium_size = dfu_get_medium_size_ram;
 	dfu->read_medium = dfu_read_medium_ram;
 
 	dfu->inited = 0;

include/dfu.h

@@ -35,6 +35,7 @@ enum dfu_layout {
 enum dfu_op {
 	DFU_OP_READ = 1,
 	DFU_OP_WRITE,
+	DFU_OP_SIZE,
 };
 
 struct mmc_internal_data {
@@ -96,6 +97,8 @@ struct dfu_entity {
 		struct ram_internal_data ram;
 	} data;
 
+	long (*get_medium_size)(struct dfu_entity *dfu);
+
 	int (*read_medium)(struct dfu_entity *dfu,
 			u64 offset, void *buf, long *len);