[U-Boot] [PATCH v4] dfu: Introduction of the "dfu_hash_algo" env variable for checksum method setting

Lukasz Majewski
2014-05-12T08:43:36Z

Up till now the CRC32 of received data was calculated unconditionally.
The standard crc32 implementation causes long delay when large images
were uploaded.

The "dfu_hash_algo" environment variable gives the opportunity to
disable on demand the hash (crc32) calculation.
It can be done without the need to recompile the u-boot binary.

By default the crc32 is calculated, which means that legacy behavior
has been preserved.

Tests results:
400 MiB ums.img file
With crc32 calculation: 65 sec [avg 6.29 MB/s]
Without crc32 calculation: 25 sec [avg 16.17 MB/s]

Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Cc: Marek Vasut <marex@denx.de>

---
Changes for v2:
- Utilization of hash_block generic function to calculate CRC32 checksum
Changes for v3:
- Remove dependency on altering the lib/hash.c generic implementation
- Use of hash_update() function to calculate crc32 in the same way as
it was done with crc32
Changes for v4:
- When dfu_hash_algo env is not defined, the crc32 is calculated
---
drivers/dfu/dfu.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 47 insertions(+), 5 deletions(-)

diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c
index a938109..5878f99 100644
--- a/drivers/dfu/dfu.c
+++ b/drivers/dfu/dfu.c
@@ -13,6 +13,7 @@
#include <mmc.h>
#include <fat.h>
#include <dfu.h>
+#include <hash.h>
#include <linux/list.h>
#include <linux/compiler.h>

@@ -20,6 +21,7 @@ static bool dfu_reset_request;
static LIST_HEAD(dfu_list);
static int dfu_alt_num;
static int alt_num_cnt;
+static struct hash_algo *dfu_hash_algo;

bool dfu_reset(void)
{
@@ -99,6 +101,29 @@ unsigned char *dfu_get_buf(void)
return dfu_buf;
}

+static char *dfu_get_hash_algo(void)
+{
+ char *s;
+
+ s = getenv("dfu_hash_algo");
+ /*
+ * By default the legacy behaviour to calculate the crc32 hash
+ * value is preserved.
+ *
+ * To disable calculation of the hash algorithm for received data
+ * specify the "dfu_hash_algo = disabled" at your board envs.
+ */
+ debug("%s: DFU hash method: %s\n", __func__, s ? s : "not specified");
+
+ if (!s || !strcmp(s, "crc32"))
+ return "crc32";
+
+ if (!strcmp(s, "disabled"))
+ return NULL;
+
+ return NULL;
+}
+
static int dfu_write_buffer_drain(struct dfu_entity *dfu)
{
long w_size;
@@ -109,8 +134,9 @@ static int dfu_write_buffer_drain(struct dfu_entity *dfu)
if (w_size == 0)
return 0;

- /* update CRC32 */
- dfu->crc = crc32(dfu->crc, dfu->i_buf_start, w_size);
+ if (dfu_hash_algo)
+ dfu_hash_algo->hash_update(dfu_hash_algo, &dfu->crc,
+ dfu->i_buf_start, w_size, 0);

ret = dfu->write_medium(dfu, dfu->offset, dfu->i_buf_start, &w_size);
if (ret)
@@ -138,7 +164,9 @@ int dfu_flush(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
if (dfu->flush_medium)
ret = dfu->flush_medium(dfu);

- printf("\nDFU complete CRC32: 0x%08x\n", dfu->crc);
+ if (dfu_hash_algo)
+ printf("\nDFU complete %s: 0x%08x\n", dfu_hash_algo->name,
+ dfu->crc);

/* clear everything */
dfu_free_buf();
@@ -238,7 +266,11 @@ static int dfu_read_buffer_fill(struct dfu_entity *dfu, void *buf, int size)
/* consume */
if (chunk > 0) {
memcpy(buf, dfu->i_buf, chunk);
- dfu->crc = crc32(dfu->crc, buf, chunk);
+ if (dfu_hash_algo)
+ dfu_hash_algo->hash_update(dfu_hash_algo,
+ &dfu->crc, buf,
+ chunk, 0);
+
dfu->i_buf += chunk;
dfu->b_left -= chunk;
dfu->r_left -= chunk;
@@ -322,7 +354,9 @@ int dfu_read(struct dfu_entity *dfu, void *buf, int size, int blk_seq_num)
}

if (ret < size) {
- debug("%s: %s CRC32: 0x%x\n", __func__, dfu->name, dfu->crc);
+ if (dfu_hash_algo)
+ debug("%s: %s %s: 0x%x\n", __func__, dfu->name,
+ dfu_hash_algo->name, dfu->crc);
puts("\nUPLOAD ... done\nCtrl+C to exit ...\n");

dfu_free_buf();
@@ -397,6 +431,14 @@ int dfu_config_entities(char *env, char *interface, int num)
dfu_alt_num = dfu_find_alt_num(env);
debug("%s: dfu_alt_num=%d\n", __func__, dfu_alt_num);

+ dfu_hash_algo = NULL;
+ s = dfu_get_hash_algo();
+ if (s) {
+ ret = hash_lookup_algo(s, &dfu_hash_algo);
+ if (ret)
+ error("Hash algorithm %s not supported\n", s);
+ }
+
dfu = calloc(sizeof(*dfu), dfu_alt_num);
if (!dfu)
return -1;
--
1.7.10.4