Hi Lukasz,
On Mar 31, 2014, at 3:04 PM, Lukasz Majewski wrote:
Hi Pantelis,
Hi Lukasz,
On Mar 31, 2014, at 11:48 AM, Lukasz Majewski wrote:
Up till now the CRC32 of received data was calculated unconditionally. The standard crc32 implementation causes long delays when large images were uploaded.
The "dfu_checksum_method" environment variable gives the opportunity to enable on demand (when e.g. debugging) the crc32 calculation. It can be done without need to recompile the u-boot binary.
By default the crc32 is not calculated.
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]
That's interesting; I'm surprised that there's so much difference. Can we get some info about the environment? I.e. board, whether cache is enabled etc.
Board Exynos4412 - Trats2. Cache L1 enabled, cache L2 disabled.
Crc32 is calculated for 32 MiB chunks of data in the received buffer. I'm using the standard software crc32 u-boot's implementation. It is the same as the one for perl-crc32 debian package.
Thanks for the report. Would it be too much to ask for the time it takes to do a crc32 of the same image on user-space after boot?
I'm interested in the effect the disabling of L2 has.
The crc table is per byte and I guess lookups maybe expensive.
It seems so. Moreover the Exynos4412 has HW crypto engine which supports SHA1, MD5 and other algorithms. Unfortunately it doesn't provide speedup for crc32.
You could do a basic tradeoff of speed vs memory by creating larger tables but it might not work if we're cache trashing.
Or even try using CRC with smaller tables (i.e. 4 bits) which would not affect the cache much.
Regards
-- Pantelis
Regards
-- Pantelis
Signed-off-by: Lukasz Majewski l.majewski@samsung.com
drivers/dfu/dfu.c | 34 ++++++++++++++++++++++++++++++---- include/dfu.h | 5 +++++ 2 files changed, 35 insertions(+), 4 deletions(-)
diff --git a/drivers/dfu/dfu.c b/drivers/dfu/dfu.c index e15f959..5d50b47 100644 --- a/drivers/dfu/dfu.c +++ b/drivers/dfu/dfu.c @@ -20,6 +20,7 @@ static bool dfu_reset_request; static LIST_HEAD(dfu_list); static int dfu_alt_num; static int alt_num_count; +static int dfu_checksum_method;
bool dfu_reset(void) { @@ -99,6 +100,23 @@ unsigned char *dfu_get_buf(void) return dfu_buf; }
+static int dfu_get_checksum_method(void) +{
- char *s;
- s = getenv("dfu_checksum_method");
- if (!s)
return DFU_NO_CHECKSUM;- if (!strcmp(s, "crc32")) {
debug("%s: DFU checksum method: %s\n", __func__,s);
return DFU_CRC32;- } else {
error("DFU checksum method: %s not supported!\n",s);
return -EINVAL;- }
+}
static int dfu_write_buffer_drain(struct dfu_entity *dfu) { long w_size; @@ -109,8 +127,8 @@ 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_checksum_method == DFU_CRC32)
dfu->crc = crc32(dfu->crc, dfu->i_buf_start,w_size);
ret = dfu->write_medium(dfu, dfu->offset, dfu->i_buf_start, &w_size); if (ret) @@ -234,7 +252,8 @@ 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_checksum_method == DFU_CRC32)dfu->crc = crc32(dfu->crc, buf,chunk); dfu->i_buf += chunk; dfu->b_left -= chunk; dfu->r_left -= chunk; @@ -318,7 +337,9 @@ 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_checksum_method == DFU_CRC32)debug("%s: %s CRC32: 0x%x\n", __func__,dfu->name,
dfu->crc);puts("\nUPLOAD ... done\nCtrl+C to exit ...\n");
dfu_free_buf();
@@ -393,6 +414,11 @@ 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);
- ret = dfu_get_checksum_method();
- if (ret < 0)
return ret;- dfu_checksum_method = ret;
- dfu = calloc(sizeof(*dfu), dfu_alt_num); if (!dfu) return -1;
diff --git a/include/dfu.h b/include/dfu.h index 751f0fd..855d6dc 100644 --- a/include/dfu.h +++ b/include/dfu.h @@ -37,6 +37,11 @@ enum dfu_op { DFU_OP_WRITE, };
+enum dfu_checksum {
- DFU_NO_CHECKSUM = 0,
- DFU_CRC32,
+};
#define DFU_NOT_SUPPORTED -1
struct mmc_internal_data {
1.7.10.4
-- Best regards,
Lukasz Majewski
Samsung R&D Institute Poland (SRPOL) | Linux Platform Group