crc32 may be required in PBL for checking data integrity. Add it to PBL
when CONFIG_CRC32 is enabled.
To save some memory use a slower-but-smaller variant of the crc32 algorithm
in the PBL.
Signed-off-by: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
---
To: Barebox Mailing List <barebox@xxxxxxxxxxxxxxxxxxx>
Cc: Johannes Zink <j.zink@xxxxxxxxxxxxxx>
Cc: patchwork-jzi@xxxxxxxxxxxxxx
---
Changes:
v1->v2: Worked in Ahmad's review (thank you for reviewing my patch):
- instead of using CRC32_EARLY, always add crc32.o to obj and pbl if
CONFIG_CRC is set and rely on LTO to remove unused symbols instead
- use a CRC32 implementation without a prepopulated Lookup Table,
which trades in speed for code size in the PBL, analogously to what
Sascha implemented in [1]
- add hints on some of the #endifs for better readability of nested
ifdef blocks
- reword commit message to reflect on the changes made
[1] 2d13b856604b ("crc: Add PBL variant for crc_itu_t()")
---
crypto/Makefile | 2 +-
crypto/crc32.c | 34 ++++++++++++++++++++++++++++------
2 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/crypto/Makefile b/crypto/Makefile
index 22035d4f69ee..4a1c7e9615b8 100644
--- a/crypto/Makefile
+++ b/crypto/Makefile
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_CRC32) += crc32.o
+obj-pbl-$(CONFIG_CRC32) += crc32.o
obj-pbl-$(CONFIG_CRC_ITU_T) += crc-itu-t.o
obj-$(CONFIG_CRC7) += crc7.o
obj-$(CONFIG_DIGEST) += digest.o
diff --git a/crypto/crc32.c b/crypto/crc32.c
index 95cb2212db2b..2cf13144c1d2 100644
--- a/crypto/crc32.c
+++ b/crypto/crc32.c
@@ -22,7 +22,7 @@
#define STATIC static inline
#endif
-#ifdef CONFIG_DYNAMIC_CRC_TABLE
+#if defined(CONFIG_DYNAMIC_CRC_TABLE) && !defined(__PBL__)
static uint32_t *crc_table;
@@ -73,7 +73,7 @@ static void make_crc_table(void)
crc_table[n] = c;
}
}
-#else
+#elif !defined(__PBL__)
/* ========================================================================
* Table of CRC-32's of all single-byte values (made by make_crc_table)
*/
@@ -131,9 +131,30 @@ static const uint32_t crc_table[256] = {
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L, 0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL
};
-#endif
+#endif /* defined(CONFIG_DYNAMIC_CRC_TABLE) && !defined(__PBL__) */
+
+
+
+#ifdef __PBL__
+#define CRC32_POLY 0xEDB88320L
+STATIC uint32_t crc32(uint32_t crc, const void *_buf, unsigned int len)
+{
+ int i, j;
+ const unsigned char *buf = _buf;
+ crc = crc ^ 0xffffffffL;
+ for (i=0; i< len; i++) {
+ crc ^= buf[i];
+ for (j = 0; j < 8; j++) {
+ crc = (crc >> 1) ^ ((crc & 1) ? CRC32_POLY : 0);
+ }
+ }
+
+ crc = crc ^ 0xffffffffL;
+ return crc;
+}
+#else
/* ========================================================================= */
#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
#define DO2(buf) DO1(buf); DO1(buf);
@@ -148,7 +169,7 @@ STATIC uint32_t crc32(uint32_t crc, const void *_buf, unsigned int len)
#ifdef CONFIG_DYNAMIC_CRC_TABLE
if (!crc_table)
make_crc_table();
-#endif
+#endif /* CONFIG_DYNAMIC_CRC_TABLE */
crc = crc ^ 0xffffffffL;
while (len >= 8)
{
@@ -162,7 +183,7 @@ STATIC uint32_t crc32(uint32_t crc, const void *_buf, unsigned int len)
}
#ifdef __BAREBOX__
EXPORT_SYMBOL(crc32);
-#endif
+#endif /* __BAREBOX__ */
/* No ones complement version. JFFS2 (and other things ?)
* don't use ones compliment in their CRC calculations.
@@ -174,7 +195,7 @@ STATIC uint32_t crc32_no_comp(uint32_t crc, const void *_buf, unsigned int len)
#ifdef CONFIG_DYNAMIC_CRC_TABLE
if (!crc_table)
make_crc_table();
-#endif
+#endif /* CONFIG_DYNAMIC_CRC_TABLE */
while (len >= 8)
{
DO8(buf);
@@ -186,6 +207,7 @@ STATIC uint32_t crc32_no_comp(uint32_t crc, const void *_buf, unsigned int len)
return crc;
}
+#endif /* __PBL__ */
STATIC uint32_t crc32_be(uint32_t crc, const void *_buf, unsigned int len)
{
---
base-commit: bef38b18eeb5d2f1fac334fb8b831e47261e099c
change-id: 20230829-crc32_in_pbl-4d824629d4e2
Best regards,
--
Johannes Zink <j.zink@xxxxxxxxxxxxxx>
