[U-Boot] [PATCH v3 07/20] sha256: Use const where possible and add watchdog function

[Simon Glass]

In preparation for making the hash function common, we may as well use
const where we can.

Also add a watchdog version of the hashing function.

Signed-off-by: Simon Glass <s...@chromium.org>
---
Changes in v3: None
Changes in v2:
- Add new patch to adjust sha256 functions to const and watchdog

 include/sha256.h |    8 +++++++-
 lib/sha256.c     |   37 +++++++++++++++++++++++++++++++++++--
 2 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/include/sha256.h b/include/sha256.h
index e38ea89..beadab3 100644
--- a/include/sha256.h
+++ b/include/sha256.h
@@ -3,6 +3,9 @@
 
 #define SHA256_SUM_LEN 32
 
+/* Reset watchdog each time we process this many bytes */
+#define CHUNKSZ_SHA256 (64 * 1024)
+
 typedef struct {
        uint32_t total[2];
        uint32_t state[8];
@@ -10,7 +13,10 @@ typedef struct {
 } sha256_context;
 
 void sha256_starts(sha256_context * ctx);
-void sha256_update(sha256_context * ctx, uint8_t * input, uint32_t length);
+void sha256_update(sha256_context *ctx, const uint8_t *input, uint32_t length);
 void sha256_finish(sha256_context * ctx, uint8_t digest[SHA256_SUM_LEN]);
 
+void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
+               unsigned char *output, unsigned int chunk_sz);
+
 #endif /* _SHA256_H */
diff --git a/lib/sha256.c b/lib/sha256.c
index deb63a4..ab2db48 100644
--- a/lib/sha256.c
+++ b/lib/sha256.c
@@ -60,7 +60,7 @@ void sha256_starts(sha256_context * ctx)
        ctx->state[7] = 0x5BE0CD19;
 }
 
-void sha256_process(sha256_context * ctx, uint8_t data[64])
+static void sha256_process(sha256_context *ctx, const uint8_t data[64])
 {
        uint32_t temp1, temp2;
        uint32_t W[64];
@@ -191,7 +191,7 @@ void sha256_process(sha256_context * ctx, uint8_t data[64])
        ctx->state[7] += H;
 }
 
-void sha256_update(sha256_context * ctx, uint8_t * input, uint32_t length)
+void sha256_update(sha256_context *ctx, const uint8_t *input, uint32_t length)
 {
        uint32_t left, fill;
 
@@ -260,3 +260,36 @@ void sha256_finish(sha256_context * ctx, uint8_t 
digest[32])
        PUT_UINT32_BE(ctx->state[6], digest, 24);
        PUT_UINT32_BE(ctx->state[7], digest, 28);
 }
+
+/*
+ * Output = SHA-256( input buffer ). Trigger the watchdog every 'chunk_sz'
+ * bytes of input processed.
+ */
+void sha256_csum_wd(const unsigned char *input, unsigned int ilen,
+               unsigned char *output, unsigned int chunk_sz)
+{
+       sha256_context ctx;
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+       unsigned char *end, *curr;
+       int chunk;
+#endif
+
+       sha256_starts(&ctx);
+
+#if defined(CONFIG_HW_WATCHDOG) || defined(CONFIG_WATCHDOG)
+       curr = input;
+       end = input + ilen;
+       while (curr < end) {
+               chunk = end - curr;
+               if (chunk > chunk_sz)
+                       chunk = chunk_sz;
+               sha256_update(&ctx, curr, chunk);
+               curr += chunk;
+               WATCHDOG_RESET();
+       }
+#else
+       sha256_update(&ctx, input, ilen);
+#endif
+
+       sha256_finish(&ctx, output);
+}
-- 
1.7.7.3

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