3 files changed, 32 insertions, 0 deletions
diff --git a/lib/842/842.h b/lib/842/842.h
index 7c20003..e0a122bc 100644
--- a/lib/842/842.h
+++ b/lib/842/842.h
@@ -76,6 +76,7 @@
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/bitops.h>
+#include <linux/crc32.h>
 #include <asm/unaligned.h>
 
 #include <linux/sw842.h>
@@ -98,6 +99,7 @@
 #define I2_BITS		(8)
 #define I4_BITS		(9)
 #define I8_BITS		(8)
+#define CRC_BITS	(32)
 
 #define REPEAT_BITS_MAX		(0x3f)
 #define SHORT_DATA_BITS_MAX	(0x7)
diff --git a/lib/842/842_compress.c b/lib/842/842_compress.c
index 7ce6894..4051339 100644
--- a/lib/842/842_compress.c
+++ b/lib/842/842_compress.c
@@ -490,6 +490,7 @@ int sw842_compress(const u8 *in, unsigned int ilen,
 	int ret;
 	u64 last, next, pad, total;
 	u8 repeat_count = 0;
+	u32 crc;
 
 	BUILD_BUG_ON(sizeof(*p) > SW842_MEM_COMPRESS);
 
@@ -580,6 +581,18 @@ skip_comp:
 	if (ret)
 		return ret;
 
+	/*
+	 * crc(0:31) is appended to target data starting with the next
+	 * bit after End of stream template.
+	 * nx842 calculates CRC for data in big-endian format. So doing
+	 * same here so that sw842 decompression can be used for both
+	 * compressed data.
+	 */
+	crc = crc32_be(0, in, ilen);
+	ret = add_bits(p, crc, CRC_BITS);
+	if (ret)
+		return ret;
+
 	if (p->bit) {
 		p->out++;
 		p->olen--;
diff --git a/lib/842/842_decompress.c b/lib/842/842_decompress.c
index 5446ff0..8881dad 100644
--- a/lib/842/842_decompress.c
+++ b/lib/842/842_decompress.c
@@ -285,6 +285,7 @@ int sw842_decompress(const u8 *in, unsigned int ilen,
 	struct sw842_param p;
 	int ret;
 	u64 op, rep, tmp, bytes, total;
+	u64 crc;
 
 	p.in = (u8 *)in;
 	p.bit = 0;
@@ -375,6 +376,22 @@ int sw842_decompress(const u8 *in, unsigned int ilen,
 		}
 	} while (op != OP_END);
 
+	/*
+	 * crc(0:31) is saved in compressed data starting with the
+	 * next bit after End of stream template.
+	 */
+	ret = next_bits(&p, &crc, CRC_BITS);
+	if (ret)
+		return ret;
+
+	/*
+	 * Validate CRC saved in compressed data.
+	 */
+	if (crc != (u64)crc32_be(0, out, total - p.olen)) {
+		pr_debug("CRC mismatch for decompression\n");
+		return -EINVAL;
+	}
+
 	if (unlikely((total - p.olen) > UINT_MAX))
 		return -ENOSPC;