[PATCH v2 20/30] mtd: use parity16 in ssfdc

From: zengzhaoxiu
Date: Wed Apr 06 2016 - 05:53:51 EST


From: Zhaoxiu Zeng <zhaoxiu.zeng@xxxxxxxxx>

The original get_parity return even parity of the input number. So
hweight of "block_address & 0x7ff" must be odd if block_address is valid.

This patch use parity16, and rearrange the code.

Signed-off-by: Zhaoxiu Zeng <zhaoxiu.zeng@xxxxxxxxx>
---
drivers/mtd/ssfdc.c | 31 ++++++++-----------------------
1 file changed, 8 insertions(+), 23 deletions(-)

diff --git a/drivers/mtd/ssfdc.c b/drivers/mtd/ssfdc.c
index daf82ba..1d55f15 100644
--- a/drivers/mtd/ssfdc.c
+++ b/drivers/mtd/ssfdc.c
@@ -182,24 +182,10 @@ static int read_raw_oob(struct mtd_info *mtd, loff_t offs, uint8_t *buf)
return 0;
}

-/* Parity calculator on a word of n bit size */
-static int get_parity(int number, int size)
-{
- int k;
- int parity;
-
- parity = 1;
- for (k = 0; k < size; k++) {
- parity += (number >> k);
- parity &= 1;
- }
- return parity;
-}
-
/* Read and validate the logical block address field stored in the OOB */
static int get_logical_address(uint8_t *oob_buf)
{
- int block_address, parity;
+ int block_address;
int offset[2] = {6, 11}; /* offset of the 2 address fields within OOB */
int j;
int ok = 0;
@@ -215,18 +201,17 @@ static int get_logical_address(uint8_t *oob_buf)

/* Check for the signature bits in the address field (MSBits) */
if ((block_address & ~0x7FF) == 0x1000) {
- parity = block_address & 0x01;
block_address &= 0x7FF;
- block_address >>= 1;

- if (get_parity(block_address, 10) != parity) {
- pr_debug("SSFDC_RO: logical address field%d"
- "parity error(0x%04X)\n", j+1,
- block_address);
- } else {
- ok = 1;
+ ok = parity16(block_address);
+ if (ok) {
+ block_address >>= 1;
break;
}
+
+ pr_debug("SSFDC_RO: logical address field%d"
+ "parity error(0x%04X)\n", j+1,
+ block_address);
}
}

--
2.5.0