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authorMiquel Raynal <miquel.raynal@bootlin.com>2020-05-19 10:45:43 +0300
committerMiquel Raynal <miquel.raynal@bootlin.com>2020-05-24 21:48:11 +0300
commit1759279ad138cb0a903224a89f4bf40f69c417e8 (patch)
treecff67a52837088ec35b5c787c182eeb810d3a04f /include/linux/bch.h
parentc8ae3f744ddca0da164bcacee42d1d4b6fe7027d (diff)
downloadlinux-1759279ad138cb0a903224a89f4bf40f69c417e8.tar.xz
lib/bch: Allow easy bit swapping
It seems that several hardware ECC engine use a swapped representation of bytes compared to software. This might having to do with how the ECC engine is wired to the NAND controller or the order the bits are passed to the hardware BCH logic. This means that when the software BCH engine is working in conjunction with data generated with hardware, sometimes we might need to swap the bits inside bytes, eg: 0x0A = b0000_1010 -> b0101_0000 = 0x50 Make it possible by adding a boolean to the BCH initialization routine. Regarding the implementation itself, this is a rather simple approach that can probably be enhanced in the future by preparing the ->a_{mod,pow}_tab tables with the swapping in mind. Suggested-by: Boris Brezillon <boris.brezillon@collabora.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com> Link: https://lore.kernel.org/linux-mtd/20200519074549.23673-3-miquel.raynal@bootlin.com
Diffstat (limited to 'include/linux/bch.h')
-rw-r--r--include/linux/bch.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/bch.h b/include/linux/bch.h
index 9c35e7cd5890..85fdce83d4e2 100644
--- a/include/linux/bch.h
+++ b/include/linux/bch.h
@@ -33,6 +33,7 @@
* @cache: log-based polynomial representation buffer
* @elp: error locator polynomial
* @poly_2t: temporary polynomials of degree 2t
+ * @swap_bits: swap bits within data and syndrome bytes
*/
struct bch_control {
unsigned int m;
@@ -51,9 +52,11 @@ struct bch_control {
int *cache;
struct gf_poly *elp;
struct gf_poly *poly_2t[4];
+ bool swap_bits;
};
-struct bch_control *bch_init(int m, int t, unsigned int prim_poly);
+struct bch_control *bch_init(int m, int t, unsigned int prim_poly,
+ bool swap_bits);
void bch_free(struct bch_control *bch);