sunxi_nand_spl: Use kernel driver algorithm for determining ecc_mode / _off

Sync the code for figuring out the ecc_mode and ecc_offset with the linux
kernel v4.1. Keeping this in sync seems like a good idea in general, and
it fixes / adds support for ecc strengths of 56, 60 and 64 bits.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>

diff --git a/drivers/mtd/nand/sunxi_nand_spl.c b/drivers/mtd/nand/sunxi_nand_spl.c
index 663c03ec4fdf2c91a9411a56228c3fa6da910c26..61eb393446fb205e4ae031b37dadb937bfd85924 100644 (file)
--- a/drivers/mtd/nand/sunxi_nand_spl.c
+++ b/drivers/mtd/nand/sunxi_nand_spl.c
@@ -181,60 +181,26 @@ static void nand_read_page(unsigned int real_addr, dma_addr_t dst,
                           int syndrome, uint32_t *ecc_errors)
 {
        uint32_t val;
-       int ecc_off = 0;
+       int i, ecc_off = 0;
        uint16_t ecc_mode = 0;
        uint16_t rand_seed;
        uint32_t page;
        uint16_t column;
        uint32_t oob_offset;
+       static const u8 strengths[] = { 16, 24, 28, 32, 40, 48, 56, 60, 64 };
 
-       switch (CONFIG_NAND_SUNXI_SPL_ECC_STRENGTH) {
-       case 16:
-               ecc_mode = 0;
-               ecc_off = 0x20;
-               break;
-       case 24:
-               ecc_mode = 1;
-               ecc_off = 0x2e;
-               break;
-       case 28:
-               ecc_mode = 2;
-               ecc_off = 0x32;
-               break;
-       case 32:
-               ecc_mode = 3;
-               ecc_off = 0x3c;
-               break;
-       case 40:
-               ecc_mode = 4;
-               ecc_off = 0x4a;
-               break;
-       case 48:
-               ecc_mode = 4;
-               ecc_off = 0x52;
-               break;
-       case 56:
-               ecc_mode = 4;
-               ecc_off = 0x60;
-               break;
-       case 60:
-               ecc_mode = 4;
-               ecc_off = 0x0;
-               break;
-       case 64:
-               ecc_mode = 4;
-               ecc_off = 0x0;
-               break;
-       default:
-               ecc_mode = 0;
-               ecc_off = 0;
+       for (i = 0; i < ARRAY_SIZE(strengths); i++) {
+               if (CONFIG_NAND_SUNXI_SPL_ECC_STRENGTH == strengths[i]) {
+                       ecc_mode = i;
+                       break;
+               }
        }
 
-       if (ecc_off == 0) {
-               printf("Unsupported ECC strength (%d)!\n",
-                      CONFIG_NAND_SUNXI_SPL_ECC_STRENGTH);
-               return;
-       }
+       /* HW ECC always request ECC bytes for 1024 bytes blocks */
+       ecc_off = DIV_ROUND_UP(CONFIG_NAND_SUNXI_SPL_ECC_STRENGTH * fls(8 * 1024), 8);
+       /* HW ECC always work with even numbers of ECC bytes */
+       ecc_off += (ecc_off & 1);
+       ecc_off += 4; /* prepad */
 
        page = real_addr / CONFIG_NAND_SUNXI_SPL_PAGE_SIZE;
        column = real_addr % CONFIG_NAND_SUNXI_SPL_PAGE_SIZE;