On Mon, Aug 18, 2014 at 03:08:40PM +0800, Josh Wu wrote:
> If there is no PMECC lookup table stored in ROM, or lookup table offset is
> not specified, PMECC driver should build it in DDR by itself.
>
> That make the PMECC driver work for some board which doesn't has PMECC
> lookup table in ROM.
>
> Signed-off-by: Josh Wu <josh...@atmel.com>
> Cc: devicetree@vger.kernel.org
> ---
> This patch is based on mtd-l2/next branch
>
> v1 -> v2:
> make create_lookup_table() static.
sparse gives me several new complaints:
+drivers/mtd/nand/atmel_nand.c:1219:50: warning: incorrect type in argument 2
(different signedness) [sparse]
+drivers/mtd/nand/atmel_nand.c:1219:50: expected signed short [usertype]
*index_of [sparse]
+drivers/mtd/nand/atmel_nand.c:1219:50: got unsigned short [usertype] *addr
[sparse]
+drivers/mtd/nand/atmel_nand.c:1219:61: warning: incorrect type in argument 3
(different signedness) [sparse]
+drivers/mtd/nand/atmel_nand.c:1219:61: expected signed short [usertype]
*alpha_to [sparse]
+drivers/mtd/nand/atmel_nand.c:1219:61: got unsigned short [usertype] *
[sparse]
+drivers/mtd/nand/atmel_nand.c:1292:38: warning: incorrect type in assignment
(different address spaces) [sparse]
+drivers/mtd/nand/atmel_nand.c:1292:38: expected void [noderef]
<asn:2>*pmecc_rom_base [sparse]
+drivers/mtd/nand/atmel_nand.c:1292:38: got unsigned short [usertype]
*[assigned] galois_table [sparse]
The third one might be a false positive. I suppose it's safe to use
regular memory with __iomem accessors (but not vice versa).
> .../devicetree/bindings/mtd/atmel-nand.txt | 6 +-
> drivers/mtd/nand/atmel_nand.c | 136
> ++++++++++++++++++++-
> 2 files changed, 136 insertions(+), 6 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> index c472883..75d1847 100644
> --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt
> @@ -5,7 +5,9 @@ Required properties:
> - reg : should specify localbus address and size used for the chip,
> and hardware ECC controller if available.
> If the hardware ECC is PMECC, it should contain address and size for
> - PMECC, PMECC Error Location controller and ROM which has lookup tables.
> + PMECC and PMECC Error Location controller.
> + The PMECC lookup table address and size in ROM is optional. If not
> + specified, driver will build it in runtime.
> - atmel,nand-addr-offset : offset for the address latch.
> - atmel,nand-cmd-offset : offset for the command latch.
> - #address-cells, #size-cells : Must be present if the device has sub-nodes
> @@ -27,7 +29,7 @@ Optional properties:
> are: 512, 1024.
> - atmel,pmecc-lookup-table-offset : includes two offsets of lookup table in
> ROM
> for different sector size. First one is for sector size 512, the next is
> for
> - sector size 1024.
> + sector size 1024. If not specified, driver will build the table in runtime.
> - nand-bus-width : 8 or 16 bus width if not present 8
> - nand-on-flash-bbt: boolean to enable on flash bbt option if not present
> false
> - Nand Flash Controller(NFC) is a slave driver under Atmel nand flash
> diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
> index effa7a29..84af313 100644
> --- a/drivers/mtd/nand/atmel_nand.c
> +++ b/drivers/mtd/nand/atmel_nand.c
> @@ -124,6 +124,7 @@ struct atmel_nand_host {
> bool has_pmecc;
> u8 pmecc_corr_cap;
> u16 pmecc_sector_size;
> + bool has_no_lookup_table;
> u32 pmecc_lookup_table_offset;
> u32 pmecc_lookup_table_offset_512;
> u32 pmecc_lookup_table_offset_1024;
> @@ -1109,12 +1110,121 @@ static int pmecc_choose_ecc(struct atmel_nand_host
> *host,
> return 0;
> }
>
> +static int pmecc_build_galois_table(int mm,
> + int16_t *index_of, int16_t *alpha_to)
> +{
> + unsigned int i, mask, nn;
> + unsigned int p[PMECC_GF_DIMENSION_14 + 1];
> +
> + nn = (1 << mm) - 1;
> + /* set default value */
> + for (i = 1; i < mm; i++)
> + p[i] = 0;
> +
> + /* 1 + X^mm */
> + p[0] = 1;
> + p[mm] = 1;
> +
> + /* others */
> + switch (mm) {
> + case 3:
> + case 4:
> + case 6:
> + case 15:
> + p[1] = 1;
> + break;
> + case 5:
> + case 11:
> + p[2] = 1;
> + break;
> + case 7:
> + case 10:
> + p[3] = 1;
> + break;
> + case 8:
> + p[2] = p[3] = p[4] = 1;
> + break;
> + case 9:
> + p[4] = 1;
> + break;
> + case 12:
> + p[1] = p[4] = p[6] = 1;
> + break;
> + case 13:
> + p[1] = p[3] = p[4] = 1;
> + break;
> + case 14:
> + p[1] = p[6] = p[10] = 1;
> + break;
> + default:
> + /* Error */
> + return -EINVAL;
> + }
> +
> + /* Build alpha ^ mm it will help to generate the field (primitiv) */
> + alpha_to[mm] = 0;
> + for (i = 0; i < mm; i++)
> + if (p[i])
> + alpha_to[mm] |= 1 << i;
> +
> + /*
> + * Then build elements from 0 to mm - 1. As degree is less than mm
> + * so it is just a logical shift.
> + */
> + mask = 1;
> + for (i = 0; i < mm; i++) {
> + alpha_to[i] = mask;
> + index_of[alpha_to[i]] = i;
> + mask <<= 1;
> + }
> +
> + index_of[alpha_to[mm]] = mm;
> +
> + /* use a mask to select the MSB bit of the LFSR */
> + mask >>= 1;
> +
> + /* then finish the building */
> + for (i = mm + 1; i <= nn; i++) {
> + /* check if the msb bit of the lfsr is set */
> + if (alpha_to[i - 1] & mask)
> + alpha_to[i] = alpha_to[mm] ^
> + ((alpha_to[i - 1] ^ mask) << 1);
> + else
> + alpha_to[i] = alpha_to[i - 1] << 1;
> +
> + index_of[alpha_to[i]] = i % nn;
> + }
> +
> + /* index of 0 is undefined in a multiplicative field */
> + index_of[0] = -1;
> +
> + return 0;
> +}
Is this algorithm documented? How did you come up with this?
> +
> +static uint16_t *create_lookup_table(struct device *dev, int sector_size)
> +{
> + int table_size = (sector_size == 512) ?
> + PMECC_LOOKUP_TABLE_SIZE_512 :
> + PMECC_LOOKUP_TABLE_SIZE_1024;
> + int degree = (sector_size == 512) ?
> + PMECC_GF_DIMENSION_13 :
> + PMECC_GF_DIMENSION_14;
> + uint16_t *addr = devm_kzalloc(dev, 2 * table_size * sizeof(uint16_t),
> + GFP_KERNEL);
> +
> + if (addr)
> + pmecc_build_galois_table(degree, addr, addr + table_size);
> +
> + return addr;
> +}
> +
> static int atmel_pmecc_nand_init_params(struct platform_device *pdev,
> struct atmel_nand_host *host)
> {
> struct mtd_info *mtd = &host->mtd;
> struct nand_chip *nand_chip = &host->nand_chip;
> struct resource *regs, *regs_pmerr, *regs_rom;
> + uint16_t *galois_table;
> int cap, sector_size, err_no;
>
> err_no = pmecc_choose_ecc(host, &cap, §or_size);
> @@ -1160,8 +1270,24 @@ static int atmel_pmecc_nand_init_params(struct
> platform_device *pdev,
> regs_rom = platform_get_resource(pdev, IORESOURCE_MEM, 3);
> host->pmecc_rom_base = devm_ioremap_resource(&pdev->dev, regs_rom);
> if (IS_ERR(host->pmecc_rom_base)) {
> - err_no = PTR_ERR(host->pmecc_rom_base);
> - goto err;
> + if (!host->has_no_lookup_table)
> + /* Don't display the information again */
> + dev_err(host->dev, "Can not get I/O resource for ROM,
> will build a lookup table in runtime!\n");
> +
> + host->has_no_lookup_table = true;
> + }
> +
> + if (host->has_no_lookup_table) {
> + /* Build the look-up table in runtime */
> + galois_table = create_lookup_table(host->dev, sector_size);
> + if (!galois_table) {
> + dev_err(host->dev, "Failed to build a lookup table in
> runtime!\n");
> + err_no = -ENOMEM;
> + goto err;
> + }
> +
> + host->pmecc_rom_base = galois_table;
> + host->pmecc_lookup_table_offset = 0;
> }
>
> nand_chip->ecc.size = sector_size;
> @@ -1498,8 +1624,10 @@ static int atmel_of_init_port(struct atmel_nand_host
> *host,
>
> if (of_property_read_u32_array(np, "atmel,pmecc-lookup-table-offset",
> offset, 2) != 0) {
> - dev_err(host->dev, "Cannot get PMECC lookup table offset\n");
> - return -EINVAL;
> + dev_err(host->dev, "Cannot get PMECC lookup table offset, will
> build a lookup table in runtime.\n");
> + host->has_no_lookup_table = true;
> + /* Will build a lookup table and initialize the offset later */
> + return 0;
> }
> if (!offset[0] && !offset[1]) {
> dev_err(host->dev, "Invalid PMECC lookup table offset\n");
Brian
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