2 files changed, 81 insertions, 4 deletions

diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 19d1e9d17bf9..5c1423a2ffb5 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -127,6 +127,7 @@ 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;
@@ -1112,12 +1113,66 @@ static int pmecc_choose_ecc(struct atmel_nand_host *host,
 	return 0;
 }
 
+static inline int deg(unsigned int poly)
+{
+	/* polynomial degree is the most-significant bit index */
+	return fls(poly) - 1;
+}
+
+static int build_gf_tables(int mm, unsigned int poly,
+		int16_t *index_of, int16_t *alpha_to)
+{
+	unsigned int i, x = 1;
+	const unsigned int k = 1 << deg(poly);
+	unsigned int nn = (1 << mm) - 1;
+
+	/* primitive polynomial must be of degree m */
+	if (k != (1u << mm))
+		return -EINVAL;
+
+	for (i = 0; i < nn; i++) {
+		alpha_to[i] = x;
+		index_of[x] = i;
+		if (i && (x == 1))
+			/* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
+			return -EINVAL;
+		x <<= 1;
+		if (x & k)
+			x ^= poly;
+	}
+	alpha_to[nn] = 1;
+	index_of[0] = 0;
+
+	return 0;
+}
+
+static uint16_t *create_lookup_table(struct device *dev, int sector_size)
+{
+	int degree = (sector_size == 512) ?
+			PMECC_GF_DIMENSION_13 :
+			PMECC_GF_DIMENSION_14;
+	unsigned int poly = (sector_size == 512) ?
+			PMECC_GF_13_PRIMITIVE_POLY :
+			PMECC_GF_14_PRIMITIVE_POLY;
+	int table_size = (sector_size == 512) ?
+			PMECC_LOOKUP_TABLE_SIZE_512 :
+			PMECC_LOOKUP_TABLE_SIZE_1024;
+
+	int16_t *addr = devm_kzalloc(dev, 2 * table_size * sizeof(uint16_t),
+			GFP_KERNEL);
+	if (addr && build_gf_tables(degree, poly, addr, addr + table_size))
+		return NULL;
+
+	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, &sector_size);
@@ -1163,8 +1218,24 @@ 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 = -EINVAL;
+			goto err;
+		}
+
+		host->pmecc_rom_base = (void __iomem *)galois_table;
+		host->pmecc_lookup_table_offset = 0;
 	}
 
 	nand_chip->ecc.size = sector_size;
@@ -1501,8 +1572,10 @@ 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");
diff --git a/drivers/mtd/nand/atmel_nand_ecc.h b/drivers/mtd/nand/atmel_nand_ecc.h
index 8a1e9a686759..d4035e335ad8 100644
--- a/drivers/mtd/nand/atmel_nand_ecc.h
+++ b/drivers/mtd/nand/atmel_nand_ecc.h
@@ -142,6 +142,10 @@
 #define PMECC_GF_DIMENSION_13			13
 #define PMECC_GF_DIMENSION_14			14
 
+/* Primitive Polynomial used by PMECC */
+#define PMECC_GF_13_PRIMITIVE_POLY		0x201b
+#define PMECC_GF_14_PRIMITIVE_POLY		0x4443
+
 #define PMECC_LOOKUP_TABLE_SIZE_512		0x2000
 #define PMECC_LOOKUP_TABLE_SIZE_1024		0x4000