This adds hardware ECC support using the BCH encoder in the NFC IP. The ECC encoder supports up to 32-bit correction by using 60 error correction bytes. There is no sub-page ECC step, ECC is calculated always accross the whole page (up to 2k pages). Raw writes writes are possible through the common nand_write_page_raw implementation, however raw reads are not possible since the hardware ECC mode need to be enabled at command time. Signed-off-by: Bill Pringlemeir <bpringlemeir@xxxxxxxxx> Signed-off-by: Stefan Agner <stefan@xxxxxxxx> --- drivers/mtd/nand/Kconfig | 6 +- drivers/mtd/nand/vf610_nfc.c | 201 ++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 204 insertions(+), 3 deletions(-) diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig index 9ceac79..944e588 100644 --- a/drivers/mtd/nand/Kconfig +++ b/drivers/mtd/nand/Kconfig @@ -472,8 +472,10 @@ config MTD_NAND_VF610_NFC help Enables support for NAND Flash Controller on some Freescale processors like the VF610, MPC5125, MCF54418 or Kinetis K70. - The driver supports a maximum 2k page size. The driver - currently does not support hardware ECC. + The driver supports a maximum 2k page size. With 2k pages and + 64 bytes or more of OOB, hardware ECC with up to 32-bit error + correction is supported. Hardware ECC is only enabled through + device tree. config MTD_NAND_MXC tristate "MXC NAND support" diff --git a/drivers/mtd/nand/vf610_nfc.c b/drivers/mtd/nand/vf610_nfc.c index bb5ee11..c0d4189 100644 --- a/drivers/mtd/nand/vf610_nfc.c +++ b/drivers/mtd/nand/vf610_nfc.c @@ -19,6 +19,8 @@ * - Untested on MPC5125 and M54418. * - DMA not used. * - 2K pages or less. + * - Only 2K page w. 64+ OOB and hardware ECC. + * - Raw page reads not implemented when using ECC. */ #include <linux/module.h> @@ -72,6 +74,8 @@ /* NFC ECC mode define */ #define ECC_BYPASS 0 +#define ECC_45_BYTE 6 +#define ECC_60_BYTE 7 /*** Register Mask and bit definitions */ @@ -104,6 +108,8 @@ #define STATUS_BYTE1_MASK 0x000000FF /* NFC_FLASH_CONFIG Field */ +#define CONFIG_ECC_SRAM_ADDR_MASK 0x7FC00000 +#define CONFIG_ECC_SRAM_ADDR_SHIFT 22 #define CONFIG_ECC_SRAM_REQ_BIT (1<<21) #define CONFIG_DMA_REQ_BIT (1<<20) #define CONFIG_ECC_MODE_MASK 0x000E0000 @@ -122,6 +128,21 @@ #define CMD_DONE_CLEAR_BIT (1<<18) #define IDLE_CLEAR_BIT (1<<17) +/* ECC status placed at end of buffers. */ +#define ECC_SRAM_ADDR ((PAGE_2K + 256 - 8) >> 3) +#define ECC_STATUS_MASK 0x80 +#define ECC_ERR_COUNT 0x3F + +/* + * ECC status is stored at NFC_CFG[ECCADD] +4 for little-endian + * and +7 for big-endian SoCs. + */ +#ifdef __LITTLE_ENDIAN +#define ECC_OFFSET 4 +#else +#define ECC_OFFSET 7 +#endif + struct vf610_nfc { struct mtd_info mtd; struct nand_chip chip; @@ -136,10 +157,40 @@ struct vf610_nfc { #define ALT_BUF_STAT 2 #define ALT_BUF_ONFI 3 struct clk *clk; + bool use_hw_ecc; + u32 ecc_mode; }; #define mtd_to_nfc(_mtd) container_of(_mtd, struct vf610_nfc, mtd) +static struct nand_ecclayout vf610_nfc_ecc45 = { + .eccbytes = 45, + .eccpos = {19, 20, 21, 22, 23, + 24, 25, 26, 27, 28, 29, 30, 31, + 32, 33, 34, 35, 36, 37, 38, 39, + 40, 41, 42, 43, 44, 45, 46, 47, + 48, 49, 50, 51, 52, 53, 54, 55, + 56, 57, 58, 59, 60, 61, 62, 63}, + .oobfree = { + {.offset = 2, + .length = 17} } +}; + +static struct nand_ecclayout vf610_nfc_ecc60 = { + .eccbytes = 60, + .eccpos = { 4, 5, 6, 7, 8, 9, 10, 11, + 12, 13, 14, 15, 16, 17, 18, 19, + 20, 21, 22, 23, 24, 25, 26, 27, + 28, 29, 30, 31, 32, 33, 34, 35, + 36, 37, 38, 39, 40, 41, 42, 43, + 44, 45, 46, 47, 48, 49, 50, 51, + 52, 53, 54, 55, 56, 57, 58, 59, + 60, 61, 62, 63 }, + .oobfree = { + {.offset = 2, + .length = 2} } +}; + static inline u32 vf610_nfc_read(struct vf610_nfc *nfc, uint reg) { return readl(nfc->regs + reg); @@ -284,6 +335,13 @@ static void vf610_nfc_addr_cycle(struct vf610_nfc *nfc, int column, int page) ROW_ADDR_SHIFT, page); } +static inline void vf610_nfc_ecc_mode(struct vf610_nfc *nfc, int ecc_mode) +{ + vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG, + CONFIG_ECC_MODE_MASK, + CONFIG_ECC_MODE_SHIFT, ecc_mode); +} + static inline void vf610_nfc_transfer_size(void __iomem *regbase, int size) { writel_relaxed(size, regbase + NFC_SECTOR_SIZE); @@ -302,13 +360,20 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command, case NAND_CMD_SEQIN: /* Use valid column/page from preread... */ vf610_nfc_addr_cycle(nfc, column, page); + nfc->buf_offset = 0; + /* * SEQIN => data => PAGEPROG sequence is done by the controller * hence we do not need to issue the command here... */ return; case NAND_CMD_PAGEPROG: - page_sz += mtd->writesize + mtd->oobsize; + page_sz += nfc->page_sz; + if (nfc->use_hw_ecc) + vf610_nfc_ecc_mode(nfc, nfc->ecc_mode); + else + vf610_nfc_ecc_mode(nfc, ECC_BYPASS); + vf610_nfc_transfer_size(nfc->regs, page_sz); vf610_nfc_send_commands(nfc, NAND_CMD_SEQIN, command, PROGRAM_PAGE_CMD_CODE); @@ -326,11 +391,13 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command, vf610_nfc_send_commands(nfc, NAND_CMD_READ0, NAND_CMD_READSTART, READ_PAGE_CMD_CODE); vf610_nfc_addr_cycle(nfc, column, page); + vf610_nfc_ecc_mode(nfc, ECC_BYPASS); break; case NAND_CMD_READ0: page_sz += mtd->writesize + mtd->oobsize; vf610_nfc_transfer_size(nfc->regs, page_sz); + vf610_nfc_ecc_mode(nfc, nfc->ecc_mode); vf610_nfc_send_commands(nfc, NAND_CMD_READ0, NAND_CMD_READSTART, READ_PAGE_CMD_CODE); vf610_nfc_addr_cycle(nfc, column, page); @@ -342,6 +409,7 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command, vf610_nfc_send_command(nfc, command, READ_ONFI_PARAM_CMD_CODE); vf610_nfc_set_field(nfc, NFC_ROW_ADDR, ROW_ADDR_MASK, ROW_ADDR_SHIFT, column); + vf610_nfc_ecc_mode(nfc, ECC_BYPASS); break; case NAND_CMD_ERASE1: @@ -370,6 +438,9 @@ static void vf610_nfc_command(struct mtd_info *mtd, unsigned command, } vf610_nfc_done(nfc); + + nfc->use_hw_ecc = false; + nfc->page_sz = 0; } static void vf610_nfc_read_buf(struct mtd_info *mtd, u_char *buf, int len) @@ -395,6 +466,7 @@ static void vf610_nfc_write_buf(struct mtd_info *mtd, const uint8_t *buf, l = min_t(uint, len, mtd->writesize + mtd->oobsize - c); vf610_nfc_memcpy(nfc->regs + NFC_MAIN_AREA(0) + c, buf, l); + nfc->page_sz += l; nfc->buf_offset += l; } @@ -462,6 +534,84 @@ static void vf610_nfc_select_chip(struct mtd_info *mtd, int chip) #endif } +/* Count the number of 0's in buff up to max_bits */ +static inline int count_written_bits(uint8_t *buff, int size, int max_bits) +{ + uint32_t *buff32 = (uint32_t *)buff; + int k, written_bits = 0; + + for (k = 0; k < (size / 4); k++) { + written_bits += hweight32(~buff32[k]); + if (written_bits > max_bits) + break; + } + + return written_bits; +} + +static inline int vf610_nfc_correct_data(struct mtd_info *mtd, uint8_t *dat) +{ + struct vf610_nfc *nfc = mtd_to_nfc(mtd); + u8 ecc_status; + u8 ecc_count; + int flip; + + ecc_status = __raw_readb(nfc->regs + ECC_SRAM_ADDR * 8 + ECC_OFFSET); + ecc_count = ecc_status & ECC_ERR_COUNT; + if (!(ecc_status & ECC_STATUS_MASK)) + return ecc_count; + + /* + * On an erased page, bit count should be zero or at least + * less then half of the ECC strength + */ + flip = count_written_bits(dat, nfc->chip.ecc.size, ecc_count); + + if (flip > ecc_count && flip > (nfc->chip.ecc.strength / 2)) + return -1; + + /* Erased page. */ + memset(dat, 0xff, nfc->chip.ecc.size); + return 0; +} + +static int vf610_nfc_read_page(struct mtd_info *mtd, struct nand_chip *chip, + uint8_t *buf, int oob_required, int page) +{ + int eccsize = chip->ecc.size; + int stat; + + vf610_nfc_read_buf(mtd, buf, eccsize); + + if (oob_required) + vf610_nfc_read_buf(mtd, chip->oob_poi, mtd->oobsize); + + stat = vf610_nfc_correct_data(mtd, buf); + + if (stat < 0) + mtd->ecc_stats.failed++; + else + mtd->ecc_stats.corrected += stat; + + return 0; +} + +static int vf610_nfc_write_page(struct mtd_info *mtd, struct nand_chip *chip, + const uint8_t *buf, int oob_required) +{ + struct vf610_nfc *nfc = mtd_to_nfc(mtd); + + vf610_nfc_write_buf(mtd, buf, mtd->writesize); + if (oob_required) + vf610_nfc_write_buf(mtd, chip->oob_poi, mtd->oobsize); + + /* Always write whole page including OOB due to HW ECC */ + nfc->use_hw_ecc = true; + nfc->page_sz = mtd->writesize + mtd->oobsize; + + return 0; +} + static const struct of_device_id vf610_nfc_dt_ids[] = { { .compatible = "fsl,vf610-nfc" }, { .compatible = "fsl,mpc5125-nfc" }, @@ -487,6 +637,16 @@ static int vf610_nfc_init_controller(struct vf610_nfc *nfc) vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG, CONFIG_PAGE_CNT_MASK, CONFIG_PAGE_CNT_SHIFT, 1); + if (nfc->chip.ecc.mode == NAND_ECC_HW) { + /* Set ECC_STATUS offset */ + vf610_nfc_set_field(nfc, NFC_FLASH_CONFIG, + CONFIG_ECC_SRAM_ADDR_MASK, + CONFIG_ECC_SRAM_ADDR_SHIFT, ECC_SRAM_ADDR); + + /* Enable ECC_STATUS */ + vf610_nfc_set(nfc, NFC_FLASH_CONFIG, CONFIG_ECC_SRAM_REQ_BIT); + } + return 0; } @@ -569,6 +729,45 @@ static int vf610_nfc_probe(struct platform_device *pdev) goto error; } + if (chip->ecc.mode == NAND_ECC_HW) { + if (mtd->writesize != PAGE_2K && mtd->oobsize < 64) { + dev_err(nfc->dev, "Unsupported flash with hwecc\n"); + err = -ENXIO; + goto error; + } + + if (chip->ecc.size != mtd->writesize) { + dev_err(nfc->dev, "Step size needs to be page size\n"); + err = -ENXIO; + goto error; + } + + /* Only 64 byte ECC layouts known */ + if (mtd->oobsize > 64) + mtd->oobsize = 64; + + if (chip->ecc.strength == 32) { + nfc->ecc_mode = ECC_60_BYTE; + chip->ecc.bytes = 60; + chip->ecc.layout = &vf610_nfc_ecc60; + } else if (chip->ecc.strength == 24) { + nfc->ecc_mode = ECC_45_BYTE; + chip->ecc.bytes = 45; + chip->ecc.layout = &vf610_nfc_ecc45; + } else { + dev_err(nfc->dev, "Unsupported ECC strength\n"); + err = -ENXIO; + goto error; + } + + /* propagate ecc.layout to mtd_info */ + mtd->ecclayout = chip->ecc.layout; + chip->ecc.read_page = vf610_nfc_read_page; + chip->ecc.write_page = vf610_nfc_write_page; + + chip->ecc.size = PAGE_2K; + } + /* second phase scan */ if (nand_scan_tail(mtd)) { err = -ENXIO; -- 2.4.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html