From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wi0-f174.google.com ([209.85.212.174]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Wfnkz-0002vR-Fj for linux-mtd@lists.infradead.org; Thu, 01 May 2014 09:58:22 +0000 Received: by mail-wi0-f174.google.com with SMTP id d1so409643wiv.7 for ; Thu, 01 May 2014 02:57:59 -0700 (PDT) From: Lee Jones To: linux-kernel@vger.kernel.org Subject: [PATCH 25/47] mtd: nand: stm_nand_bch: provide read functionality (BCH) Date: Thu, 1 May 2014 10:56:32 +0100 Message-Id: <1398938214-17847-26-git-send-email-lee.jones@linaro.org> In-Reply-To: <1398938214-17847-1-git-send-email-lee.jones@linaro.org> References: <1398938214-17847-1-git-send-email-lee.jones@linaro.org> Cc: Lee Jones , computersforpeace@gmail.com, linux-mtd@lists.infradead.org, kernel@stlinux.com List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Use DMA to read a single page of data. Signed-off-by: Lee Jones --- drivers/mtd/nand/stm_nand_bch.c | 96 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c index 2ff72c9..72c9734 100644 --- a/drivers/mtd/nand/stm_nand_bch.c +++ b/drivers/mtd/nand/stm_nand_bch.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include #include @@ -512,6 +513,99 @@ static int check_erased_page(uint8_t *data, uint32_t page_size, int max_zeros) return zeros; } +/* Returns the number of ECC errors, or '-1' for uncorrectable error */ +static int bch_read_page(struct nandi_controller *nandi, + loff_t offs, + uint8_t *buf) +{ + struct bch_prog *prog = &bch_prog_read_page; + uint32_t page_size = nandi->info.mtd.writesize; + unsigned long list_phys; + unsigned long buf_phys; + uint32_t ecc_err; + int ret = 0; + + dev_dbg(nandi->dev, "%s: offs = 0x%012llx\n", __func__, offs); + + BUG_ON(offs & (NANDI_BCH_DMA_ALIGNMENT - 1)); + + emiss_nandi_select(STM_NANDI_BCH); + + nandi_enable_interrupts(nandi, NANDBCH_INT_SEQNODESOVER); + reinit_completion(&nandi->seq_completed); + + /* Reset ECC stats */ + writel(CFG_RESET_ECC_ALL | CFG_ENABLE_AFM, + nandi->base + NANDBCH_CONTROLLER_CFG); + writel(CFG_ENABLE_AFM, nandi->base + NANDBCH_CONTROLLER_CFG); + + prog->addr = (uint32_t)((offs >> (nandi->page_shift - 8)) & 0xffffff00); + + buf_phys = dma_map_single(NULL, buf, page_size, DMA_FROM_DEVICE); + + memset(nandi->buf_list, 0x00, NANDI_BCH_BUF_LIST_SIZE); + nandi->buf_list[0] = buf_phys | (nandi->sectors_per_page - 1); + + list_phys = dma_map_single(NULL, nandi->buf_list, + NANDI_BCH_BUF_LIST_SIZE, DMA_TO_DEVICE); + + writel(list_phys, nandi->base + NANDBCH_BUFFER_LIST_PTR); + + bch_load_prog_cpu(nandi, prog); + + bch_wait_seq(nandi); + + nandi_disable_interrupts(nandi, NANDBCH_INT_SEQNODESOVER); + + dma_unmap_single(NULL, list_phys, NANDI_BCH_BUF_LIST_SIZE, + DMA_TO_DEVICE); + dma_unmap_single(NULL, buf_phys, page_size, DMA_FROM_DEVICE); + + /* Use the maximum per-sector ECC count! */ + ecc_err = readl(nandi->base + NANDBCH_ECC_SCORE_REG_A) & 0xff; + if (ecc_err == 0xff) { + /* + * Downgrade uncorrectable ECC error for an erased page, + * tolerating 'bitflip_threshold' bits at zero. + */ + ret = check_erased_page(buf, page_size, + nandi->bitflip_threshold); + if (ret >= 0) + dev_dbg(nandi->dev, + "%s: erased page detected: \n" + " downgrading uncorrectable ECC error.\n", + __func__); + } else { + ret = (int)ecc_err; + } + + return ret; +} + +static int bch_read(struct mtd_info *mtd, struct nand_chip *chip, + uint8_t *buf, int oob_required, int page) +{ + struct nandi_controller *nandi = chip->priv; + uint32_t page_size = mtd->writesize; + loff_t offs = page * page_size; + bool bounce = false; + uint8_t *p; + int ret; + + if (((unsigned int)buf & (NANDI_BCH_DMA_ALIGNMENT - 1)) || + (!virt_addr_valid(buf))) /* vmalloc'd buffer! */ + bounce = true; + + p = bounce ? nandi->page_buf : buf; + + ret = bch_read_page(nandi, offs, p); + + if (bounce) + memcpy(buf, p, page_size); + + return ret; +} + /* * Initialisation */ @@ -590,6 +684,8 @@ static void nandi_set_mtd_defaults(struct nandi_controller *nandi, mtd->flags = MTD_CAP_NANDFLASH; mtd->ecclayout = &info->ecclayout; mtd->subpage_sft = 0; + + chip->ecc.read_page = bch_read; } /* -- 1.8.3.2