From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-we0-f176.google.com ([74.125.82.176]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1WSMbw-0007rR-3P for linux-mtd@lists.infradead.org; Tue, 25 Mar 2014 08:21:30 +0000 Received: by mail-we0-f176.google.com with SMTP id x48so77930wes.35 for ; Tue, 25 Mar 2014 01:21:02 -0700 (PDT) From: Lee Jones To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [RFC 23/47] mtd: nand: stm_nand_bch: read and write page (BCH) Date: Tue, 25 Mar 2014 08:19:40 +0000 Message-Id: <1395735604-26706-24-git-send-email-lee.jones@linaro.org> In-Reply-To: <1395735604-26706-1-git-send-email-lee.jones@linaro.org> References: <1395735604-26706-1-git-send-email-lee.jones@linaro.org> Cc: angus.clark@st.com, kernel@stlinux.com, lee.jones@linaro.org, linux-mtd@lists.infradead.org, pekon@ti.com, computersforpeace@gmail.com, dwmw2@infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Use DMA to read and/or write a single page of data. Signed-off-by: Lee Jones --- drivers/mtd/nand/stm_nand_bch.c | 119 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 119 insertions(+) diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c index 7874d85..6323590 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 @@ -345,6 +346,124 @@ 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((unsigned long)buf & (NANDI_BCH_DMA_ALIGNMENT - 1)); + 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 'sectors_per_page' bits at zero. + */ + ret = check_erased_page(buf, page_size, + nandi->sectors_per_page); + 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; +} + +/* Returns the status of the NAND device following the write operation */ +static uint8_t bch_write_page(struct nandi_controller *nandi, + loff_t offs, const uint8_t *buf) +{ + struct bch_prog *prog = &bch_prog_write_page; + uint32_t page_size = nandi->info.mtd.writesize; + uint8_t *p = (uint8_t *)buf; + unsigned long list_phys; + unsigned long buf_phys; + uint8_t status; + + dev_dbg(nandi->dev, "%s: offs = 0x%012llx\n", __func__, offs); + + BUG_ON((unsigned int)buf & (NANDI_BCH_DMA_ALIGNMENT - 1)); + BUG_ON(offs & (page_size - 1)); + + emiss_nandi_select(STM_NANDI_BCH); + + nandi_enable_interrupts(nandi, NANDBCH_INT_SEQNODESOVER); + reinit_completion(&nandi->seq_completed); + + prog->addr = (uint32_t)((offs >> (nandi->page_shift - 8)) & 0xffffff00); + + buf_phys = dma_map_single(NULL, p, page_size, DMA_TO_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); + + status = (uint8_t)(readl(nandi->base + + NANDBCH_CHECK_STATUS_REG_A) & 0xff); + + return status; +} + /* * Initialisation */ -- 1.8.3.2