From 6054d4d56307839bffabb687767c24d5ff62563b Mon Sep 17 00:00:00 2001 From: Josh Wu Date: Mon, 5 Aug 2013 19:14:37 +0800 Subject: mtd: atmel_nand: enable Nand Flash Controller (NFC) write via sram This patch enable writing nand flash via NFC SRAM. It will minimize the CPU overhead. The SRAM write only support ECC_NONE and ECC_HW with PMECC. To enable this NFC write by SRAM feature, you can add a string in dts under NFC driver node. This driver has been tested on SAMA5D3X-EK with JFFS2, YAFFS2, UBIFS and mtd-utils. Here is part of mtd_speedtest (writing test) result, compare with non-NFC writing, it reduces %65 cpu load with loss %12 speed. - commands use to test: # insmod /mnt/mtd_speedtest.ko dev=2 & # top -n 30 -d 1 | grep speedtest - test result: ================================================= mtd_speedtest: MTD device: 2 mtd_speedtest: MTD device size 41943040, eraseblock size 131072, page size 2048, count of eraseblocks 320, pages per eraseblock 64, OOB size 64 mtd_speedtest: testing eraseblock write speed 509 495 root D 1164 0% 7% insmod /mnt/mtd_speedtest.ko dev=2 509 495 root D 1164 0% 8% insmod /mnt/mtd_speedtest.ko dev=2 509 495 root R 1164 0% 5% insmod /mnt/mtd_speedtest.ko dev=2 mtd_speedtest: eraseblock write speed is 5194 KiB/s mtd_speedtest: testing page write speed 509 495 root D 1164 0% 32% insmod /mnt/mtd_speedtest.ko dev=2 509 495 root D 1164 0% 27% insmod /mnt/mtd_speedtest.ko dev=2 509 495 root D 1164 0% 25% insmod /mnt/mtd_speedtest.ko dev=2 509 495 root D 1164 0% 30% insmod /mnt/mtd_speedtest.ko dev=2 mtd_speedtest: page write speed is 5024 KiB/s Signed-off-by: Josh Wu Acked-by: Jean-Christophe PLAGNIOL-VILLARD Signed-off-by: Artem Bityutskiy Signed-off-by: David Woodhouse diff --git a/Documentation/devicetree/bindings/mtd/atmel-nand.txt b/Documentation/devicetree/bindings/mtd/atmel-nand.txt index 5d8b7d5..c472883 100644 --- a/Documentation/devicetree/bindings/mtd/atmel-nand.txt +++ b/Documentation/devicetree/bindings/mtd/atmel-nand.txt @@ -36,6 +36,8 @@ Optional properties: - reg : should specify the address and size used for NFC command registers, NFC registers and NFC Sram. NFC Sram address and size can be absent if don't want to use it. + - Optional properties: + - atmel,write-by-sram: boolean to enable NFC write by sram. Examples: nand0: nand@40000000,0 { diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 1905aa6..65b302c 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -94,12 +94,14 @@ struct atmel_nfc { void __iomem *sram_bank0; dma_addr_t sram_bank0_phys; bool use_nfc_sram; + bool write_by_sram; bool is_initialized; struct completion comp_nfc; /* Point to the sram bank which include readed data via NFC */ void __iomem *data_in_sram; + bool will_write_sram; }; static struct atmel_nfc nand_nfc; @@ -261,6 +263,16 @@ static void memcpy32_fromio(void *trg, const void __iomem *src, size_t size) *t++ = readl_relaxed(s++); } +static void memcpy32_toio(void __iomem *trg, const void *src, int size) +{ + int i; + u32 __iomem *t = trg; + const u32 *s = src; + + for (i = 0; i < (size >> 2); i++) + writel_relaxed(*s++, t++); +} + /* * Minimal-overhead PIO for data access. */ @@ -382,7 +394,11 @@ static int atmel_nand_dma_op(struct mtd_info *mtd, void *buf, int len, dma_dst_addr = phys_addr; } else { dma_src_addr = phys_addr; - dma_dst_addr = host->io_phys; + + if (nfc && nfc->write_by_sram) + dma_dst_addr = nfc_sram_phys(host); + else + dma_dst_addr = host->io_phys; } tx = dma_dev->device_prep_dma_memcpy(host->dma_chan, dma_dst_addr, @@ -954,9 +970,10 @@ static int atmel_nand_pmecc_write_page(struct mtd_info *mtd, int i, j; unsigned long end_time; - pmecc_enable(host, NAND_ECC_WRITE); - - chip->write_buf(mtd, (u8 *)buf, mtd->writesize); + if (!host->nfc || !host->nfc->write_by_sram) { + pmecc_enable(host, NAND_ECC_WRITE); + chip->write_buf(mtd, (u8 *)buf, mtd->writesize); + } end_time = jiffies + msecs_to_jiffies(PMECC_MAX_TIMEOUT_MS); while ((pmecc_readl_relaxed(host->ecc, SR) & PMECC_SR_BUSY)) { @@ -1798,6 +1815,8 @@ static void nfc_nand_command(struct mtd_info *mtd, unsigned int command, case NAND_CMD_SEQIN: case NAND_CMD_RNDIN: nfcwr = NFCADDR_CMD_NFCWR; + if (host->nfc->will_write_sram && command == NAND_CMD_SEQIN) + dataen = NFCADDR_CMD_DATAEN; break; default: break; @@ -1842,6 +1861,68 @@ static void nfc_nand_command(struct mtd_info *mtd, unsigned int command, } } +static int nfc_sram_write_page(struct mtd_info *mtd, struct nand_chip *chip, + uint32_t offset, int data_len, const uint8_t *buf, + int oob_required, int page, int cached, int raw) +{ + int cfg, len; + int status = 0; + struct atmel_nand_host *host = chip->priv; + void __iomem *sram = host->nfc->sram_bank0 + nfc_get_sram_off(host); + + /* Subpage write is not supported */ + if (offset || (data_len < mtd->writesize)) + return -EINVAL; + + cfg = nfc_readl(host->nfc->hsmc_regs, CFG); + len = mtd->writesize; + + if (unlikely(raw)) { + len += mtd->oobsize; + nfc_writel(host->nfc->hsmc_regs, CFG, cfg | NFC_CFG_WSPARE); + } else + nfc_writel(host->nfc->hsmc_regs, CFG, cfg & ~NFC_CFG_WSPARE); + + /* Copy page data to sram that will write to nand via NFC */ + if (use_dma) { + if (atmel_nand_dma_op(mtd, (void *)buf, len, 0) != 0) + /* Fall back to use cpu copy */ + memcpy32_toio(sram, buf, len); + } else { + memcpy32_toio(sram, buf, len); + } + + if (chip->ecc.mode == NAND_ECC_HW && host->has_pmecc) + /* + * When use NFC sram, need set up PMECC before send + * NAND_CMD_SEQIN command. Since when the nand command + * is sent, nfc will do transfer from sram and nand. + */ + pmecc_enable(host, NAND_ECC_WRITE); + + host->nfc->will_write_sram = true; + chip->cmdfunc(mtd, NAND_CMD_SEQIN, 0x00, page); + host->nfc->will_write_sram = false; + + if (likely(!raw)) + /* Need to write ecc into oob */ + status = chip->ecc.write_page(mtd, chip, buf, oob_required); + + if (status < 0) + return status; + + chip->cmdfunc(mtd, NAND_CMD_PAGEPROG, -1, -1); + status = chip->waitfunc(mtd, chip); + + if ((status & NAND_STATUS_FAIL) && (chip->errstat)) + status = chip->errstat(mtd, chip, FL_WRITING, status, page); + + if (status & NAND_STATUS_FAIL) + return -EIO; + + return 0; +} + static int nfc_sram_init(struct mtd_info *mtd) { struct nand_chip *chip = mtd->priv; @@ -1884,10 +1965,20 @@ static int nfc_sram_init(struct mtd_info *mtd) nfc_writel(host->nfc->hsmc_regs, CFG, cfg_nfc); + host->nfc->will_write_sram = false; nfc_set_sram_bank(host, 0); - dev_info(host->dev, "Using NFC Sram read\n"); + /* Use Write page with NFC SRAM only for PMECC or ECC NONE. */ + if (host->nfc->write_by_sram) { + if ((chip->ecc.mode == NAND_ECC_HW && host->has_pmecc) || + chip->ecc.mode == NAND_ECC_NONE) + chip->write_page = nfc_sram_write_page; + else + host->nfc->write_by_sram = false; + } + dev_info(host->dev, "Using NFC Sram read %s\n", + host->nfc->write_by_sram ? "and write" : ""); return 0; } @@ -2147,6 +2238,11 @@ static int atmel_nand_nfc_probe(struct platform_device *pdev) } else { nfc->use_nfc_sram = true; nfc->sram_bank0_phys = (dma_addr_t)nfc_sram->start; + + if (pdev->dev.of_node) + nfc->write_by_sram = of_property_read_bool( + pdev->dev.of_node, + "atmel,write-by-sram"); } } -- cgit v0.10.2