From 59e9c5ae17179fe561103fbe0808fac5976ca1bd Mon Sep 17 00:00:00 2001 From: vimal singh Date: Mon, 13 Jul 2009 16:26:24 +0530 Subject: mtd: omap: add support for nand prefetch-read and post-write This patch adds prefetch support to access nand flash in mpu mode. This patch also adds 8-bit nand support (omap_read/write_buf8). Prefetch can be used for both 8- and 16-bit devices. Signed-off-by: Vimal Singh Acked-by: Tony Lindgren Signed-off-by: David Woodhouse --- drivers/mtd/nand/Kconfig | 8 +++ drivers/mtd/nand/omap2.c | 161 ++++++++++++++++++++++++++++++++++++++++++++--- 2 files changed, 160 insertions(+), 9 deletions(-) (limited to 'drivers/mtd') diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig index 707d7ee495df..7dab79caed44 100644 --- a/drivers/mtd/nand/Kconfig +++ b/drivers/mtd/nand/Kconfig @@ -80,6 +80,14 @@ config MTD_NAND_OMAP2 help Support for NAND flash on Texas Instruments OMAP2 and OMAP3 platforms. +config MTD_NAND_OMAP_PREFETCH + bool "GPMC prefetch support for NAND Flash device" + depends on MTD_NAND && MTD_NAND_OMAP2 + default y + help + The NAND device can be accessed for Read/Write using GPMC PREFETCH engine + to improve the performance. + config MTD_NAND_TS7250 tristate "NAND Flash device on TS-7250 board" depends on MACH_TS72XX diff --git a/drivers/mtd/nand/omap2.c b/drivers/mtd/nand/omap2.c index ebd07e95b814..6736822c4751 100644 --- a/drivers/mtd/nand/omap2.c +++ b/drivers/mtd/nand/omap2.c @@ -112,6 +112,16 @@ static const char *part_probes[] = { "cmdlinepart", NULL }; #endif +#ifdef CONFIG_MTD_NAND_OMAP_PREFETCH +static int use_prefetch = 1; + +/* "modprobe ... use_prefetch=0" etc */ +module_param(use_prefetch, bool, 0); +MODULE_PARM_DESC(use_prefetch, "enable/disable use of PREFETCH"); +#else +const int use_prefetch; +#endif + struct omap_nand_info { struct nand_hw_control controller; struct omap_nand_platform_data *pdata; @@ -124,6 +134,7 @@ struct omap_nand_info { unsigned long phys_base; void __iomem *gpmc_cs_baseaddr; void __iomem *gpmc_baseaddr; + void __iomem *nand_pref_fifo_add; }; /** @@ -188,6 +199,38 @@ static void omap_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl) __raw_writeb(cmd, info->nand.IO_ADDR_W); } +/** + * omap_read_buf8 - read data from NAND controller into buffer + * @mtd: MTD device structure + * @buf: buffer to store date + * @len: number of bytes to read + */ +static void omap_read_buf8(struct mtd_info *mtd, u_char *buf, int len) +{ + struct nand_chip *nand = mtd->priv; + + ioread8_rep(nand->IO_ADDR_R, buf, len); +} + +/** + * omap_write_buf8 - write buffer to NAND controller + * @mtd: MTD device structure + * @buf: data buffer + * @len: number of bytes to write + */ +static void omap_write_buf8(struct mtd_info *mtd, const u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + u_char *p = (u_char *)buf; + + while (len--) { + iowrite8(*p++, info->nand.IO_ADDR_W); + while (GPMC_BUF_EMPTY == (readl(info->gpmc_baseaddr + + GPMC_STATUS) & GPMC_BUF_FULL)); + } +} + /** * omap_read_buf16 - read data from NAND controller into buffer * @mtd: MTD device structure @@ -198,7 +241,7 @@ static void omap_read_buf16(struct mtd_info *mtd, u_char *buf, int len) { struct nand_chip *nand = mtd->priv; - __raw_readsw(nand->IO_ADDR_R, buf, len / 2); + ioread16_rep(nand->IO_ADDR_R, buf, len / 2); } /** @@ -217,13 +260,101 @@ static void omap_write_buf16(struct mtd_info *mtd, const u_char * buf, int len) len >>= 1; while (len--) { - writew(*p++, info->nand.IO_ADDR_W); + iowrite16(*p++, info->nand.IO_ADDR_W); while (GPMC_BUF_EMPTY == (readl(info->gpmc_baseaddr + GPMC_STATUS) & GPMC_BUF_FULL)) ; } } + +/** + * omap_read_buf_pref - read data from NAND controller into buffer + * @mtd: MTD device structure + * @buf: buffer to store date + * @len: number of bytes to read + */ +static void omap_read_buf_pref(struct mtd_info *mtd, u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + uint32_t pfpw_status = 0, r_count = 0; + int ret = 0; + u32 *p = (u32 *)buf; + + /* take care of subpage reads */ + for (; len % 4 != 0; ) { + *buf++ = __raw_readb(info->nand.IO_ADDR_R); + len--; + } + p = (u32 *) buf; + + /* configure and start prefetch transfer */ + ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x0); + if (ret) { + /* PFPW engine is busy, use cpu copy method */ + if (info->nand.options & NAND_BUSWIDTH_16) + omap_read_buf16(mtd, buf, len); + else + omap_read_buf8(mtd, buf, len); + } else { + do { + pfpw_status = gpmc_prefetch_status(); + r_count = ((pfpw_status >> 24) & 0x7F) >> 2; + ioread32_rep(info->nand_pref_fifo_add, p, r_count); + p += r_count; + len -= r_count << 2; + } while (len); + + /* disable and stop the PFPW engine */ + gpmc_prefetch_reset(); + } +} + +/** + * omap_write_buf_pref - write buffer to NAND controller + * @mtd: MTD device structure + * @buf: data buffer + * @len: number of bytes to write + */ +static void omap_write_buf_pref(struct mtd_info *mtd, + const u_char *buf, int len) +{ + struct omap_nand_info *info = container_of(mtd, + struct omap_nand_info, mtd); + uint32_t pfpw_status = 0, w_count = 0; + int i = 0, ret = 0; + u16 *p = (u16 *) buf; + + /* take care of subpage writes */ + if (len % 2 != 0) { + writeb(*buf, info->nand.IO_ADDR_R); + p = (u16 *)(buf + 1); + len--; + } + + /* configure and start prefetch transfer */ + ret = gpmc_prefetch_enable(info->gpmc_cs, 0x0, len, 0x1); + if (ret) { + /* PFPW engine is busy, use cpu copy method */ + if (info->nand.options & NAND_BUSWIDTH_16) + omap_write_buf16(mtd, buf, len); + else + omap_write_buf8(mtd, buf, len); + } else { + pfpw_status = gpmc_prefetch_status(); + while (pfpw_status & 0x3FFF) { + w_count = ((pfpw_status >> 24) & 0x7F) >> 1; + for (i = 0; (i < w_count) && len; i++, len -= 2) + iowrite16(*p++, info->nand_pref_fifo_add); + pfpw_status = gpmc_prefetch_status(); + } + + /* disable and stop the PFPW engine */ + gpmc_prefetch_reset(); + } +} + /** * omap_verify_buf - Verify chip data against buffer * @mtd: MTD device structure @@ -658,17 +789,12 @@ static int __devinit omap_nand_probe(struct platform_device *pdev) err = -ENOMEM; goto out_release_mem_region; } + info->nand.controller = &info->controller; info->nand.IO_ADDR_W = info->nand.IO_ADDR_R; info->nand.cmd_ctrl = omap_hwcontrol; - /* REVISIT: only supports 16-bit NAND flash */ - - info->nand.read_buf = omap_read_buf16; - info->nand.write_buf = omap_write_buf16; - info->nand.verify_buf = omap_verify_buf; - /* * If RDY/BSY line is connected to OMAP then use the omap ready * funcrtion and the generic nand_wait function which reads the status @@ -689,6 +815,23 @@ static int __devinit omap_nand_probe(struct platform_device *pdev) == 0x1000) info->nand.options |= NAND_BUSWIDTH_16; + if (use_prefetch) { + /* copy the virtual address of nand base for fifo access */ + info->nand_pref_fifo_add = info->nand.IO_ADDR_R; + + info->nand.read_buf = omap_read_buf_pref; + info->nand.write_buf = omap_write_buf_pref; + } else { + if (info->nand.options & NAND_BUSWIDTH_16) { + info->nand.read_buf = omap_read_buf16; + info->nand.write_buf = omap_write_buf16; + } else { + info->nand.read_buf = omap_read_buf8; + info->nand.write_buf = omap_write_buf8; + } + } + info->nand.verify_buf = omap_verify_buf; + #ifdef CONFIG_MTD_NAND_OMAP_HWECC info->nand.ecc.bytes = 3; info->nand.ecc.size = 512; @@ -746,7 +889,7 @@ static int omap_nand_remove(struct platform_device *pdev) platform_set_drvdata(pdev, NULL); /* Release NAND device, its internal structures and partitions */ nand_release(&info->mtd); - iounmap(info->nand.IO_ADDR_R); + iounmap(info->nand_pref_fifo_add); kfree(&info->mtd); return 0; } -- cgit v1.2.3