Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753675AbYF1MOp (ORCPT ); Sat, 28 Jun 2008 08:14:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756068AbYF1MOW (ORCPT ); Sat, 28 Jun 2008 08:14:22 -0400 Received: from smtpeu1.atmel.com ([195.65.72.27]:49355 "EHLO bagnes.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753544AbYF1MOO (ORCPT ); Sat, 28 Jun 2008 08:14:14 -0400 From: Haavard Skinnemoen To: David Woodhouse Cc: linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org, David Brownell , David Brownell , Haavard Skinnemoen Subject: [PATCH RESEND 1/3] atmel_nand speedup via {read,write}s{b,w}() Date: Sat, 28 Jun 2008 14:14:06 +0200 Message-Id: <1214655248-15707-1-git-send-email-haavard.skinnemoen@atmel.com> X-Mailer: git-send-email 1.5.5.4 X-OriginalArrivalTime: 28 Jun 2008 12:13:55.0778 (UTC) FILETIME=[6FC67A20:01C8D918] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3971 Lines: 124 From: David Brownell This uses __raw_{read,write}s{b,w}() primitives to access data on NAND chips for more efficient I/O. On an arm926 with memory clocked at 100 MHz, this reduced the elapsed time for a 64 MByte read by 16%. ("dd" /dev/mtd0 to /dev/null, with an 8-bit NAND using hardware ECC and 128KB blocksize.) Also some minor section tweaks: - Use platform_driver_probe() so no pointer to probe() lingers after that code has been removed at run-time. - Use __exit and __exit_p so the remove() code will normally be removed by the linker. Since these buffer read/write calls are new, this increases the runtime code footprint (by 88 bytes on my build, after the section tweaks). Signed-off-by: David Brownell [haavard.skinnemoen@atmel.com: rebase onto atmel_nand rename] Signed-off-by: Haavard Skinnemoen Acked-by: Andrew Victor --- Resending the series with Andrew's ACKs added, no other changes. drivers/mtd/nand/atmel_nand.c | 46 ++++++++++++++++++++++++++++++++++++---- 1 files changed, 41 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c index 50700ab..4814fc9 100644 --- a/drivers/mtd/nand/atmel_nand.c +++ b/drivers/mtd/nand/atmel_nand.c @@ -142,6 +142,37 @@ static int atmel_nand_device_ready(struct mtd_info *mtd) } /* + * Minimal-overhead PIO for data access. + */ +static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_readsb(nand_chip->IO_ADDR_R, buf, len); +} + +static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2); +} + +static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_writesb(nand_chip->IO_ADDR_W, buf, len); +} + +static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len) +{ + struct nand_chip *nand_chip = mtd->priv; + + __raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2); +} + +/* * write oob for small pages */ static int atmel_nand_write_oob_512(struct mtd_info *mtd, @@ -436,8 +467,14 @@ static int __init atmel_nand_probe(struct platform_device *pdev) nand_chip->chip_delay = 20; /* 20us command delay time */ - if (host->board->bus_width_16) /* 16-bit bus width */ + if (host->board->bus_width_16) { /* 16-bit bus width */ nand_chip->options |= NAND_BUSWIDTH_16; + nand_chip->read_buf = atmel_read_buf16; + nand_chip->write_buf = atmel_write_buf16; + } else { + nand_chip->read_buf = atmel_read_buf; + nand_chip->write_buf = atmel_write_buf; + } platform_set_drvdata(pdev, host); atmel_nand_enable(host); @@ -546,7 +583,7 @@ err_nand_ioremap: /* * Remove a NAND device. */ -static int __devexit atmel_nand_remove(struct platform_device *pdev) +static int __exit atmel_nand_remove(struct platform_device *pdev) { struct atmel_nand_host *host = platform_get_drvdata(pdev); struct mtd_info *mtd = &host->mtd; @@ -564,8 +601,7 @@ static int __devexit atmel_nand_remove(struct platform_device *pdev) } static struct platform_driver atmel_nand_driver = { - .probe = atmel_nand_probe, - .remove = atmel_nand_remove, + .remove = __exit_p(atmel_nand_remove), .driver = { .name = "atmel_nand", .owner = THIS_MODULE, @@ -574,7 +610,7 @@ static struct platform_driver atmel_nand_driver = { static int __init atmel_nand_init(void) { - return platform_driver_register(&atmel_nand_driver); + return platform_driver_probe(&atmel_nand_driver, atmel_nand_probe); } -- 1.5.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/