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authorDavid Brownell <david-b@pacbell.net>2008-07-04 02:40:16 -0400
committerDavid Woodhouse <David.Woodhouse@intel.com>2008-07-11 09:51:21 -0400
commit23a346ca4a5a6f50f81062456af955155f68e313 (patch)
treed2e37dfb9bdc350aab668ee0cac9168a43cc78ea /drivers/mtd/nand/atmel_nand.c
parent175428b2b3eeacf90dcc171d5915d6b4dc86e917 (diff)
[MTD] [NAND] atmel_nand speedup via {read,write}s{b,w}()
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 MiB read by 16%. ("dd" /dev/mtd0 to /dev/null, with an 8-bit NAND using hardware ECC and 128KiB 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). [haavard.skinnemoen@atmel.com: rebase onto atmel_nand rename] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: HÃ¥vard Skinnemoen <haavard.skinnemoen@atmel.com> Acked-by: Andrew Victor <linux@maxim.org.za> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Diffstat (limited to 'drivers/mtd/nand/atmel_nand.c')
-rw-r--r--drivers/mtd/nand/atmel_nand.c46
1 files changed, 41 insertions, 5 deletions
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 50700ab5a57a..4814fc9b237b 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)
142} 142}
143 143
144/* 144/*
145 * Minimal-overhead PIO for data access.
146 */
147static void atmel_read_buf(struct mtd_info *mtd, u8 *buf, int len)
148{
149 struct nand_chip *nand_chip = mtd->priv;
150
151 __raw_readsb(nand_chip->IO_ADDR_R, buf, len);
152}
153
154static void atmel_read_buf16(struct mtd_info *mtd, u8 *buf, int len)
155{
156 struct nand_chip *nand_chip = mtd->priv;
157
158 __raw_readsw(nand_chip->IO_ADDR_R, buf, len / 2);
159}
160
161static void atmel_write_buf(struct mtd_info *mtd, const u8 *buf, int len)
162{
163 struct nand_chip *nand_chip = mtd->priv;
164
165 __raw_writesb(nand_chip->IO_ADDR_W, buf, len);
166}
167
168static void atmel_write_buf16(struct mtd_info *mtd, const u8 *buf, int len)
169{
170 struct nand_chip *nand_chip = mtd->priv;
171
172 __raw_writesw(nand_chip->IO_ADDR_W, buf, len / 2);
173}
174
175/*
145 * write oob for small pages 176 * write oob for small pages
146 */ 177 */
147static int atmel_nand_write_oob_512(struct mtd_info *mtd, 178static int atmel_nand_write_oob_512(struct mtd_info *mtd,
@@ -436,8 +467,14 @@ static int __init atmel_nand_probe(struct platform_device *pdev)
436 467
437 nand_chip->chip_delay = 20; /* 20us command delay time */ 468 nand_chip->chip_delay = 20; /* 20us command delay time */
438 469
439 if (host->board->bus_width_16) /* 16-bit bus width */ 470 if (host->board->bus_width_16) { /* 16-bit bus width */
440 nand_chip->options |= NAND_BUSWIDTH_16; 471 nand_chip->options |= NAND_BUSWIDTH_16;
472 nand_chip->read_buf = atmel_read_buf16;
473 nand_chip->write_buf = atmel_write_buf16;
474 } else {
475 nand_chip->read_buf = atmel_read_buf;
476 nand_chip->write_buf = atmel_write_buf;
477 }
441 478
442 platform_set_drvdata(pdev, host); 479 platform_set_drvdata(pdev, host);
443 atmel_nand_enable(host); 480 atmel_nand_enable(host);
@@ -546,7 +583,7 @@ err_nand_ioremap:
546/* 583/*
547 * Remove a NAND device. 584 * Remove a NAND device.
548 */ 585 */
549static int __devexit atmel_nand_remove(struct platform_device *pdev) 586static int __exit atmel_nand_remove(struct platform_device *pdev)
550{ 587{
551 struct atmel_nand_host *host = platform_get_drvdata(pdev); 588 struct atmel_nand_host *host = platform_get_drvdata(pdev);
552 struct mtd_info *mtd = &host->mtd; 589 struct mtd_info *mtd = &host->mtd;
@@ -564,8 +601,7 @@ static int __devexit atmel_nand_remove(struct platform_device *pdev)
564} 601}
565 602
566static struct platform_driver atmel_nand_driver = { 603static struct platform_driver atmel_nand_driver = {
567 .probe = atmel_nand_probe, 604 .remove = __exit_p(atmel_nand_remove),
568 .remove = atmel_nand_remove,
569 .driver = { 605 .driver = {
570 .name = "atmel_nand", 606 .name = "atmel_nand",
571 .owner = THIS_MODULE, 607 .owner = THIS_MODULE,
@@ -574,7 +610,7 @@ static struct platform_driver atmel_nand_driver = {
574 610
575static int __init atmel_nand_init(void) 611static int __init atmel_nand_init(void)
576{ 612{
577 return platform_driver_register(&atmel_nand_driver); 613 return platform_driver_probe(&atmel_nand_driver, atmel_nand_probe);
578} 614}
579 615
580 616