The patch titled
atmel_nand speedup via {read,write}s{b,w}()
has been added to the -mm tree. Its filename is
atmel_nand-speedup-via-readwritesbw.patch
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------------------------------------------------------
Subject: atmel_nand speedup via {read,write}s{b,w}()
From: David Brownell <david-b@xxxxxxxxxxx>
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).
[haavard.skinnemoen@xxxxxxxxx: rebase onto atmel_nand rename]
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@xxxxxxxxx>
Acked-by: Andrew Victor <linux@xxxxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/mtd/nand/atmel_nand.c | 46 ++++++++++++++++++++++++++++----
1 file changed, 41 insertions(+), 5 deletions(-)
diff -puN drivers/mtd/nand/atmel_nand.c~atmel_nand-speedup-via-readwritesbw drivers/mtd/nand/atmel_nand.c
--- a/drivers/mtd/nand/atmel_nand.c~atmel_nand-speedup-via-readwritesbw
+++ a/drivers/mtd/nand/atmel_nand.c
@@ -142,6 +142,37 @@ static int atmel_nand_device_ready(struc
}
/*
+ * 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(struc
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(s
}
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
static int __init atmel_nand_init(void)
{
- return platform_driver_register(&atmel_nand_driver);
+ return platform_driver_probe(&atmel_nand_driver, atmel_nand_probe);
}
_
Patches currently in -mm which might be from david-b@xxxxxxxxxxx are
origin.patch
rtc_read_alarm-handles-wraparound.patch
gpio-pca953x-i2c-handles-max7310-too.patch
ntp-let-update_persistent_clock-sleep.patch
jffs2-summary-allocation-dont-use-vmalloc.patch
atmel_nand-speedup-via-readwritesbw.patch
asic3-gpiolib-support.patch
asic3-remove-children-platform-data.patch
asic3-new-gpio-configuration-code.patch
sm501-add-gpiolib-support.patch
sm501-gpio-dynamic-registration-for-pci-devices.patch
sm501-gpio-i2c-support.patch
rtc-rtc-rs5c372-smbus-conversion-support.patch
rtc-rtc-rs5c732-add-support-for-ricoh-r2025s-d-rtc.patch
rtc-m41t80-sort-header-inclusions-for-readability.patch
rtc-m41t80-use-pr_info-as-appropriate.patch
rtc-remove-bkl-for-ioctl.patch
rtc-add-support-for-st-m41t94-spi-rtc.patch
gpio-gpio-driver-for-max7301-spi-gpio-expander.patch
gpio-gpio-driver-for-max7301-spi-gpio-expander-checkpatch-fixes.patch
gpio-sysfs-interface-updated-update.patch
gpio-mcp23s08-handles-multiple-chips-per-chipselect.patch
gpio-add-bt8xxgpio-driver.patch
gpio-add-bt8xxgpio-driver-checkpatch-fixes.patch
gpio-add-bt8xxgpio-driver-checkpatch-fixes-cleanup.patch
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