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nand_imx: Speed up sequential read 

When reading a page from nand prefetch the next page afterwards to
keep the controller busy. This way we can improve sequential reading
from NAND which is the common case for barebox.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This commit is contained in:
Sascha Hauer 2010-03-25 16:15:35 +01:00
parent 9d9be6ba9b
commit d5578b8179
1 changed files with 47 additions and 13 deletions
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60
drivers/nand/nand_imx.c
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@ -295,7 +295,7 @@ static void __nand_boot_init noinline send_addr(struct imx_nand_host *host, u16
* @param spare_only set true if only the spare area is transferred
*/
static void __nand_boot_init send_page(struct imx_nand_host *host,
unsigned int ops)
unsigned int ops, int wait)
{
int bufs, i;
@ -311,7 +311,8 @@ static void __nand_boot_init send_page(struct imx_nand_host *host,
writew(ops, host->regs + NFC_CONFIG2);
/* Wait for operation to complete */
wait_op_done(host);
if (wait)
wait_op_done(host);
}
}
@ -671,11 +672,17 @@ static void imx_nand_command(struct mtd_info *mtd, unsigned command,
{
struct nand_chip *nand_chip = mtd->priv;
struct imx_nand_host *host = nand_chip->priv;
static int cached = -1;
MTD_DEBUG(MTD_DEBUG_LEVEL3,
"imx_nand_command (cmd = 0x%x, col = 0x%x, page = 0x%x)\n",
command, column, page_addr);
if (cached != -1)
wait_op_done(host);
if (command != NAND_CMD_READ0)
cached = -1;
/*
* Reset command state information
*/
@ -702,17 +709,44 @@ static void imx_nand_command(struct mtd_info *mtd, unsigned command,
command = NAND_CMD_READ0;
send_cmd(host, command);
mxc_do_addr_cycle(mtd, column, page_addr);
if (cached == page_addr) {
memcpy32(host->data_buf, host->main_area0, mtd->writesize);
copy_spare(mtd, 1);
if (host->pagesize_2k)
/* send read confirm command */
send_cmd(host, NAND_CMD_READSTART);
send_cmd(host, command);
mxc_do_addr_cycle(mtd, column, page_addr + 1);
send_page(host, NFC_OUTPUT);
if (host->pagesize_2k)
/* send read confirm command */
send_cmd(host, NAND_CMD_READSTART);
send_page(host, NFC_OUTPUT, 0);
cached = page_addr + 1;
} else {
host->buf_start = column;
send_cmd(host, command);
mxc_do_addr_cycle(mtd, column, page_addr);
if (host->pagesize_2k)
/* send read confirm command */
send_cmd(host, NAND_CMD_READSTART);
send_page(host, NFC_OUTPUT, 1);
memcpy32(host->data_buf, host->main_area0, mtd->writesize);
copy_spare(mtd, 1);
send_cmd(host, command);
mxc_do_addr_cycle(mtd, column, page_addr + 1);
if (host->pagesize_2k)
/* send read confirm command */
send_cmd(host, NAND_CMD_READSTART);
send_page(host, NFC_OUTPUT, 0);
cached = page_addr + 1;
}
memcpy32(host->data_buf, host->main_area0, mtd->writesize);
copy_spare(mtd, 1);
break;
case NAND_CMD_SEQIN:
@ -749,7 +783,7 @@ static void imx_nand_command(struct mtd_info *mtd, unsigned command,
case NAND_CMD_PAGEPROG:
memcpy32(host->main_area0, host->data_buf, mtd->writesize);
copy_spare(mtd, 0);
send_page(host, NFC_INPUT);
send_page(host, NFC_INPUT, 1);
send_cmd(host, command);
mxc_do_addr_cycle(mtd, column, page_addr);
break;
@ -850,7 +884,7 @@ static int __init imxnd_probe(struct device_d *dev)
#endif
/* Allocate memory for MTD device structure and private data */
host = kzalloc(sizeof(struct imx_nand_host) + NAND_MAX_PAGESIZE +
NAND_MAX_OOBSIZE, GFP_KERNEL);
NAND_MAX_OOBSIZE * 2, GFP_KERNEL);
if (!host)
return -ENOMEM;
@ -1137,7 +1171,7 @@ void __nand_boot_init imx_nand_load_image(void *dest, int size)
page * pagesize);
if (host.pagesize_2k)
send_cmd(&host, NAND_CMD_READSTART);
send_page(&host, NFC_OUTPUT);
send_page(&host, NFC_OUTPUT, 1);
page++;
if (host.pagesize_2k) {