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qi-improve-nand-read-512-granularity.patch

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Previously we insisted on NAND block granularity read addressing
and buffer length, even though we normalized the block indexing to
512 bytes to be compatible with ext2 and SD.

This patch improves the read functions so they are completely 512-
block friendly, any number of 512 byte blocks can be fetched from
any 512 byte boundary now.

Signed-off-by: Andy Green <andy@openmoko.com>
This commit is contained in:
Andy Green 2009-02-03 18:06:39 +00:00 committed by Andy Green
parent 25b5a9ba62
commit bb67ea1a84
1 changed files with 15 additions and 17 deletions
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32
qiboot/src/cpu/s3c2442/nand_read.c
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@ -80,14 +80,18 @@ int s3c2442_nand_is_bad_block(unsigned long block_index)
return 0; return 0;
} }
static int nand_read_page_ll(unsigned char *buf, unsigned long block512) static int nand_read_page_ll(unsigned char *buf, unsigned long block512, int blocks512)
{ {
unsigned short *ptr16 = (unsigned short *)buf; unsigned short *ptr16 = (unsigned short *)buf;
unsigned int i, page_num; unsigned int i, page_num;
#if 0 unsigned int block_amount;
unsigned char ecc[64]; int blocks_possible = (3 - (block512 & 3)) + 1;
unsigned short *p16 = (unsigned short *)ecc;
#endif
if (blocks512 > blocks_possible)
blocks512 = blocks_possible;
block_amount = (NAND_PAGE_SIZE / 4 / 2) * blocks512;
nand_clear_RnB(); nand_clear_RnB();
@ -96,23 +100,20 @@ static int nand_read_page_ll(unsigned char *buf, unsigned long block512)
page_num = block512 >> 2; /* 512 block -> 2048 block */ page_num = block512 >> 2; /* 512 block -> 2048 block */
/* Write Address */ /* Write Address */
NFADDR = 0; NFADDR = 0;
NFADDR = 0; NFADDR = (block512 & 3) << 1; /* which 512 block in 2048 */
NFADDR = page_num & 0xff; NFADDR = page_num & 0xff;
NFADDR = (page_num >> 8) & 0xff; NFADDR = (page_num >> 8) & 0xff;
NFADDR = (page_num >> 16) & 0xff; NFADDR = (page_num >> 16) & 0xff;
NFCMD = NAND_CMD_READSTART; NFCMD = NAND_CMD_READSTART;
nand_wait(); nand_wait();
for (i = 0; i < NAND_PAGE_SIZE/2; i++) for (i = 0; i < block_amount; i++)
*ptr16++ = NFDATA16; *ptr16++ = NFDATA16;
#if 0
for (i = 0; i < 64 / 2; i++) { return blocks512;
*p16++ = NFDATA16;
}
#endif
return 4;
} }
/* low level nand read function */ /* low level nand read function */
int nand_read_ll(unsigned char *buf, unsigned long start_block512, int nand_read_ll(unsigned char *buf, unsigned long start_block512,
int blocks512) int blocks512)
@ -120,9 +121,6 @@ int nand_read_ll(unsigned char *buf, unsigned long start_block512,
int i, j; int i, j;
int bad_count = 0; int bad_count = 0;
if (start_block512 & 3) /* inside 2048-byte block */
return -1;
/* chip Enable */ /* chip Enable */
nand_select(); nand_select();
nand_clear_RnB(); nand_clear_RnB();
@ -140,7 +138,7 @@ int nand_read_ll(unsigned char *buf, unsigned long start_block512,
continue; continue;
} }
j = nand_read_page_ll(buf, start_block512); j = nand_read_page_ll(buf, start_block512, blocks512);
start_block512 += j; start_block512 += j;
buf += j << 9; buf += j << 9;
blocks512 -= j; blocks512 -= j;