[NAND]: Avoid reading bad block marker for each page
Add support to prepare bad block table and use the same to
check for bad blocks before reading any page. This would
avoid calling isbad() function for each page and will be more
efficient. With current implementation we are calling isbad()
function around 2048 times for reading 8MB of boot image.
Change-Id: I9b58c43a71de6a3e42997d2f1a150f3330df33c2
CRs-Fixed: 288863
diff --git a/platform/msm_shared/nand.c b/platform/msm_shared/nand.c
index 6264220..4529594 100644
--- a/platform/msm_shared/nand.c
+++ b/platform/msm_shared/nand.c
@@ -78,6 +78,7 @@
static unsigned ECC_BCH_CFG;
static uint32_t enable_bch_ecc;
+static unsigned int *bbtbl;
#define CFG1_WIDE_FLASH (1U << 1)
@@ -789,12 +790,33 @@
unsigned n;
int isbad = 0;
unsigned cwperpage;
+ unsigned block = 0;
cwperpage = (flash_pagesize >> 9);
- /* Check for bad block and read only from a good block */
- isbad = flash_nand_block_isbad(cmdlist, ptrlist, page);
- if (isbad)
+ /* Find the block no for the page */
+ block = page / num_pages_per_blk;
+
+ /* Check the bad block table for each block
+ * -1: indicates the block needs to be checked if good or bad
+ * 1 : The block is bad
+ * 0 : The block is good
+ */
+ if(bbtbl[block] == -1) {
+ isbad = flash_nand_block_isbad(cmdlist, ptrlist, page);
+ if(isbad) {
+ /* Found bad , set the bad table entry */
+ bbtbl[block] = 1;
+ return -2;
+ } else {
+ /* Found good block , set the table entry &
+ * continue reading the data
+ */
+ bbtbl[block] = 0;
+ }
+ } else if(bbtbl[block] == 1) {
+ /* If the block is already identified as bad, return error*/
return -2;
+ }
data->cmd = NAND_CMD_PAGE_READ_ECC;
data->addr0 = page << 16;
@@ -3351,6 +3373,7 @@
void flash_init(void)
{
+ int i = 0;
ASSERT(flash_ptable == NULL);
flash_ptrlist = memalign(32, 1024);
@@ -3366,6 +3389,10 @@
ASSERT(0);
}
}
+ /* Create a bad block table */
+ bbtbl = (unsigned int *) malloc(sizeof(unsigned int) * flash_info.num_blocks);
+ for(i = 0 ; i < flash_info.num_blocks ; i++)
+ bbtbl[i] = -1 ;
}
struct ptable *flash_get_ptable(void)