mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 09:59:32 +00:00
[MTD] [NAND] Verify probe by retrying to checking the results match
With modern systems using bus-hold instead of bus pull-up, it can often lead to erroneous reporting of NAND devices where there are none. Do a double probe to ensure that the result we got the first time is repeatable, and if it is not then return that there is no chip there. Signed-off-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
parent
37e5ffa3f1
commit
ed8165c75e
1 changed files with 21 additions and 0 deletions
|
@ -2229,6 +2229,7 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
|
|||
{
|
||||
struct nand_flash_dev *type = NULL;
|
||||
int i, dev_id, maf_idx;
|
||||
int tmp_id, tmp_manf;
|
||||
|
||||
/* Select the device */
|
||||
chip->select_chip(mtd, 0);
|
||||
|
@ -2240,6 +2241,26 @@ static struct nand_flash_dev *nand_get_flash_type(struct mtd_info *mtd,
|
|||
*maf_id = chip->read_byte(mtd);
|
||||
dev_id = chip->read_byte(mtd);
|
||||
|
||||
/* Try again to make sure, as some systems the bus-hold or other
|
||||
* interface concerns can cause random data which looks like a
|
||||
* possibly credible NAND flash to appear. If the two results do
|
||||
* not match, ignore the device completely.
|
||||
*/
|
||||
|
||||
chip->cmdfunc(mtd, NAND_CMD_READID, 0x00, -1);
|
||||
|
||||
/* Read manufacturer and device IDs */
|
||||
|
||||
tmp_manf = chip->read_byte(mtd);
|
||||
tmp_id = chip->read_byte(mtd);
|
||||
|
||||
if (tmp_manf != *maf_id || tmp_id != dev_id) {
|
||||
printk(KERN_INFO "%s: second ID read did not match "
|
||||
"%02x,%02x against %02x,%02x\n", __func__,
|
||||
*maf_id, dev_id, tmp_manf, tmp_id);
|
||||
return ERR_PTR(-ENODEV);
|
||||
}
|
||||
|
||||
/* Lookup the flash id */
|
||||
for (i = 0; nand_flash_ids[i].name != NULL; i++) {
|
||||
if (dev_id == nand_flash_ids[i].id) {
|
||||
|
|
Loading…
Reference in a new issue