The Denali NAND IP has no way to read out the current signal level
of the R/B# pin. Instead, denali_dev_ready() checks if the R/B#
transition has already happened. (The INTR__INT_ACT interrupt is
asserted at the rising edge of the R/B# pin.) It is not a correct
way to implement the ->dev_ready() hook.
In fact, it has a drawback; in the nand_scan_ident phase, the chip
detection iterates over maxchips until it fails to find a homogeneous
chip. For the last loop, nand_reset() fails if no chip is there.
If ->dev_ready hook exists, nand_command(_lp) calls nand_wait_ready()
after NAND_CMD_RESET. However, we know denali_dev_ready() never
returns 1 unless there exists a chip that toggles R/B# in that chip
select. Then, nand_wait_ready() just ends up with wasting 400 msec,
in the end, shows the "timeout while waiting for chip to become ready"
warning.
Let's remove the mis-implemented dev_ready hook, and fallback to
sending the NAND_CMD_STATUS and nand_wait_status_ready(), which
bails out more quickly.
Signed-off-by: Masahiro Yamada
---
drivers/mtd/nand/raw/denali.c | 22 +-
1 file changed, 1 insertion(+), 21 deletions(-)
diff --git a/drivers/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c
index f88a5dc..f069184 100644
--- a/drivers/mtd/nand/raw/denali.c
+++ b/drivers/mtd/nand/raw/denali.c
@@ -203,18 +203,6 @@ static uint32_t denali_wait_for_irq(struct
denali_nand_info *denali,
return denali->irq_status;
}
-static uint32_t denali_check_irq(struct denali_nand_info *denali)
-{
- unsigned long flags;
- uint32_t irq_status;
-
- spin_lock_irqsave(&denali->irq_lock, flags);
- irq_status = denali->irq_status;
- spin_unlock_irqrestore(&denali->irq_lock, flags);
-
- return irq_status;
-}
-
static void denali_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
struct denali_nand_info *denali = mtd_to_denali(mtd);
@@ -294,7 +282,7 @@ static void denali_cmd_ctrl(struct mtd_info *mtd, int dat,
unsigned int ctrl)
return;
/*
-* Some commands are followed by chip->dev_ready or chip->waitfunc.
+* Some commands are followed by chip->waitfunc.
* irq_status must be cleared here to catch the R/B# interrupt later.
*/
if (ctrl & NAND_CTRL_CHANGE)
@@ -303,13 +291,6 @@ static void denali_cmd_ctrl(struct mtd_info *mtd, int dat,
unsigned int ctrl)
denali->host_write(denali, DENALI_BANK(denali) | type, dat);
}
-static int denali_dev_ready(struct mtd_info *mtd)
-{
- struct denali_nand_info *denali = mtd_to_denali(mtd);
-
- return !!(denali_check_irq(denali) & INTR__INT_ACT);
-}
-
static int denali_check_erased_page(struct mtd_info *mtd,
struct nand_chip *chip, uint8_t *buf,
unsigned long uncor_ecc_flags,
@@ -1349,7 +1330,6 @@ int denali_init(struct denali_nand_info *denali)
chip->write_byte = denali_write_byte;
chip->read_word = denali_read_word;
chip->cmd_ctrl = denali_cmd_ctrl;
- chip->dev_ready = denali_dev_ready;
chip->waitfunc = denali_waitfunc;
if (features & FEATURES__INDEX_ADDR) {
--
2.7.4
