From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: linux-mtd@lists.infradead.org,
Boris Brezillon <boris.brezillon@bootlin.com>,
Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>,
linux-kernel@vger.kernel.org, Marek Vasut <marek.vasut@gmail.com>,
Brian Norris <computersforpeace@gmail.com>,
Richard Weinberger <richard@nod.at>,
David Woodhouse <dwmw2@infradead.org>
Subject: [PATCH v2 1/2] mtd: rawnand: denali: remove ->dev_ready() hook
Date: Wed, 28 Nov 2018 14:27:36 +0900 [thread overview]
Message-ID: <1543382857-30827-2-git-send-email-yamada.masahiro@socionext.com> (raw)
In-Reply-To: <1543382857-30827-1-git-send-email-yamada.masahiro@socionext.com>
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 <yamada.masahiro@socionext.com>
---
Changes in v2:
- Rebase
drivers/mtd/nand/raw/denali.c | 23 +----------------------
1 file changed, 1 insertion(+), 22 deletions(-)
diff --git a/drivers/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c
index 830ea24..ead6e60 100644
--- a/drivers/mtd/nand/raw/denali.c
+++ b/drivers/mtd/nand/raw/denali.c
@@ -204,18 +204,6 @@ 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 nand_chip *chip, uint8_t *buf, int len)
{
struct mtd_info *mtd = nand_to_mtd(chip);
@@ -288,8 +276,7 @@ static void denali_cmd_ctrl(struct nand_chip *chip, int dat, unsigned int ctrl)
return;
/*
- * Some commands are followed by chip->legacy.dev_ready or
- * chip->legacy.waitfunc.
+ * Some commands are followed by chip->legacy.waitfunc.
* irq_status must be cleared here to catch the R/B# interrupt later.
*/
if (ctrl & NAND_CTRL_CHANGE)
@@ -298,13 +285,6 @@ static void denali_cmd_ctrl(struct nand_chip *chip, int dat, unsigned int ctrl)
denali->host_write(denali, DENALI_BANK(denali) | type, dat);
}
-static int denali_dev_ready(struct nand_chip *chip)
-{
- struct denali_nand_info *denali = mtd_to_denali(nand_to_mtd(chip));
-
- 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,
@@ -1359,7 +1339,6 @@ int denali_init(struct denali_nand_info *denali)
chip->legacy.read_byte = denali_read_byte;
chip->legacy.write_byte = denali_write_byte;
chip->legacy.cmd_ctrl = denali_cmd_ctrl;
- chip->legacy.dev_ready = denali_dev_ready;
chip->legacy.waitfunc = denali_waitfunc;
if (features & FEATURES__INDEX_ADDR) {
--
2.7.4
next prev parent reply other threads:[~2018-11-28 5:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-28 5:27 [PATCH v2 0/2] mtd: rawnand: denali: clean-up unnecessary hook and device reset Masahiro Yamada
2018-11-28 5:27 ` Masahiro Yamada [this message]
2018-11-28 5:27 ` [PATCH v2 2/2] mtd: rawnand: denali: remove denali_reset_banks() Masahiro Yamada
2018-12-07 7:46 ` [PATCH v2 0/2] mtd: rawnand: denali: clean-up unnecessary hook and device reset Miquel Raynal
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