From: Masahiro Yamada <yamada.masahiro@socionext.com>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>,
Enrico Jorns <ejo@pengutronix.de>,
Richard Weinberger <richard@nod.at>,
Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>,
Artem Bityutskiy <artem.bityutskiy@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Marek Vasut <marek.vasut@gmail.com>,
linux-mtd@lists.infradead.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Chuanxiao Dong <chuanxiao.dong@intel.com>,
Jassi Brar <jaswinder.singh@linaro.org>,
Brian Norris <computersforpeace@gmail.com>,
David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH v5 07/23] mtd: nand: denali: do not propagate NAND_STATUS_FAIL to waitfunc()
Date: Thu, 8 Jun 2017 18:43:47 +0900 [thread overview]
Message-ID: <CAK7LNAT3JkSccFO=fJm737wLGCOLZBu+0z8zxeB=VmhoggF-Cg@mail.gmail.com> (raw)
In-Reply-To: <20170608090503.11969545@bbrezillon>
Hi Boris,
2017-06-08 16:05 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
> Le Thu, 8 Jun 2017 15:11:03 +0900,
> Masahiro Yamada <yamada.masahiro@socionext.com> a écrit :
>
>> Hi Boris,
>>
>>
>> 2017-06-07 22:33 GMT+09:00 Boris Brezillon <boris.brezillon@free-electrons.com>:
>> > On Wed, 7 Jun 2017 20:52:16 +0900
>> > Masahiro Yamada <yamada.masahiro@socionext.com> wrote:
>> >
>> >> Currently, the error handling of denali_write_page(_raw) is a bit
>> >> complicated. If the program command fails, NAND_STATUS_FAIL is set
>> >> to the driver internal denali->status, then read out later by
>> >> denali_waitfunc().
>> >>
>> >> We can avoid it by exploiting the nand_write_page() implementation.
>> >> If chip->ecc.write_page(_raw) returns negative code (i.e. -EIO), it
>> >> errors out immediately. This gives the same result as returning
>> >> NAND_STATUS_FAIL from chip->waitfunc. In either way, -EIO is
>> >> returned to the upper MTD layer.
>> >
>> > Actually, this is how it's supposed to work now (when they set
>> > the NAND_ECC_CUSTOM_PAGE_ACCESS flag, drivers are expected to wait for
>> > the program operation to finish and return -EIO if it failed), so you're
>> > all good ;-).
>> >
>> >>
>> >> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
>> >> ---
>> >>
>> >> Changes in v5: None
>> >> Changes in v4: None
>> >> Changes in v3: None
>> >> Changes in v2:
>> >> - Newly added
>> >>
>> >> drivers/mtd/nand/denali.c | 12 ++++--------
>> >> drivers/mtd/nand/denali.h | 1 -
>> >> 2 files changed, 4 insertions(+), 9 deletions(-)
>> >>
>> >> diff --git a/drivers/mtd/nand/denali.c b/drivers/mtd/nand/denali.c
>> >> index 1897fe238290..22acfc34b546 100644
>> >> --- a/drivers/mtd/nand/denali.c
>> >> +++ b/drivers/mtd/nand/denali.c
>> >> @@ -1005,6 +1005,7 @@ static int write_page(struct mtd_info *mtd, struct nand_chip *chip,
>> >> size_t size = mtd->writesize + mtd->oobsize;
>> >> uint32_t irq_status;
>> >> uint32_t irq_mask = INTR__DMA_CMD_COMP | INTR__PROGRAM_FAIL;
>> >
>> > As mentioned in my previous patch, I think you should wait for
>> > INTR__PROGRAM_COMP | INTR__PROGRAM_FAIL here.
>>
>> No.
>> It is intentional to use INTR__DMA_CMD_COMP
>> instead of INTR__PROGRAM_COMP here.
>>
>>
>> This is very strange of this IP,
>> INTR__PROGRAM_COMP is never set when DMA mode is being used.
>> (INTR__DMA_CMD_COMP is set instead.)
>
> Indeed, this is really strange. Are you sure the page is actually
> programmed when you receive the INTR__DMA_CMD_COMP interrupt?
Yes.
After my test, I concluded INTR__DMA_CMD_COMP is asserted
when page program is completed.
Rationale:
Denali User's Guide describes the IRQ bits as follows:
Bit 2 (dma_cmd_comp) A data DMA command has completed on this bank
...
Bit 7 (program_comp) Device finished the last issued program command
...
Bit 12 (INT_act) R/B pin of device transitioned from low to high
...
Bit 15 (page_xfer_inc) For every page of data transfer to or from the device,
this bit will be set.
In my test, ->write_page() hook triggers IRQ bits as follows:
- Write access with DMA
bit 15 is asserted first,
then some timer later bit 12 and bit 2 are asserted at the same time
- Write access with PIO
bit 15 is asserted first,
then some time later bit 12 and bit 7 are asserted at the same time
NAND devices toggle R/B# pin when page program is completed.
So, bit 2 (dma_cmd_comp) means the completion of page program.
I assume your next question here.
"So, why don't you wait for INTR__INT_ACT
instead of INTR__DMA_CMD_COMP / INTR__PROGRAM_COMP?
It should work regardless of transfer mode."
This has a point.
We can always check R/B# transition for read, write, erase, or whatever.
This is just a matter of taste, but I am just keeping code that uses
dedicated IRQ bits for each mode.
> Because INTR__DMA_CMD_COMP is likely to happen before the PAGEPROG
> command has finished, which is not good (the core might start a new
> operation while the NAND is still busy).
As explained above, INTR__PAGE_XFER_INC happens before the PAGEPROG.
Then, INTR__DMA_CMD_COMP happens when the PAGEPROG has finished.
> Anyway, if INTR__DMA_CMD_COMP is what should be set, it clearly
> deserves a comment.
Will add a comment.
>>
>>
>> As far as I tested this IP,
>> INTR__PROGRAM_COMP is set only when data are written by PIO mode.
>
> It doesn't make much sense (not saying you're wrong, just that the IP
> is weird). PROG completed should be independent of the data transfer
> step. Sure it happens after transferring data to the NAND, but then you
> still have to execute the PAGEPROG command and wait until the NAND
> becomes ready again. That's when I'd expect PROGRAM_COMP (or
> PROGRAM_FAIL) to be triggered.
You can do like that (execute 0x10 command separately)
by using the raw command mode. (MODE_11)
When using high level interface of this IP,
the controller will take care of 0x80 command, address cycle,
data cycle, then 0x10 command.
Anyway, we agree this IP is strange.
>>
>>
>> I introduced PIO transfer in
>> http://patchwork.ozlabs.org/patch/772398/
>>
>> I used INTR__PROGRAM_COMP in denali_pio_write().
>>
>
> Yep, I see that.
>
>>
>>
>> >> + int ret = 0;
>> >>
>> >> denali->page = page;
>> >>
>> >> @@ -1038,13 +1039,13 @@ static int write_page(struct mtd_info *mtd, struct nand_chip *chip,
>> >> if (irq_status == 0) {
>> >> dev_err(denali->dev, "timeout on write_page (type = %d)\n",
>> >> raw_xfer);
>> >> - denali->status = NAND_STATUS_FAIL;
>> >> + ret = -EIO;
>> >> }
>> >
>> > if (irq_status & INTR__PROGRAM_FAIL) {
>> > dev_err(denali->dev, "page program failed (type = %d)\n",
>> > raw_xfer);
>> > ret = -EIO;
>> > }
>>
>> This will be fixed anyway by
>> http://patchwork.ozlabs.org/patch/772414/
>
> Note that PROG_FAILED is quite different from a timeout (usually
> happens when a block becomes bad), so it probably deserve a specific
> error message.
>
OK. Will consider it.
--
Best Regards
Masahiro Yamada
next prev parent reply other threads:[~2017-06-08 9:43 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-07 11:52 [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 01/23] mtd: nand: add generic helpers to check, match, maximize ECC settings Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 02/23] mtd: nand: add a shorthand to generate nand_ecc_caps structure Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 03/23] mtd: nand: denali: avoid hard-coding ECC step, strength, bytes Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 04/23] mtd: nand: denali: remove Toshiba and Hynix specific fixup code Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 05/23] mtd: nand: denali_dt: add compatible strings for UniPhier SoC variants Masahiro Yamada
2017-06-07 19:01 ` Rob Herring
2017-06-07 11:52 ` [PATCH v5 06/23] mtd: nand: denali: set NAND_ECC_CUSTOM_PAGE_ACCESS Masahiro Yamada
2017-06-07 13:26 ` Boris Brezillon
2017-06-08 7:32 ` Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 07/23] mtd: nand: denali: do not propagate NAND_STATUS_FAIL to waitfunc() Masahiro Yamada
2017-06-07 13:33 ` Boris Brezillon
2017-06-08 6:11 ` Masahiro Yamada
2017-06-08 7:05 ` Boris Brezillon
2017-06-08 9:43 ` Masahiro Yamada [this message]
2017-06-08 10:04 ` Boris Brezillon
2017-06-07 11:52 ` [PATCH v5 08/23] mtd: nand: denali: remove unneeded find_valid_banks() Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 09/23] mtd: nand: denali: handle timing parameters by setup_data_interface() Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 10/23] mtd: nand: denali: rework interrupt handling Masahiro Yamada
2017-06-07 13:57 ` Boris Brezillon
2017-06-08 6:10 ` Masahiro Yamada
2017-06-08 7:12 ` Boris Brezillon
2017-06-08 10:41 ` Masahiro Yamada
2017-06-08 11:26 ` Boris Brezillon
2017-06-08 12:58 ` Masahiro Yamada
2017-06-08 15:43 ` Boris Brezillon
2017-06-08 17:26 ` Masahiro Yamada
2017-06-08 17:30 ` Masahiro Yamada
2017-06-09 7:58 ` Boris Brezillon
2017-06-13 4:41 ` Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 11/23] mtd: nand: denali: fix NAND_CMD_STATUS handling Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 12/23] mtd: nand: denali: fix NAND_CMD_PARAM handling Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 13/23] mtd: nand: denali: switch over to cmd_ctrl instead of cmdfunc Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 14/23] mtd: nand: denali: fix bank reset function to detect the number of chips Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 15/23] mtd: nand: denali: use interrupt instead of polling for bank reset Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 16/23] mtd: nand: denali: propagate page to helpers via function argument Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 17/23] mtd: nand: denali: merge struct nand_buf into struct denali_nand_info Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 18/23] mtd: nand: denali: use flag instead of register macro for direction Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 19/23] mtd: nand: denali: fix raw and oob accessors for syndrome page layout Masahiro Yamada
2017-06-07 14:09 ` Boris Brezillon
2017-06-08 11:22 ` Masahiro Yamada
2017-06-13 4:42 ` Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 20/23] mtd: nand: denali: support hardware-assisted erased page detection Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 21/23] mtd: nand: denali: skip driver internal bounce buffer when possible Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 22/23] mtd: nand: denali: use non-managed kmalloc() for DMA buffer Masahiro Yamada
2017-06-07 11:52 ` [PATCH v5 23/23] mtd: nand: denali: enable bad block table scan Masahiro Yamada
2017-06-08 6:16 ` [PATCH v5 00/23] mtd: nand: denali: Denali NAND IP patch bomb Masahiro Yamada
2017-06-08 7:12 ` Masahiro Yamada
2017-06-08 7:18 ` Boris Brezillon
2017-06-11 20:14 ` Boris Brezillon
2017-06-08 7:14 ` Boris Brezillon
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