All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sanjaikumar V S <sanjaikumarvs@gmail.com>
To: mwalle@kernel.org, pratyush@kernel.org
Cc: hd@os-cillation.de, linux-kernel@vger.kernel.org,
	linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com,
	richard@nod.at, sanjaikumar.vs@dicortech.com,
	sanjaikumarvs@gmail.com, stable@vger.kernel.org,
	tudor.ambarus@linaro.org, vigneshr@ti.com
Subject: Re: [PATCH v4 2/2] mtd: spi-nor: core: Fix AAI mode when dirmap is not available
Date: Tue, 31 Mar 2026 06:24:17 +0000	[thread overview]
Message-ID: <20260331062417.26-1-sanjaikumarvs@gmail.com> (raw)
In-Reply-To: <2vxz1ph11jmq.fsf@kernel.org>

Hi,

> But if the controller does support direct mapping, won't it end up
> using the wrong opcode? Would it be a better idea to update the
> dirmap_info with the right opcodes?

You're right. If the controller supports direct mapping, it would still
use the wrong opcode from the template created at probe time.

Updating dirmap_info at runtime is problematic because SST AAI mode
requires dynamic changes per write:
- cmd.opcode: SPINOR_OP_BP (single byte) vs SPINOR_OP_AAI_WP (word)
- addr.nbytes: must be 0 for subsequent AAI writes

Controllers may also cache the template at dirmap_create time, so
modifying it at runtime could cause issues.

A cleaner approach is to disable dirmap for SST AAI devices by setting
nodirmap=1 in sst_nor_late_init(). This ensures all writes go through
spi_nor_spimem_exec_op() which uses the runtime opcode.

This only affects devices with SST_WRITE flag (sst25wf*, sst25vf016b,
sst25vf032b, sst25vf040b, sst25vf080b). Other SST devices that use
standard page program can still benefit from dirmap.

I'll send a v5 with this change.

Thanks,
Sanjaikumar

______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/

WARNING: multiple messages have this Message-ID (diff)
From: Sanjaikumar V S <sanjaikumarvs@gmail.com>
To: mwalle@kernel.org, pratyush@kernel.org
Cc: hd@os-cillation.de, linux-kernel@vger.kernel.org,
	linux-mtd@lists.infradead.org, miquel.raynal@bootlin.com,
	richard@nod.at, sanjaikumar.vs@dicortech.com,
	sanjaikumarvs@gmail.com, stable@vger.kernel.org,
	tudor.ambarus@linaro.org, vigneshr@ti.com
Subject: Re: [PATCH v4 2/2] mtd: spi-nor: core: Fix AAI mode when dirmap is not available
Date: Tue, 31 Mar 2026 06:24:17 +0000	[thread overview]
Message-ID: <20260331062417.26-1-sanjaikumarvs@gmail.com> (raw)
In-Reply-To: <2vxz1ph11jmq.fsf@kernel.org>

Hi,

> But if the controller does support direct mapping, won't it end up
> using the wrong opcode? Would it be a better idea to update the
> dirmap_info with the right opcodes?

You're right. If the controller supports direct mapping, it would still
use the wrong opcode from the template created at probe time.

Updating dirmap_info at runtime is problematic because SST AAI mode
requires dynamic changes per write:
- cmd.opcode: SPINOR_OP_BP (single byte) vs SPINOR_OP_AAI_WP (word)
- addr.nbytes: must be 0 for subsequent AAI writes

Controllers may also cache the template at dirmap_create time, so
modifying it at runtime could cause issues.

A cleaner approach is to disable dirmap for SST AAI devices by setting
nodirmap=1 in sst_nor_late_init(). This ensures all writes go through
spi_nor_spimem_exec_op() which uses the runtime opcode.

This only affects devices with SST_WRITE flag (sst25wf*, sst25vf016b,
sst25vf032b, sst25vf040b, sst25vf080b). Other SST devices that use
standard page program can still benefit from dirmap.

I'll send a v5 with this change.

Thanks,
Sanjaikumar

  reply	other threads:[~2026-03-31  6:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-11 10:30 [PATCH v4 0/2] mtd: spi-nor: Fix SST AAI write mode Sanjaikumar V S
2026-03-11 10:30 ` Sanjaikumar V S
2026-03-11 10:30 ` [PATCH v4 1/2] mtd: spi-nor: sst: Fix write enable before AAI sequence Sanjaikumar V S
2026-03-11 10:30   ` Sanjaikumar V S
2026-03-16 13:44   ` Hendrik Donner
2026-03-16 13:44     ` Hendrik Donner
2026-03-30 14:21   ` Pratyush Yadav
2026-03-30 14:21     ` Pratyush Yadav
2026-03-11 10:30 ` [PATCH v4 2/2] mtd: spi-nor: core: Fix AAI mode when dirmap is not available Sanjaikumar V S
2026-03-11 10:30   ` Sanjaikumar V S
2026-03-16 13:44   ` Hendrik Donner
2026-03-16 13:44     ` Hendrik Donner
2026-03-30 14:23   ` Pratyush Yadav
2026-03-30 14:23     ` Pratyush Yadav
2026-03-31  6:24     ` Sanjaikumar V S [this message]
2026-03-31  6:24       ` Sanjaikumar V S
2026-03-30  7:31 ` [PATCH v4 0/2] mtd: spi-nor: Fix SST AAI write mode Sanjaikumar V S
2026-03-30  7:31   ` Sanjaikumar V S
2026-03-30 14:25   ` Pratyush Yadav
2026-03-30 14:25     ` Pratyush Yadav

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260331062417.26-1-sanjaikumarvs@gmail.com \
    --to=sanjaikumarvs@gmail.com \
    --cc=hd@os-cillation.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mtd@lists.infradead.org \
    --cc=miquel.raynal@bootlin.com \
    --cc=mwalle@kernel.org \
    --cc=pratyush@kernel.org \
    --cc=richard@nod.at \
    --cc=sanjaikumar.vs@dicortech.com \
    --cc=stable@vger.kernel.org \
    --cc=tudor.ambarus@linaro.org \
    --cc=vigneshr@ti.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.