From: Boris Brezillon <boris.brezillon@collabora.com>
To: Tomer Maimon <tmaimon77@gmail.com>
Cc: yogeshnarayan.gaur@nxp.com, vigneshr@ti.com,
bbrezillon@kernel.org, richard@nod.at,
tudor.ambarus@microchip.com, linux-spi@vger.kernel.org,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
marek.vasut@gmail.com, frieder.schrempf@exceet.de,
broonie@kernel.org, linux-mtd@lists.infradead.org,
miquel.raynal@bootlin.com, tglx@linutronix.de,
computersforpeace@gmail.com, dwmw2@infradead.org
Subject: Re: [RFC v1 0/3] *spi-mem: adding setup and callback function
Date: Mon, 29 Jul 2019 17:28:59 +0200 [thread overview]
Message-ID: <20190729172859.4374a2ad@collabora.com> (raw)
In-Reply-To: <20190729142504.188336-1-tmaimon77@gmail.com>
Hi Tomer,
On Mon, 29 Jul 2019 17:25:01 +0300
Tomer Maimon <tmaimon77@gmail.com> wrote:
> Lately we have working on Flash interface unit (FIU) SPI driver that
> using spi-mem interface, Our FIU HW module support direct Flash Rd//Wr.
>
> In our SOC (32 bit dual core ARM) we have 3 FIU's that using memory mapping as follow:
>
> FIU0 - have 2 chip select and each one have 128MB memory mapping (total 256MB memory mapping)
> FIU1 - have 4 chip select and each one have 128MB memory mapping (total 512MB memory mapping)
> FIU2 - have 4 chip select and each one have 16MB memory mapping (total 32MB memory mapping)
>
> Totally 800MB memory mapping.
>
> When the FIU driver probe it don't know the size of each Flash that
> connected to the FIU, so the entire memory mapping is allocated for each FIU
> according the FIU device tree memory map parameters.
Do you need those mappings to be active to support simple reg accesses?
> It means, if we enable all three FIU's the drivers will try to allocate totally 800MB.
>
> In 32bit system it is problematic because the kernel have only 1GB
> of memory allocation so the vmalloc cannot take 800MB.
>
> When implementing the FIU driver in the mtd/spi-nor we allocating memory address only
> for detected Flash with exact size (usually we are not using 128MB Flash), and in that case usually we allocating much less memory.
>
> To solve this issue we needed to overcome two things:
>
> 1. Get argument from the upper layer (spi-mem layer)
> 2. Calling the get argument function after SPI_NOR_SCAN function. (the MTD Flash size filled in SPI_NOR_SCAN function)
That's clearly breaking the layering we've tried to restore with the
spi-nor/spi-mem split, and I don't see why this is needed since we now
have a way to create direct mappings dynamically (with the dirmap API).
Have you tried implementing the dirmap hooks in your driver?
Regards,
Boris
______________________________________________________
Linux MTD discussion mailing list
http://lists.infradead.org/mailman/listinfo/linux-mtd/
next prev parent reply other threads:[~2019-07-29 15:29 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-29 14:25 [RFC v1 0/3] *spi-mem: adding setup and callback function Tomer Maimon
2019-07-29 14:25 ` [RFC v1 1/3] spi: spi-mem: add spi-mem setup function Tomer Maimon
2019-07-29 14:25 ` [RFC v1 2/3] spi: spi-mem: add callback function to spi-mem device Tomer Maimon
2019-07-29 14:25 ` [RFC v1 3/3] mtd: m25p80: add get Flash size callback support Tomer Maimon
2019-07-29 15:28 ` Boris Brezillon [this message]
[not found] ` <CAP6Zq1iPXDX_Gtz6ZWYm3JoHgHjdapotVLGw-Lq4tc2X-6eAug@mail.gmail.com>
2019-07-30 6:54 ` [RFC v1 0/3] *spi-mem: adding setup and callback function Boris Brezillon
2019-07-30 16:53 ` Sergei Shtylyov
2019-07-30 17:48 ` Vignesh Raghavendra
2019-07-30 18:04 ` Boris Brezillon
[not found] ` <CAP6Zq1hfVoS8+VU0rAtKAX7D22qTVHDMosiCRMKV8sQB_m0qOQ@mail.gmail.com>
2019-08-01 6:42 ` Vignesh Raghavendra
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=20190729172859.4374a2ad@collabora.com \
--to=boris.brezillon@collabora.com \
--cc=bbrezillon@kernel.org \
--cc=broonie@kernel.org \
--cc=computersforpeace@gmail.com \
--cc=dwmw2@infradead.org \
--cc=frieder.schrempf@exceet.de \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mtd@lists.infradead.org \
--cc=linux-spi@vger.kernel.org \
--cc=marek.vasut@gmail.com \
--cc=miquel.raynal@bootlin.com \
--cc=richard@nod.at \
--cc=tglx@linutronix.de \
--cc=tmaimon77@gmail.com \
--cc=tudor.ambarus@microchip.com \
--cc=vigneshr@ti.com \
--cc=yogeshnarayan.gaur@nxp.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).