From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v6 3/4 UPDATED] drivers: of: add initialization code for dma reserved memory
Date: Fri, 23 Aug 2013 13:27:11 -0600 [thread overview]
Message-ID: <5217B78F.1080300@wwwdotorg.org> (raw)
In-Reply-To: <1377247141-11284-1-git-send-email-m.szyprowski@samsung.com>
On 08/23/2013 02:39 AM, wrote:
> From: Marek Szyprowski <m.szyprowski@samsung•com>
>
> This patch adds device tree support for contiguous and reserved memory
> regions defined in device tree.
>
> Large memory blocks can be reliably reserved only during early boot.
> This must happen before the whole memory management subsystem is
> initialized, because we need to ensure that the given contiguous blocks
> are not yet allocated by kernel. Also it must happen before kernel
> mappings for the whole low memory are created, to ensure that there will
> be no mappings (for reserved blocks) or mapping with special properties
> can be created (for CMA blocks). This all happens before device tree
> structures are unflattened, so we need to get reserved memory layout
> directly from fdt.
>
> Later, those reserved memory regions are assigned to devices on each
> device structure initialization.
I think the binding looks OK now; just a couple minor comments below.
> diff --git a/Documentation/devicetree/bindings/memory.txt b/Documentation/devicetree/bindings/memory.txt
> +*** Reserved memory regions ***
> +compatible: one or more of:
> + - "linux,contiguous-memory-region" - enables binding of this
> + region to Contiguous Memory Allocator (special region for
> + contiguous memory allocations, shared with movable system
> + memory, Linux kernel-specific).
> + - "reserved-memory-region" - compatibility is defined, given
> + region is assigned for exclusive usage for by the respective
> + devices.
I'm slightly hesitant to agree with "linux" in the name here, since it
seems like the concept of a memory region where DMA buffers/... should
be allocated is pretty OS-independant. Similar for:
> +linux,default-contiguous-region: property indicating that the region
> + is the default region for all contiguous memory
> + allocations, Linux specific (optional)
But, I guess there's nothing stopping any other OS from parsing this
same property, so I suppose it's OK. What do other DT maintainers think?
> +*** Example ***
> + reserved-memory {
...
> + contig_region at 0 {
...
> + display_mem: region at 78000000 {
...
> + multimedia_mem: region at 77000000 {
Nit: I think all 3 of those nodes should be called region, but it's
probably fine as-is.
So, the binding,
Acked-by: Stephen Warren <swarren@nvidia•com>
next prev parent reply other threads:[~2013-08-23 19:27 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-19 15:04 [PATCH v6 0/4] Device Tree support for CMA (Contiguous Memory Allocator) Marek Szyprowski
2013-08-19 15:04 ` [PATCH v6 1/4] drivers: dma-contiguous: clean source code and prepare for device tree Marek Szyprowski
2013-08-19 15:04 ` [PATCH v6 2/4] drivers: of: add function to scan fdt nodes given by path Marek Szyprowski
2013-08-26 12:09 ` Rob Herring
2013-08-19 15:04 ` [PATCH v6 3/4] drivers: of: add initialization code for dma reserved memory Marek Szyprowski
2013-08-19 21:49 ` Stephen Warren
2013-08-19 22:02 ` Tomasz Figa
2013-08-19 22:17 ` Stephen Warren
2013-08-19 22:24 ` Tomasz Figa
2013-08-19 22:27 ` Stephen Warren
2013-08-19 22:40 ` Tomasz Figa
2013-08-19 22:54 ` Stephen Warren
2013-08-20 10:57 ` Marek Szyprowski
2013-08-20 16:35 ` Stephen Warren
2013-08-21 14:38 ` Marek Szyprowski
2013-08-22 20:08 ` Stephen Warren
2013-08-21 15:39 ` Tomasz Figa
2013-08-29 21:20 ` Grant Likely
2013-08-29 21:12 ` Grant Likely
2013-08-21 15:56 ` Matt Sealey
[not found] ` <1377247141-11284-1-git-send-email-m.szyprowski@samsung.com>
2013-08-23 19:27 ` Stephen Warren [this message]
2013-08-26 12:20 ` Rob Herring
2013-08-19 15:04 ` [PATCH v6 4/4] ARM: init: add support for reserved memory defined by device tree Marek Szyprowski
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=5217B78F.1080300@wwwdotorg.org \
--to=swarren@wwwdotorg$(echo .)org \
--cc=linux-arm-kernel@lists$(echo .)infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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