From: Nate Drude <nate.d@variscite.com>
To: iommu@lists.linux.dev
Cc: Jonathan Corbet <corbet@lwn.net>, Christoph Hellwig <hch@lst.de>,
Marek Szyprowski <m.szyprowski@samsung.com>,
Robin Murphy <robin.murphy@arm.com>, Borislav Petkov <bp@suse.de>,
"Paul E. McKenney" <paulmck@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Randy Dunlap <rdunlap@infradead.org>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
Muchun Song <songmuchun@bytedance.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
eran.m@variscite.com, Nate Drude <nate.d@variscite.com>
Subject: [PATCH] dma-contiguous: add optional cma_name for cma= kernel parameter
Date: Mon, 12 Sep 2022 11:38:05 -0500 [thread overview]
Message-ID: <20220912163805.4113238-1-nate.d@variscite.com> (raw)
When cma is defined in the device tree, the device tree node
name is used as the cma name. In the following example, the cma
will be named 'linux,cma':
linux,cma {
compatible = "shared-dma-pool";
reusable;
size = <0 0x3c000000>;
alloc-ranges = <0 0x40000000 0 0xC0000000>;
linux,cma-default;
};
And a device /dev/dma_heap/linux,cma is created.
However, when cma is provided by command line, a default
name of 'reserved' is used, and the device path changes to
/dev/dma_heap/reserved.
This is problematic because some user space applications,
like gstreamer plugins, are expecting /dev/dma_heap/linux,cma.
This parameter allows overriding the default 'reserved' name.
Signed-off-by: Nate Drude <nate.d@variscite.com>
---
.../admin-guide/kernel-parameters.txt | 7 +++++++
kernel/dma/contiguous.c | 21 ++++++++++++++++++-
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 51397a320f5e..975ec862d071 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -644,6 +644,13 @@
altogether. For more information, see
kernel/dma/contiguous.c
+ cma_name= Override the cma heap name
+ Format: <string>
+ When passing the cma kernel parameter, the default
+ cma name is 'reserved'. This parameter allows it to
+ be overriden to align with the device tree name,
+ like 'linux,cma'.
+
cma_pernuma=nn[MG]
[ARM64,KNL,CMA]
Sets the size of kernel per-numa memory area for
diff --git a/kernel/dma/contiguous.c b/kernel/dma/contiguous.c
index 3d63d91cba5c..e89819ec183e 100644
--- a/kernel/dma/contiguous.c
+++ b/kernel/dma/contiguous.c
@@ -74,6 +74,7 @@ static const phys_addr_t size_bytes __initconst =
static phys_addr_t size_cmdline __initdata = -1;
static phys_addr_t base_cmdline __initdata;
static phys_addr_t limit_cmdline __initdata;
+static char name_cmdline[CMA_MAX_NAME] = "reserved";
static int __init early_cma(char *p)
{
@@ -96,6 +97,24 @@ static int __init early_cma(char *p)
}
early_param("cma", early_cma);
+static int __init early_cma_name(char *p)
+{
+ if (!p) {
+ pr_err("Config string not provided\n");
+ return -EINVAL;
+ }
+
+ if (!strlen(p)) {
+ pr_err("cma_name must have at least one character\n");
+ return -EINVAL;
+ }
+
+ snprintf(name_cmdline, CMA_MAX_NAME, p);
+
+ return 0;
+}
+early_param("cma_name", early_cma_name);
+
#ifdef CONFIG_DMA_PERNUMA_CMA
static struct cma *dma_contiguous_pernuma_area[MAX_NUMNODES];
@@ -231,7 +250,7 @@ int __init dma_contiguous_reserve_area(phys_addr_t size, phys_addr_t base,
int ret;
ret = cma_declare_contiguous(base, size, limit, 0, 0, fixed,
- "reserved", res_cma);
+ name_cmdline, res_cma);
if (ret)
return ret;
--
2.37.3
next reply other threads:[~2022-09-12 16:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-12 16:38 Nate Drude [this message]
2022-09-13 10:45 ` [PATCH] dma-contiguous: add optional cma_name for cma= kernel parameter Robin Murphy
2022-09-23 14:48 ` Christoph Hellwig
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=20220912163805.4113238-1-nate.d@variscite.com \
--to=nate.d@variscite.com \
--cc=akpm@linux-foundation.org \
--cc=bp@suse.de \
--cc=corbet@lwn.net \
--cc=damien.lemoal@opensource.wdc.com \
--cc=eran.m@variscite.com \
--cc=hch@lst.de \
--cc=iommu@lists.linux.dev \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=m.szyprowski@samsung.com \
--cc=paulmck@kernel.org \
--cc=quic_neeraju@quicinc.com \
--cc=rdunlap@infradead.org \
--cc=robin.murphy@arm.com \
--cc=songmuchun@bytedance.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).