linux-kernel - [PATCH v6 14/14] media: vivid: add cache

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Date:   Fri, 15 May 2020 01:01:53 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Hans Verkuil <hans.verkuil@...co.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Tomasz Figa <tfiga@...omium.org>, linux-media@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Sergey Senozhatsky <senozhatsky@...omium.org>
Subject: [PATCH v6 14/14] media: vivid: add cache_hints module param

From: Sergey Senozhatsky <senozhatsky@...omium.org>

Add a cache_hints module param to control per-queue user space cache
hints support.

Signed-off-by: Sergey Senozhatsky <senozhatsky@...omium.org>
---
 Documentation/admin-guide/media/vivid.rst     | 9 +++++++++
 drivers/media/test-drivers/vivid/vivid-core.c | 9 +++++++++
 2 files changed, 18 insertions(+)

diff --git a/Documentation/admin-guide/media/vivid.rst b/Documentation/admin-guide/media/vivid.rst
index 52e57b773f07..6d7175f96f74 100644
--- a/Documentation/admin-guide/media/vivid.rst
+++ b/Documentation/admin-guide/media/vivid.rst
@@ -293,6 +293,15 @@ all configurable using the following module options:
 		- 0: vmalloc
 		- 1: dma-contig
 
+- cache_hints:
+
+	specifies if the device should set queues' user-space cache and memory
+	consistency hint capability (V4L2_BUF_CAP_SUPPORTS_MMAP_CACHE_HINTS).
+	The hints are valid only when using MMAP streaming I/O. Default is 0.
+
+		- 0: forbid hints
+		- 1: allow hints
+
 Taken together, all these module options allow you to precisely customize
 the driver behavior and test your application with all sorts of permutations.
 It is also very suitable to emulate hardware that is not yet available, e.g.
diff --git a/drivers/media/test-drivers/vivid/vivid-core.c b/drivers/media/test-drivers/vivid/vivid-core.c
index 6c740e3e6999..5c986df4a8d4 100644
--- a/drivers/media/test-drivers/vivid/vivid-core.c
+++ b/drivers/media/test-drivers/vivid/vivid-core.c
@@ -169,6 +169,14 @@ MODULE_PARM_DESC(allocators, " memory allocator selection, default is 0.\n"
 			     "\t\t    0 == vmalloc\n"
 			     "\t\t    1 == dma-contig");
 
+static unsigned int cache_hints[VIVID_MAX_DEVS] = {
+	[0 ... (VIVID_MAX_DEVS - 1)] = 0
+};
+module_param_array(cache_hints, uint, NULL, 0444);
+MODULE_PARM_DESC(cache_hints, " user-space cache hints, default is 0.\n"
+			     "\t\t    0 == forbid\n"
+			     "\t\t    1 == allow");
+
 static struct vivid_dev *vivid_devs[VIVID_MAX_DEVS];
 
 const struct v4l2_rect vivid_min_rect = {
@@ -819,6 +827,7 @@ static int vivid_create_queue(struct vivid_dev *dev,
 	q->lock = &dev->mutex;
 	q->dev = dev->v4l2_dev.dev;
 	q->supports_requests = true;
+	q->allow_cache_hints = (cache_hints[dev->inst] == 1);
 
 	return vb2_queue_init(q);
 }
-- 
2.26.2