Thread (27 messages) flat view 27 messages, 6 authors, 2021-02-26

Re: [PATCH v3 4/9] media: uapi: Add a control for HANTRO driver

From: Ezequiel Garcia <hidden>
Date: 2021-02-25 14:06:55
Also in: linux-devicetree, linux-media, linux-rockchip, lkml

Hi Benjamin,

On Mon, 2021-02-22 at 13:24 +0100, Benjamin Gaignard wrote:
The HEVC HANTRO driver needs to know the number of bits to skip at
s/HANTRO/Hantro
the beginning of the slice header.
As discussed in a different thread, we should describe exactly
what the hardware is expecting, so applications can parse that
and pass a correct value.
quoted hunk ↗ jump to hunk
That is a hardware specific requirement so create a dedicated control
that this purpose.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
---
version 3:
- Fix typo in field name

 include/uapi/linux/hantro-v4l2-controls.h | 20 ++++++++++++++++++++
 include/uapi/linux/v4l2-controls.h        |  5 +++++
 2 files changed, 25 insertions(+)
 create mode 100644 include/uapi/linux/hantro-v4l2-controls.h
diff --git a/include/uapi/linux/hantro-v4l2-controls.h b/include/uapi/linux/hantro-v4l2-controls.h
new file mode 100644
index 000000000000..a8dfd6b1a2a9
--- /dev/null
+++ b/include/uapi/linux/hantro-v4l2-controls.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+
+#ifndef __UAPI_HANTRO_V4L2_CONYTROLS_H__
+#define __UAPI_HANTRO_V4L2_CONYTROLS_H__
+
+#include <linux/v4l2-controls.h>
+#include <media/hevc-ctrls.h>
+
+#define V4L2_CID_HANTRO_HEVC_EXTRA_DECODE_PARAMS       (V4L2_CID_USER_HANTRO_BASE + 0)
+
+/**
+ * struct hantro_hevc_extra_decode_params - extra decode parameters for hantro driver
+ * @hevc_hdr_skip_length:      header first bits offset
+ */
+struct hantro_hevc_extra_decode_params {
+       __u32   hevc_hdr_skip_length;
+       __u8    padding[4];
+};
+
I think we can get away with a simpler solution. Since it's just one integer
we need, there's no need for a compound control. Something like this:

                .codec = HANTRO_HEVC_DECODER,                                    
                .cfg = {                                                         
                        .id = V4L2_CID_HANTRO_HEVC_SLICE_HEADER_SKIP,            
                        .name = "Hantro HEVC slice header skip bytes",           
                        .type = V4L2_CTRL_TYPE_INTEGER,                          
                        .min = 0,                                                
                        .max = 0x7fffffff,                                       
                        .step = 1,                                               
                },     

Also see V4L2_CID_CODA_MB_ERR_CNT which is defined in drivers/media/platform/coda/coda.h.
The control is sufficiently special that it could be kept in an internal driver header.
quoted hunk ↗ jump to hunk
+#endif
diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h
index 039c0d7add1b..ced7486c7f46 100644
--- a/include/uapi/linux/v4l2-controls.h
+++ b/include/uapi/linux/v4l2-controls.h
@@ -209,6 +209,11 @@ enum v4l2_colorfx {
  * We reserve 128 controls for this driver.
  */
 #define V4L2_CID_USER_CCS_BASE                 (V4L2_CID_USER_BASE + 0x10f0)
+/*
+ * The base for HANTRO driver controls.
+ * We reserve 32 controls for this driver.
+ */
+#define V4L2_CID_USER_HANTRO_BASE              (V4L2_CID_USER_BASE + 0x1170)
 
 /* MPEG-class control IDs */
 /* The MPEG controls are applicable to all codec controls
Thanks,
Ezequiel


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