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Subject: Re: [PATCH v5 2/2] media: platform: Add Aspeed Video Engine driver
To:     Eddie James <eajames@linux.ibm.com>, linux-kernel@vger.kernel.org
Cc:     mchehab@kernel.org, linux-media@vger.kernel.org,
        robh+dt@kernel.org, andrew@aj.id.au, linux-aspeed@lists.ozlabs.org,
        devicetree@vger.kernel.org, mark.rutland@arm.com
References: <1542056431-18146-1-git-send-email-eajames@linux.ibm.com>
 <1542056431-18146-3-git-send-email-eajames@linux.ibm.com>
From:   Hans Verkuil <hverkuil@xs4all.nl>
Message-ID: <da0fce71-0cf8-ce41-e77b-1c02c93ade76@xs4all.nl>
Date:   Thu, 15 Nov 2018 09:56:06 +0100
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On 11/12/2018 10:00 PM, Eddie James wrote:
> The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs
> can capture and compress video data from digital or analog sources. With
> the Aspeed chip acting a service processor, the Video Engine can capture
> the host processor graphics output.
> 
> Add a V4L2 driver to capture video data and compress it to JPEG images.
> Make the video frames available through the V4L2 streaming interface.
> 
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
>  MAINTAINERS                           |    8 +
>  drivers/media/platform/Kconfig        |    9 +
>  drivers/media/platform/Makefile       |    1 +
>  drivers/media/platform/aspeed-video.c | 1711 +++++++++++++++++++++++++++++++++
>  4 files changed, 1729 insertions(+)
>  create mode 100644 drivers/media/platform/aspeed-video.c
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fa45ff3..f8f08a4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2414,6 +2414,14 @@ S:	Maintained
>  F:	Documentation/hwmon/asc7621
>  F:	drivers/hwmon/asc7621.c
>  
> +ASPEED VIDEO ENGINE DRIVER
> +M:	Eddie James <eajames@linux.ibm.com>
> +L:	linux-media@vger.kernel.org
> +L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
> +S:	Maintained
> +F:	drivers/media/platform/aspeed-video.c
> +F:	Documentation/devicetree/bindings/media/aspeed-video.txt
> +
>  ASUS NOTEBOOKS AND EEEPC ACPI/WMI EXTRAS DRIVERS
>  M:	Corentin Chary <corentin.chary@gmail.com>
>  L:	acpi4asus-user@lists.sourceforge.net
> diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
> index 70c4f6c..ba78dd5 100644
> --- a/drivers/media/platform/Kconfig
> +++ b/drivers/media/platform/Kconfig
> @@ -32,6 +32,15 @@ source "drivers/media/platform/davinci/Kconfig"
>  
>  source "drivers/media/platform/omap/Kconfig"
>  
> +config VIDEO_ASPEED
> +	tristate "Aspeed AST2400 and AST2500 Video Engine driver"
> +	depends on VIDEO_V4L2
> +	select VIDEOBUF2_DMA_CONTIG
> +	help
> +	  Support for the Aspeed Video Engine (VE) embedded in the Aspeed
> +	  AST2400 and AST2500 SOCs. The VE can capture and compress video data
> +	  from digital or analog sources.
> +
>  config VIDEO_SH_VOU
>  	tristate "SuperH VOU video output driver"
>  	depends on MEDIA_CAMERA_SUPPORT
> diff --git a/drivers/media/platform/Makefile b/drivers/media/platform/Makefile
> index 6ab6200..2973953 100644
> --- a/drivers/media/platform/Makefile
> +++ b/drivers/media/platform/Makefile
> @@ -3,6 +3,7 @@
>  # Makefile for the video capture/playback device drivers.
>  #
>  
> +obj-$(CONFIG_VIDEO_ASPEED)		+= aspeed-video.o
>  obj-$(CONFIG_VIDEO_CADENCE)		+= cadence/
>  obj-$(CONFIG_VIDEO_VIA_CAMERA) += via-camera.o
>  obj-$(CONFIG_VIDEO_CAFE_CCIC) += marvell-ccic/
> diff --git a/drivers/media/platform/aspeed-video.c b/drivers/media/platform/aspeed-video.c
> new file mode 100644
> index 0000000..a2fd0bf
> --- /dev/null
> +++ b/drivers/media/platform/aspeed-video.c
> @@ -0,0 +1,1711 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +
> +#include <linux/atomic.h>
> +#include <linux/bitfield.h>
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/interrupt.h>
> +#include <linux/jiffies.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/platform_device.h>
> +#include <linux/reset.h>
> +#include <linux/sched.h>
> +#include <linux/spinlock.h>
> +#include <linux/string.h>
> +#include <linux/v4l2-controls.h>
> +#include <linux/videodev2.h>
> +#include <linux/wait.h>
> +#include <linux/workqueue.h>
> +#include <media/v4l2-ctrls.h>
> +#include <media/v4l2-dev.h>
> +#include <media/v4l2-device.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-dma-contig.h>
> +
> +#define DEVICE_NAME			"aspeed-video"
> +
> +#define ASPEED_VIDEO_JPEG_NUM_QUALITIES	12
> +#define ASPEED_VIDEO_JPEG_HEADER_SIZE	10
> +#define ASPEED_VIDEO_JPEG_QUANT_SIZE	116
> +#define ASPEED_VIDEO_JPEG_DCT_SIZE	34
> +
> +#define MAX_FRAME_RATE			60
> +#define MAX_HEIGHT			1200
> +#define MAX_WIDTH			1920
> +#define MIN_HEIGHT			480
> +#define MIN_WIDTH			640
> +
> +#define NUM_POLARITY_CHECKS		10
> +#define INVALID_RESOLUTION_RETRIES	2
> +#define INVALID_RESOLUTION_DELAY	msecs_to_jiffies(250)
> +#define RESOLUTION_CHANGE_DELAY		msecs_to_jiffies(500)
> +#define MODE_DETECT_TIMEOUT		msecs_to_jiffies(500)
> +#define STOP_TIMEOUT			msecs_to_jiffies(250)
> +#define DIRECT_FETCH_THRESHOLD		0x0c0000 /* 1024 * 768 */
> +
> +#define VE_MAX_SRC_BUFFER_SIZE		0x8ca000 /* 1920 * 1200, 32bpp */
> +#define VE_JPEG_HEADER_SIZE		0x006000 /* 512 * 12 * 4 */
> +
> +#define VE_PROTECTION_KEY		0x000
> +#define  VE_PROTECTION_KEY_UNLOCK	0x1a038aa8
> +
> +#define VE_SEQ_CTRL			0x004
> +#define  VE_SEQ_CTRL_TRIG_MODE_DET	BIT(0)
> +#define  VE_SEQ_CTRL_TRIG_CAPTURE	BIT(1)
> +#define  VE_SEQ_CTRL_FORCE_IDLE		BIT(2)
> +#define  VE_SEQ_CTRL_MULT_FRAME		BIT(3)
> +#define  VE_SEQ_CTRL_TRIG_COMP		BIT(4)
> +#define  VE_SEQ_CTRL_AUTO_COMP		BIT(5)
> +#define  VE_SEQ_CTRL_EN_WATCHDOG	BIT(7)
> +#define  VE_SEQ_CTRL_YUV420		BIT(10)
> +#define  VE_SEQ_CTRL_COMP_FMT		GENMASK(11, 10)
> +#define  VE_SEQ_CTRL_HALT		BIT(12)
> +#define  VE_SEQ_CTRL_EN_WATCHDOG_COMP	BIT(14)
> +#define  VE_SEQ_CTRL_TRIG_JPG		BIT(15)
> +#define  VE_SEQ_CTRL_CAP_BUSY		BIT(16)
> +#define  VE_SEQ_CTRL_COMP_BUSY		BIT(18)
> +
> +#ifdef CONFIG_MACH_ASPEED_G5
> +#define  VE_SEQ_CTRL_JPEG_MODE		BIT(13)	/* AST2500 */
> +#else
> +#define  VE_SEQ_CTRL_JPEG_MODE		BIT(8)	/* AST2400 */
> +#endif /* CONFIG_MACH_ASPEED_G5 */
> +
> +#define VE_CTRL				0x008
> +#define  VE_CTRL_HSYNC_POL		BIT(0)
> +#define  VE_CTRL_VSYNC_POL		BIT(1)
> +#define  VE_CTRL_SOURCE			BIT(2)
> +#define  VE_CTRL_INT_DE			BIT(4)
> +#define  VE_CTRL_DIRECT_FETCH		BIT(5)
> +#define  VE_CTRL_YUV			BIT(6)
> +#define  VE_CTRL_RGB			BIT(7)
> +#define  VE_CTRL_CAPTURE_FMT		GENMASK(7, 6)
> +#define  VE_CTRL_AUTO_OR_CURSOR		BIT(8)
> +#define  VE_CTRL_CLK_INVERSE		BIT(11)
> +#define  VE_CTRL_CLK_DELAY		GENMASK(11, 9)
> +#define  VE_CTRL_INTERLACE		BIT(14)
> +#define  VE_CTRL_HSYNC_POL_CTRL		BIT(15)
> +#define  VE_CTRL_FRC			GENMASK(23, 16)
> +
> +#define VE_TGS_0			0x00c
> +#define VE_TGS_1			0x010
> +#define  VE_TGS_FIRST			GENMASK(28, 16)
> +#define  VE_TGS_LAST			GENMASK(12, 0)
> +
> +#define VE_SCALING_FACTOR		0x014
> +#define VE_SCALING_FILTER0		0x018
> +#define VE_SCALING_FILTER1		0x01c
> +#define VE_SCALING_FILTER2		0x020
> +#define VE_SCALING_FILTER3		0x024
> +
> +#define VE_CAP_WINDOW			0x030
> +#define VE_COMP_WINDOW			0x034
> +#define VE_COMP_PROC_OFFSET		0x038
> +#define VE_COMP_OFFSET			0x03c
> +#define VE_JPEG_ADDR			0x040
> +#define VE_SRC0_ADDR			0x044
> +#define VE_SRC_SCANLINE_OFFSET		0x048
> +#define VE_SRC1_ADDR			0x04c
> +#define VE_COMP_ADDR			0x054
> +
> +#define VE_STREAM_BUF_SIZE		0x058
> +#define  VE_STREAM_BUF_SIZE_N_PACKETS	GENMASK(5, 3)
> +#define  VE_STREAM_BUF_SIZE_P_SIZE	GENMASK(2, 0)
> +
> +#define VE_COMP_CTRL			0x060
> +#define  VE_COMP_CTRL_VQ_DCT_ONLY	BIT(0)
> +#define  VE_COMP_CTRL_VQ_4COLOR		BIT(1)
> +#define  VE_COMP_CTRL_QUANTIZE		BIT(2)
> +#define  VE_COMP_CTRL_EN_BQ		BIT(4)
> +#define  VE_COMP_CTRL_EN_CRYPTO		BIT(5)
> +#define  VE_COMP_CTRL_DCT_CHR		GENMASK(10, 6)
> +#define  VE_COMP_CTRL_DCT_LUM		GENMASK(15, 11)
> +#define  VE_COMP_CTRL_EN_HQ		BIT(16)
> +#define  VE_COMP_CTRL_RSVD		BIT(19)
> +#define  VE_COMP_CTRL_ENCODE		GENMASK(21, 20)
> +#define  VE_COMP_CTRL_HQ_DCT_CHR	GENMASK(26, 22)
> +#define  VE_COMP_CTRL_HQ_DCT_LUM	GENMASK(31, 27)
> +
> +#define VE_OFFSET_COMP_STREAM		0x078
> +
> +#define VE_SRC_LR_EDGE_DET		0x090
> +#define  VE_SRC_LR_EDGE_DET_LEFT	GENMASK(11, 0)
> +#define  VE_SRC_LR_EDGE_DET_NO_V	BIT(12)
> +#define  VE_SRC_LR_EDGE_DET_NO_H	BIT(13)
> +#define  VE_SRC_LR_EDGE_DET_NO_DISP	BIT(14)
> +#define  VE_SRC_LR_EDGE_DET_NO_CLK	BIT(15)
> +#define  VE_SRC_LR_EDGE_DET_RT_SHF	16
> +#define  VE_SRC_LR_EDGE_DET_RT		GENMASK(27, VE_SRC_LR_EDGE_DET_RT_SHF)
> +#define  VE_SRC_LR_EDGE_DET_INTERLACE	BIT(31)
> +
> +#define VE_SRC_TB_EDGE_DET		0x094
> +#define  VE_SRC_TB_EDGE_DET_TOP		GENMASK(12, 0)
> +#define  VE_SRC_TB_EDGE_DET_BOT_SHF	16
> +#define  VE_SRC_TB_EDGE_DET_BOT		GENMASK(28, VE_SRC_TB_EDGE_DET_BOT_SHF)
> +
> +#define VE_MODE_DETECT_STATUS		0x098
> +#define  VE_MODE_DETECT_H_PIXELS	GENMASK(11, 0)
> +#define  VE_MODE_DETECT_V_LINES_SHF	16
> +#define  VE_MODE_DETECT_V_LINES		GENMASK(27, VE_MODE_DETECT_V_LINES_SHF)
> +#define  VE_MODE_DETECT_STATUS_VSYNC	BIT(28)
> +#define  VE_MODE_DETECT_STATUS_HSYNC	BIT(29)
> +
> +#define VE_SYNC_STATUS			0x09c
> +#define  VE_SYNC_STATUS_HSYNC		GENMASK(11, 0)
> +#define  VE_SYNC_STATUS_VSYNC_SHF	16
> +#define  VE_SYNC_STATUS_VSYNC		GENMASK(27, VE_SYNC_STATUS_VSYNC_SHF)
> +
> +#define VE_INTERRUPT_CTRL		0x304
> +#define VE_INTERRUPT_STATUS		0x308
> +#define  VE_INTERRUPT_MODE_DETECT_WD	BIT(0)
> +#define  VE_INTERRUPT_CAPTURE_COMPLETE	BIT(1)
> +#define  VE_INTERRUPT_COMP_READY	BIT(2)
> +#define  VE_INTERRUPT_COMP_COMPLETE	BIT(3)
> +#define  VE_INTERRUPT_MODE_DETECT	BIT(4)
> +#define  VE_INTERRUPT_FRAME_COMPLETE	BIT(5)
> +#define  VE_INTERRUPT_DECODE_ERR	BIT(6)
> +#define  VE_INTERRUPT_HALT_READY	BIT(8)
> +#define  VE_INTERRUPT_HANG_WD		BIT(9)
> +#define  VE_INTERRUPT_STREAM_DESC	BIT(10)
> +#define  VE_INTERRUPT_VSYNC_DESC	BIT(11)
> +
> +#define VE_MODE_DETECT			0x30c
> +#define VE_MEM_RESTRICT_START		0x310
> +#define VE_MEM_RESTRICT_END		0x314
> +
> +enum {
> +	VIDEO_MODE_DETECT_DONE,
> +	VIDEO_RES_CHANGE,
> +	VIDEO_STREAMING,
> +	VIDEO_FRAME_INPRG,
> +};
> +
> +struct aspeed_video_addr {
> +	unsigned int size;
> +	dma_addr_t dma;
> +	void *virt;
> +};
> +
> +struct aspeed_video_buffer {
> +	struct vb2_v4l2_buffer vb;
> +	struct list_head link;
> +};
> +
> +#define to_aspeed_video_buffer(x) \
> +	container_of((x), struct aspeed_video_buffer, vb)
> +
> +struct aspeed_video {
> +	void __iomem *base;
> +	struct clk *eclk;
> +	struct clk *vclk;
> +	struct reset_control *rst;
> +
> +	struct device *dev;
> +	struct v4l2_ctrl_handler ctrl_handler;
> +	struct v4l2_device v4l2_dev;
> +	struct v4l2_pix_format pix_fmt;
> +	struct v4l2_bt_timings timings;

You need two v4l2_bt_timings structs here:

	struct v4l2_bt_timings active_timings;
	struct v4l2_bt_timings detected_timings;

The first is what s_dv_timings set (and must also be initialized to
some timing at probe time), the second is what aspeed_video_get_resolution
fills in.

See more about this below.

> +	struct vb2_queue queue;
> +	struct video_device vdev;
> +	struct mutex video_lock;
> +
> +	atomic_t clients;
> +	wait_queue_head_t wait;
> +	spinlock_t lock;
> +	struct delayed_work res_work;
> +	struct list_head buffers;
> +	unsigned long flags;
> +	unsigned int sequence;
> +
> +	unsigned int max_compressed_size;
> +	struct aspeed_video_addr srcs[2];
> +	struct aspeed_video_addr jpeg;
> +	struct aspeed_video_addr detect;
> +
> +	bool yuv420;
> +	unsigned int frame_rate;
> +	unsigned int jpeg_quality;
> +	unsigned int capture_height;
> +	unsigned int capture_width;
> +};
> +
> +#define to_aspeed_video(x) container_of((x), struct aspeed_video, v4l2_dev)
> +
> +static const u32 aspeed_video_jpeg_header[ASPEED_VIDEO_JPEG_HEADER_SIZE] = {
> +	0xe0ffd8ff, 0x464a1000, 0x01004649, 0x60000101, 0x00006000, 0x0f00feff,
> +	0x00002d05, 0x00000000, 0x00000000, 0x00dbff00
> +};
> +
> +static const u32 aspeed_video_jpeg_quant[ASPEED_VIDEO_JPEG_QUANT_SIZE] = {
> +	0x081100c0, 0x00000000, 0x00110103, 0x03011102, 0xc4ff0111, 0x00001f00,
> +	0x01010501, 0x01010101, 0x00000000, 0x00000000, 0x04030201, 0x08070605,
> +	0xff0b0a09, 0x10b500c4, 0x03010200, 0x03040203, 0x04040505, 0x7d010000,
> +	0x00030201, 0x12051104, 0x06413121, 0x07615113, 0x32147122, 0x08a19181,
> +	0xc1b14223, 0xf0d15215, 0x72623324, 0x160a0982, 0x1a191817, 0x28272625,
> +	0x35342a29, 0x39383736, 0x4544433a, 0x49484746, 0x5554534a, 0x59585756,
> +	0x6564635a, 0x69686766, 0x7574736a, 0x79787776, 0x8584837a, 0x89888786,
> +	0x9493928a, 0x98979695, 0xa3a29a99, 0xa7a6a5a4, 0xb2aaa9a8, 0xb6b5b4b3,
> +	0xbab9b8b7, 0xc5c4c3c2, 0xc9c8c7c6, 0xd4d3d2ca, 0xd8d7d6d5, 0xe2e1dad9,
> +	0xe6e5e4e3, 0xeae9e8e7, 0xf4f3f2f1, 0xf8f7f6f5, 0xc4fffaf9, 0x00011f00,
> +	0x01010103, 0x01010101, 0x00000101, 0x00000000, 0x04030201, 0x08070605,
> +	0xff0b0a09, 0x11b500c4, 0x02010200, 0x04030404, 0x04040507, 0x77020100,
> +	0x03020100, 0x21050411, 0x41120631, 0x71610751, 0x81322213, 0x91421408,
> +	0x09c1b1a1, 0xf0523323, 0xd1726215, 0x3424160a, 0x17f125e1, 0x261a1918,
> +	0x2a292827, 0x38373635, 0x44433a39, 0x48474645, 0x54534a49, 0x58575655,
> +	0x64635a59, 0x68676665, 0x74736a69, 0x78777675, 0x83827a79, 0x87868584,
> +	0x928a8988, 0x96959493, 0x9a999897, 0xa5a4a3a2, 0xa9a8a7a6, 0xb4b3b2aa,
> +	0xb8b7b6b5, 0xc3c2bab9, 0xc7c6c5c4, 0xd2cac9c8, 0xd6d5d4d3, 0xdad9d8d7,
> +	0xe5e4e3e2, 0xe9e8e7e6, 0xf4f3f2ea, 0xf8f7f6f5, 0xdafffaf9, 0x01030c00,
> +	0x03110200, 0x003f0011
> +};
> +
> +static const u32 aspeed_video_jpeg_dct[ASPEED_VIDEO_JPEG_NUM_QUALITIES]
> +				      [ASPEED_VIDEO_JPEG_DCT_SIZE] = {
> +	{ 0x0d140043, 0x0c0f110f, 0x11101114, 0x17141516, 0x1e20321e,
> +	  0x3d1e1b1b, 0x32242e2b, 0x4b4c3f48, 0x44463f47, 0x61735a50,
> +	  0x566c5550, 0x88644644, 0x7a766c65, 0x4d808280, 0x8c978d60,
> +	  0x7e73967d, 0xdbff7b80, 0x1f014300, 0x272d2121, 0x3030582d,
> +	  0x697bb958, 0xb8b9b97b, 0xb9b8a6a6, 0xb9b9b9b9, 0xb9b9b9b9,
> +	  0xb9b9b9b9, 0xb9b9b9b9, 0xb9b9b9b9, 0xb9b9b9b9, 0xb9b9b9b9,
> +	  0xb9b9b9b9, 0xb9b9b9b9, 0xb9b9b9b9, 0xffb9b9b9 },
> +	{ 0x0c110043, 0x0a0d0f0d, 0x0f0e0f11, 0x14111213, 0x1a1c2b1a,
> +	  0x351a1818, 0x2b1f2826, 0x4142373f, 0x3c3d373e, 0x55644e46,
> +	  0x4b5f4a46, 0x77573d3c, 0x6b675f58, 0x43707170, 0x7a847b54,
> +	  0x6e64836d, 0xdbff6c70, 0x1b014300, 0x22271d1d, 0x2a2a4c27,
> +	  0x5b6ba04c, 0xa0a0a06b, 0xa0a0a0a0, 0xa0a0a0a0, 0xa0a0a0a0,
> +	  0xa0a0a0a0, 0xa0a0a0a0, 0xa0a0a0a0, 0xa0a0a0a0, 0xa0a0a0a0,
> +	  0xa0a0a0a0, 0xa0a0a0a0, 0xa0a0a0a0, 0xffa0a0a0 },
> +	{ 0x090e0043, 0x090a0c0a, 0x0c0b0c0e, 0x110e0f10, 0x15172415,
> +	  0x2c151313, 0x241a211f, 0x36372e34, 0x31322e33, 0x4653413a,
> +	  0x3e4e3d3a, 0x62483231, 0x58564e49, 0x385d5e5d, 0x656d6645,
> +	  0x5b536c5a, 0xdbff595d, 0x16014300, 0x1c201818, 0x22223f20,
> +	  0x4b58853f, 0x85858558, 0x85858585, 0x85858585, 0x85858585,
> +	  0x85858585, 0x85858585, 0x85858585, 0x85858585, 0x85858585,
> +	  0x85858585, 0x85858585, 0x85858585, 0xff858585 },
> +	{ 0x070b0043, 0x07080a08, 0x0a090a0b, 0x0d0b0c0c, 0x11121c11,
> +	  0x23110f0f, 0x1c141a19, 0x2b2b2429, 0x27282428, 0x3842332e,
> +	  0x313e302e, 0x4e392827, 0x46443e3a, 0x2c4a4a4a, 0x50565137,
> +	  0x48425647, 0xdbff474a, 0x12014300, 0x161a1313, 0x1c1c331a,
> +	  0x3d486c33, 0x6c6c6c48, 0x6c6c6c6c, 0x6c6c6c6c, 0x6c6c6c6c,
> +	  0x6c6c6c6c, 0x6c6c6c6c, 0x6c6c6c6c, 0x6c6c6c6c, 0x6c6c6c6c,
> +	  0x6c6c6c6c, 0x6c6c6c6c, 0x6c6c6c6c, 0xff6c6c6c },
> +	{ 0x06090043, 0x05060706, 0x07070709, 0x0a09090a, 0x0d0e160d,
> +	  0x1b0d0c0c, 0x16101413, 0x21221c20, 0x1e1f1c20, 0x2b332824,
> +	  0x26302624, 0x3d2d1f1e, 0x3735302d, 0x22393a39, 0x3f443f2b,
> +	  0x38334338, 0xdbff3739, 0x0d014300, 0x11130e0e, 0x15152613,
> +	  0x2d355026, 0x50505035, 0x50505050, 0x50505050, 0x50505050,
> +	  0x50505050, 0x50505050, 0x50505050, 0x50505050, 0x50505050,
> +	  0x50505050, 0x50505050, 0x50505050, 0xff505050 },
> +	{ 0x04060043, 0x03040504, 0x05040506, 0x07060606, 0x09090f09,
> +	  0x12090808, 0x0f0a0d0d, 0x16161315, 0x14151315, 0x1d221b18,
> +	  0x19201918, 0x281e1514, 0x2423201e, 0x17262726, 0x2a2d2a1c,
> +	  0x25222d25, 0xdbff2526, 0x09014300, 0x0b0d0a0a, 0x0e0e1a0d,
> +	  0x1f25371a, 0x37373725, 0x37373737, 0x37373737, 0x37373737,
> +	  0x37373737, 0x37373737, 0x37373737, 0x37373737, 0x37373737,
> +	  0x37373737, 0x37373737, 0x37373737, 0xff373737 },
> +	{ 0x02030043, 0x01020202, 0x02020203, 0x03030303, 0x04040704,
> +	  0x09040404, 0x07050606, 0x0b0b090a, 0x0a0a090a, 0x0e110d0c,
> +	  0x0c100c0c, 0x140f0a0a, 0x1211100f, 0x0b131313, 0x1516150e,
> +	  0x12111612, 0xdbff1213, 0x04014300, 0x05060505, 0x07070d06,
> +	  0x0f121b0d, 0x1b1b1b12, 0x1b1b1b1b, 0x1b1b1b1b, 0x1b1b1b1b,
> +	  0x1b1b1b1b, 0x1b1b1b1b, 0x1b1b1b1b, 0x1b1b1b1b, 0x1b1b1b1b,
> +	  0x1b1b1b1b, 0x1b1b1b1b, 0x1b1b1b1b, 0xff1b1b1b },
> +	{ 0x01020043, 0x01010101, 0x01010102, 0x02020202, 0x03030503,
> +	  0x06030202, 0x05030404, 0x07070607, 0x06070607, 0x090b0908,
> +	  0x080a0808, 0x0d0a0706, 0x0c0b0a0a, 0x070c0d0c, 0x0e0f0e09,
> +	  0x0c0b0f0c, 0xdbff0c0c, 0x03014300, 0x03040303, 0x04040804,
> +	  0x0a0c1208, 0x1212120c, 0x12121212, 0x12121212, 0x12121212,
> +	  0x12121212, 0x12121212, 0x12121212, 0x12121212, 0x12121212,
> +	  0x12121212, 0x12121212, 0x12121212, 0xff121212 },
> +	{ 0x01020043, 0x01010101, 0x01010102, 0x02020202, 0x03030503,
> +	  0x06030202, 0x05030404, 0x07070607, 0x06070607, 0x090b0908,
> +	  0x080a0808, 0x0d0a0706, 0x0c0b0a0a, 0x070c0d0c, 0x0e0f0e09,
> +	  0x0c0b0f0c, 0xdbff0c0c, 0x02014300, 0x03030202, 0x04040703,
> +	  0x080a0f07, 0x0f0f0f0a, 0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f,
> +	  0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f,
> +	  0x0f0f0f0f, 0x0f0f0f0f, 0x0f0f0f0f, 0xff0f0f0f },
> +	{ 0x01010043, 0x01010101, 0x01010101, 0x01010101, 0x02020302,
> +	  0x04020202, 0x03020303, 0x05050405, 0x05050405, 0x07080606,
> +	  0x06080606, 0x0a070505, 0x09080807, 0x05090909, 0x0a0b0a07,
> +	  0x09080b09, 0xdbff0909, 0x02014300, 0x02030202, 0x03030503,
> +	  0x07080c05, 0x0c0c0c08, 0x0c0c0c0c, 0x0c0c0c0c, 0x0c0c0c0c,
> +	  0x0c0c0c0c, 0x0c0c0c0c, 0x0c0c0c0c, 0x0c0c0c0c, 0x0c0c0c0c,
> +	  0x0c0c0c0c, 0x0c0c0c0c, 0x0c0c0c0c, 0xff0c0c0c },
> +	{ 0x01010043, 0x01010101, 0x01010101, 0x01010101, 0x01010201,
> +	  0x03010101, 0x02010202, 0x03030303, 0x03030303, 0x04050404,
> +	  0x04050404, 0x06050303, 0x06050505, 0x03060606, 0x07070704,
> +	  0x06050706, 0xdbff0606, 0x01014300, 0x01020101, 0x02020402,
> +	  0x05060904, 0x09090906, 0x09090909, 0x09090909, 0x09090909,
> +	  0x09090909, 0x09090909, 0x09090909, 0x09090909, 0x09090909,
> +	  0x09090909, 0x09090909, 0x09090909, 0xff090909 },
> +	{ 0x01010043, 0x01010101, 0x01010101, 0x01010101, 0x01010101,
> +	  0x01010101, 0x01010101, 0x01010101, 0x01010101, 0x02020202,
> +	  0x02020202, 0x03020101, 0x03020202, 0x01030303, 0x03030302,
> +	  0x03020303, 0xdbff0403, 0x01014300, 0x01010101, 0x01010201,
> +	  0x03040602, 0x06060604, 0x06060606, 0x06060606, 0x06060606,
> +	  0x06060606, 0x06060606, 0x06060606, 0x06060606, 0x06060606,
> +	  0x06060606, 0x06060606, 0x06060606, 0xff060606 }
> +};
> +
> +static void aspeed_video_init_jpeg_table(u32 *table, bool yuv420)
> +{
> +	int i;
> +	unsigned int base;
> +
> +	for (i = 0; i < ASPEED_VIDEO_JPEG_NUM_QUALITIES; i++) {
> +		base = 256 * i;	/* AST HW requires this header spacing */
> +		memcpy(&table[base], aspeed_video_jpeg_header,
> +		       sizeof(aspeed_video_jpeg_header));
> +
> +		base += ASPEED_VIDEO_JPEG_HEADER_SIZE;
> +		memcpy(&table[base], aspeed_video_jpeg_dct[i],
> +		       sizeof(aspeed_video_jpeg_dct[i]));
> +
> +		base += ASPEED_VIDEO_JPEG_DCT_SIZE;
> +		memcpy(&table[base], aspeed_video_jpeg_quant,
> +		       sizeof(aspeed_video_jpeg_quant));
> +
> +		if (yuv420)
> +			table[base + 2] = 0x00220103;
> +	}
> +}
> +
> +static void aspeed_video_update(struct aspeed_video *video, u32 reg, u32 clear,
> +				u32 bits)
> +{
> +	u32 t = readl(video->base + reg);
> +	u32 before = t;
> +
> +	t &= ~clear;
> +	t |= bits;
> +	writel(t, video->base + reg);
> +	dev_dbg(video->dev, "update %03x[%08x -> %08x]\n", reg, before,
> +		readl(video->base + reg));
> +}
> +
> +static u32 aspeed_video_read(struct aspeed_video *video, u32 reg)
> +{
> +	u32 t = readl(video->base + reg);
> +
> +	dev_dbg(video->dev, "read %03x[%08x]\n", reg, t);
> +	return t;
> +}
> +
> +static void aspeed_video_write(struct aspeed_video *video, u32 reg, u32 val)
> +{
> +	writel(val, video->base + reg);
> +	dev_dbg(video->dev, "write %03x[%08x]\n", reg,
> +		readl(video->base + reg));
> +}
> +
> +static bool aspeed_video_engine_busy(struct aspeed_video *video)
> +{
> +	u32 seq_ctrl = aspeed_video_read(video, VE_SEQ_CTRL);
> +
> +	if (!(seq_ctrl & VE_SEQ_CTRL_COMP_BUSY) ||
> +	    !(seq_ctrl & VE_SEQ_CTRL_CAP_BUSY)) {
> +		dev_err(video->dev, "video engine busy\n");
> +		return true;
> +	}
> +
> +	return false;
> +}
> +
> +static int aspeed_video_start_frame(struct aspeed_video *video)
> +{
> +	dma_addr_t addr;
> +	unsigned long flags;
> +	struct aspeed_video_buffer *buf;
> +
> +	if (aspeed_video_engine_busy(video))
> +		return -EBUSY;
> +
> +	spin_lock_irqsave(&video->lock, flags);
> +	buf = list_first_entry_or_null(&video->buffers,
> +				       struct aspeed_video_buffer, link);
> +	if (!buf) {
> +		spin_unlock_irqrestore(&video->lock, flags);
> +		return -EPROTO;
> +	}
> +
> +	set_bit(VIDEO_FRAME_INPRG, &video->flags);
> +	addr = vb2_dma_contig_plane_dma_addr(&buf->vb.vb2_buf, 0);
> +	spin_unlock_irqrestore(&video->lock, flags);
> +
> +	aspeed_video_write(video, VE_COMP_PROC_OFFSET, 0);
> +	aspeed_video_write(video, VE_COMP_OFFSET, 0);
> +	aspeed_video_write(video, VE_COMP_ADDR, addr);
> +
> +	aspeed_video_update(video, VE_INTERRUPT_CTRL, 0,
> +			    VE_INTERRUPT_COMP_COMPLETE |
> +			    VE_INTERRUPT_CAPTURE_COMPLETE);
> +
> +	aspeed_video_update(video, VE_SEQ_CTRL, 0,
> +			    VE_SEQ_CTRL_TRIG_CAPTURE | VE_SEQ_CTRL_TRIG_COMP);
> +
> +	return 0;
> +}
> +
> +static void aspeed_video_start_mode_detect(struct aspeed_video *video)
> +{
> +	/* Enable mode detect interrupts */
> +	aspeed_video_update(video, VE_INTERRUPT_CTRL, 0,
> +			    VE_INTERRUPT_MODE_DETECT);
> +
> +	/* Trigger mode detect */
> +	aspeed_video_update(video, VE_SEQ_CTRL, 0, VE_SEQ_CTRL_TRIG_MODE_DET);
> +}
> +
> +static void aspeed_video_disable_mode_detect(struct aspeed_video *video)

Somewhat weird naming for this pair of functions: either use start/stop or
enable/disable (my preference), not start/disable.

> +{
> +	/* Disable mode detect interrupts */
> +	aspeed_video_update(video, VE_INTERRUPT_CTRL,
> +			    VE_INTERRUPT_MODE_DETECT, 0);
> +
> +	/* Disable mode detect */
> +	aspeed_video_update(video, VE_SEQ_CTRL, VE_SEQ_CTRL_TRIG_MODE_DET, 0);
> +}
> +
> +static void aspeed_video_off(struct aspeed_video *video)
> +{
> +	/* Reset the engine */
> +	reset_control_assert(video->rst);
> +	udelay(100);
> +	reset_control_deassert(video->rst);
> +
> +	/* Turn off the relevant clocks */
> +	clk_disable_unprepare(video->vclk);
> +	clk_disable_unprepare(video->eclk);
> +}
> +
> +static void aspeed_video_on(struct aspeed_video *video)
> +{
> +	/* Turn on the relevant clocks */
> +	clk_prepare_enable(video->eclk);
> +	clk_prepare_enable(video->vclk);
> +
> +	/* Reset the engine */
> +	reset_control_assert(video->rst);
> +	udelay(100);
> +	reset_control_deassert(video->rst);
> +}
> +
> +static void aspeed_video_bufs_done(struct aspeed_video *video,
> +				   enum vb2_buffer_state state)
> +{
> +	unsigned long flags;
> +	struct aspeed_video_buffer *buf;
> +
> +	spin_lock_irqsave(&video->lock, flags);
> +	list_for_each_entry(buf, &video->buffers, link) {
> +		if (list_is_last(&buf->link, &video->buffers))
> +			buf->vb.flags |= V4L2_BUF_FLAG_LAST;

You don't need to use this flag. It's meant for hardware codecs,
not for a regular video capture driver.

> +		vb2_buffer_done(&buf->vb.vb2_buf, state);
> +	}
> +	INIT_LIST_HEAD(&video->buffers);
> +	spin_unlock_irqrestore(&video->lock, flags);
> +}
> +
> +static irqreturn_t aspeed_video_irq(int irq, void *arg)
> +{
> +	struct aspeed_video *video = arg;
> +	u32 sts = aspeed_video_read(video, VE_INTERRUPT_STATUS);
> +
> +	if (atomic_read(&video->clients) == 0) {
> +		dev_info(video->dev, "irq with no client; disabling irqs\n");
> +
> +		aspeed_video_write(video, VE_INTERRUPT_CTRL, 0);
> +		aspeed_video_write(video, VE_INTERRUPT_STATUS, 0xffffffff);
> +		return IRQ_HANDLED;
> +	}
> +
> +	/* Resolution changed; reset entire engine and reinitialize */
> +	if (sts & VE_INTERRUPT_MODE_DETECT_WD) {
> +		dev_info(video->dev, "resolution changed; resetting\n");
> +		set_bit(VIDEO_RES_CHANGE, &video->flags);
> +		clear_bit(VIDEO_FRAME_INPRG, &video->flags);
> +		clear_bit(VIDEO_STREAMING, &video->flags);
> +
> +		aspeed_video_off(video);
> +		aspeed_video_bufs_done(video, VB2_BUF_STATE_ERROR);
> +
> +		schedule_delayed_work(&video->res_work,
> +				      RESOLUTION_CHANGE_DELAY);
> +		return IRQ_HANDLED;
> +	}
> +
> +	if (sts & VE_INTERRUPT_MODE_DETECT) {
> +		aspeed_video_update(video, VE_INTERRUPT_CTRL,
> +				    VE_INTERRUPT_MODE_DETECT, 0);
> +		aspeed_video_write(video, VE_INTERRUPT_STATUS,
> +				   VE_INTERRUPT_MODE_DETECT);
> +
> +		set_bit(VIDEO_MODE_DETECT_DONE, &video->flags);
> +		wake_up_interruptible_all(&video->wait);
> +	}
> +
> +	if ((sts & VE_INTERRUPT_COMP_COMPLETE) &&
> +	    (sts & VE_INTERRUPT_CAPTURE_COMPLETE)) {
> +		struct aspeed_video_buffer *buf;
> +		u32 frame_size = aspeed_video_read(video,
> +						   VE_OFFSET_COMP_STREAM);
> +
> +		spin_lock(&video->lock);
> +		clear_bit(VIDEO_FRAME_INPRG, &video->flags);
> +		buf = list_first_entry_or_null(&video->buffers,
> +					       struct aspeed_video_buffer,
> +					       link);
> +		if (buf) {
> +			vb2_set_plane_payload(&buf->vb.vb2_buf, 0, frame_size);
> +
> +			if (!list_is_last(&buf->link, &video->buffers)) {
> +				buf->vb.vb2_buf.timestamp = ktime_get_ns();
> +				buf->vb.sequence = video->sequence++;
> +				buf->vb.field = V4L2_FIELD_NONE;
> +				vb2_buffer_done(&buf->vb.vb2_buf,
> +						VB2_BUF_STATE_DONE);
> +				list_del(&buf->link);
> +			}
> +		}
> +		spin_unlock(&video->lock);
> +
> +		aspeed_video_update(video, VE_SEQ_CTRL,
> +				    VE_SEQ_CTRL_TRIG_CAPTURE |
> +				    VE_SEQ_CTRL_FORCE_IDLE |
> +				    VE_SEQ_CTRL_TRIG_COMP, 0);
> +		aspeed_video_update(video, VE_INTERRUPT_CTRL,
> +				    VE_INTERRUPT_COMP_COMPLETE |
> +				    VE_INTERRUPT_CAPTURE_COMPLETE, 0);
> +		aspeed_video_write(video, VE_INTERRUPT_STATUS,
> +				   VE_INTERRUPT_COMP_COMPLETE |
> +				   VE_INTERRUPT_CAPTURE_COMPLETE);
> +
> +		if (test_bit(VIDEO_STREAMING, &video->flags) && buf)
> +			aspeed_video_start_frame(video);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static void aspeed_video_check_polarity(struct aspeed_video *video)

This function should be moved to just before the get_resolution function,
since that's the one that calls this.

> +{
> +	int i;
> +	int hsync_counter = 0;
> +	int vsync_counter = 0;
> +	u32 sts;
> +
> +	for (i = 0; i < NUM_POLARITY_CHECKS; ++i) {
> +		sts = aspeed_video_read(video, VE_MODE_DETECT_STATUS);
> +		if (sts & VE_MODE_DETECT_STATUS_VSYNC)
> +			vsync_counter--;
> +		else
> +			vsync_counter++;
> +
> +		if (sts & VE_MODE_DETECT_STATUS_HSYNC)
> +			hsync_counter--;
> +		else
> +			hsync_counter++;
> +	}
> +
> +	if (hsync_counter < 0 || vsync_counter < 0) {
> +		u32 ctrl;
> +
> +		if (hsync_counter < 0)
> +			ctrl = VE_CTRL_HSYNC_POL;
> +		else
> +			video->timings.polarities |= V4L2_DV_HSYNC_POS_POL;

You should set this for video->detected_timings.
You also don't clear the polarities flag if the polarity is negative.

> +
> +		if (vsync_counter < 0)
> +			ctrl = VE_CTRL_VSYNC_POL;
> +		else
> +			video->timings.polarities |= V4L2_DV_VSYNC_POS_POL;
> +
> +		aspeed_video_update(video, VE_CTRL, 0, ctrl);

It would make more sense to write to this register either when you
start streaming or when s_dv_timings is called. That's when you need it,
not when detecting a new timing.

> +	}
> +}
> +
> +static bool aspeed_video_alloc_buf(struct aspeed_video *video,
> +				   struct aspeed_video_addr *addr,
> +				   unsigned int size)
> +{
> +	addr->virt = dma_alloc_coherent(video->dev, size, &addr->dma,
> +					GFP_KERNEL);
> +	if (!addr->virt)
> +		return false;
> +
> +	addr->size = size;
> +	return true;
> +}
> +
> +static void aspeed_video_free_buf(struct aspeed_video *video,
> +				  struct aspeed_video_addr *addr)
> +{
> +	dma_free_coherent(video->dev, addr->size, addr->virt, addr->dma);
> +	addr->size = 0;
> +	addr->dma = 0ULL;
> +	addr->virt = NULL;
> +}
> +
> +/*
> + * Get the minimum HW-supported compression buffer size for the frame size.
> + * Assume worst-case JPEG compression size is 1/8 raw size. This should be
> + * plenty even for maximum quality; any worse and the engine will simply return
> + * incomplete JPEGs.
> + */
> +static void aspeed_video_calc_compressed_size(struct aspeed_video *video)
> +{
> +	int i, j;
> +	u32 compression_buffer_size_reg = 0;
> +	unsigned int size;
> +	const unsigned int num_compression_packets = 4;
> +	const unsigned int compression_packet_size = 1024;
> +	const unsigned int max_compressed_size =
> +		video->capture_width * video->capture_height / 2;
> +
> +	video->max_compressed_size = UINT_MAX;
> +
> +	for (i = 0; i < 6; ++i) {
> +		for (j = 0; j < 8; ++j) {
> +			size = (num_compression_packets << i) *
> +				(compression_packet_size << j);
> +			if (size < max_compressed_size)
> +				continue;
> +
> +			if (size < video->max_compressed_size) {
> +				compression_buffer_size_reg = (i << 3) | j;
> +				video->max_compressed_size = size;
> +			}
> +		}
> +	}
> +
> +	aspeed_video_write(video, VE_STREAM_BUF_SIZE,
> +			   compression_buffer_size_reg);
> +
> +	dev_dbg(video->dev, "max compressed size: %x\n",
> +		video->max_compressed_size);
> +}
> +
> +#define res_check(v) test_and_clear_bit(VIDEO_MODE_DETECT_DONE, &(v)->flags)
> +
> +static int aspeed_video_get_resolution(struct aspeed_video *video)
> +{
> +	bool invalid_resolution = true;
> +	int rc;
> +	int tries = 0;
> +	unsigned int bottom;
> +	unsigned int left;
> +	unsigned int right;
> +	unsigned int top;
> +	u32 mds;
> +	u32 src_lr_edge;
> +	u32 src_tb_edge;
> +	u32 sync;
> +

If I understand the code correctly, when this is called we're not supposed to
be streaming video, right?

> +	if (video->srcs[1].size)
> +		aspeed_video_free_buf(video, &video->srcs[1]);
> +
> +	if (!video->detect.size) {
> +		if (video->srcs[0].size >= VE_MAX_SRC_BUFFER_SIZE) {
> +			video->detect = video->srcs[0];
> +
> +			video->srcs[0].size = 0;
> +			video->srcs[0].dma = 0ULL;
> +			video->srcs[0].virt = NULL;
> +		} else {
> +			if (video->srcs[0].size)
> +				aspeed_video_free_buf(video, &video->srcs[0]);
> +
> +			if (!aspeed_video_alloc_buf(video, &video->detect,
> +						    VE_MAX_SRC_BUFFER_SIZE)) {
> +				dev_err(video->dev,
> +					"failed to allocate source buffers\n");
> +				return -ENOMEM;
> +			}
> +		}
> +	}
> +
> +	aspeed_video_write(video, VE_SRC0_ADDR, video->detect.dma);
> +
> +	video->timings.width = 0;
> +	video->timings.height = 0;

detected_timings

> +
> +	do {
> +		if (tries) {
> +			set_current_state(TASK_INTERRUPTIBLE);
> +			if (schedule_timeout(INVALID_RESOLUTION_DELAY))
> +				return -EINTR;
> +		}
> +
> +		aspeed_video_start_mode_detect(video);
> +
> +		rc = wait_event_interruptible_timeout(video->wait,
> +						      res_check(video),
> +						      MODE_DETECT_TIMEOUT);
> +		if (!rc) {
> +			dev_err(video->dev, "timed out on 1st mode detect\n");
> +			aspeed_video_disable_mode_detect(video);
> +			return -ETIMEDOUT;
> +		}
> +
> +		/* Disable mode detect in order to re-trigger */
> +		aspeed_video_update(video, VE_SEQ_CTRL,
> +				    VE_SEQ_CTRL_TRIG_MODE_DET, 0);
> +
> +		aspeed_video_check_polarity(video);
> +
> +		aspeed_video_start_mode_detect(video);

Just curious: why is check_polarity done before starting the mode_detect?
I would expect it to be the other way around.

As mentioned above, aspeed_video_check_polarity doesn't just check the polarity,
it also seems to set it. If this is required before you can do a mode detect,
then that should be documented and the function should be renamed to
check_and_set_polarity.

> +
> +		rc = wait_event_interruptible_timeout(video->wait,
> +						      res_check(video),
> +						      MODE_DETECT_TIMEOUT);
> +		if (!rc) {
> +			dev_err(video->dev, "timed out on 2nd mode detect\n");
> +			aspeed_video_disable_mode_detect(video);
> +			return -ETIMEDOUT;
> +		}
> +
> +		src_lr_edge = aspeed_video_read(video, VE_SRC_LR_EDGE_DET);
> +		src_tb_edge = aspeed_video_read(video, VE_SRC_TB_EDGE_DET);
> +		mds = aspeed_video_read(video, VE_MODE_DETECT_STATUS);
> +		sync = aspeed_video_read(video, VE_SYNC_STATUS);
> +
> +		bottom = (src_tb_edge & VE_SRC_TB_EDGE_DET_BOT) >>
> +			VE_SRC_TB_EDGE_DET_BOT_SHF;
> +		top = src_tb_edge & VE_SRC_TB_EDGE_DET_TOP;
> +		video->timings.vfrontporch = top;
> +		video->timings.vbackporch = ((mds & VE_MODE_DETECT_V_LINES) >>
> +			VE_MODE_DETECT_V_LINES_SHF) - bottom;
> +		video->timings.vsync = (sync & VE_SYNC_STATUS_VSYNC) >>
> +			VE_SYNC_STATUS_VSYNC_SHF;
> +		if (top > bottom)
> +			continue;
> +
> +		right = (src_lr_edge & VE_SRC_LR_EDGE_DET_RT) >>
> +			VE_SRC_LR_EDGE_DET_RT_SHF;
> +		left = src_lr_edge & VE_SRC_LR_EDGE_DET_LEFT;
> +		video->timings.hfrontporch = left;
> +		video->timings.hbackporch = (mds & VE_MODE_DETECT_H_PIXELS) -
> +			right;
> +		video->timings.hsync = sync & VE_SYNC_STATUS_HSYNC;
> +		if (left > right)
> +			continue;
> +
> +		invalid_resolution = false;
> +	} while (invalid_resolution && (tries++ < INVALID_RESOLUTION_RETRIES));
> +
> +	if (invalid_resolution) {
> +		dev_err(video->dev, "invalid resolution detected\n");
> +		return -ERANGE;
> +	}
> +
> +	video->timings.height = (bottom - top) + 1;
> +	video->timings.width = (right - left) + 1;
> +
> +	/* Don't use direct mode below 1024 x 768 (irqs don't fire) */
> +	if (video->timings.width * video->timings.height < DIRECT_FETCH_THRESHOLD) {
> +		aspeed_video_write(video, VE_TGS_0,
> +				   FIELD_PREP(VE_TGS_FIRST, left - 1) |
> +				   FIELD_PREP(VE_TGS_LAST, right));
> +		aspeed_video_write(video, VE_TGS_1,
> +				   FIELD_PREP(VE_TGS_FIRST, top) |
> +				   FIELD_PREP(VE_TGS_LAST, bottom + 1));
> +		aspeed_video_update(video, VE_CTRL, 0, VE_CTRL_INT_DE);
> +	} else {
> +		aspeed_video_update(video, VE_CTRL, 0, VE_CTRL_DIRECT_FETCH);
> +	}

Shouldn't this be done in set_capture_resolution?

> +
> +	aspeed_video_update(video, VE_INTERRUPT_CTRL, 0,
> +			    VE_INTERRUPT_MODE_DETECT_WD);
> +	aspeed_video_update(video, VE_SEQ_CTRL, 0,
> +			    VE_SEQ_CTRL_AUTO_COMP | VE_SEQ_CTRL_EN_WATCHDOG);

What do these two lines do? Perhaps a comment would help.

> +
> +	dev_dbg(video->dev, "got resolution[%dx%d]\n", video->timings.width,
> +		video->timings.height);
> +
> +	return 0;
> +
> +}
> +
> +static int aspeed_video_set_capture_resolution(struct aspeed_video *video)
> +{
> +	unsigned int size = video->timings.width * video->timings.height;

active_timings

> +	struct aspeed_video_addr detect = video->detect;
> +
> +	video->detect.size = 0;
> +	video->detect.dma = 0ULL;
> +	video->detect.virt = NULL;
> +
> +	video->capture_width = video->timings.width;
> +	video->capture_height = video->timings.height;
> +
> +	aspeed_video_write(video, VE_CAP_WINDOW,
> +			   video->capture_width << 16 | video->capture_height);
> +	aspeed_video_write(video, VE_COMP_WINDOW,
> +			   video->capture_width << 16 | video->capture_height);
> +	aspeed_video_write(video, VE_SRC_SCANLINE_OFFSET,
> +			   video->capture_width * 4);
> +
> +	size *= 4;
> +	if (size == detect.size / 2) {
> +		aspeed_video_write(video, VE_SRC1_ADDR, detect.dma + size);
> +		video->srcs[0] = detect;
> +	} else if (size == detect.size) {
> +		video->srcs[0] = detect;
> +
> +		if (!aspeed_video_alloc_buf(video, &video->srcs[1], size))
> +			goto err_mem;
> +
> +		aspeed_video_write(video, VE_SRC1_ADDR, video->srcs[1].dma);
> +	} else {
> +		aspeed_video_free_buf(video, &detect);
> +
> +		if (!aspeed_video_alloc_buf(video, &video->srcs[0], size))
> +			goto err_mem;
> +
> +		if (!aspeed_video_alloc_buf(video, &video->srcs[1], size))
> +			goto err_mem;
> +
> +		aspeed_video_write(video, VE_SRC0_ADDR, video->srcs[0].dma);
> +		aspeed_video_write(video, VE_SRC1_ADDR, video->srcs[1].dma);
> +	}
> +
> +	aspeed_video_calc_compressed_size(video);
> +
> +	dev_dbg(video->dev, "set resolution[%dx%d]\n", video->capture_width,
> +		video->capture_height);
> +
> +	return 0;
> +
> +err_mem:
> +	dev_err(video->dev, "failed to allocate source buffers\n");
> +
> +	if (video->srcs[0].size)
> +		aspeed_video_free_buf(video, &video->srcs[0]);
> +
> +	return -ENOMEM;
> +}
> +
> +static void aspeed_video_init_regs(struct aspeed_video *video)
> +{
> +	u32 comp_ctrl = VE_COMP_CTRL_RSVD |
> +		FIELD_PREP(VE_COMP_CTRL_DCT_LUM, video->jpeg_quality) |
> +		FIELD_PREP(VE_COMP_CTRL_DCT_CHR, video->jpeg_quality | 0x10);
> +	u32 ctrl = VE_CTRL_AUTO_OR_CURSOR;
> +	u32 seq_ctrl = VE_SEQ_CTRL_JPEG_MODE;
> +
> +	if (video->frame_rate)
> +		ctrl |= FIELD_PREP(VE_CTRL_FRC, video->frame_rate);
> +
> +	if (video->yuv420)
> +		seq_ctrl |= VE_SEQ_CTRL_YUV420;
> +
> +	/* Unlock VE registers */
> +	aspeed_video_write(video, VE_PROTECTION_KEY, VE_PROTECTION_KEY_UNLOCK);
> +
> +	/* Disable interrupts */
> +	aspeed_video_write(video, VE_INTERRUPT_CTRL, 0);
> +	aspeed_video_write(video, VE_INTERRUPT_STATUS, 0xffffffff);
> +
> +	/* Clear the offset */
> +	aspeed_video_write(video, VE_COMP_PROC_OFFSET, 0);
> +	aspeed_video_write(video, VE_COMP_OFFSET, 0);
> +
> +	aspeed_video_write(video, VE_JPEG_ADDR, video->jpeg.dma);
> +
> +	/* Set control registers */
> +	aspeed_video_write(video, VE_SEQ_CTRL, seq_ctrl);
> +	aspeed_video_write(video, VE_CTRL, ctrl);
> +	aspeed_video_write(video, VE_COMP_CTRL, comp_ctrl);
> +
> +	/* Don't downscale */
> +	aspeed_video_write(video, VE_SCALING_FACTOR, 0x10001000);
> +	aspeed_video_write(video, VE_SCALING_FILTER0, 0x00200000);
> +	aspeed_video_write(video, VE_SCALING_FILTER1, 0x00200000);
> +	aspeed_video_write(video, VE_SCALING_FILTER2, 0x00200000);
> +	aspeed_video_write(video, VE_SCALING_FILTER3, 0x00200000);
> +
> +	/* Set mode detection defaults */
> +	aspeed_video_write(video, VE_MODE_DETECT, 0x22666500);
> +}
> +
> +static int aspeed_video_start(struct aspeed_video *video)
> +{
> +	int rc;
> +
> +	aspeed_video_on(video);
> +
> +	aspeed_video_init_regs(video);
> +
> +	rc = aspeed_video_get_resolution(video);

No, this shouldn't be called here. Only query_dv_timings should call this.

> +	if (rc)
> +		return rc;
> +
> +	rc = aspeed_video_set_capture_resolution(video);
> +	if (rc)
> +		return rc;
> +
> +	video->pix_fmt.width = video->timings.width;
> +	video->pix_fmt.height = video->timings.height;
> +	video->pix_fmt.sizeimage = video->max_compressed_size;

You don't set that here: otherwise opening the device node would magically
change the format. That's not what should happen.

The golden rule is that you never change timings and/or format unless
explicitly commanded by the application through S_DV_TIMINGS and S_FMT.

> +
> +	return 0;
> +}
> +
> +static void aspeed_video_stop(struct aspeed_video *video)
> +{
> +	cancel_delayed_work_sync(&video->res_work);
> +
> +	aspeed_video_off(video);
> +
> +	if (video->srcs[0].size)
> +		aspeed_video_free_buf(video, &video->srcs[0]);
> +
> +	if (video->srcs[1].size)
> +		aspeed_video_free_buf(video, &video->srcs[1]);
> +
> +	if (video->detect.size)
> +		aspeed_video_free_buf(video, &video->detect);
> +
> +	video->flags = 0;
> +}
> +
> +static int aspeed_video_querycap(struct file *file, void *fh,
> +				 struct v4l2_capability *cap)
> +{
> +	strscpy(cap->driver, DEVICE_NAME, sizeof(cap->driver));
> +	strscpy(cap->card, "Aspeed Video Engine", sizeof(cap->card));
> +	snprintf(cap->bus_info, sizeof(cap->bus_info), "platform:%s",
> +		 DEVICE_NAME);
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_enum_format(struct file *file, void *fh,
> +				    struct v4l2_fmtdesc *f)
> +{
> +	if (f->index)
> +		return -EINVAL;
> +
> +	f->pixelformat = V4L2_PIX_FMT_JPEG;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_get_format(struct file *file, void *fh,
> +				   struct v4l2_format *f)
> +{
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	f->fmt.pix = video->pix_fmt;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_enum_input(struct file *file, void *fh,
> +				   struct v4l2_input *inp)
> +{
> +	if (inp->index)
> +		return -EINVAL;
> +
> +	strscpy(inp->name, "Host VGA capture", sizeof(inp->name));
> +	inp->type = V4L2_INPUT_TYPE_CAMERA;
> +	inp->capabilities = V4L2_IN_CAP_DV_TIMINGS;
> +	inp->status = 0;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_get_input(struct file *file, void *fh, unsigned int *i)
> +{
> +	*i = 0;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_set_input(struct file *file, void *fh, unsigned int i)
> +{
> +	if (i)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_get_parm(struct file *file, void *fh,
> +				 struct v4l2_streamparm *a)
> +{
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	a->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
> +	a->parm.capture.readbuffers = 3;
> +	a->parm.capture.timeperframe.numerator = 1;
> +	if (!video->frame_rate)
> +		a->parm.capture.timeperframe.denominator = MAX_FRAME_RATE;
> +	else
> +		a->parm.capture.timeperframe.denominator = video->frame_rate;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_set_parm(struct file *file, void *fh,
> +				 struct v4l2_streamparm *a)
> +{
> +	unsigned int frame_rate = 0;
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	a->parm.capture.capability = V4L2_CAP_TIMEPERFRAME;
> +	a->parm.capture.readbuffers = 3;
> +
> +	if (a->parm.capture.timeperframe.numerator)
> +		frame_rate = a->parm.capture.timeperframe.denominator /
> +			a->parm.capture.timeperframe.numerator;
> +
> +	if (!frame_rate || frame_rate > MAX_FRAME_RATE) {
> +		frame_rate = 0;
> +		a->parm.capture.timeperframe.denominator = MAX_FRAME_RATE;
> +		a->parm.capture.timeperframe.numerator = 1;
> +	}
> +
> +	if (video->frame_rate != frame_rate) {
> +		video->frame_rate = frame_rate;
> +		aspeed_video_update(video, VE_CTRL, VE_CTRL_FRC,
> +				    FIELD_PREP(VE_CTRL_FRC, frame_rate));
> +	}
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_enum_framesizes(struct file *file, void *fh,
> +					struct v4l2_frmsizeenum *fsize)
> +{
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	if (fsize->index)
> +		return -EINVAL;
> +
> +	if (fsize->pixel_format != V4L2_PIX_FMT_JPEG)
> +		return -EINVAL;
> +
> +	fsize->discrete.width = video->pix_fmt.width;
> +	fsize->discrete.height = video->pix_fmt.height;
> +	fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_enum_frameintervals(struct file *file, void *fh,
> +					    struct v4l2_frmivalenum *fival)
> +{
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	if (fival->index)
> +		return -EINVAL;
> +
> +	if (fival->width != video->timings.width ||
> +	    fival->height != video->timings.height)
> +		return -EINVAL;
> +
> +	if (fival->pixel_format != V4L2_PIX_FMT_JPEG)
> +		return -EINVAL;
> +
> +	fival->type = V4L2_FRMIVAL_TYPE_CONTINUOUS;
> +
> +	fival->stepwise.min.denominator = MAX_FRAME_RATE;
> +	fival->stepwise.min.numerator = 1;
> +	fival->stepwise.max.denominator = 1;
> +	fival->stepwise.max.numerator = 1;
> +	fival->stepwise.step = fival->stepwise.max;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_set_dv_timings(struct file *file, void *fh,
> +				       struct v4l2_dv_timings *timings)
> +{
> +	int rc;
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	if (video->capture_width == timings->bt.width &&
> +	    video->capture_height == timings->bt.height)

Unless I am mistaken, capture_width/height just duplicates
video->pix_fmt.width/height. I'd drop capture_width/height and only
use pix_fmt.

> +		return 0;
> +
> +	if (vb2_is_busy(&video->queue))
> +		return -EBUSY;
> +
> +	if (video->timings.width != timings->bt.width ||
> +	    video->timings.height != timings->bt.height)
> +		return -EINVAL;

This 'if' makes no sense. It is perfectly fine (if silly) to set
timings that do not match the current resolution. The timings can
change at any time anyway, so there is no point to check this.

> +
> +	rc = aspeed_video_set_capture_resolution(video);
> +	if (rc)
> +		return rc;
> +
> +	video->pix_fmt.width = timings->bt.width;
> +	video->pix_fmt.height = timings->bt.height;
> +	video->pix_fmt.sizeimage = video->max_compressed_size;
> +
> +	timings->type = V4L2_DV_BT_656_1120;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_get_dv_timings(struct file *file, void *fh,
> +				       struct v4l2_dv_timings *timings)
> +{
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	timings->type = V4L2_DV_BT_656_1120;
> +	timings->bt = video->timings;

Should return active_timings.

> +
> +	return 0;
> +}
> +
> +static int aspeed_video_query_dv_timings(struct file *file, void *fh,
> +					 struct v4l2_dv_timings *timings)
> +{
> +	int rc;
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	if (file->f_flags & O_NONBLOCK) {
> +		if (test_bit(VIDEO_RES_CHANGE, &video->flags))
> +			return -EAGAIN;
> +	} else {
> +		rc = wait_event_interruptible(video->wait,
> +					      !test_bit(VIDEO_RES_CHANGE,
> +							&video->flags));
> +		if (rc)
> +			return -EINTR;
> +	}
> +
> +	timings->type = V4L2_DV_BT_656_1120;
> +	timings->bt = video->timings;
> +	timings->bt.width = video->timings.width;
> +	timings->bt.height = video->timings.height;

Should return the detected_timings.

Why assign bt.width/height again? Those two lines can be dropped.

> +
> +	return 0;
> +}
> +
> +static int aspeed_video_enum_dv_timings(struct file *file, void *fh,
> +					struct v4l2_enum_dv_timings *timings)
> +{
> +	if (timings->index)
> +		return -EINVAL;
> +
> +	return aspeed_video_get_dv_timings(file, fh, &timings->timings);
> +}
> +
> +static int aspeed_video_dv_timings_cap(struct file *file, void *fh,
> +				       struct v4l2_dv_timings_cap *cap)
> +{
> +	cap->type = V4L2_DV_BT_656_1120;
> +	cap->bt.capabilities = V4L2_DV_BT_CAP_PROGRESSIVE;
> +	cap->bt.min_width = MIN_WIDTH;
> +	cap->bt.max_width = MAX_WIDTH;
> +	cap->bt.min_height = MIN_HEIGHT;
> +	cap->bt.max_height = MAX_HEIGHT;

I would create a static const struct v4l2_dv_timings_cap at the top of the source
and return that here.

You can then use the helpers v4l2_valid_dv_timings in s_dv_timings and
v4l2_enum_dv_timings_cap in enum_dv_timings.

You need to set the V4L2_DV_BT_CAP_REDUCED_BLANKING capability as well.
And fill in cap->bt.min/max_pixelclock and standards (CEA861|DMT|CVT|GTF).

> +
> +	return 0;
> +}
> +
> +static int aspeed_video_sub_event(struct v4l2_fh *fh,
> +				  const struct v4l2_event_subscription *sub)
> +{
> +	switch (sub->type) {
> +	case V4L2_EVENT_SOURCE_CHANGE:
> +		return v4l2_src_change_event_subscribe(fh, sub);
> +	}
> +
> +	return v4l2_ctrl_subscribe_event(fh, sub);
> +}
> +
> +static const struct v4l2_ioctl_ops aspeed_video_ioctl_ops = {
> +	.vidioc_querycap = aspeed_video_querycap,
> +
> +	.vidioc_enum_fmt_vid_cap = aspeed_video_enum_format,
> +	.vidioc_g_fmt_vid_cap = aspeed_video_get_format,
> +	.vidioc_s_fmt_vid_cap = aspeed_video_get_format,
> +	.vidioc_try_fmt_vid_cap = aspeed_video_get_format,
> +
> +	.vidioc_reqbufs = vb2_ioctl_reqbufs,
> +	.vidioc_querybuf = vb2_ioctl_querybuf,
> +	.vidioc_qbuf = vb2_ioctl_qbuf,
> +	.vidioc_dqbuf = vb2_ioctl_dqbuf,
> +	.vidioc_create_bufs = vb2_ioctl_create_bufs,
> +	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
> +	.vidioc_streamon = vb2_ioctl_streamon,
> +	.vidioc_streamoff = vb2_ioctl_streamoff,
> +
> +	.vidioc_enum_input = aspeed_video_enum_input,
> +	.vidioc_g_input = aspeed_video_get_input,
> +	.vidioc_s_input = aspeed_video_set_input,
> +
> +	.vidioc_g_parm = aspeed_video_get_parm,
> +	.vidioc_s_parm = aspeed_video_set_parm,
> +	.vidioc_enum_framesizes = aspeed_video_enum_framesizes,
> +	.vidioc_enum_frameintervals = aspeed_video_enum_frameintervals,
> +
> +	.vidioc_s_dv_timings = aspeed_video_set_dv_timings,
> +	.vidioc_g_dv_timings = aspeed_video_get_dv_timings,
> +	.vidioc_query_dv_timings = aspeed_video_query_dv_timings,
> +	.vidioc_enum_dv_timings = aspeed_video_enum_dv_timings,
> +	.vidioc_dv_timings_cap = aspeed_video_dv_timings_cap,
> +
> +	.vidioc_subscribe_event = aspeed_video_sub_event,
> +	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
> +};
> +
> +static void aspeed_video_update_jpeg_quality(struct aspeed_video *video)
> +{
> +	u32 comp_ctrl = FIELD_PREP(VE_COMP_CTRL_DCT_LUM, video->jpeg_quality) |
> +		FIELD_PREP(VE_COMP_CTRL_DCT_CHR, video->jpeg_quality | 0x10);
> +
> +	aspeed_video_update(video, VE_COMP_CTRL,
> +			    VE_COMP_CTRL_DCT_LUM | VE_COMP_CTRL_DCT_CHR,
> +			    comp_ctrl);
> +}
> +
> +static void aspeed_video_update_subsampling(struct aspeed_video *video)
> +{
> +	if (video->jpeg.virt)
> +		aspeed_video_init_jpeg_table(video->jpeg.virt, video->yuv420);
> +
> +	if (video->yuv420)
> +		aspeed_video_update(video, VE_SEQ_CTRL, 0, VE_SEQ_CTRL_YUV420);
> +	else
> +		aspeed_video_update(video, VE_SEQ_CTRL, VE_SEQ_CTRL_YUV420, 0);
> +}
> +
> +static int aspeed_video_set_ctrl(struct v4l2_ctrl *ctrl)
> +{
> +	struct aspeed_video *video = container_of(ctrl->handler,
> +						  struct aspeed_video,
> +						  ctrl_handler);
> +
> +	switch (ctrl->id) {
> +	case V4L2_CID_JPEG_COMPRESSION_QUALITY:
> +		video->jpeg_quality = ctrl->val;
> +		aspeed_video_update_jpeg_quality(video);
> +		break;
> +	case V4L2_CID_JPEG_CHROMA_SUBSAMPLING:
> +		if (ctrl->val == V4L2_JPEG_CHROMA_SUBSAMPLING_420) {
> +			video->yuv420 = true;
> +			aspeed_video_update_subsampling(video);
> +		} else {
> +			video->yuv420 = false;
> +			aspeed_video_update_subsampling(video);
> +		}
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct v4l2_ctrl_ops aspeed_video_ctrl_ops = {
> +	.s_ctrl = aspeed_video_set_ctrl,
> +};
> +
> +static void aspeed_video_resolution_work(struct work_struct *work)
> +{
> +	int rc;
> +	struct delayed_work *dwork = to_delayed_work(work);
> +	struct aspeed_video *video = container_of(dwork, struct aspeed_video,
> +						  res_work);
> +
> +	/* No clients remaining after delay */
> +	if (atomic_read(&video->clients) == 0)
> +		goto done;
> +
> +	aspeed_video_on(video);
> +
> +	aspeed_video_init_regs(video);
> +
> +	rc = aspeed_video_get_resolution(video);
> +	if (rc)
> +		dev_err(video->dev,
> +			"resolution changed; couldn't get new resolution\n");
> +
> +	if (video->timings.width != video->pix_fmt.width ||
> +	    video->timings.height != video->pix_fmt.height) {
> +		static const struct v4l2_event ev = {
> +			.type = V4L2_EVENT_SOURCE_CHANGE,
> +			.u.src_change.changes = V4L2_EVENT_SRC_CH_RESOLUTION,
> +		};
> +
> +		v4l2_event_queue(&video->vdev, &ev);
> +	}
> +
> +done:
> +	clear_bit(VIDEO_RES_CHANGE, &video->flags);
> +	wake_up_interruptible_all(&video->wait);
> +}
> +
> +static int aspeed_video_open(struct file *file)
> +{
> +	int rc;
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	mutex_lock(&video->video_lock);
> +
> +	if (atomic_inc_return(&video->clients) == 1) {

No need for a clients refcount. You can use the v4l2_fh_is_singular(_file) helpers.
See how other drivers do this.

> +		rc = aspeed_video_start(video);
> +		if (rc) {
> +			dev_err(video->dev, "Failed to start video engine\n");
> +			atomic_dec(&video->clients);
> +			mutex_unlock(&video->video_lock);
> +			return rc;
> +		}
> +	}
> +
> +	mutex_unlock(&video->video_lock);
> +
> +	return v4l2_fh_open(file);
> +}
> +
> +static int aspeed_video_release(struct file *file)
> +{
> +	int rc;
> +	struct aspeed_video *video = video_drvdata(file);
> +
> +	rc = vb2_fop_release(file);
> +
> +	mutex_lock(&video->video_lock);
> +
> +	if (atomic_dec_return(&video->clients) == 0)
> +		aspeed_video_stop(video);
> +
> +	mutex_unlock(&video->video_lock);
> +
> +	return rc;
> +}
> +
> +static const struct v4l2_file_operations aspeed_video_v4l2_fops = {
> +	.owner = THIS_MODULE,
> +	.read = vb2_fop_read,
> +	.poll = vb2_fop_poll,
> +	.unlocked_ioctl = video_ioctl2,
> +	.mmap = vb2_fop_mmap,
> +	.open = aspeed_video_open,
> +	.release = aspeed_video_release,
> +};
> +
> +static int aspeed_video_queue_setup(struct vb2_queue *q,
> +				    unsigned int *num_buffers,
> +				    unsigned int *num_planes,
> +				    unsigned int sizes[],
> +				    struct device *alloc_devs[])
> +{
> +	struct aspeed_video *video = vb2_get_drv_priv(q);
> +
> +	if (*num_planes) {
> +		if (sizes[0] < video->max_compressed_size)
> +			return -EINVAL;
> +
> +		return 0;
> +	}
> +
> +	*num_planes = 1;
> +	sizes[0] = video->max_compressed_size;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_buf_prepare(struct vb2_buffer *vb)
> +{
> +	struct aspeed_video *video = vb2_get_drv_priv(vb->vb2_queue);
> +
> +	if (vb2_plane_size(vb, 0) < video->max_compressed_size)
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_start_streaming(struct vb2_queue *q,
> +					unsigned int count)
> +{
> +	int rc;
> +	struct aspeed_video *video = vb2_get_drv_priv(q);
> +
> +	rc = aspeed_video_start_frame(video);
> +	if (rc) {
> +		aspeed_video_bufs_done(video, VB2_BUF_STATE_QUEUED);
> +		return rc;
> +	}
> +
> +	video->sequence = 0;
> +	set_bit(VIDEO_STREAMING, &video->flags);
> +	return 0;
> +}
> +
> +static void aspeed_video_stop_streaming(struct vb2_queue *q)
> +{
> +	int rc;
> +	struct aspeed_video *video = vb2_get_drv_priv(q);
> +
> +	clear_bit(VIDEO_STREAMING, &video->flags);
> +
> +	rc = wait_event_timeout(video->wait,
> +				!test_bit(VIDEO_FRAME_INPRG, &video->flags),
> +				STOP_TIMEOUT);
> +	if (!rc) {
> +		dev_err(video->dev, "Timed out when stopping streaming\n");
> +		aspeed_video_stop(video);
> +	}
> +
> +	aspeed_video_bufs_done(video, VB2_BUF_STATE_ERROR);
> +}
> +
> +static void aspeed_video_buf_queue(struct vb2_buffer *vb)
> +{
> +	struct aspeed_video *video = vb2_get_drv_priv(vb->vb2_queue);
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct aspeed_video_buffer *avb = to_aspeed_video_buffer(vbuf);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&video->lock, flags);
> +	list_add_tail(&avb->link, &video->buffers);
> +	spin_unlock_irqrestore(&video->lock, flags);
> +}
> +
> +static const struct vb2_ops aspeed_video_vb2_ops = {
> +	.queue_setup = aspeed_video_queue_setup,
> +	.wait_prepare = vb2_ops_wait_prepare,
> +	.wait_finish = vb2_ops_wait_finish,
> +	.buf_prepare = aspeed_video_buf_prepare,
> +	.start_streaming = aspeed_video_start_streaming,
> +	.stop_streaming = aspeed_video_stop_streaming,
> +	.buf_queue =  aspeed_video_buf_queue,
> +};
> +
> +static int aspeed_video_setup_video(struct aspeed_video *video)
> +{
> +	const u64 mask = ~(BIT(V4L2_JPEG_CHROMA_SUBSAMPLING_444) |
> +			   BIT(V4L2_JPEG_CHROMA_SUBSAMPLING_420));
> +	struct v4l2_device *v4l2_dev = &video->v4l2_dev;
> +	struct vb2_queue *vbq = &video->queue;
> +	struct video_device *vdev = &video->vdev;
> +	int rc;
> +
> +	video->pix_fmt.pixelformat = V4L2_PIX_FMT_JPEG;
> +	video->pix_fmt.field = V4L2_FIELD_NONE;
> +	video->pix_fmt.colorspace = V4L2_COLORSPACE_SRGB;
> +	video->pix_fmt.quantization = V4L2_QUANTIZATION_FULL_RANGE;
> +
> +	rc = v4l2_device_register(video->dev, v4l2_dev);
> +	if (rc) {
> +		dev_err(video->dev, "Failed to register v4l2 device\n");
> +		return rc;
> +	}
> +
> +	v4l2_ctrl_handler_init(&video->ctrl_handler, 2);
> +	v4l2_ctrl_new_std(&video->ctrl_handler, &aspeed_video_ctrl_ops,
> +			  V4L2_CID_JPEG_COMPRESSION_QUALITY, 0,
> +			  ASPEED_VIDEO_JPEG_NUM_QUALITIES - 1, 1, 0);
> +	v4l2_ctrl_new_std_menu(&video->ctrl_handler, &aspeed_video_ctrl_ops,
> +			       V4L2_CID_JPEG_CHROMA_SUBSAMPLING,
> +			       V4L2_JPEG_CHROMA_SUBSAMPLING_420, mask,
> +			       V4L2_JPEG_CHROMA_SUBSAMPLING_444);
> +
> +	if (video->ctrl_handler.error) {
> +		v4l2_ctrl_handler_free(&video->ctrl_handler);
> +		v4l2_device_unregister(v4l2_dev);
> +
> +		dev_err(video->dev, "Failed to init controls: %d\n",
> +			video->ctrl_handler.error);
> +		return rc;
> +	}
> +
> +	v4l2_dev->ctrl_handler = &video->ctrl_handler;
> +
> +	vbq->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
> +	vbq->io_modes = VB2_MMAP | VB2_READ | VB2_DMABUF;
> +	vbq->dev = v4l2_dev->dev;
> +	vbq->lock = &video->video_lock;
> +	vbq->ops = &aspeed_video_vb2_ops;
> +	vbq->mem_ops = &vb2_dma_contig_memops;
> +	vbq->drv_priv = video;
> +	vbq->buf_struct_size = sizeof(struct aspeed_video_buffer);
> +	vbq->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	vbq->min_buffers_needed = 3;
> +
> +	rc = vb2_queue_init(vbq);
> +	if (rc) {
> +		v4l2_ctrl_handler_free(&video->ctrl_handler);
> +		v4l2_device_unregister(v4l2_dev);
> +
> +		dev_err(video->dev, "Failed to init vb2 queue\n");
> +		return rc;
> +	}
> +
> +	vdev->queue = vbq;
> +	vdev->fops = &aspeed_video_v4l2_fops;
> +	vdev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE |
> +		V4L2_CAP_STREAMING;
> +	vdev->v4l2_dev = v4l2_dev;
> +	strscpy(vdev->name, DEVICE_NAME, sizeof(vdev->name));
> +	vdev->vfl_type = VFL_TYPE_GRABBER;
> +	vdev->vfl_dir = VFL_DIR_RX;
> +	vdev->release = video_device_release_empty;
> +	vdev->ioctl_ops = &aspeed_video_ioctl_ops;
> +	vdev->lock = &video->video_lock;
> +
> +	video_set_drvdata(vdev, video);
> +	rc = video_register_device(vdev, VFL_TYPE_GRABBER, 0);
> +	if (rc) {
> +		vb2_queue_release(vbq);
> +		v4l2_ctrl_handler_free(&video->ctrl_handler);
> +		v4l2_device_unregister(v4l2_dev);
> +
> +		dev_err(video->dev, "Failed to register video device\n");
> +		return rc;
> +	}
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_init(struct aspeed_video *video)
> +{
> +	int irq;
> +	int rc;
> +	struct device *dev = video->dev;
> +
> +	irq = irq_of_parse_and_map(dev->of_node, 0);
> +	if (!irq) {
> +		dev_err(dev, "Unable to find IRQ\n");
> +		return -ENODEV;
> +	}
> +
> +	rc = devm_request_irq(dev, irq, aspeed_video_irq, IRQF_SHARED,
> +			      DEVICE_NAME, video);
> +	if (rc < 0) {
> +		dev_err(dev, "Unable to request IRQ %d\n", irq);
> +		return rc;
> +	}
> +
> +	video->eclk = devm_clk_get(dev, "eclk");
> +	if (IS_ERR(video->eclk)) {
> +		dev_err(dev, "Unable to get ECLK\n");
> +		return PTR_ERR(video->eclk);
> +	}
> +
> +	video->vclk = devm_clk_get(dev, "vclk");
> +	if (IS_ERR(video->vclk)) {
> +		dev_err(dev, "Unable to get VCLK\n");
> +		return PTR_ERR(video->vclk);
> +	}
> +
> +	video->rst = devm_reset_control_get_exclusive(dev, NULL);
> +	if (IS_ERR(video->rst)) {
> +		dev_err(dev, "Unable to get VE reset\n");
> +		return PTR_ERR(video->rst);
> +	}
> +
> +	rc = of_reserved_mem_device_init(dev);
> +	if (rc) {
> +		dev_err(dev, "Unable to reserve memory\n");
> +		return rc;
> +	}
> +
> +	rc = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> +	if (rc) {
> +		dev_err(dev, "Failed to set DMA mask\n");
> +		of_reserved_mem_device_release(dev);
> +		return rc;
> +	}
> +
> +	if (!aspeed_video_alloc_buf(video, &video->jpeg,
> +				    VE_JPEG_HEADER_SIZE)) {
> +		dev_err(dev, "Failed to allocate DMA for JPEG header\n");
> +		of_reserved_mem_device_release(dev);
> +		return rc;
> +	}
> +
> +	aspeed_video_init_jpeg_table(video->jpeg.virt, video->yuv420);
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_probe(struct platform_device *pdev)
> +{
> +	int rc;
> +	struct resource *res;
> +	struct aspeed_video *video = kzalloc(sizeof(*video), GFP_KERNEL);
> +
> +	if (!video)
> +		return -ENOMEM;
> +
> +	video->frame_rate = 30;
> +	video->dev = &pdev->dev;
> +	mutex_init(&video->video_lock);
> +	init_waitqueue_head(&video->wait);
> +	INIT_DELAYED_WORK(&video->res_work, aspeed_video_resolution_work);
> +	INIT_LIST_HEAD(&video->buffers);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +
> +	video->base = devm_ioremap_resource(video->dev, res);
> +
> +	if (IS_ERR(video->base))
> +		return PTR_ERR(video->base);
> +
> +	rc = aspeed_video_init(video);
> +	if (rc)
> +		return rc;
> +
> +	rc = aspeed_video_setup_video(video);
> +	if (rc)
> +		return rc;
> +
> +	return 0;
> +}
> +
> +static int aspeed_video_remove(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
> +	struct aspeed_video *video = to_aspeed_video(v4l2_dev);
> +
> +	video_unregister_device(&video->vdev);
> +
> +	vb2_queue_release(&video->queue);
> +
> +	v4l2_ctrl_handler_free(&video->ctrl_handler);
> +
> +	v4l2_device_unregister(v4l2_dev);
> +
> +	dma_free_coherent(video->dev, VE_JPEG_HEADER_SIZE, video->jpeg.virt,
> +			  video->jpeg.dma);
> +
> +	of_reserved_mem_device_release(dev);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id aspeed_video_of_match[] = {
> +	{ .compatible = "aspeed,ast2400-video-engine" },
> +	{ .compatible = "aspeed,ast2500-video-engine" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, aspeed_video_of_match);
> +
> +static struct platform_driver aspeed_video_driver = {
> +	.driver = {
> +		.name = DEVICE_NAME,
> +		.of_match_table = aspeed_video_of_match,
> +	},
> +	.probe = aspeed_video_probe,
> +	.remove = aspeed_video_remove,
> +};
> +
> +module_platform_driver(aspeed_video_driver);
> +
> +MODULE_DESCRIPTION("ASPEED Video Engine Driver");
> +MODULE_AUTHOR("Eddie James");
> +MODULE_LICENSE("GPL v2");
> 

Regards,

	Hans