drivers/media/platform/renesas/vsp1/vsp1_uds.c

Source file repositories/reference/linux-study-clean/drivers/media/platform/renesas/vsp1/vsp1_uds.c

File Facts

System
Linux kernel
Corpus path
drivers/media/platform/renesas/vsp1/vsp1_uds.c
Extension
.c
Size
11304 bytes
Lines
411
Domain
Driver Families
Bucket
drivers/media
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0+
/*
 * vsp1_uds.c  --  R-Car VSP1 Up and Down Scaler
 *
 * Copyright (C) 2013-2014 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/gfp.h>
#include <linux/mutex.h>

#include <media/v4l2-subdev.h>

#include "vsp1.h"
#include "vsp1_dl.h"
#include "vsp1_entity.h"
#include "vsp1_pipe.h"
#include "vsp1_uds.h"

#define UDS_MIN_SIZE				4U
#define UDS_MAX_SIZE				8190U

#define UDS_MIN_FACTOR				0x0100
#define UDS_MAX_FACTOR				0xffff

/* -----------------------------------------------------------------------------
 * Device Access
 */

static inline void vsp1_uds_write(struct vsp1_uds *uds,
				  struct vsp1_dl_body *dlb, u32 reg, u32 data)
{
	vsp1_dl_body_write(dlb, reg + uds->entity.index * VI6_UDS_OFFSET, data);
}

/* -----------------------------------------------------------------------------
 * Scaling Computation
 */

void vsp1_uds_set_alpha(struct vsp1_entity *entity, struct vsp1_dl_body *dlb,
			unsigned int alpha)
{
	struct vsp1_uds *uds = to_uds(&entity->subdev);

	vsp1_uds_write(uds, dlb, VI6_UDS_ALPVAL,
		       alpha << VI6_UDS_ALPVAL_VAL0_SHIFT);
}

/*
 * uds_output_size - Return the output size for an input size and scaling ratio
 * @input: input size in pixels
 * @ratio: scaling ratio in U4.12 fixed-point format
 */
static unsigned int uds_output_size(unsigned int input, unsigned int ratio)
{
	if (ratio > 4096) {
		/* Down-scaling */
		unsigned int mp;

		mp = ratio / 4096;
		mp = mp < 4 ? 1 : (mp < 8 ? 2 : 4);

		return (input - 1) / mp * mp * 4096 / ratio + 1;
	} else {
		/* Up-scaling */
		return (input - 1) * 4096 / ratio + 1;
	}
}

/*
 * uds_output_limits - Return the min and max output sizes for an input size
 * @input: input size in pixels
 * @minimum: minimum output size (returned)
 * @maximum: maximum output size (returned)
 */
static void uds_output_limits(unsigned int input,
			      unsigned int *minimum, unsigned int *maximum)
{
	*minimum = max(uds_output_size(input, UDS_MAX_FACTOR), UDS_MIN_SIZE);
	*maximum = min(uds_output_size(input, UDS_MIN_FACTOR), UDS_MAX_SIZE);
}

/*
 * uds_passband_width - Return the passband filter width for a scaling ratio
 * @ratio: scaling ratio in U4.12 fixed-point format
 */
static unsigned int uds_passband_width(unsigned int ratio)

Annotation

Implementation Notes