path: root/drivers/gpu/drm/rcar-du/rcar_du_crtc.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * rcar_du_crtc.c  --  R-Car Display Unit CRTCs
 *
 * Copyright (C) 2013-2015 Renesas Electronics Corporation
 *
 * Contact: Laurent Pinchart (laurent.pinchart@ideasonboard.com)
 */

#include <linux/clk.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/sys_soc.h>

#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_device.h>
#include <drm/drm_fb_cma_helper.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_vblank.h>

#include "rcar_du_crtc.h"
#include "rcar_du_drv.h"
#include "rcar_du_encoder.h"
#include "rcar_du_kms.h"
#include "rcar_du_plane.h"
#include "rcar_du_regs.h"
#include "rcar_du_vsp.h"
#include "rcar_lvds.h"

static u32 rcar_du_crtc_read(struct rcar_du_crtc *rcrtc, u32 reg)
{
	struct rcar_du_device *rcdu = rcrtc->dev;

	return rcar_du_read(rcdu, rcrtc->mmio_offset + reg);
}

static void rcar_du_crtc_write(struct rcar_du_crtc *rcrtc, u32 reg, u32 data)
{
	struct rcar_du_device *rcdu = rcrtc->dev;

	rcar_du_write(rcdu, rcrtc->mmio_offset + reg, data);
}

static void rcar_du_crtc_clr(struct rcar_du_crtc *rcrtc, u32 reg, u32 clr)
{
	struct rcar_du_device *rcdu = rcrtc->dev;

	rcar_du_write(rcdu, rcrtc->mmio_offset + reg,
		      rcar_du_read(rcdu, rcrtc->mmio_offset + reg) & ~clr);
}

static void rcar_du_crtc_set(struct rcar_du_crtc *rcrtc, u32 reg, u32 set)
{
	struct rcar_du_device *rcdu = rcrtc->dev;

	rcar_du_write(rcdu, rcrtc->mmio_offset + reg,
		      rcar_du_read(rcdu, rcrtc->mmio_offset + reg) | set);
}

void rcar_du_crtc_dsysr_clr_set(struct rcar_du_crtc *rcrtc, u32 clr, u32 set)
{
	struct rcar_du_device *rcdu = rcrtc->dev;

	rcrtc->dsysr = (rcrtc->dsysr & ~clr) | set;
	rcar_du_write(rcdu, rcrtc->mmio_offset + DSYSR, rcrtc->dsysr);
}

/* -----------------------------------------------------------------------------
 * Hardware Setup
 */

struct dpll_info {
	unsigned int output;
	unsigned int fdpll;
	unsigned int n;
	unsigned int m;
};

static void rcar_du_dpll_divider(struct rcar_du_crtc *rcrtc,
				 struct dpll_info *dpll,
				 unsigned long input,
				 unsigned long target)
{
	unsigned long best_diff = (unsigned long)-1;
	unsigned long diff;
	unsigned int fdpll;
	unsigned int m;
	unsigned int n;

	/*
	 *   fin                                 fvco        fout       fclkout
	 * in --> [1/M] --> |PD| -> [LPF] -> [VCO] -> [1/P] -+-> [1/FDPLL] -> out
	 *              +-> |  |                             |
	 *              |                                    |
	 *              +---------------- [1/N] <------------+
	 *
	 *	fclkout = fvco / P / FDPLL -- (1)
	 *
	 * fin/M = fvco/P/N
	 *
	 *	fvco = fin * P *  N / M -- (2)
	 *
	 * (1) + (2) indicates
	 *
	 *	fclkout = fin * N / M / FDPLL
	 *
	 * NOTES
	 *	N	: (n + 1)
	 *	M	: (m + 1)
	 *	FDPLL	: (fdpll + 1)
	 *	P	: 2
	 *	2kHz < fvco < 4096MHz
	 *
	 * To minimize the jitter,
	 * N : as large as possible
	 * M : as small as possible
	 */
	for (m = 0; m < 4; m++) {
		for (n = 119; n > 38; n--) {
			/*
			 * This code only runs on 64-bit architectures, the
			 * unsigned long type can thus be used for 64-bit
			 * computation. It will still compile without any
			 * warning on 32-bit architectures.
			 *
			 * To optimize calculations, use fout instead of fvco
			 * to verify the VCO frequency constraint.
			 */
			unsigned long fout = input * (n + 1) / (m + 1);

			if (fout