path: root/drivers/clk/sifive/fu540-prci.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2019 Western Digital Corporation or its affiliates.
 *
 * Copyright (C) 2018 SiFive, Inc.
 * Wesley Terpstra
 * Paul Walmsley
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * The FU540 PRCI implements clock and reset control for the SiFive
 * FU540-C000 chip.   This driver assumes that it has sole control
 * over all PRCI resources.
 *
 * This driver is based on the PRCI driver written by Wesley Terpstra.
 *
 * Refer, commit 999529edf517ed75b56659d456d221b2ee56bb60 of:
 * https://github.com/riscv/riscv-linux
 *
 * References:
 * - SiFive FU540-C000 manual v1p0, Chapter 7 "Clocking and Reset"
 */

#include <common.h>
#include <clk-uclass.h>
#include <clk.h>
#include <div64.h>
#include <dm.h>
#include <dm/device.h>
#include <dm/device_compat.h>
#include <dm/uclass.h>
#include <dt-bindings/clock/sifive-fu540-prci.h>
#include <dt-bindings/reset/sifive-fu540-prci.h>
#include <errno.h>
#include <reset-uclass.h>
#include <asm/io.h>
#include <asm/arch/reset.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/math64.h>
#include <linux/clk/analogbits-wrpll-cln28hpc.h>

/*
 * EXPECTED_CLK_PARENT_COUNT: how many parent clocks this driver expects:
 *     hfclk and rtcclk
 */
#define EXPECTED_CLK_PARENT_COUNT	2

/*
 * Register offsets and bitmasks
 */

/* COREPLLCFG0 */
#define PRCI_COREPLLCFG0_OFFSET		0x4
#define PRCI_COREPLLCFG0_DIVR_SHIFT	0
#define PRCI_COREPLLCFG0_DIVR_MASK	(0x3f << PRCI_COREPLLCFG0_DIVR_SHIFT)
#define PRCI_COREPLLCFG0_DIVF_SHIFT	6
#define PRCI_COREPLLCFG0_DIVF_MASK	(0x1ff << PRCI_COREPLLCFG0_DIVF_SHIFT)
#define PRCI_COREPLLCFG0_DIVQ_SHIFT	15
#define PRCI_COREPLLCFG0_DIVQ_MASK	(0x7 << PRCI_COREPLLCFG0_DIVQ_SHIFT)
#define PRCI_COREPLLCFG0_RANGE_SHIFT	18
#define PRCI_COREPLLCFG0_RANGE_MASK	(0x7 << PRCI_COREPLLCFG0_RANGE_SHIFT)
#define PRCI_COREPLLCFG0_BYPASS_SHIFT	24
#define PRCI_COREPLLCFG0_BYPASS_MASK	(0x1 << PRCI_COREPLLCFG0_BYPASS_SHIFT)
#define PRCI_COREPLLCFG0_FSE_SHIFT	25
#define PRCI_COREPLLCFG0_FSE_MASK	(0x1 << PRCI_COREPLLCFG0_FSE_SHIFT)
#define PRCI_COREPLLCFG0_LOCK_SHIFT	31
#define PRCI_COREPLLCFG0_LOCK_MASK	(0x1 << PRCI_COREPLLCFG0_LOCK_SHIFT)

/* COREPLLCFG1 */
#define PRCI_COREPLLCFG1_OFFSET		0x8
#define PRCI_COREPLLCFG1_CKE_SHIFT	31
#define PRCI_COREPLLCFG1_CKE_MASK	(0x1 << PRCI_COREPLLCFG1_CKE_SHIFT)

/* DDRPLLCFG0 */
#define PRCI_DDRPLLCFG0_OFFSET		0xc
#define PRCI_DDRPLLCFG0_DIVR_SHIFT	0
#define PRCI_DDRPLLCFG0_DIVR_MASK	(0x3f << PRCI_DDRPLLCFG0_DIVR_SHIFT)
#define PRCI_DDRPLLCFG0_DIVF_SHIFT	6
#define PRCI_DDRPLLCFG0_DIVF_MASK	(0x1ff << PRCI_DDRPLLCFG0_DIVF_SHIFT)
#define PRCI_DDRPLLCFG0_DIVQ_SHIFT	15
#define PRCI_DDRPLLCFG0_DIVQ_MASK	(0x7 << PRCI_DDRPLLCFG0_DIVQ_SHIFT)
#define PRCI_DDRPLLCFG0_RANGE_SHIFT	18
#define PRCI_DDRPLLCFG0_RANGE_MASK	(0x7 << PRCI_DDRPLLCFG0_RANGE_SHIFT)
#define PRCI_DDRPLLCFG0_BYPASS_SHIFT	24
#define PRCI_DDRPLLCFG0_BYPASS_MASK	(0x1 << PRCI_DDRPLLCFG0_BYPASS_SHIFT)
#define PRCI_DDRPLLCFG0_FSE_SHIFT	25
#define PRCI_DDRPLLCFG0_FSE_MASK	(0x1 << PRCI_DDRPLLCFG0_FSE_SHIFT)
#define PRCI_DDRPLLCFG0_LOCK_SHIFT	31
#define PRCI_DDRPLLCFG0_LOCK_MASK	(0x1 << PRCI_DDRPLLCFG0_LOCK_SHIFT)

/* DDRPLLCFG1 */
#define PRCI_DDRPLLCFG1_OFFSET		0x10
#define PRCI_DDRPLLCFG1_CKE_SHIFT	31
#define PRCI_DDRPLLCFG1_CKE_MASK	(0x1 << PRCI_DDRPLLCFG1_CKE_SHIFT)

/* GEMGXLPLLCFG0 */
#define PRCI_GEMGXLPLLCFG0_OFFSET	0x1c
#define PRCI_GEMGXLPLLCFG0_DIVR_SHIFT	0
#define PRCI_GEMGXLPLLCFG0_DIVR_MASK	\
			(0x3f << PRCI_GEMGXLPLLCFG0_DIVR_SHIFT)
#define PRCI_GEMGXLPLLCFG0_DIVF_SHIFT	6
#define PRCI_GEMGXLPLLCFG0_DIVF_MASK	\
			(0x1ff << PRCI_GEMGXLPLLCFG0_DIVF_SHIFT)
#define PRCI_GEMGXLPLLCFG0_DIVQ_SHIFT	15
#define PRCI_GEMGXLPLLCFG0_DIVQ_MASK	(0x7 << PRCI_GEMGXLPLLCFG0_DIVQ_SHIFT)
#define PRCI_GEMGXLPLLCFG0_RANGE_SHIFT	18
#define PRCI_GEMGXLPLLCFG0_RANGE_MASK	\
			(0x7 << PRCI_GEMGXLPLLCFG0_RANGE_SHIFT)
#define PRCI_GEMGXLPLLCFG0_BYPASS_SHIFT 24
#define PRCI_GEMGXLPLLCFG0_BYPASS_MASK	\
			(0x1 << PRCI_GEMGXLPLLCFG0_BYPASS_SHIFT)
#define PRCI_GEMGXLPLLCFG0_FSE_SHIFT	25
#define PRCI_GEMGXLPLLCFG0_FSE_MASK	\
			(0x1 << PRCI_GEMGXLPLLCFG0_FSE_SHIFT)
#define PRCI_GEMGXLPLLCFG0_LOCK_SHIFT	31
#define PRCI_GEMGXLPLLCFG0_LOCK_MASK	(0x1 << PRCI_GEMGXLPLLCFG0_LOCK_SHIFT)

/* GEMGXLPLLCFG1 */
#define PRCI_GEMGXLPLLCFG1_OFFSET	0x20
#define PRCI_GEMGXLPLLCFG1_CKE_SHIFT	31
#define PRCI_GEMGXLPLLCFG1_CKE_MASK	(0x1 << PRCI_GEMGXLPLLCFG1_CKE_SHIFT)

/* CORECLKSEL */
#define PRCI_CORECLKSEL_OFFSET		0x24
#define PRCI_CORECLKSEL_CORECLKSEL_SHIFT 0
#define PRCI_CORECLKSEL_CORECLKSEL_MASK \
			(0x1 << PRCI_CORECLKSEL_CORECLKSEL_SHIFT)

/* DEVICESRESETREG */
#define PRCI_DEVICESRESETREG_OFFSET	0x28
#define PRCI_DEVICERESETCNT 5

#define PRCI_DEVICESRESETREG_DDR_CTRL_RST_N_MASK \
			(0x1 << PRCI_RST_DDR_CTRL_N)
#define PRCI_DEVICESRESETREG_DDR_AXI_RST_N_MASK \
			(0x1 << PRCI_RST_DDR_AXI_N)
#define PRCI_DEVICESRESETREG_DDR_AHB_RST_N_MASK \
			(0x1 << PRCI_RST_DDR_AHB_N)
#define PRCI_DEVICESRESETREG_DDR_PHY_RST_N_MASK \
			(0x1 << PRCI_RST_DDR_PHY_N)
#define PRCI_DEVICESRESETREG_GEMGXL_RST_N_MASK \
			(0x1 << PRCI_RST_GEMGXL_N)

/* CLKMUXSTATUSREG */
#define PRCI_CLKMUXSTATUSREG_OFFSET	0x2c
#define PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_SHIFT 1
#define PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_MASK \
			(0x1 << PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_SHIFT)

/* PROCMONCFG */
#define PRCI_PROCMONCFG_OFFSET		0xF0
#define PRCI_PROCMONCFG_CORE_CLOCK_SHIFT	24
#define PRCI_PROCMONCFG_CORE_CLOCK_MASK \
			(0x1 << PRCI_PROCMONCFG_CORE_CLOCK_SHIFT)

/*
 * Private structures
 */

/**
 * struct __prci_data - per-device-instance data
 * @va: base virtual address of the PRCI IP block
 * @parent: parent clk instance
 *
 * PRCI per-device instance data
 */
struct __prci_data {
	void *va;
	struct clk parent_hfclk;
	struct clk parent_rtcclk;
};

/**
 * struct __prci_wrpll_data - WRPLL configuration and integration data
 * @c: WRPLL current configuration record
 * @enable_bypass: fn ptr to code to bypass the WRPLL (if applicable; else NULL)
 * @disable_bypass: fn ptr to code to not bypass the WRPLL (or NULL)
 * @cfg0_offs: WRPLL CFG0 register offset (in bytes) from the PRCI base address
 * @cfg1_offs: WRPLL CFG1 register offset (in bytes) from the PRCI base address
 * @release_reset: fn ptr to code to release clock reset
 *
 * @enable_bypass and @disable_bypass are used for WRPLL instances
 * that contain a separate external glitchless clock mux downstream
 * from the PLL.  The WRPLL internal bypass mux is not glitchless.
 */
struct __prci_wrpll_data {
	struct wrpll_cfg c;
	void (*enable_bypass)(struct __prci_data *pd);
	void (*disable_bypass)(struct __prci_data *pd);
	u8 cfg0_offs;
	u8 cfg1_offs;
	void (*release_reset)(struct __prci_data *pd);
};

struct __prci_clock;

/* struct __prci_clock_ops - clock operations */
struct __prci_clock_ops {
	int (*set_rate)(struct __prci_clock *pc,
			unsigned long rate,
			unsigned long parent_rate);
	unsigned long (*round_rate)(struct __prci_clock *pc,
				    unsigned long rate,
				    unsigned long *parent_rate);
	unsigned long (*recalc_rate)(struct __prci_clock *pc,
				     unsigned long parent_rate);
	int (*enable_clk)(struct __prci_clock *pc, bool enable);
};

/**
 * struct __prci_clock - describes a clock device managed by PRCI
 * @name: user-readable clock name string - should match the manual
 * @parent_name: parent name for this clock
 * @ops: struct __prci_clock_ops for control
 * @pwd: WRPLL-specific data, associated with this clock (if not NULL)
 * @pd: PRCI-specific data associated with this clock (if not NULL)
 *
 * PRCI clock data.  Used by the PRCI driver to register PRCI-provided
 * clocks to the Linux clock infrastructure.
 */
struct __prci_clock {
	const char *name;
	const char *parent_name;
	const struct __prci_clock_ops *ops;
	struct __prci_wrpll_data *pwd;
	struct __prci_data *pd;
};

/*
 * Private functions
 */

/**
 * __prci_readl() - read from a PRCI register
 * @pd: PRCI context
 * @offs: register offset to read from (in bytes, from PRCI base address)
 *
 * Read the register located at offset @offs from the base virtual
 * address of the PRCI register target described by @pd, and return
 * the value to the caller.
 *
 * Context: Any context.
 *
 * Return: the contents of the register described by @pd and @offs.
 */
static u32 __prci_readl(struct __prci_data *pd, u32 offs)
{
	return readl(pd->va + offs);
}

static void __prci_writel(u32 v, u32 offs, struct __prci_data *pd)
{
	writel(v, pd->va + offs);
}

/* WRPLL-related private functions */

/**
 * __prci_wrpll_unpack() - unpack WRPLL configuration registers into parameters
 * @c: ptr to a struct wrpll_cfg record to write config into
 * @r: value read from the PRCI PLL configuration register
 *
 * Given a value @r read from an FU540 PRCI PLL configuration register,
 * split it into fields and populate it into the WRPLL configuration record
 * pointed to by @c.
 *
 * The COREPLLCFG0 macros are used below, but the other *PLLCFG0 macros
 * have the same register layout.
 *
 * Context: Any context.
 */
static void __prci_wrpll_unpack(struct wrpll_cfg *c, u32 r)
{
	u32 v;

	v = r & PRCI_COREPLLCFG0_DIVR_MASK;
	v >>= PRCI_COREPLLCFG0_DIVR_SHIFT;
	c->divr = v;

	v = r & PRCI_COREPLLCFG0_DIVF_MASK;
	v >>= PRCI_COREPLLCFG0_DIVF_SHIFT;
	c->divf = v;

	v = r & PRCI_COREPLLCFG0_DIVQ_MASK;
	v >>= PRCI_COREPLLCFG0_DIVQ_SHIFT;
	c->divq = v;

	v = r & PRCI_COREPLLCFG0_RANGE_MASK;
	v >>= PRCI_COREPLLCFG0_RANGE_SHIFT;
	c->range = v;

	c->flags &= (WRPLL_FLAGS_INT_FEEDBACK_MASK |
		     WRPLL_FLAGS_EXT_FEEDBACK_MASK);

	/* external feedback mode not supported */
	c->flags |= WRPLL_FLAGS_INT_FEEDBACK_MASK;
}

/**
 * __prci_wrpll_pack() - pack PLL configuration parameters into a register value
 * @c: pointer to a struct wrpll_cfg record containing the PLL's cfg
 *
 * Using a set of WRPLL configuration values pointed to by @c,
 * assemble a PRCI PLL configuration register value, and return it to
 * the caller.
 *
 * Context: Any context.  Caller must ensure that the contents of the
 *          record pointed to by @c do not change during the execution
 *          of this function.
 *
 * Returns: a value suitable for writing into a PRCI PLL configuration
 *          register
 */
static u32 __prci_wrpll_pack(const struct wrpll_cfg *c)
{
	u32 r = 0;

	r |= c->divr << PRCI_COREPLLCFG0_DIVR_SHIFT;
	r |= c->divf << PRCI_COREPLLCFG0_DIVF_SHIFT;
	r |= c->divq << PRCI_COREPLLCFG0_DIVQ_SHIFT;
	r |= c->range << PRCI_COREPLLCFG0_RANGE_SHIFT;

	/* external feedback mode not supported */
	r |= PRCI_COREPLLCFG0_FSE_MASK;

	return r;
}

/**
 * __prci_wrpll_read_cfg0() - read the WRPLL configuration from the PRCI
 * @pd: PRCI context
 * @pwd: PRCI WRPLL metadata
 *
 * Read the current configuration of the PLL identified by @pwd from
 * the PRCI identified by @pd, and store it into the local configuration
 * cache in @pwd.
 *
 * Context: Any context.  Caller must prevent the records pointed to by
 *          @pd and @pwd from changing during execution.
 */
static void __prci_wrpll_read_cfg0(struct __prci_data *pd,
				   struct __prci_wrpll_data *pwd)
{
	__prci_wrpll_unpack(&pwd->c, __prci_readl(pd, pwd->cfg0_offs));
}

/**
 * __prci_wrpll_write_cfg0() - write WRPLL configuration into the PRCI
 * @pd: PRCI context
 * @pwd: PRCI WRPLL metadata
 * @c: WRPLL configuration record to write
 *
 * Write the WRPLL configuration described by @c into the WRPLL
 * configuration register identified by @pwd in the PRCI instance
 * described by @c.  Make a cached copy of the WRPLL's current
 * configuration so it can be used by other code.
 *
 * Context: Any context.  Caller must prevent the records pointed to by
 *          @pd and @pwd from changing during execution.
 */
static void __prci_wrpll_write_cfg0(struct __prci_data *pd,
				    struct __prci_wrpll_data *pwd,
				    struct wrpll_cfg *c)
{
	__prci_writel(__prci_wrpll_pack(c), pwd->cfg0_offs, pd);

	memcpy(&pwd->c, c, sizeof(*c));
}

/**
 * __prci_wrpll_write_cfg1() - write Clock enable/disable configuration
 * into the PRCI
 * @pd: PRCI context
 * @pwd: PRCI WRPLL metadata
 * @enable: Clock enable or disable value
 */
static void __prci_wrpll_write_cfg1(struct __prci_data *pd,
				    struct __prci_wrpll_data *pwd,
				    u32 enable)
{
	__prci_writel(enable, pwd->cfg1_offs, pd);
}

/* Core clock mux control */

/**
 * __prci_coreclksel_use_hfclk() - switch the CORECLK mux to output HFCLK
 * @pd: struct __prci_data * for the PRCI containing the CORECLK mux reg
 *
 * Switch the CORECLK mux to the HFCLK input source; return once complete.
 *
 * Context: Any context.  Caller must prevent concurrent changes to the
 *          PRCI_CORECLKSEL_OFFSET register.
 */
static void __prci_coreclksel_use_hfclk(struct __prci_data *pd)
{
	u32 r;

	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET);
	r |= PRCI_CORECLKSEL_CORECLKSEL_MASK;
	__prci_writel(r, PRCI_CORECLKSEL_OFFSET, pd);

	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET); /* barrier */
}

/**
 * __prci_coreclksel_use_corepll() - switch the CORECLK mux to output COREPLL
 * @pd: struct __prci_data * for the PRCI containing the CORECLK mux reg
 *
 * Switch the CORECLK mux to the PLL output clock; return once complete.
 *
 * Context: Any context.  Caller must prevent concurrent changes to the
 *          PRCI_CORECLKSEL_OFFSET register.
 */
static void __prci_coreclksel_use_corepll(struct __prci_data *pd)
{
	u32 r;

	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET);
	r &= ~PRCI_CORECLKSEL_CORECLKSEL_MASK;
	__prci_writel(r, PRCI_CORECLKSEL_OFFSET, pd);

	r = __prci_readl(pd, PRCI_CORECLKSEL_OFFSET); /* barrier */
}

static unsigned long sifive_fu540_prci_wrpll_recalc_rate(
						struct __prci_clock *pc,
						unsigned long parent_rate)
{
	struct __prci_wrpll_data *pwd = pc->pwd;

	return wrpll_calc_output_rate(&pwd->c, parent_rate);
}

static unsigned long sifive_fu540_prci_wrpll_round_rate(
						struct __prci_clock *pc,
						unsigned long rate,
						unsigned long *parent_rate)
{
	struct __prci_wrpll_data *pwd = pc->pwd;
	struct wrpll_cfg c;

	memcpy(&c, &pwd->c, sizeof(c));

	wrpll_configure_for_rate(&c, rate, *parent_rate);

	return wrpll_calc_output_rate(&c, *parent_rate);
}

static int sifive_fu540_prci_wrpll_set_rate(struct __prci_clock *pc,
					    unsigned long rate,
					    unsigned long parent_rate)
{
	struct __prci_wrpll_data *pwd = pc->pwd;
	struct __prci_data *pd = pc->pd;
	int r;

	r = wrpll_configure_for_rate(&pwd->c, rate, parent_rate);
	if (r)
		return r;

	if (pwd->enable_bypass)
		pwd->enable_bypass(pd);

	__prci_wrpll_write_cfg0(pd, pwd, &pwd->c);

	udelay(wrpll_calc_max_lock_us(&pwd->c));

	if (pwd->disable_bypass)
		pwd->disable_bypass(pd);

	return 0;
}

static int sifive_fu540_prci_clock_enable(struct __prci_clock *pc, bool enable)
{
	struct __prci_wrpll_data *pwd = pc->pwd;
	struct __prci_data *pd = pc->pd;

	if (enable) {
		__prci_wrpll_write_cfg1(pd, pwd, PRCI_COREPLLCFG1_CKE_MASK);

		if (pwd->release_reset)
			pwd->release_reset(pd);
	} else {
		u32 r;

		r = __prci_readl(pd, pwd->cfg1_offs);
		r &= ~PRCI_COREPLLCFG1_CKE_MASK;

		__prci_wrpll_write_cfg1(pd, pwd, r);
	}

	return 0;
}

static const struct __prci_clock_ops sifive_fu540_prci_wrpll_clk_ops = {
	.set_rate = sifive_fu540_prci_wrpll_set_rate,
	.round_rate = sifive_fu540_prci_wrpll_round_rate,
	.recalc_rate = sifive_fu540_prci_wrpll_recalc_rate,
	.enable_clk = sifive_fu540_prci_clock_enable,
};

/* TLCLKSEL clock integration */

static unsigned long sifive_fu540_prci_tlclksel_recalc_rate(
						struct __prci_clock *pc,
						unsigned long parent_rate)
{
	struct __prci_data *pd = pc->pd;
	u32 v;
	u8 div;

	v = __prci_readl(pd, PRCI_CLKMUXSTATUSREG_OFFSET);
	v &= PRCI_CLKMUXSTATUSREG_TLCLKSEL_STATUS_MASK;
	div = v ? 1 : 2;

	return div_u64(parent_rate, div);
}

static const struct __prci_clock_ops sifive_fu540_prci_tlclksel_clk_ops = {
	.recalc_rate = sifive_fu540_prci_tlclksel_recalc_rate,
};

static int __prci_consumer_reset(const char *rst_name, bool trigger)
{
	struct udevice *dev;
	struct reset_ctl rst_sig;
	int ret;

	ret = uclass_get_device_by_driver(UCLASS_RESET,
					  DM_GET_DRIVER(sifive_reset),
					  &dev);
	if (ret) {
		dev_err(dev, "Reset driver not found: %d\n", ret);
		return ret;
	}

	ret = reset_get_by_name(dev, rst_name, &rst_sig);
	if (ret) {
		dev_err(dev, "failed to get %s reset\n", rst_name);
		return ret;
	}

	if (reset_valid(&rst_sig)) {
		if (trigger)
			ret = reset_deassert(&rst_sig);
		else
			ret = reset_assert(&rst_sig);
		if (ret) {
			dev_err(dev, "failed to trigger reset id = %ld\n",
				rst_sig.id);
			return ret;
		}
	}

	return ret;
}

/**
 * __prci_ddr_release_reset() - Release DDR reset
 * @pd: struct __prci_data * for the PRCI containing the DDRCLK mux reg
 *
 */
static void __prci_ddr_release_reset(struct __prci_data *pd)
{
	/* Release DDR ctrl reset */
	__prci_consumer_reset("ddr_ctrl", true);

	/* HACK to get the '1 full controller clock cycle'. */
	asm volatile ("fence");

	/* Release DDR AXI reset */
	__prci_consumer_reset("ddr_axi", true);

	/* Release DDR AHB reset */
	__prci_consumer_reset("ddr_ahb", true);

	/* Release DDR PHY reset */
	__prci_consumer_reset("ddr_phy", true);

	/* HACK to get the '1 full controller clock cycle'. */
	asm volatile ("fence");

	/*
	 * These take like 16 cycles to actually propagate. We can't go sending
	 * stuff before they come out of reset. So wait.
	 */
	for (int i = 0; i < 256; i++)
		asm volatile ("nop");
}

/**
 * __prci_ethernet_release_reset() - Release ethernet reset
 * @pd: struct __prci_data * for the PRCI containing the Ethernet CLK mux reg
 *
 */
static void __prci_ethernet_release_reset(struct __prci_data *pd)
{
	/* Release GEMGXL reset */
	__prci_consumer_reset("gemgxl_reset", true);

	/* Procmon => core clock */
	__prci_writel(PRCI_PROCMONCFG_CORE_CLOCK_MASK, PRCI_PROCMONCFG_OFFSET,
		      pd);
}

/*
 * PRCI integration data for each WRPLL instance
 */

static struct __prci_wrpll_data __prci_corepll_data = {
	.cfg0_offs = PRCI_COREPLLCFG0_OFFSET,
	.cfg1_offs = PRCI_COREPLLCFG1_OFFSET,
	.enable_bypass = __prci_coreclksel_use_hfclk,
	.disable_bypass = __prci_coreclksel_use_corepll,
};

static struct __prci_wrpll_data __prci_ddrpll_data = {
	.cfg0_offs = PRCI_DDRPLLCFG0_OFFSET,
	.cfg1_offs = PRCI_DDRPLLCFG1_OFFSET,
	.release_reset = __prci_ddr_release_reset,
};

static struct __prci_wrpll_data __prci_gemgxlpll_data = {
	.cfg0_offs = PRCI_GEMGXLPLLCFG0_OFFSET,
	.cfg1_offs = PRCI_GEMGXLPLLCFG1_OFFSET,
	.release_reset = __prci_ethernet_release_reset,
};

/*
 * List of clock controls provided by the PRCI
 */

static struct __prci_clock __prci_init_clocks[] = {
	[PRCI_CLK_COREPLL] = {
		.name = "corepll",
		.parent_name = "hfclk",
		.ops = &sifive_fu540_prci_wrpll_clk_ops,
		.pwd = &__prci_corepll_data,
	},
	[PRCI_CLK_DDRPLL] = {
		.name = "ddrpll",
		.parent_name = "hfclk",
		.ops = &sifive_fu540_prci_wrpll_clk_ops,
		.pwd = &__prci_ddrpll_data,
	},
	[PRCI_CLK_GEMGXLPLL] = {
		.name = "gemgxlpll",
		.parent_name = "hfclk",
		.ops = &sifive_fu540_prci_wrpll_clk_ops,
		.pwd = &__prci_gemgxlpll_data,
	},
	[PRCI_CLK_TLCLK] = {
		.name = "tlclk",
		.parent_name = "corepll",
		.ops = &sifive_fu540_prci_tlclksel_clk_ops,
	},
};

static ulong sifive_fu540_prci_parent_rate(struct __prci_clock *pc)
{
	ulong parent_rate;
	struct __prci_clock *p;

	if (strcmp(pc->parent_name, "corepll") == 0) {
		p = &__prci_init_clocks[PRCI_CLK_COREPLL];
		if (!p->pd || !p->ops->recalc_rate)
			return -ENXIO;

		return p->ops->recalc_rate(p, sifive_fu540_prci_parent_rate(p));
	}

	if (strcmp(pc->parent_name, "rtcclk") == 0)
		parent_rate = clk_get_rate(&pc->pd->parent_rtcclk);
	else
		parent_rate = clk_get_rate(&pc->pd->parent_hfclk);

	return parent_rate;
}

static ulong sifive_fu540_prci_get_rate(struct clk *clk)
{
	struct __prci_clock *pc;

	if (ARRAY_SIZE(__prci_init_clocks) <= clk->id)
		return -ENXIO;

	pc = &__prci_init_clocks[clk->id];
	if (!pc->pd || !pc->ops->recalc_rate)
		return -ENXIO;

	return pc->ops->recalc_rate(pc, sifive_fu540_prci_parent_rate(pc));
}

static ulong sifive_fu540_prci_set_rate(struct clk *clk, ulong rate)
{
	int err;
	struct __prci_clock *pc;

	if (ARRAY_SIZE(__prci_init_clocks) <= clk->id)
		return -ENXIO;

	pc = &__prci_init_clocks[clk->id];
	if (!pc->pd || !pc->ops->set_rate)
		return -ENXIO;

	err = pc->ops->set_rate(pc, rate, sifive_fu540_prci_parent_rate(pc));
	if (err)
		return err;

	return rate;
}

static int sifive_fu540_prci_enable(struct clk *clk)
{
	struct __prci_clock *pc;
	int ret = 0;

	if (ARRAY_SIZE(__prci_init_clocks) <= clk->id)
		return -ENXIO;

	pc = &__prci_init_clocks[clk->id];
	if (!pc->pd)
		return -ENXIO;

	if (pc->ops->enable_clk)
		ret = pc->ops->enable_clk(pc, 1);

	return ret;
}

static int sifive_fu540_prci_disable(struct clk *clk)
{
	struct __prci_clock *pc;
	int ret = 0;

	if (ARRAY_SIZE(__prci_init_clocks) <= clk->id)
		return -ENXIO;

	pc = &__prci_init_clocks[clk->id];
	if (!pc->pd)
		return -ENXIO;

	if (pc->ops->enable_clk)
		ret = pc->ops->enable_clk(pc, 0);

	return ret;
}

static int sifive_fu540_prci_probe(struct udevice *dev)
{
	int i, err;
	struct __prci_clock *pc;
	struct __prci_data *pd = dev_get_priv(dev);

	pd->va = (void *)dev_read_addr(dev);
	if (IS_ERR(pd->va))
		return PTR_ERR(pd->va);

	err = clk_get_by_index(dev, 0, &pd->parent_hfclk);
	if (err)
		return err;

	err = clk_get_by_index(dev, 1, &pd->parent_rtcclk);
	if (err)
		return err;

	for (i = 0; i < ARRAY_SIZE(__prci_init_clocks); ++i) {
		pc = &__prci_init_clocks[i];
		pc->pd = pd;
		if (pc->pwd)
			__prci_wrpll_read_cfg0(pd, pc->pwd);
	}

	return 0;
}

static struct clk_ops sifive_fu540_prci_ops = {
	.set_rate = sifive_fu540_prci_set_rate,
	.get_rate = sifive_fu540_prci_get_rate,
	.enable = sifive_fu540_prci_enable,
	.disable = sifive_fu540_prci_disable,
};

static int sifive_fu540_clk_bind(struct udevice *dev)
{
	return sifive_reset_bind(dev, PRCI_DEVICERESETCNT);
}

static const struct udevice_id sifive_fu540_prci_ids[] = {
	{ .compatible = "sifive,fu540-c000-prci" },
	{ }
};

U_BOOT_DRIVER(sifive_fu540_prci) = {
	.name = "sifive-fu540-prci",
	.id = UCLASS_CLK,
	.of_match = sifive_fu540_prci_ids,
	.probe = sifive_fu540_prci_probe,
	.ops = &sifive_fu540_prci_ops,
	.priv_auto_alloc_size = sizeof(struct __prci_data),
	.bind = sifive_fu540_clk_bind,
};