/*
 * Synopsys HSDK SDP CGU clock driver
 *
 * Copyright (C) 2017 Synopsys
 * Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2. This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 */

#include <common.h>
#include <clk-uclass.h>
#include <div64.h>
#include <dm.h>
#include <linux/io.h>

/*
 * Synopsys ARC HSDK clock tree.
 *
 *   ------------------
 *   | 33.33 MHz xtal |
 *   ------------------
 *            |
 *            |   -----------
 *            |-->| ARC PLL |
 *            |   -----------
 *            |        |
 *            |        |-->|CGU_ARC_IDIV|----------->
 *            |        |-->|CREG_CORE_IF_DIV|------->
 *            |
 *            |   --------------
 *            |-->| SYSTEM PLL |
 *            |   --------------
 *            |        |
 *            |        |-->|CGU_SYS_IDIV_APB|------->
 *            |        |-->|CGU_SYS_IDIV_AXI|------->
 *            |        |-->|CGU_SYS_IDIV_*|--------->
 *            |        |-->|CGU_SYS_IDIV_EBI_REF|--->
 *            |
 *            |   --------------
 *            |-->| TUNNEL PLL |
 *            |   --------------
 *            |        |
 *            |        |-->|CGU_TUN_IDIV|----------->
 *            |
 *            |   ------------
 *            |-->| HDMI PLL |
 *            |   ------------
 *            |        |
 *            |        |-->|CGU_HDMI_IDIV_APB|------>
 *            |
 *            |   -----------
 *            |-->| DDR PLL |
 *                -----------
 *                     |
 *                     |---------------------------->
 */

DECLARE_GLOBAL_DATA_PTR;

#define CGU_ARC_IDIV		0x080
#define CGU_TUN_IDIV		0x380
#define CGU_HDMI_IDIV_APB	0x480
#define CGU_SYS_IDIV_APB	0x180
#define CGU_SYS_IDIV_AXI	0x190
#define CGU_SYS_IDIV_ETH	0x1A0
#define CGU_SYS_IDIV_USB	0x1B0
#define CGU_SYS_IDIV_SDIO	0x1C0
#define CGU_SYS_IDIV_HDMI	0x1D0
#define CGU_SYS_IDIV_GFX_CORE	0x1E0
#define CGU_SYS_IDIV_GFX_DMA	0x1F0
#define CGU_SYS_IDIV_GFX_CFG	0x200
#define CGU_SYS_IDIV_DMAC_CORE	0x210
#define CGU_SYS_IDIV_DMAC_CFG	0x220
#define CGU_SYS_IDIV_SDIO_REF	0x230
#define CGU_SYS_IDIV_SPI_REF	0x240
#define CGU_SYS_IDIV_I2C_REF	0x250
#define CGU_SYS_IDIV_UART_REF	0x260
#define CGU_SYS_IDIV_EBI_REF	0x270

#define CGU_IDIV_MASK		0xFF /* All idiv have 8 significant bits */

#define CGU_ARC_PLL		0x0
#define CGU_SYS_PLL		0x10
#define CGU_DDR_PLL		0x20
#define CGU_TUN_PLL		0x30
#define CGU_HDMI_PLL		0x40

#define CGU_PLL_CTRL		0x000 /* ARC PLL control register */
#define CGU_PLL_STATUS		0x004 /* ARC PLL status register */
#define CGU_PLL_FMEAS		0x008 /* ARC PLL frequency measurement register */
#define CGU_PLL_MON		0x00C /* ARC PLL monitor register */

#define CGU_PLL_CTRL_ODIV_SHIFT		2
#define CGU_PLL_CTRL_IDIV_SHIFT		4
#define CGU_PLL_CTRL_FBDIV_SHIFT	9
#define CGU_PLL_CTRL_BAND_SHIFT		20

#define CGU_PLL_CTRL_ODIV_MASK		GENMASK(3, CGU_PLL_CTRL_ODIV_SHIFT)
#define CGU_PLL_CTRL_IDIV_MASK		GENMASK(8, CGU_PLL_CTRL_IDIV_SHIFT)
#define CGU_PLL_CTRL_FBDIV_MASK		GENMASK(15, CGU_PLL_CTRL_FBDIV_SHIFT)

#define CGU_PLL_CTRL_PD			BIT(0)
#define CGU_PLL_CTRL_BYPASS		BIT(1)

#define CGU_PLL_STATUS_LOCK		BIT(0)
#define CGU_PLL_STATUS_ERR		BIT(1)

#define HSDK_PLL_MAX_LOCK_TIME		100 /* 100 us */

#define CREG_CORE_IF_DIV		0x000 /* ARC CORE interface divider */
#define CORE_IF_CLK_THRESHOLD_HZ	500000000
#define CREG_CORE_IF_CLK_DIV_1		0x0
#define CREG_CORE_IF_CLK_DIV_2		0x1

#define PARENT_RATE			33333333 /* fixed clock - xtal */
#define CGU_MAX_CLOCKS			24

struct hsdk_pll_cfg {
	u32 rate;
	u32 idiv;
	u32 fbdiv;
	u32 odiv;
	u32 band;
};

static const struct hsdk_pll_cfg asdt_pll_cfg[] = {
	{ 100000000,  0, 11, 3, 0 },
	{ 125000000,  0, 14, 3, 0 },
	{ 133000000,  0, 15, 3, 0 },
	{ 150000000,  0, 17, 3, 0 },
	{ 200000000,  1, 47, 3, 0 },
	{ 233000000,  1, 27, 2, 0 },
	{ 300000000,  1, 35, 2, 0 },
	{ 333000000,  1, 39, 2, 0 },
	{ 400000000,  1, 47, 2, 0 },
	{ 500000000,  0, 14, 1, 0 },
	{ 600000000,  0, 17, 1, 0 },
	{ 700000000,  0, 20, 1, 0 },
	{ 800000000,  0, 23, 1, 0 },
	{ 900000000,  1, 26, 0, 0 },
	{ 1000000000, 1, 29, 0, 0 },
	{ 1100000000, 1, 32, 0, 0 },
	{ 1200000000, 1, 35, 0, 0 },
	{ 1300000000, 1, 38, 0, 0 },
	{ 1400000000, 1, 41, 0, 0 },
	{ 1500000000, 1, 44, 0, 0 },
	{ 1600000000, 1, 47, 0, 0 },
	{}
};

static const struct hsdk_pll_cfg hdmi_pll_cfg[] = {
	{ 297000000,  0, 21, 2, 0 },
	{ 540000000,  0, 19, 1, 0 },
	{ 594000000,  0, 21, 1, 0 },
	{}
};

struct hsdk_cgu_clk {
	/* CGU block register */
	void __iomem *cgu_regs;
	/* CREG block register */
	void __iomem *creg_regs;

	/* PLLs registers */
	void __iomem *regs;
	/* PLLs special registers */
	void __iomem *spec_regs;
	/* PLLs devdata */
	const struct hsdk_pll_devdata *pll_devdata;

	/* Dividers registers */
	void __iomem *idiv_regs;
};

struct hsdk_pll_devdata {
	const struct hsdk_pll_cfg *pll_cfg;
	int (*update_rate)(struct hsdk_cgu_clk *clk, unsigned long rate,
			   const struct hsdk_pll_cfg *cfg);
};

static int hsdk_pll_core_update_rate(struct hsdk_cgu_clk *, unsigned long,
				     const struct hsdk_pll_cfg *);
static int hsdk_pll_comm_update_rate(struct hsdk_cgu_clk *, unsigned long,
				     const struct hsdk_pll_cfg *);

static const struct hsdk_pll_devdata core_pll_dat = {
	.pll_cfg = asdt_pll_cfg,
	.update_rate = hsdk_pll_core_update_rate,
};

static const struct hsdk_pll_devdata sdt_pll_dat = {
	.pll_cfg = asdt_pll_cfg,
	.update_rate = hsdk_pll_comm_update_rate,
};

static const struct hsdk_pll_devdata hdmi_pll_dat = {
	.pll_cfg = hdmi_pll_cfg,
	.update_rate = hsdk_pll_comm_update_rate,
};

static ulong idiv_set(struct clk *, ulong);
static ulong idiv_get(struct clk *);
static int idiv_off(struct clk *);
static ulong pll_set(struct clk *, ulong);
static ulong pll_get(struct clk *);

struct hsdk_cgu_clock_map {
	u32 cgu_pll_oft;
	u32 creg_div_oft;
	u32 cgu_div_oft;
	const struct hsdk_pll_devdata *pll_devdata;
	ulong (*get_rate)(struct clk *clk);
	ulong (*set_rate)(struct clk *clk, ulong rate);
	int (*disable)(struct clk *clk);
};

static const struct hsdk_cgu_clock_map clock_map[] = {
	{ CGU_ARC_PLL, 0, 0, &core_pll_dat, pll_get, pll_set, NULL },
	{ CGU_ARC_PLL, 0, CGU_ARC_IDIV, &core_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_DDR_PLL, 0, 0, &sdt_pll_dat, pll_get, pll_set, NULL },
	{ CGU_SYS_PLL, 0, 0, &sdt_pll_dat, pll_get, pll_set, NULL },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_APB, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_AXI, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_ETH, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_USB, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_SDIO, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_HDMI, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_GFX_CORE, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_GFX_DMA, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_GFX_CFG, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_DMAC_CORE, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_DMAC_CFG, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_SDIO_REF, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_SPI_REF, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_I2C_REF, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_UART_REF, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_SYS_PLL, 0, CGU_SYS_IDIV_EBI_REF, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_TUN_PLL, 0, 0, &sdt_pll_dat, pll_get, pll_set, NULL },
	{ CGU_TUN_PLL, 0, CGU_TUN_IDIV, &sdt_pll_dat, idiv_get, idiv_set, idiv_off },
	{ CGU_HDMI_PLL, 0, 0, &hdmi_pll_dat, pll_get, pll_set, NULL },
	{ CGU_HDMI_PLL, 0, CGU_HDMI_IDIV_APB, &hdmi_pll_dat, idiv_get, idiv_set, idiv_off }
};

static inline void hsdk_idiv_write(struct hsdk_cgu_clk *clk, u32 val)
{
	iowrite32(val, clk->idiv_regs);
}

static inline u32 hsdk_idiv_read(struct hsdk_cgu_clk *clk)
{
	return ioread32(clk->idiv_regs);
}

static inline void hsdk_pll_write(struct hsdk_cgu_clk *clk, u32 reg, u32 val)
{
	iowrite32(val, clk->regs + reg);
}

static inline u32 hsdk_pll_read(struct hsdk_cgu_clk *clk, u32 reg)
{
	return ioread32(clk->regs + reg);
}

static inline void hsdk_pll_spcwrite(struct hsdk_cgu_clk *clk, u32 reg, u32 val)
{
	iowrite32(val, clk->spec_regs + reg);
}

static inline u32 hsdk_pll_spcread(struct hsdk_cgu_clk *clk, u32 reg)
{
	return ioread32(clk->spec_regs + reg);
}

static inline void hsdk_pll_set_cfg(struct hsdk_cgu_clk *clk,
				    const struct hsdk_pll_cfg *cfg)
{
	u32 val = 0;

	/* Powerdown and Bypass bits should be cleared */
	val |= cfg->idiv << CGU_PLL_CTRL_IDIV_SHIFT;
	val |= cfg->fbdiv << CGU_PLL_CTRL_FBDIV_SHIFT;
	val |= cfg->odiv << CGU_PLL_CTRL_ODIV_SHIFT;
	val |= cfg->band << CGU_PLL_CTRL_BAND_SHIFT;

	pr_debug("write configurarion: %#x\n", val);

	hsdk_pll_write(clk, CGU_PLL_CTRL, val);
}

static inline bool hsdk_pll_is_locked(struct hsdk_cgu_clk *clk)
{
	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_LOCK);
}

static inline bool hsdk_pll_is_err(struct hsdk_cgu_clk *clk)
{
	return !!(hsdk_pll_read(clk, CGU_PLL_STATUS) & CGU_PLL_STATUS_ERR);
}

static ulong pll_get(struct clk *sclk)
{
	u32 val;
	u64 rate;
	u32 idiv, fbdiv, odiv;
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);

	val = hsdk_pll_read(clk, CGU_PLL_CTRL);

	pr_debug("current configurarion: %#x\n", val);

	/* Check if PLL is disabled */
	if (val & CGU_PLL_CTRL_PD)
		return 0;

	/* Check if PLL is bypassed */
	if (val & CGU_PLL_CTRL_BYPASS)
		return PARENT_RATE;

	/* input divider = reg.idiv + 1 */
	idiv = 1 + ((val & CGU_PLL_CTRL_IDIV_MASK) >> CGU_PLL_CTRL_IDIV_SHIFT);
	/* fb divider = 2*(reg.fbdiv + 1) */
	fbdiv = 2 * (1 + ((val & CGU_PLL_CTRL_FBDIV_MASK) >> CGU_PLL_CTRL_FBDIV_SHIFT));
	/* output divider = 2^(reg.odiv) */
	odiv = 1 << ((val & CGU_PLL_CTRL_ODIV_MASK) >> CGU_PLL_CTRL_ODIV_SHIFT);

	rate = (u64)PARENT_RATE * fbdiv;
	do_div(rate, idiv * odiv);

	return rate;
}

static unsigned long hsdk_pll_round_rate(struct clk *sclk, unsigned long rate)
{
	int i;
	unsigned long best_rate;
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);
	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;

	if (pll_cfg[0].rate == 0)
		return -EINVAL;

	best_rate = pll_cfg[0].rate;

	for (i = 1; pll_cfg[i].rate != 0; i++) {
		if (abs(rate - pll_cfg[i].rate) < abs(rate - best_rate))
			best_rate = pll_cfg[i].rate;
	}

	pr_debug("chosen best rate: %lu\n", best_rate);

	return best_rate;
}

static int hsdk_pll_comm_update_rate(struct hsdk_cgu_clk *clk,
				     unsigned long rate,
				     const struct hsdk_pll_cfg *cfg)
{
	hsdk_pll_set_cfg(clk, cfg);

	/*
	 * Wait until CGU relocks and check error status.
	 * If after timeout CGU is unlocked yet return error.
	 */
	udelay(HSDK_PLL_MAX_LOCK_TIME);
	if (!hsdk_pll_is_locked(clk))
		return -ETIMEDOUT;

	if (hsdk_pll_is_err(clk))
		return -EINVAL;

	return 0;
}

static int hsdk_pll_core_update_rate(struct hsdk_cgu_clk *clk,
				     unsigned long rate,
				     const struct hsdk_pll_cfg *cfg)
{
	/*
	 * When core clock exceeds 500MHz, the divider for the interface
	 * clock must be programmed to div-by-2.
	 */
	if (rate > CORE_IF_CLK_THRESHOLD_HZ)
		hsdk_pll_spcwrite(clk, CREG_CORE_IF_DIV, CREG_CORE_IF_CLK_DIV_2);

	hsdk_pll_set_cfg(clk, cfg);

	/*
	 * Wait until CGU relocks and check error status.
	 * If after timeout CGU is unlocked yet return error.
	 */
	udelay(HSDK_PLL_MAX_LOCK_TIME);
	if (!hsdk_pll_is_locked(clk))
		return -ETIMEDOUT;

	if (hsdk_pll_is_err(clk))
		return -EINVAL;

	/*
	 * Program divider to div-by-1 if we succesfuly set core clock below
	 * 500MHz threshold.
	 */
	if (rate <= CORE_IF_CLK_THRESHOLD_HZ)
		hsdk_pll_spcwrite(clk, CREG_CORE_IF_DIV, CREG_CORE_IF_CLK_DIV_1);

	return 0;
}

static ulong pll_set(struct clk *sclk, ulong rate)
{
	int i;
	unsigned long best_rate;
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);
	const struct hsdk_pll_cfg *pll_cfg = clk->pll_devdata->pll_cfg;

	best_rate = hsdk_pll_round_rate(sclk, rate);

	for (i = 0; pll_cfg[i].rate != 0; i++) {
		if (pll_cfg[i].rate == best_rate) {
			return clk->pll_devdata->update_rate(clk, best_rate,
							     &pll_cfg[i]);
		}
	}

	pr_err("invalid rate=%ld, parent_rate=%d\n", best_rate, PARENT_RATE);

	return -EINVAL;
}

static int idiv_off(struct clk *sclk)
{
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);

	hsdk_idiv_write(clk, 0);

	return 0;
}

static ulong idiv_get(struct clk *sclk)
{
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);
	ulong parent_rate = pll_get(sclk);
	u32 div_factor = hsdk_idiv_read(clk);

	div_factor &= CGU_IDIV_MASK;

	pr_debug("current configurarion: %#x (%d)\n", div_factor, div_factor);

	if (div_factor == 0)
		return 0;

	return parent_rate / div_factor;
}

static ulong idiv_set(struct clk *sclk, ulong rate)
{
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);
	ulong parent_rate = pll_get(sclk);
	u32 div_factor;

	div_factor = parent_rate / rate;
	if (abs(rate - parent_rate / (div_factor + 1)) <=
	    abs(rate - parent_rate / div_factor)) {
		div_factor += 1;
	}

	if (div_factor & ~CGU_IDIV_MASK) {
		pr_err("invalid rate=%ld, parent_rate=%ld, div=%d: max divider valie is%d\n",
		       rate, parent_rate, div_factor, CGU_IDIV_MASK);

		div_factor = CGU_IDIV_MASK;
	}

	if (div_factor == 0) {
		pr_err("invalid rate=%ld, parent_rate=%ld, div=%d: min divider valie is 1\n",
		       rate, parent_rate, div_factor);

		div_factor = 1;
	}

	hsdk_idiv_write(clk, div_factor);

	return 0;
}

static int hsdk_prepare_clock_tree_branch(struct clk *sclk)
{
	struct hsdk_cgu_clk *clk = dev_get_priv(sclk->dev);

	if (sclk->id >= CGU_MAX_CLOCKS)
		return -EINVAL;

	clk->pll_devdata = clock_map[sclk->id].pll_devdata;
	clk->regs = clk->cgu_regs + clock_map[sclk->id].cgu_pll_oft;
	clk->spec_regs = clk->creg_regs + clock_map[sclk->id].creg_div_oft;
	clk->idiv_regs = clk->cgu_regs + clock_map[sclk->id].cgu_div_oft;

	return 0;
}

static ulong hsdk_cgu_get_rate(struct clk *sclk)
{
	if (hsdk_prepare_clock_tree_branch(sclk))
		return -EINVAL;

	return clock_map[sclk->id].get_rate(sclk);
}

static ulong hsdk_cgu_set_rate(struct clk *sclk, ulong rate)
{
	if (hsdk_prepare_clock_tree_branch(sclk))
		return -EINVAL;

	return clock_map[sclk->id].set_rate(sclk, rate);
}

static int hsdk_cgu_disable(struct clk *sclk)
{
	if (hsdk_prepare_clock_tree_branch(sclk))
		return -EINVAL;

	if (clock_map[sclk->id].disable)
		return clock_map[sclk->id].disable(sclk);

	return -ENOTSUPP;
}

static const struct clk_ops hsdk_cgu_ops = {
	.set_rate = hsdk_cgu_set_rate,
	.get_rate = hsdk_cgu_get_rate,
	.disable = hsdk_cgu_disable,
};

static int hsdk_cgu_clk_probe(struct udevice *dev)
{
	struct hsdk_cgu_clk *pll_clk = dev_get_priv(dev);

	BUILD_BUG_ON(ARRAY_SIZE(clock_map) != CGU_MAX_CLOCKS);

	pll_clk->cgu_regs = (void __iomem *)devfdt_get_addr_index(dev, 0);
	if (!pll_clk->cgu_regs)
		return -EINVAL;

	pll_clk->creg_regs = (void __iomem *)devfdt_get_addr_index(dev, 1);
	if (!pll_clk->creg_regs)
		return -EINVAL;

	return 0;
}

static const struct udevice_id hsdk_cgu_clk_id[] = {
	{ .compatible = "snps,hsdk-cgu-clock" },
	{ }
};

U_BOOT_DRIVER(hsdk_cgu_clk) = {
	.name = "hsdk-cgu-clk",
	.id = UCLASS_CLK,
	.of_match = hsdk_cgu_clk_id,
	.probe = hsdk_cgu_clk_probe,
	.platdata_auto_alloc_size = sizeof(struct hsdk_cgu_clk),
	.ops = &hsdk_cgu_ops,
};