drivers/clk/aspeed/clk_ast2500.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0
 /*
  * (C) Copyright 2016 Google, Inc
  */

 #include <common.h>
 #include <clk-uclass.h>
 #include <dm.h>
 #include <asm/io.h>
 #include <asm/arch/scu_ast2500.h>
 #include <dm/lists.h>
 #include <dt-bindings/clock/ast2500-scu.h>

 /*
  * MAC Clock Delay settings, taken from Aspeed SDK
  */
 #define RGMII_TXCLK_ODLY		8
 #define RMII_RXCLK_IDLY		2

 /*
  * TGMII Clock Duty constants, taken from Aspeed SDK
  */
 #define RGMII2_TXCK_DUTY	0x66
 #define RGMII1_TXCK_DUTY	0x64

 #define D2PLL_DEFAULT_RATE	(250 * 1000 * 1000)

 DECLARE_GLOBAL_DATA_PTR;

 /*
  * Clock divider/multiplier configuration struct.
  * For H-PLL and M-PLL the formula is
  * (Output Frequency) = CLKIN * ((M + 1) / (N + 1)) / (P + 1)
  * M - Numerator
  * N - Denumerator
  * P - Post Divider
  * They have the same layout in their control register.
  *
  * D-PLL and D2-PLL have extra divider (OD + 1), which is not
  * yet needed and ignored by clock configurations.
  */
 struct ast2500_div_config {
 	unsigned int num;
 	unsigned int denum;
 	unsigned int post_div;
 };

 /*
  * Get the rate of the M-PLL clock from input clock frequency and
  * the value of the M-PLL Parameter Register.
  */
 static ulong ast2500_get_mpll_rate(ulong clkin, u32 mpll_reg)
 {
 	const ulong num = (mpll_reg & SCU_MPLL_NUM_MASK) >> SCU_MPLL_NUM_SHIFT;
 	const ulong denum = (mpll_reg & SCU_MPLL_DENUM_MASK)
 			>> SCU_MPLL_DENUM_SHIFT;
 	const ulong post_div = (mpll_reg & SCU_MPLL_POST_MASK)
 			>> SCU_MPLL_POST_SHIFT;

 	return (clkin * ((num + 1) / (denum + 1))) / (post_div + 1);
 }

 /*
  * Get the rate of the H-PLL clock from input clock frequency and
  * the value of the H-PLL Parameter Register.
  */
 static ulong ast2500_get_hpll_rate(ulong clkin, u32 hpll_reg)
 {
 	const ulong num = (hpll_reg & SCU_HPLL_NUM_MASK) >> SCU_HPLL_NUM_SHIFT;
 	const ulong denum = (hpll_reg & SCU_HPLL_DENUM_MASK)
 			>> SCU_HPLL_DENUM_SHIFT;
 	const ulong post_div = (hpll_reg & SCU_HPLL_POST_MASK)
 			>> SCU_HPLL_POST_SHIFT;

 	return (clkin * ((num + 1) / (denum + 1))) / (post_div + 1);
 }

 static ulong ast2500_get_clkin(struct ast2500_scu *scu)
 {
 	return readl(&scu->hwstrap) & SCU_HWSTRAP_CLKIN_25MHZ
 			? 25 * 1000 * 1000 : 24 * 1000 * 1000;
 }

 /**
  * Get current rate or uart clock
  *
  * @scu SCU registers
  * @uart_index UART index, 1-5
  *
  * @return current setting for uart clock rate
  */
 static ulong ast2500_get_uart_clk_rate(struct ast2500_scu *scu, int uart_index)
 {
 	/*
 	 * ast2500 datasheet is very confusing when it comes to UART clocks,
 	 * especially when CLKIN = 25 MHz. The settings are in
 	 * different registers and it is unclear how they interact.
 	 *
 	 * This has only been tested with default settings and CLKIN = 24 MHz.
 	 */
 	ulong uart_clkin;

 	if (readl(&scu->misc_ctrl2) &
 	    (1 << (uart_index - 1 + SCU_MISC2_UARTCLK_SHIFT)))
 		uart_clkin = 192 * 1000 * 1000;
 	else
 		uart_clkin = 24 * 1000 * 1000;

 	if (readl(&scu->misc_ctrl1) & SCU_MISC_UARTCLK_DIV13)
 		uart_clkin /= 13;

 	return uart_clkin;
 }

 static ulong ast2500_clk_get_rate(struct clk *clk)
 {
 	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);
 	ulong clkin = ast2500_get_clkin(priv->scu);
 	ulong rate;

 	switch (clk->id) {
 	case PLL_HPLL:
 	case ARMCLK:
 		/*
 		 * This ignores dynamic/static slowdown of ARMCLK and may
 		 * be inaccurate.
 		 */
 		rate = ast2500_get_hpll_rate(clkin,
 					     readl(&priv->scu->h_pll_param));
 		break;
 	case MCLK_DDR:
 		rate = ast2500_get_mpll_rate(clkin,
 					     readl(&priv->scu->m_pll_param));
 		break;
 	case BCLK_PCLK:
 		{
 			ulong apb_div = 4 + 4 * ((readl(&priv->scu->clk_sel1)
 						  & SCU_PCLK_DIV_MASK)
 						 >> SCU_PCLK_DIV_SHIFT);
 			rate = ast2500_get_hpll_rate(clkin,
 						     readl(&priv->
 							   scu->h_pll_param));
 			rate = rate / apb_div;
 		}
 		break;
 	case BCLK_SDCLK:
 		{
 			ulong apb_div = 4 + 4 * ((readl(&priv->scu->clk_sel1)
 						  & SCU_SDCLK_DIV_MASK)
 						 >> SCU_SDCLK_DIV_SHIFT);
 			rate = ast2500_get_hpll_rate(clkin,
 						     readl(&priv->
 							   scu->h_pll_param));
 			rate = rate / apb_div;
 		}
 		break;
 	case PCLK_UART1:
 		rate = ast2500_get_uart_clk_rate(priv->scu, 1);
 		break;
 	case PCLK_UART2:
 		rate = ast2500_get_uart_clk_rate(priv->scu, 2);
 		break;
 	case PCLK_UART3:
 		rate = ast2500_get_uart_clk_rate(priv->scu, 3);
 		break;
 	case PCLK_UART4:
 		rate = ast2500_get_uart_clk_rate(priv->scu, 4);
 		break;
 	case PCLK_UART5:
 		rate = ast2500_get_uart_clk_rate(priv->scu, 5);
 		break;
 	default:
 		return -ENOENT;
 	}

 	return rate;
 }

 struct ast2500_clock_config {
 	ulong input_rate;
 	ulong rate;
 	struct ast2500_div_config cfg;
 };

 static const struct ast2500_clock_config ast2500_clock_config_defaults[] = {
 	{ 24000000, 250000000, { .num = 124, .denum = 1, .post_div = 5 } },
 };

 static bool ast2500_get_clock_config_default(ulong input_rate,
 					     ulong requested_rate,
 					     struct ast2500_div_config *cfg)
 {
 	int i;

 	for (i = 0; i < ARRAY_SIZE(ast2500_clock_config_defaults); i++) {
 		const struct ast2500_clock_config *default_cfg =
 			&ast2500_clock_config_defaults[i];
 		if (default_cfg->input_rate == input_rate &&
 		    default_cfg->rate == requested_rate) {
 			*cfg = default_cfg->cfg;
 			return true;
 		}
 	}

 	return false;
 }

 /*
  * @input_rate - the rate of input clock in Hz
  * @requested_rate - desired output rate in Hz
  * @div - this is an IN/OUT parameter, at input all fields of the config
  * need to be set to their maximum allowed values.
  * The result (the best config we could find), would also be returned
  * in this structure.
  *
  * @return The clock rate, when the resulting div_config is used.
  */
 static ulong ast2500_calc_clock_config(ulong input_rate, ulong requested_rate,
 				       struct ast2500_div_config *cfg)
 {
 	/*
 	 * The assumption is that kHz precision is good enough and
 	 * also enough to avoid overflow when multiplying.
 	 */
 	const ulong input_rate_khz = input_rate / 1000;
 	const ulong rate_khz = requested_rate / 1000;
 	const struct ast2500_div_config max_vals = *cfg;
 	struct ast2500_div_config it = { 0, 0, 0 };
 	ulong delta = rate_khz;
 	ulong new_rate_khz = 0;

 	/*
 	 * Look for a well known frequency first.
 	 */
 	if (ast2500_get_clock_config_default(input_rate, requested_rate, cfg))
 		return requested_rate;

 	for (; it.denum <= max_vals.denum; ++it.denum) {
 		for (it.post_div = 0; it.post_div <= max_vals.post_div;
 		     ++it.post_div) {
 			it.num = (rate_khz * (it.post_div + 1) / input_rate_khz)
 			    * (it.denum + 1);
 			if (it.num > max_vals.num)
 				continue;

 			new_rate_khz = (input_rate_khz
 					* ((it.num + 1) / (it.denum + 1)))
 			    / (it.post_div + 1);

 			/* Keep the rate below requested one. */
 			if (new_rate_khz > rate_khz)
 				continue;

 			if (new_rate_khz - rate_khz < delta) {
 				delta = new_rate_khz - rate_khz;
 				*cfg = it;
 				if (delta == 0)
 					return new_rate_khz * 1000;
 			}
 		}
 	}

 	return new_rate_khz * 1000;
 }

 static ulong ast2500_configure_ddr(struct ast2500_scu *scu, ulong rate)
 {
 	ulong clkin = ast2500_get_clkin(scu);
 	u32 mpll_reg;
 	struct ast2500_div_config div_cfg = {
 		.num = (SCU_MPLL_NUM_MASK >> SCU_MPLL_NUM_SHIFT),
 		.denum = (SCU_MPLL_DENUM_MASK >> SCU_MPLL_DENUM_SHIFT),
 		.post_div = (SCU_MPLL_POST_MASK >> SCU_MPLL_POST_SHIFT),
 	};

 	ast2500_calc_clock_config(clkin, rate, &div_cfg);

 	mpll_reg = readl(&scu->m_pll_param);
 	mpll_reg &= ~(SCU_MPLL_POST_MASK | SCU_MPLL_NUM_MASK
 		      | SCU_MPLL_DENUM_MASK);
 	mpll_reg |= (div_cfg.post_div << SCU_MPLL_POST_SHIFT)
 	    | (div_cfg.num << SCU_MPLL_NUM_SHIFT)
 	    | (div_cfg.denum << SCU_MPLL_DENUM_SHIFT);

 	ast_scu_unlock(scu);
 	writel(mpll_reg, &scu->m_pll_param);
 	ast_scu_lock(scu);

 	return ast2500_get_mpll_rate(clkin, mpll_reg);
 }

 static ulong ast2500_configure_mac(struct ast2500_scu *scu, int index)
 {
 	ulong clkin = ast2500_get_clkin(scu);
 	ulong hpll_rate = ast2500_get_hpll_rate(clkin,
 						readl(&scu->h_pll_param));
 	ulong required_rate;
 	u32 hwstrap;
 	u32 divisor;
 	u32 reset_bit;
 	u32 clkstop_bit;

 	/*
 	 * According to data sheet, for 10/100 mode the MAC clock frequency
 	 * should be at least 25MHz and for 1000 mode at least 100MHz
 	 */
 	hwstrap = readl(&scu->hwstrap);
 	if (hwstrap & (SCU_HWSTRAP_MAC1_RGMII | SCU_HWSTRAP_MAC2_RGMII))
 		required_rate = 100 * 1000 * 1000;
 	else
 		required_rate = 25 * 1000 * 1000;

 	divisor = hpll_rate / required_rate;

 	if (divisor < 4) {
 		/* Clock can't run fast enough, but let's try anyway */
 		debug("MAC clock too slow\n");
 		divisor = 4;
 	} else if (divisor > 16) {
 		/* Can't slow down the clock enough, but let's try anyway */
 		debug("MAC clock too fast\n");
 		divisor = 16;
 	}

 	switch (index) {
 	case 1:
 		reset_bit = SCU_SYSRESET_MAC1;
 		clkstop_bit = SCU_CLKSTOP_MAC1;
 		break;
 	case 2:
 		reset_bit = SCU_SYSRESET_MAC2;
 		clkstop_bit = SCU_CLKSTOP_MAC2;
 		break;
 	default:
 		return -EINVAL;
 	}

 	ast_scu_unlock(scu);
 	clrsetbits_le32(&scu->clk_sel1, SCU_MACCLK_MASK,
 			((divisor - 2) / 2) << SCU_MACCLK_SHIFT);

 	/*
 	 * Disable MAC, start its clock and re-enable it.
 	 * The procedure and the delays (100us & 10ms) are
 	 * specified in the datasheet.
 	 */
 	setbits_le32(&scu->sysreset_ctrl1, reset_bit);
 	udelay(100);
 	clrbits_le32(&scu->clk_stop_ctrl1, clkstop_bit);
 	mdelay(10);
 	clrbits_le32(&scu->sysreset_ctrl1, reset_bit);

 	writel((RGMII2_TXCK_DUTY << SCU_CLKDUTY_RGMII2TXCK_SHIFT)
 	       | (RGMII1_TXCK_DUTY << SCU_CLKDUTY_RGMII1TXCK_SHIFT),
 	       &scu->clk_duty_sel);

 	ast_scu_lock(scu);

 	return required_rate;
 }

 static ulong ast2500_configure_d2pll(struct ast2500_scu *scu, ulong rate)
 {
 	/*
 	 * The values and the meaning of the next three
 	 * parameters are undocumented. Taken from Aspeed SDK.
 	 *
 	 * TODO(clg@kaod.org): the SIP and SIC values depend on the
 	 * Numerator value
 	 */
 	const u32 d2_pll_ext_param = 0x2c;
 	const u32 d2_pll_sip = 0x11;
 	const u32 d2_pll_sic = 0x18;
 	u32 clk_delay_settings =
 	    (RMII_RXCLK_IDLY << SCU_MICDS_MAC1RMII_RDLY_SHIFT)
 	    | (RMII_RXCLK_IDLY << SCU_MICDS_MAC2RMII_RDLY_SHIFT)
 	    | (RGMII_TXCLK_ODLY << SCU_MICDS_MAC1RGMII_TXDLY_SHIFT)
 	    | (RGMII_TXCLK_ODLY << SCU_MICDS_MAC2RGMII_TXDLY_SHIFT);
 	struct ast2500_div_config div_cfg = {
 		.num = SCU_D2PLL_NUM_MASK >> SCU_D2PLL_NUM_SHIFT,
 		.denum = SCU_D2PLL_DENUM_MASK >> SCU_D2PLL_DENUM_SHIFT,
 		.post_div = SCU_D2PLL_POST_MASK >> SCU_D2PLL_POST_SHIFT,
 	};
 	ulong clkin = ast2500_get_clkin(scu);
 	ulong new_rate;

 	ast_scu_unlock(scu);
 	writel((d2_pll_ext_param << SCU_D2PLL_EXT1_PARAM_SHIFT)
 	       | SCU_D2PLL_EXT1_OFF
 	       | SCU_D2PLL_EXT1_RESET, &scu->d2_pll_ext_param[0]);

 	/*
 	 * Select USB2.0 port1 PHY clock as a clock source for GCRT.
 	 * This would disconnect it from D2-PLL.
 	 */
 	clrsetbits_le32(&scu->misc_ctrl1, SCU_MISC_D2PLL_OFF,
 			SCU_MISC_GCRT_USB20CLK);

 	new_rate = ast2500_calc_clock_config(clkin, rate, &div_cfg);
 	writel((d2_pll_sip << SCU_D2PLL_SIP_SHIFT)
 	       | (d2_pll_sic << SCU_D2PLL_SIC_SHIFT)
 	       | (div_cfg.num << SCU_D2PLL_NUM_SHIFT)
 	       | (div_cfg.denum << SCU_D2PLL_DENUM_SHIFT)
 	       | (div_cfg.post_div << SCU_D2PLL_POST_SHIFT),
 	       &scu->d2_pll_param);

 	clrbits_le32(&scu->d2_pll_ext_param[0],
 		     SCU_D2PLL_EXT1_OFF | SCU_D2PLL_EXT1_RESET);

 	clrsetbits_le32(&scu->misc_ctrl2,
 			SCU_MISC2_RGMII_HPLL | SCU_MISC2_RMII_MPLL
 			| SCU_MISC2_RGMII_CLKDIV_MASK |
 			SCU_MISC2_RMII_CLKDIV_MASK,
 			(4 << SCU_MISC2_RMII_CLKDIV_SHIFT));

 	writel(clk_delay_settings | SCU_MICDS_RGMIIPLL, &scu->mac_clk_delay);
 	writel(clk_delay_settings, &scu->mac_clk_delay_100M);
 	writel(clk_delay_settings, &scu->mac_clk_delay_10M);

 	ast_scu_lock(scu);

 	return new_rate;
 }

 static ulong ast2500_clk_set_rate(struct clk *clk, ulong rate)
 {
 	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);

 	ulong new_rate;
 	switch (clk->id) {
 	case PLL_MPLL:
 	case MCLK_DDR:
 		new_rate = ast2500_configure_ddr(priv->scu, rate);
 		break;
 	case PLL_D2PLL:
 		new_rate = ast2500_configure_d2pll(priv->scu, rate);
 		break;
 	default:
 		return -ENOENT;
 	}

 	return new_rate;
 }

 static int ast2500_clk_enable(struct clk *clk)
 {
 	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);

 	switch (clk->id) {
 	case BCLK_SDCLK:
 		if (readl(&priv->scu->clk_stop_ctrl1) & SCU_CLKSTOP_SDCLK) {
 			ast_scu_unlock(priv->scu);

 			setbits_le32(&priv->scu->sysreset_ctrl1,
 				     SCU_SYSRESET_SDIO);
 			udelay(100);
 			clrbits_le32(&priv->scu->clk_stop_ctrl1,
 				     SCU_CLKSTOP_SDCLK);
 			mdelay(10);
 			clrbits_le32(&priv->scu->sysreset_ctrl1,
 				     SCU_SYSRESET_SDIO);

 			ast_scu_lock(priv->scu);
 		}
 		break;
 	/*
 	 * For MAC clocks the clock rate is
 	 * configured based on whether RGMII or RMII mode has been selected
 	 * through hardware strapping.
 	 */
 	case PCLK_MAC1:
 		ast2500_configure_mac(priv->scu, 1);
 		break;
 	case PCLK_MAC2:
 		ast2500_configure_mac(priv->scu, 2);
 		break;
 	case PLL_D2PLL:
 		ast2500_configure_d2pll(priv->scu, D2PLL_DEFAULT_RATE);
 		break;
 	default:
 		return -ENOENT;
 	}

 	return 0;
 }

 struct clk_ops ast2500_clk_ops = {
 	.get_rate = ast2500_clk_get_rate,
 	.set_rate = ast2500_clk_set_rate,
 	.enable = ast2500_clk_enable,
 };

 static int ast2500_clk_ofdata_to_platdata(struct udevice *dev)
 {
 	struct ast2500_clk_priv *priv = dev_get_priv(dev);

 	priv->scu = devfdt_get_addr_ptr(dev);
 	if (IS_ERR(priv->scu))
 		return PTR_ERR(priv->scu);

 	return 0;
 }

 static int ast2500_clk_bind(struct udevice *dev)
 {
 	int ret;

 	/* The reset driver does not have a device node, so bind it here */
 	ret = device_bind_driver(gd->dm_root, "ast_sysreset", "reset", &dev);
 	if (ret)
 		debug("Warning: No reset driver: ret=%d\n", ret);

 	return 0;
 }

 static const struct udevice_id ast2500_clk_ids[] = {
 	{ .compatible = "aspeed,ast2500-scu" },
 	{ }
 };

 U_BOOT_DRIVER(aspeed_ast2500_scu) = {
 	.name		= "aspeed_ast2500_scu",
 	.id		= UCLASS_CLK,
 	.of_match	= ast2500_clk_ids,
 	.priv_auto_alloc_size = sizeof(struct ast2500_clk_priv),
 	.ops		= &ast2500_clk_ops,
 	.bind		= ast2500_clk_bind,
 	.ofdata_to_platdata		= ast2500_clk_ofdata_to_platdata,
 };
	// SPDX-License-Identifier: GPL-2.0
	/*
	* (C) Copyright 2016 Google, Inc
	*/

	#include <common.h>
	#include <clk-uclass.h>
	#include <dm.h>
	#include <asm/io.h>
	#include <asm/arch/scu_ast2500.h>
	#include <dm/lists.h>
	#include <dt-bindings/clock/ast2500-scu.h>

	/*
	* MAC Clock Delay settings, taken from Aspeed SDK
	*/
	#define RGMII_TXCLK_ODLY 8
	#define RMII_RXCLK_IDLY 2

	/*
	* TGMII Clock Duty constants, taken from Aspeed SDK
	*/
	#define RGMII2_TXCK_DUTY 0x66
	#define RGMII1_TXCK_DUTY 0x64

	#define D2PLL_DEFAULT_RATE (250 * 1000 * 1000)

	DECLARE_GLOBAL_DATA_PTR;

	/*
	* Clock divider/multiplier configuration struct.
	* For H-PLL and M-PLL the formula is
	* (Output Frequency) = CLKIN * ((M + 1) / (N + 1)) / (P + 1)
	* M - Numerator
	* N - Denumerator
	* P - Post Divider
	* They have the same layout in their control register.
	*
	* D-PLL and D2-PLL have extra divider (OD + 1), which is not
	* yet needed and ignored by clock configurations.
	*/
	struct ast2500_div_config {
	unsigned int num;
	unsigned int denum;
	unsigned int post_div;
	};

	/*
	* Get the rate of the M-PLL clock from input clock frequency and
	* the value of the M-PLL Parameter Register.
	*/
	static ulong ast2500_get_mpll_rate(ulong clkin, u32 mpll_reg)
	{
	const ulong num = (mpll_reg & SCU_MPLL_NUM_MASK) >> SCU_MPLL_NUM_SHIFT;
	const ulong denum = (mpll_reg & SCU_MPLL_DENUM_MASK)
	>> SCU_MPLL_DENUM_SHIFT;
	const ulong post_div = (mpll_reg & SCU_MPLL_POST_MASK)
	>> SCU_MPLL_POST_SHIFT;

	return (clkin * ((num + 1) / (denum + 1))) / (post_div + 1);
	}

	/*
	* Get the rate of the H-PLL clock from input clock frequency and
	* the value of the H-PLL Parameter Register.
	*/
	static ulong ast2500_get_hpll_rate(ulong clkin, u32 hpll_reg)
	{
	const ulong num = (hpll_reg & SCU_HPLL_NUM_MASK) >> SCU_HPLL_NUM_SHIFT;
	const ulong denum = (hpll_reg & SCU_HPLL_DENUM_MASK)
	>> SCU_HPLL_DENUM_SHIFT;
	const ulong post_div = (hpll_reg & SCU_HPLL_POST_MASK)
	>> SCU_HPLL_POST_SHIFT;

	return (clkin * ((num + 1) / (denum + 1))) / (post_div + 1);
	}

	static ulong ast2500_get_clkin(struct ast2500_scu *scu)
	{
	return readl(&scu->hwstrap) & SCU_HWSTRAP_CLKIN_25MHZ
	? 25 * 1000 * 1000 : 24 * 1000 * 1000;
	}

	/**
	* Get current rate or uart clock
	*
	* @scu SCU registers
	* @uart_index UART index, 1-5
	*
	* @return current setting for uart clock rate
	*/
	static ulong ast2500_get_uart_clk_rate(struct ast2500_scu *scu, int uart_index)
	{
	/*
	* ast2500 datasheet is very confusing when it comes to UART clocks,
	* especially when CLKIN = 25 MHz. The settings are in
	* different registers and it is unclear how they interact.
	*
	* This has only been tested with default settings and CLKIN = 24 MHz.
	*/
	ulong uart_clkin;

	if (readl(&scu->misc_ctrl2) &
	(1 << (uart_index - 1 + SCU_MISC2_UARTCLK_SHIFT)))
	uart_clkin = 192 * 1000 * 1000;
	else
	uart_clkin = 24 * 1000 * 1000;

	if (readl(&scu->misc_ctrl1) & SCU_MISC_UARTCLK_DIV13)
	uart_clkin /= 13;

	return uart_clkin;
	}

	static ulong ast2500_clk_get_rate(struct clk *clk)
	{
	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);
	ulong clkin = ast2500_get_clkin(priv->scu);
	ulong rate;

	switch (clk->id) {
	case PLL_HPLL:
	case ARMCLK:
	/*
	* This ignores dynamic/static slowdown of ARMCLK and may
	* be inaccurate.
	*/
	rate = ast2500_get_hpll_rate(clkin,
	readl(&priv->scu->h_pll_param));
	break;
	case MCLK_DDR:
	rate = ast2500_get_mpll_rate(clkin,
	readl(&priv->scu->m_pll_param));
	break;
	case BCLK_PCLK:
	{
	ulong apb_div = 4 + 4 * ((readl(&priv->scu->clk_sel1)
	& SCU_PCLK_DIV_MASK)
	>> SCU_PCLK_DIV_SHIFT);
	rate = ast2500_get_hpll_rate(clkin,
	readl(&priv->
	scu->h_pll_param));
	rate = rate / apb_div;
	}
	break;
	case BCLK_SDCLK:
	{
	ulong apb_div = 4 + 4 * ((readl(&priv->scu->clk_sel1)
	& SCU_SDCLK_DIV_MASK)
	>> SCU_SDCLK_DIV_SHIFT);
	rate = ast2500_get_hpll_rate(clkin,
	readl(&priv->
	scu->h_pll_param));
	rate = rate / apb_div;
	}
	break;
	case PCLK_UART1:
	rate = ast2500_get_uart_clk_rate(priv->scu, 1);
	break;
	case PCLK_UART2:
	rate = ast2500_get_uart_clk_rate(priv->scu, 2);
	break;
	case PCLK_UART3:
	rate = ast2500_get_uart_clk_rate(priv->scu, 3);
	break;
	case PCLK_UART4:
	rate = ast2500_get_uart_clk_rate(priv->scu, 4);
	break;
	case PCLK_UART5:
	rate = ast2500_get_uart_clk_rate(priv->scu, 5);
	break;
	default:
	return -ENOENT;
	}

	return rate;
	}

	struct ast2500_clock_config {
	ulong input_rate;
	ulong rate;
	struct ast2500_div_config cfg;
	};

	static const struct ast2500_clock_config ast2500_clock_config_defaults[] = {
	{ 24000000, 250000000, { .num = 124, .denum = 1, .post_div = 5 } },
	};

	static bool ast2500_get_clock_config_default(ulong input_rate,
	ulong requested_rate,
	struct ast2500_div_config *cfg)
	{
	int i;

	for (i = 0; i < ARRAY_SIZE(ast2500_clock_config_defaults); i++) {
	const struct ast2500_clock_config *default_cfg =
	&ast2500_clock_config_defaults[i];
	if (default_cfg->input_rate == input_rate &&
	default_cfg->rate == requested_rate) {
	*cfg = default_cfg->cfg;
	return true;
	}
	}

	return false;
	}

	/*
	* @input_rate - the rate of input clock in Hz
	* @requested_rate - desired output rate in Hz
	* @div - this is an IN/OUT parameter, at input all fields of the config
	* need to be set to their maximum allowed values.
	* The result (the best config we could find), would also be returned
	* in this structure.
	*
	* @return The clock rate, when the resulting div_config is used.
	*/
	static ulong ast2500_calc_clock_config(ulong input_rate, ulong requested_rate,
	struct ast2500_div_config *cfg)
	{
	/*
	* The assumption is that kHz precision is good enough and
	* also enough to avoid overflow when multiplying.
	*/
	const ulong input_rate_khz = input_rate / 1000;
	const ulong rate_khz = requested_rate / 1000;
	const struct ast2500_div_config max_vals = *cfg;
	struct ast2500_div_config it = { 0, 0, 0 };
	ulong delta = rate_khz;
	ulong new_rate_khz = 0;

	/*
	* Look for a well known frequency first.
	*/
	if (ast2500_get_clock_config_default(input_rate, requested_rate, cfg))
	return requested_rate;

	for (; it.denum <= max_vals.denum; ++it.denum) {
	for (it.post_div = 0; it.post_div <= max_vals.post_div;
	++it.post_div) {
	it.num = (rate_khz * (it.post_div + 1) / input_rate_khz)
	* (it.denum + 1);
	if (it.num > max_vals.num)
	continue;

	new_rate_khz = (input_rate_khz
	* ((it.num + 1) / (it.denum + 1)))
	/ (it.post_div + 1);

	/* Keep the rate below requested one. */
	if (new_rate_khz > rate_khz)
	continue;

	if (new_rate_khz - rate_khz < delta) {
	delta = new_rate_khz - rate_khz;
	*cfg = it;
	if (delta == 0)
	return new_rate_khz * 1000;
	}
	}
	}

	return new_rate_khz * 1000;
	}

	static ulong ast2500_configure_ddr(struct ast2500_scu *scu, ulong rate)
	{
	ulong clkin = ast2500_get_clkin(scu);
	u32 mpll_reg;
	struct ast2500_div_config div_cfg = {
	.num = (SCU_MPLL_NUM_MASK >> SCU_MPLL_NUM_SHIFT),
	.denum = (SCU_MPLL_DENUM_MASK >> SCU_MPLL_DENUM_SHIFT),
	.post_div = (SCU_MPLL_POST_MASK >> SCU_MPLL_POST_SHIFT),
	};

	ast2500_calc_clock_config(clkin, rate, &div_cfg);

	mpll_reg = readl(&scu->m_pll_param);
	mpll_reg &= ~(SCU_MPLL_POST_MASK \| SCU_MPLL_NUM_MASK
	\| SCU_MPLL_DENUM_MASK);
	mpll_reg \|= (div_cfg.post_div << SCU_MPLL_POST_SHIFT)
	\| (div_cfg.num << SCU_MPLL_NUM_SHIFT)
	\| (div_cfg.denum << SCU_MPLL_DENUM_SHIFT);

	ast_scu_unlock(scu);
	writel(mpll_reg, &scu->m_pll_param);
	ast_scu_lock(scu);

	return ast2500_get_mpll_rate(clkin, mpll_reg);
	}

	static ulong ast2500_configure_mac(struct ast2500_scu *scu, int index)
	{
	ulong clkin = ast2500_get_clkin(scu);
	ulong hpll_rate = ast2500_get_hpll_rate(clkin,
	readl(&scu->h_pll_param));
	ulong required_rate;
	u32 hwstrap;
	u32 divisor;
	u32 reset_bit;
	u32 clkstop_bit;

	/*
	* According to data sheet, for 10/100 mode the MAC clock frequency
	* should be at least 25MHz and for 1000 mode at least 100MHz
	*/
	hwstrap = readl(&scu->hwstrap);
	if (hwstrap & (SCU_HWSTRAP_MAC1_RGMII \| SCU_HWSTRAP_MAC2_RGMII))
	required_rate = 100 * 1000 * 1000;
	else
	required_rate = 25 * 1000 * 1000;

	divisor = hpll_rate / required_rate;

	if (divisor < 4) {
	/* Clock can't run fast enough, but let's try anyway */
	debug("MAC clock too slow\n");
	divisor = 4;
	} else if (divisor > 16) {
	/* Can't slow down the clock enough, but let's try anyway */
	debug("MAC clock too fast\n");
	divisor = 16;
	}

	switch (index) {
	case 1:
	reset_bit = SCU_SYSRESET_MAC1;
	clkstop_bit = SCU_CLKSTOP_MAC1;
	break;
	case 2:
	reset_bit = SCU_SYSRESET_MAC2;
	clkstop_bit = SCU_CLKSTOP_MAC2;
	break;
	default:
	return -EINVAL;
	}

	ast_scu_unlock(scu);
	clrsetbits_le32(&scu->clk_sel1, SCU_MACCLK_MASK,
	((divisor - 2) / 2) << SCU_MACCLK_SHIFT);

	/*
	* Disable MAC, start its clock and re-enable it.
	* The procedure and the delays (100us & 10ms) are
	* specified in the datasheet.
	*/
	setbits_le32(&scu->sysreset_ctrl1, reset_bit);
	udelay(100);
	clrbits_le32(&scu->clk_stop_ctrl1, clkstop_bit);
	mdelay(10);
	clrbits_le32(&scu->sysreset_ctrl1, reset_bit);

	writel((RGMII2_TXCK_DUTY << SCU_CLKDUTY_RGMII2TXCK_SHIFT)
	\| (RGMII1_TXCK_DUTY << SCU_CLKDUTY_RGMII1TXCK_SHIFT),
	&scu->clk_duty_sel);

	ast_scu_lock(scu);

	return required_rate;
	}

	static ulong ast2500_configure_d2pll(struct ast2500_scu *scu, ulong rate)
	{
	/*
	* The values and the meaning of the next three
	* parameters are undocumented. Taken from Aspeed SDK.
	*
	* TODO(clg@kaod.org): the SIP and SIC values depend on the
	* Numerator value
	*/
	const u32 d2_pll_ext_param = 0x2c;
	const u32 d2_pll_sip = 0x11;
	const u32 d2_pll_sic = 0x18;
	u32 clk_delay_settings =
	(RMII_RXCLK_IDLY << SCU_MICDS_MAC1RMII_RDLY_SHIFT)
	\| (RMII_RXCLK_IDLY << SCU_MICDS_MAC2RMII_RDLY_SHIFT)
	\| (RGMII_TXCLK_ODLY << SCU_MICDS_MAC1RGMII_TXDLY_SHIFT)
	\| (RGMII_TXCLK_ODLY << SCU_MICDS_MAC2RGMII_TXDLY_SHIFT);
	struct ast2500_div_config div_cfg = {
	.num = SCU_D2PLL_NUM_MASK >> SCU_D2PLL_NUM_SHIFT,
	.denum = SCU_D2PLL_DENUM_MASK >> SCU_D2PLL_DENUM_SHIFT,
	.post_div = SCU_D2PLL_POST_MASK >> SCU_D2PLL_POST_SHIFT,
	};
	ulong clkin = ast2500_get_clkin(scu);
	ulong new_rate;

	ast_scu_unlock(scu);
	writel((d2_pll_ext_param << SCU_D2PLL_EXT1_PARAM_SHIFT)
	\| SCU_D2PLL_EXT1_OFF
	\| SCU_D2PLL_EXT1_RESET, &scu->d2_pll_ext_param[0]);

	/*
	* Select USB2.0 port1 PHY clock as a clock source for GCRT.
	* This would disconnect it from D2-PLL.
	*/
	clrsetbits_le32(&scu->misc_ctrl1, SCU_MISC_D2PLL_OFF,
	SCU_MISC_GCRT_USB20CLK);

	new_rate = ast2500_calc_clock_config(clkin, rate, &div_cfg);
	writel((d2_pll_sip << SCU_D2PLL_SIP_SHIFT)
	\| (d2_pll_sic << SCU_D2PLL_SIC_SHIFT)
	\| (div_cfg.num << SCU_D2PLL_NUM_SHIFT)
	\| (div_cfg.denum << SCU_D2PLL_DENUM_SHIFT)
	\| (div_cfg.post_div << SCU_D2PLL_POST_SHIFT),
	&scu->d2_pll_param);

	clrbits_le32(&scu->d2_pll_ext_param[0],
	SCU_D2PLL_EXT1_OFF \| SCU_D2PLL_EXT1_RESET);

	clrsetbits_le32(&scu->misc_ctrl2,
	SCU_MISC2_RGMII_HPLL \| SCU_MISC2_RMII_MPLL
	\| SCU_MISC2_RGMII_CLKDIV_MASK \|
	SCU_MISC2_RMII_CLKDIV_MASK,
	(4 << SCU_MISC2_RMII_CLKDIV_SHIFT));

	writel(clk_delay_settings \| SCU_MICDS_RGMIIPLL, &scu->mac_clk_delay);
	writel(clk_delay_settings, &scu->mac_clk_delay_100M);
	writel(clk_delay_settings, &scu->mac_clk_delay_10M);

	ast_scu_lock(scu);

	return new_rate;
	}

	static ulong ast2500_clk_set_rate(struct clk *clk, ulong rate)
	{
	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);

	ulong new_rate;
	switch (clk->id) {
	case PLL_MPLL:
	case MCLK_DDR:
	new_rate = ast2500_configure_ddr(priv->scu, rate);
	break;
	case PLL_D2PLL:
	new_rate = ast2500_configure_d2pll(priv->scu, rate);
	break;
	default:
	return -ENOENT;
	}

	return new_rate;
	}

	static int ast2500_clk_enable(struct clk *clk)
	{
	struct ast2500_clk_priv *priv = dev_get_priv(clk->dev);

	switch (clk->id) {
	case BCLK_SDCLK:
	if (readl(&priv->scu->clk_stop_ctrl1) & SCU_CLKSTOP_SDCLK) {
	ast_scu_unlock(priv->scu);

	setbits_le32(&priv->scu->sysreset_ctrl1,
	SCU_SYSRESET_SDIO);
	udelay(100);
	clrbits_le32(&priv->scu->clk_stop_ctrl1,
	SCU_CLKSTOP_SDCLK);
	mdelay(10);
	clrbits_le32(&priv->scu->sysreset_ctrl1,
	SCU_SYSRESET_SDIO);

	ast_scu_lock(priv->scu);
	}
	break;
	/*
	* For MAC clocks the clock rate is
	* configured based on whether RGMII or RMII mode has been selected
	* through hardware strapping.
	*/
	case PCLK_MAC1:
	ast2500_configure_mac(priv->scu, 1);
	break;
	case PCLK_MAC2:
	ast2500_configure_mac(priv->scu, 2);
	break;
	case PLL_D2PLL:
	ast2500_configure_d2pll(priv->scu, D2PLL_DEFAULT_RATE);
	break;
	default:
	return -ENOENT;
	}

	return 0;
	}

	struct clk_ops ast2500_clk_ops = {
	.get_rate = ast2500_clk_get_rate,
	.set_rate = ast2500_clk_set_rate,
	.enable = ast2500_clk_enable,
	};

	static int ast2500_clk_ofdata_to_platdata(struct udevice *dev)
	{
	struct ast2500_clk_priv *priv = dev_get_priv(dev);

	priv->scu = devfdt_get_addr_ptr(dev);
	if (IS_ERR(priv->scu))
	return PTR_ERR(priv->scu);

	return 0;
	}

	static int ast2500_clk_bind(struct udevice *dev)
	{
	int ret;

	/* The reset driver does not have a device node, so bind it here */
	ret = device_bind_driver(gd->dm_root, "ast_sysreset", "reset", &dev);
	if (ret)
	debug("Warning: No reset driver: ret=%d\n", ret);

	return 0;
	}

	static const struct udevice_id ast2500_clk_ids[] = {
	{ .compatible = "aspeed,ast2500-scu" },
	{ }
	};

	U_BOOT_DRIVER(aspeed_ast2500_scu) = {
	.name = "aspeed_ast2500_scu",
	.id = UCLASS_CLK,
	.of_match = ast2500_clk_ids,
	.priv_auto_alloc_size = sizeof(struct ast2500_clk_priv),
	.ops = &ast2500_clk_ops,
	.bind = ast2500_clk_bind,
	.ofdata_to_platdata = ast2500_clk_ofdata_to_platdata,
	};