tegra2: Add clock and PLL control functions

This adds functions for setting up clocks to peripherals, by selecting
a parent clock and specifying a rate.

BUG=chromium-os:13228
TEST=Build, boot on Seaboard

Change-Id: I957723b5f0ef64244c16f44ae7cbd79abf06427d
Reviewed-on: http://gerrit.chromium.org/gerrit/1290
Reviewed-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

2 files changed, 572 insertions, 8 deletions

diff --git a/arch/arm/cpu/armv7/tegra2/ap20.c b/arch/arm/cpu/armv7/tegra2/ap20.c
index 3f365aebbac..74cd583d146 100644
--- a/arch/arm/cpu/armv7/tegra2/ap20.c
+++ b/arch/arm/cpu/armv7/tegra2/ap20.c
@@ -197,7 +197,6 @@ static void reset_A9_cpu(int reset)
 
 static void clock_enable_coresight(int enable)
 {
-	struct clk_rst_ctlr *clkrst = (struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
 	u32 rst, src;
 
 	clock_set_enable(PERIPH_ID_CORESIGHT, enable);
@@ -211,7 +210,7 @@ static void clock_enable_coresight(int enable)
 		 *  (bits 7:0), so 00000001b == 1.5 (n+1 + .5)
 		 */
 		src = CLK_DIVIDER(NVBL_PLLP_KHZ, 144000);
-		writel(src, &clkrst->crc_clk_src_csite);
+		clock_ll_set_source_divisor(PERIPH_ID_CSI, 0, src);
 
 		/* Unlock the CPU CoreSight interfaces */
 		rst = 0xC5ACCE55;
diff --git a/arch/arm/cpu/armv7/tegra2/clock.c b/arch/arm/cpu/armv7/tegra2/clock.c
index 1fad0d6769c..5efbd90917c 100644
--- a/arch/arm/cpu/armv7/tegra2/clock.c
+++ b/arch/arm/cpu/armv7/tegra2/clock.c
@@ -28,6 +28,7 @@
 #include <asm/arch/timer.h>
 #include <asm/arch/tegra2.h>
 #include <common.h>
+#include <div64.h>
 
 #ifdef DEBUG
 #define assert(x) 	\
@@ -38,6 +39,369 @@
 #endif
 
 /*
+ * This is our record of the current clock rate of each clock. We don't
+ * fill all of these in since we are only really interested in clocks which
+ * we use as parents.
+ */
+static unsigned pll_rate[CLOCK_ID_COUNT];
+
+/*
+ * The oscillator frequency is fixed to one of four set values. Based on this
+ * the other clocks are set up appropriately.
+ */
+static unsigned osc_freq[CLOCK_OSC_FREQ_COUNT] = {
+	13000000,
+	19200000,
+	12000000,
+	26000000,
+};
+
+/*
+ * Clock types that we can use as a source. The Tegra2 has muxes for the
+ * peripheral clocks, and in most cases there are four options for the clock
+ * source. This gives us a clock 'type' and exploits what commonality exists
+ * in the device.
+ *
+ * Letters are obvious, except for T which means CLK_M, and S which means the
+ * clock derived from 32KHz. Beware that CLK_M (also called OSC in the
+ * datasheet) and PLL_M are different things. The former is the basic
+ * clock supplied to the SOC from an external oscillator. The latter is the
+ * memory clock PLL.
+ *
+ * See definitions in clock_id in the header file.
+ */
+enum clock_type_id {
+	CLOCK_TYPE_AXPT,	/* PLL_A, PLL_X, PLL_P, CLK_M */
+	CLOCK_TYPE_MCPA,	/* and so on */
+	CLOCK_TYPE_MCPT,
+	CLOCK_TYPE_PCM,
+	CLOCK_TYPE_PCMT,
+	CLOCK_TYPE_PCXTS,
+	CLOCK_TYPE_PDCT,
+
+	CLOCK_TYPE_COUNT,
+	CLOCK_TYPE_NONE = -1,	/* invalid clock type */
+};
+
+/* return 1 if a peripheral ID is in range */
+#define clock_type_id_isvalid(id) ((id) >= 0 && \
+		(id) < CLOCK_TYPE_COUNT)
+
+
+enum {
+	CLOCK_MAX_MUX	= 4	/* number of source options for each clock */
+};
+
+/*
+ * Clock source mux for each clock type. This just converts our enum into
+ * a list of mux sources for use by the code. Note that CLOCK_TYPE_PCXTS
+ * is special as it has 5 sources. Since it also has a different number of
+ * bits in its register for the source, we just handle it with a special
+ * case in the code.
+ */
+#define CLK(x) CLOCK_ID_ ## x
+static enum clock_id clock_source[CLOCK_TYPE_COUNT] [CLOCK_MAX_MUX] = {
+	{ CLK(AUDIO),	CLK(XCPU),	CLK(PERIPH),	CLK(OSC)	},
+	{ CLK(MEMORY),	CLK(CGENERAL),	CLK(PERIPH),	CLK(AUDIO)	},
+	{ CLK(MEMORY),	CLK(CGENERAL),	CLK(PERIPH),	CLK(OSC)	},
+	{ CLK(PERIPH),	CLK(CGENERAL),	CLK(MEMORY),	CLK(NONE)	},
+	{ CLK(PERIPH),	CLK(CGENERAL),	CLK(MEMORY),	CLK(OSC)	},
+	{ CLK(PERIPH),	CLK(CGENERAL),	CLK(XCPU),	CLK(OSC)	},
+	{ CLK(PERIPH),	CLK(DISPLAY),	CLK(CGENERAL),	CLK(OSC)	},
+};
+
+/*
+ * Clock peripheral IDs which sadly don't match up with PERIPH_ID. This is
+ * not in the header file since it is for purely internal use - we want
+ * callers to use the PERIPH_ID for all access to peripheral clocks to avoid
+ * confusion bewteen PERIPH_ID_... and PERIPHC_...
+ *
+ * We don't call this CLOCK_PERIPH_ID or PERIPH_CLOCK_ID as it would just be
+ * confusing.
+ *
+ * Note to SOC vendors: perhaps define a unified numbering for peripherals and
+ * use it for reset, clock enable, clock source/divider and even pinmuxing
+ * if you can.
+ */
+enum periphc_internal_id {
+	/* 0x00 */
+	PERIPHC_I2S1,
+	PERIPHC_I2S2,
+	PERIPHC_SPDIF_OUT,
+	PERIPHC_SPDIF_IN,
+	PERIPHC_PWM,
+	PERIPHC_SPI1,
+	PERIPHC_SPI2,
+	PERIPHC_SPI3,
+
+	/* 0x08 */
+	PERIPHC_XIO,
+	PERIPHC_I2C1,
+	PERIPHC_DVC_I2C,
+	PERIPHC_TWC,
+	PERIPHC_0c,
+	PERIPHC_10,	/* PERIPHC_SPI1, what is this really? */
+	PERIPHC_DISP1,
+	PERIPHC_DISP2,
+
+	/* 0x10 */
+	PERIPHC_CVE,
+	PERIPHC_IDE0,
+	PERIPHC_VI,
+	PERIPHC_1c,
+	PERIPHC_SDMMC1,
+	PERIPHC_SDMMC2,
+	PERIPHC_G3D,
+	PERIPHC_G2D,
+
+	/* 0x18 */
+	PERIPHC_NDFLASH,
+	PERIPHC_SDMMC4,
+	PERIPHC_VFIR,
+	PERIPHC_EPP,
+	PERIPHC_MPE,
+	PERIPHC_MIPI,
+	PERIPHC_UART1,
+	PERIPHC_UART2,
+
+	/* 0x20 */
+	PERIPHC_HOST1X,
+	PERIPHC_21,
+	PERIPHC_TVO,
+	PERIPHC_HDMI,
+	PERIPHC_24,
+	PERIPHC_TVDAC,
+	PERIPHC_I2C2,
+	PERIPHC_EMC,
+
+	/* 0x28 */
+	PERIPHC_UART3,
+	PERIPHC_29,
+	PERIPHC_VI_SENSOR,
+	PERIPHC_2b,
+	PERIPHC_2c,
+	PERIPHC_SPI4,
+	PERIPHC_I2C3,
+	PERIPHC_SDMMC3,
+
+	/* 0x30 */
+	PERIPHC_UART4,
+	PERIPHC_UART5,
+	PERIPHC_VDE,
+	PERIPHC_OWR,
+	PERIPHC_NOR,
+	PERIPHC_CSITE,
+
+	PERIPHC_COUNT,
+
+	PERIPHC_NONE = -1,
+};
+
+/* return 1 if a periphc_internal_id is in range */
+#define periphc_internal_id_isvalid(id) ((id) >= 0 && \
+		(id) < PERIPHC_COUNT)
+
+/*
+ * Clock type for each peripheral clock source. We put the name in each
+ * record just so it is easy to match things up
+ */
+#define TYPE(name, type) type
+static enum clock_type_id clock_periph_type[PERIPHC_COUNT] = {
+	/* 0x00 */
+	TYPE(PERIPHC_I2S1,	CLOCK_TYPE_AXPT),
+	TYPE(PERIPHC_I2S2,	CLOCK_TYPE_AXPT),
+	TYPE(PERIPHC_SPDIF_OUT,	CLOCK_TYPE_AXPT),
+	TYPE(PERIPHC_SPDIF_IN,	CLOCK_TYPE_PCM),
+	TYPE(PERIPHC_PWM,	CLOCK_TYPE_PCXTS),
+	TYPE(PERIPHC_SPI1,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_SPI22,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_SPI3,	CLOCK_TYPE_PCMT),
+
+	/* 0x08 */
+	TYPE(PERIPHC_XIO,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_I2C1,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_DVC_I2C,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_TWC,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_SPI1,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_DISP1,	CLOCK_TYPE_PDCT),
+	TYPE(PERIPHC_DISP2,	CLOCK_TYPE_PDCT),
+
+	/* 0x10 */
+	TYPE(PERIPHC_CVE,	CLOCK_TYPE_PDCT),
+	TYPE(PERIPHC_IDE0,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_VI,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_SDMMC1,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_SDMMC2,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_G3D,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_G2D,	CLOCK_TYPE_MCPA),
+
+	/* 0x18 */
+	TYPE(PERIPHC_NDFLASH,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_SDMMC4,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_VFIR,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_EPP,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_MPE,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_MIPI,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_UART1,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_UART2,	CLOCK_TYPE_PCMT),
+
+	/* 0x20 */
+	TYPE(PERIPHC_HOST1X,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_TVO,	CLOCK_TYPE_PDCT),
+	TYPE(PERIPHC_HDMI,	CLOCK_TYPE_PDCT),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_TVDAC,	CLOCK_TYPE_PDCT),
+	TYPE(PERIPHC_I2C2,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_EMC,	CLOCK_TYPE_MCPT),
+
+	/* 0x28 */
+	TYPE(PERIPHC_UART3,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_VI,	CLOCK_TYPE_MCPA),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_NONE,	CLOCK_TYPE_NONE),
+	TYPE(PERIPHC_SPI4,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_I2C3,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_SDMMC3,	CLOCK_TYPE_PCMT),
+
+	/* 0x30 */
+	TYPE(PERIPHC_UART4,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_UART5,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_VDE,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_OWR,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_NOR,	CLOCK_TYPE_PCMT),
+	TYPE(PERIPHC_CSITE,	CLOCK_TYPE_PCMT),
+};
+
+/*
+ * This array translates a periph_id to a periphc_internal_id
+ *
+ * Not present/matched up:
+ *	uint vi_sensor;	 _VI_SENSOR_0,		0x1A8
+ * 	SPDIF - which is both 0x08 and 0x0c
+ *
+ */
+#define NONE(name) (-1)
+#define OFFSET(name, value) PERIPHC_ ## name
+static s8 periph_id_to_internal_id[PERIPH_ID_COUNT] = {
+	/* Low word: 31:0 */
+	NONE(CPU),
+	NONE(RESERVED1),
+	NONE(RESERVED2),
+	NONE(AC97),
+	NONE(RTC),
+	NONE(TMR),
+	PERIPHC_UART1,
+	PERIPHC_UART2,	/* and vfir 0x68 */
+
+	/* 0x08 */
+	NONE(GPIO),
+	PERIPHC_SDMMC2,
+	NONE(SPDIF),		/* 0x08 and 0x0c, unclear which to use */
+	PERIPHC_I2S1,
+	PERIPHC_I2C1,
+	PERIPHC_NDFLASH,
+	PERIPHC_SDMMC1,
+	PERIPHC_SDMMC4,
+
+	/* 0x10 */
+	PERIPHC_TWC,
+	PERIPHC_PWM,
+	PERIPHC_I2S2,
+	PERIPHC_EPP,
+	PERIPHC_VI,
+	PERIPHC_G2D,
+	NONE(USBD),
+	NONE(ISP),
+
+	/* 0x18 */
+	PERIPHC_G3D,
+	PERIPHC_IDE0,
+	PERIPHC_DISP2,
+	PERIPHC_DISP1,
+	PERIPHC_HOST1X,
+	NONE(VCP),
+	NONE(RESERVED30),
+	NONE(CACHE2),
+
+	/* Middle word: 63:32 */
+	NONE(MEM),
+	NONE(AHBDMA),
+	NONE(APBDMA),
+	NONE(RESERVED35),
+	NONE(KBC),
+	NONE(STAT_MON),
+	NONE(PMC),
+	NONE(FUSE),
+
+	/* 0x28 */
+	NONE(KFUSE),
+	NONE(SBC1),	/* SBC1, 0x34, is this SPI1? */
+	PERIPHC_NOR,
+	PERIPHC_SPI1,
+	PERIPHC_SPI2,
+	PERIPHC_XIO,
+	PERIPHC_SPI3,
+	PERIPHC_DVC_I2C,
+
+	/* 0x30 */
+	NONE(DSI),
+	PERIPHC_TVO,	/* also CVE 0x40 */
+	PERIPHC_MIPI,
+	PERIPHC_HDMI,
+	PERIPHC_CSITE,
+	PERIPHC_TVDAC,
+	PERIPHC_I2C2,
+	PERIPHC_UART3,
+
+	/* 0x38 */
+	NONE(RESERVED56),
+	PERIPHC_EMC,
+	NONE(USB2),
+	NONE(USB3),
+	PERIPHC_MPE,
+	PERIPHC_VDE,
+	NONE(BSEA),
+	NONE(BSEV),
+
+	/* Upper word 95:64 */
+	NONE(SPEEDO),
+	PERIPHC_UART4,
+	PERIPHC_UART5,
+	PERIPHC_I2C3,
+	PERIPHC_SPI4,
+	PERIPHC_SDMMC3,
+	NONE(PCIE),
+	PERIPHC_OWR,
+
+	/* 0x48 */
+	NONE(AFI),
+	NONE(CORESIGHT),
+	NONE(RESERVED74),
+	NONE(AVPUCQ),
+	NONE(RESERVED76),
+	NONE(RESERVED77),
+	NONE(RESERVED78),
+	NONE(RESERVED79),
+
+	/* 0x50 */
+	NONE(RESERVED80),
+	NONE(RESERVED81),
+	NONE(RESERVED82),
+	NONE(RESERVED83),
+	NONE(IRAMA),
+	NONE(IRAMB),
+	NONE(IRAMC),
+	NONE(IRAMD),
+
+	/* 0x58 */
+	NONE(CRAM2),
+};
+
+/*
  * Get the oscillator frequency, from the corresponding hardware configuration
  * field.
  */
@@ -51,16 +415,21 @@ enum clock_osc_freq clock_get_osc_freq(void)
 	return bf_unpack(OSC_FREQ, reg);
 }
 
-unsigned long clock_start_pll(enum clock_pll_id clkid, u32 divm, u32 divn,
-		u32 divp, u32 cpcon, u32 lfcon)
+/* Returns a pointer to the registers of the given pll */
+static struct clk_pll *get_pll(enum clock_id clkid)
 {
 	struct clk_rst_ctlr *clkrst =
 			(struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
-	u32 data;
-	struct clk_pll *pll;
 
-	assert(clock_pll_id_isvalid(clkid));
-	pll = &clkrst->crc_pll[clkid];
+	assert(clock_id_isvalid(clkid));
+	return &clkrst->crc_pll[clkid];
+}
+
+unsigned long clock_start_pll(enum clock_id clkid, u32 divm, u32 divn,
+		u32 divp, u32 cpcon, u32 lfcon)
+{
+	struct clk_pll *pll = get_pll(clkid);
+	u32 data;
 
 	/*
 	 * We cheat by treating all PLL (except PLLU) in the same fashion.
@@ -89,6 +458,167 @@ unsigned long clock_start_pll(enum clock_pll_id clkid, u32 divm, u32 divn,
 	return timer_get_future_us(CLOCK_PLL_STABLE_DELAY_US);
 }
 
+/* Returns a pointer to the clock source register for a peripheral */
+static u32 *get_periph_source_reg(enum periph_id periph_id)
+{
+	struct clk_rst_ctlr *clkrst =
+			(struct clk_rst_ctlr *)NV_PA_CLK_RST_BASE;
+	enum periphc_internal_id internal_id;
+
+	assert(periph_id >= PERIPH_ID_FIRST && periph_id < PERIPH_ID_COUNT);
+	internal_id = periph_id_to_internal_id[periph_id];
+	assert(internal_id != -1);
+	return &clkrst->crc_clk_src[internal_id];
+}
+
+void clock_ll_set_source_divisor(enum periph_id periph_id, int source,
+			      unsigned divisor)
+{
+	u32 *reg = get_periph_source_reg(periph_id);
+	u32 value;
+
+	value = bf_pack(OUT_CLK_SOURCE, source) |
+			bf_pack(OUT_CLK_DIVISOR, divisor);
+	writel(value, reg);
+}
+
+void clock_ll_set_source(enum periph_id periph_id, int source)
+{
+	u32 *reg = get_periph_source_reg(periph_id);
+
+	bf_writel(OUT_CLK_SOURCE, source, reg);
+}
+
+/**
+ * Given the parent's rate and the required rate for the children, this works
+ * out the peripheral clock divider to use, in 7.1 binary format.
+ *
+ * @param parent_rate	clock rate of parent clock in Hz
+ * @param rate		required clock rate for this clock
+ */
+static int clk_div7_1_get_divider(unsigned long parent_rate, unsigned long rate)
+{
+	u64 divider = parent_rate * 2;
+
+	divider += rate - 1;
+	do_div(divider, rate);
+
+	if ((s64)divider - 2 < 0)
+		return 0;
+
+	if ((s64)divider - 2 > 255)
+		return -1;
+
+	return divider - 2;
+}
+
+unsigned long clock_get_periph_rate(enum periph_id periph_id,
+		enum clock_id parent)
+{
+	u32 *reg = get_periph_source_reg(periph_id);
+	u32 data = readl(reg);
+	u64 rate;
+	int divider;
+
+	divider = bf_unpack(OUT_CLK_DIVISOR, data);
+	rate = (u64)pll_rate[parent] * 2 ;
+	do_div (rate, divider + 2);
+	return rate;
+}
+
+
+/*
+ * Given a peripheral ID and the required source clock, this returns which
+ * value should be programmed into the source mux for that peripheral.
+ *
+ * There is special code here to handle the one source type with 5 sources.
+ *
+ * @param periph_id	peripheral to start
+ * @param source	PLL id of required parent clock
+ * @param mux_bits	Set to number of bits in mux register: 2 or 4
+ * @return mux value (0-4, or -1 if not found)
+ */
+static int get_periph_clock_source(enum periph_id periph_id,
+		enum clock_id parent, int *mux_bits)
+{
+	enum clock_type_id type;
+	enum periphc_internal_id internal_id;
+	int mux;
+
+	assert(clock_periph_id_isvalid(periph_id));
+
+	internal_id = periph_id_to_internal_id[periph_id];
+	assert(periphc_internal_id_isvalid(internal_id));
+
+	type = clock_periph_type[internal_id];
+	assert(clock_type_id_isvalid(type));
+
+	/* Special case here for the clock with a 4-bit source mux */
+	if (type == CLOCK_TYPE_PCXTS)
+		*mux_bits = 4;
+	else
+		*mux_bits = 2;
+
+	for (mux = 0; mux < CLOCK_MAX_MUX; mux++)
+		if (clock_source[type][mux] == parent)
+			return mux;
+
+	/*
+	 * Not found: it might be looking for the 'S' in CLOCK_TYPE_PCXTS
+	 * which is not in our table. If not, then they are asking for a
+	 * source which this peripheral can't access through its mux.
+	 */
+	assert(type == CLOCK_TYPE_PCXTS);
+	assert(parent == CLOCK_ID_SFROM32KHZ);
+	if (type == CLOCK_TYPE_PCXTS && parent == CLOCK_ID_SFROM32KHZ);
+		return 4;	/* mux value for this clock */
+
+	/* if we get here, either us or the caller has made a mistake */
+	printf("Caller requested bad clock: periph=%d, parent=%d\n", periph_id,
+		parent);
+	return -1;
+}
+
+unsigned clock_start_periph_pll(enum periph_id periph_id,
+		enum clock_id parent, unsigned rate)
+{
+	u32 *reg = get_periph_source_reg(periph_id);
+	int divider;
+	uint effective_rate;
+	int source, mux_bits;
+
+	reset_set_enable(periph_id, 1);
+	clock_enable(periph_id);
+
+	divider = clk_div7_1_get_divider(pll_rate[parent], rate);
+	assert(divider >= 0);
+
+	bf_writel(OUT_CLK_DIVISOR, divider, reg);
+	udelay(1);
+
+	/* work out the source clock and set it*/
+	source = get_periph_clock_source(periph_id, parent, &mux_bits);
+	if (source < 0)
+		return -1U;
+	if (mux_bits == 4)
+		bf_writel(OUT_CLK_SOURCE4, source, reg);
+	else
+		bf_writel(OUT_CLK_SOURCE, source, reg);
+	udelay(2);
+
+	debug("periph %d, rate=%d, reg=%p = %x\n", periph_id, rate,
+	       reg, readl(reg));
+
+	/* Check what we ended up with. This shouldn't matter though */
+	effective_rate = clock_get_periph_rate(periph_id, parent);
+	if (rate != effective_rate)
+		printf("Requested clock rate %u not honored (got %u)\n",
+		       rate, effective_rate);
+
+	reset_set_enable(periph_id, 0);
+	return effective_rate;
+}
+
 void clock_set_enable(enum periph_id periph_id, int enable)
 {
 	struct clk_rst_ctlr *clkrst =
@@ -161,3 +691,38 @@ void reset_cmplx_set_enable(int cpu, int which, int reset)
 	else
 		writel(mask, &clkrst->crc_cpu_cmplx_clr);
 }
+
+/**
+ * Returns the frequency of the given PLL. This assumes that the PLL is fed
+ * from the main oscillator.
+ *
+ * @param clkid		Clock to examine
+ * @return clock frequency in Hz
+ */
+static unsigned get_clock_freq(enum clock_id clkid)
+{
+	struct clk_pll *pll = get_pll(clkid);
+	u32 base = readl(&pll->pll_base);
+	u32 divm;
+	u64 parent_rate;
+	u64 rate;
+
+	parent_rate = osc_freq[clock_get_osc_freq()];
+	rate = parent_rate * bf_unpack(PLL_DIVN, base);
+	divm = bf_unpack(PLL_DIVM, base);
+	if (clkid == CLOCK_ID_USB)
+		divm <<= bf_unpack(PLLU_VCO_FREQ, base);
+	else
+		divm <<= bf_unpack(PLL_DIVP, base);
+	do_div(rate, divm);
+	return rate;
+}
+
+void clock_init(void)
+{
+	pll_rate[CLOCK_ID_MEMORY] = get_clock_freq(CLOCK_ID_MEMORY);
+	pll_rate[CLOCK_ID_PERIPH] = get_clock_freq(CLOCK_ID_PERIPH);
+	pll_rate[CLOCK_ID_SFROM32KHZ] = 32768;
+	debug("PLLM = %d\n", pll_rate[CLOCK_ID_MEMORY]);
+	debug("PLLP = %d\n", pll_rate[CLOCK_ID_PERIPH]);
+}