iMX28: Initial support for iMX28 CPU

This patch supports:
- Timers
- Debug UART
- Clock

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Detlev Zundel <dzu@denx.de>

1 files changed, 355 insertions, 0 deletions

diff --git a/arch/arm/cpu/arm926ejs/mx28/clock.c b/arch/arm/cpu/arm926ejs/mx28/clock.c
new file mode 100644
index 0000000..f698506
--- /dev/null
+++ b/arch/arm/cpu/arm926ejs/mx28/clock.c
@@ -0,0 +1,355 @@
+/*
+ * Freescale i.MX28 clock setup code
+ *
+ * Copyright (C) 2011 Marek Vasut <marek.vasut@gmail.com>
+ * on behalf of DENX Software Engineering GmbH
+ *
+ * Based on code from LTIB:
+ * Copyright (C) 2010 Freescale Semiconductor, Inc.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <asm/errno.h>
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+#include <asm/arch/imx-regs.h>
+
+/* The PLL frequency is always 480MHz, see section 10.2 in iMX28 datasheet. */
+#define	PLL_FREQ_KHZ	480000
+#define	PLL_FREQ_COEF	18
+/* The XTAL frequency is always 24MHz, see section 10.2 in iMX28 datasheet. */
+#define	XTAL_FREQ_KHZ	24000
+
+#define	PLL_FREQ_MHZ	(PLL_FREQ_KHZ / 1000)
+#define	XTAL_FREQ_MHZ	(XTAL_FREQ_KHZ / 1000)
+
+static uint32_t mx28_get_pclk(void)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+	uint32_t clkctrl, clkseq, clkfrac;
+	uint32_t frac, div;
+
+	clkctrl = readl(&clkctrl_regs->hw_clkctrl_cpu);
+
+	/* No support of fractional divider calculation */
+	if (clkctrl &
+		(CLKCTRL_CPU_DIV_XTAL_FRAC_EN | CLKCTRL_CPU_DIV_CPU_FRAC_EN)) {
+		return 0;
+	}
+
+	clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+
+	/* XTAL Path */
+	if (clkseq & CLKCTRL_CLKSEQ_BYPASS_CPU) {
+		div = (clkctrl & CLKCTRL_CPU_DIV_XTAL_MASK) >>
+			CLKCTRL_CPU_DIV_XTAL_OFFSET;
+		return XTAL_FREQ_MHZ / div;
+	}
+
+	/* REF Path */
+	clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac0);
+	frac = clkfrac & CLKCTRL_FRAC0_CPUFRAC_MASK;
+	div = clkctrl & CLKCTRL_CPU_DIV_CPU_MASK;
+	return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+static uint32_t mx28_get_hclk(void)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+	uint32_t div;
+	uint32_t clkctrl;
+
+	clkctrl = readl(&clkctrl_regs->hw_clkctrl_hbus);
+
+	/* No support of fractional divider calculation */
+	if (clkctrl & CLKCTRL_HBUS_DIV_FRAC_EN)
+		return 0;
+
+	div = clkctrl & CLKCTRL_HBUS_DIV_MASK;
+	return mx28_get_pclk() / div;
+}
+
+static uint32_t mx28_get_emiclk(void)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+	uint32_t frac, div;
+	uint32_t clkctrl, clkseq, clkfrac;
+
+	clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+	clkctrl = readl(&clkctrl_regs->hw_clkctrl_emi);
+
+	/* XTAL Path */
+	if (clkseq & CLKCTRL_CLKSEQ_BYPASS_EMI) {
+		div = (clkctrl & CLKCTRL_EMI_DIV_XTAL_MASK) >>
+			CLKCTRL_EMI_DIV_XTAL_OFFSET;
+		return XTAL_FREQ_MHZ / div;
+	}
+
+	clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac0);
+
+	/* REF Path */
+	frac = (clkfrac & CLKCTRL_FRAC0_EMIFRAC_MASK) >>
+		CLKCTRL_FRAC0_EMIFRAC_OFFSET;
+	div = clkctrl & CLKCTRL_EMI_DIV_EMI_MASK;
+	return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+static uint32_t mx28_get_gpmiclk(void)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+
+	uint32_t frac, div;
+	uint32_t clkctrl, clkseq, clkfrac;
+
+	clkseq = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+	clkctrl = readl(&clkctrl_regs->hw_clkctrl_gpmi);
+
+	/* XTAL Path */
+	if (clkseq & CLKCTRL_CLKSEQ_BYPASS_GPMI) {
+		div = clkctrl & CLKCTRL_GPMI_DIV_MASK;
+		return XTAL_FREQ_MHZ / div;
+	}
+
+	clkfrac = readl(&clkctrl_regs->hw_clkctrl_frac1);
+
+	/* REF Path */
+	frac = (clkfrac & CLKCTRL_FRAC1_GPMIFRAC_MASK) >>
+		CLKCTRL_FRAC1_GPMIFRAC_OFFSET;
+	div = clkctrl & CLKCTRL_GPMI_DIV_MASK;
+	return (PLL_FREQ_MHZ * PLL_FREQ_COEF / frac) / div;
+}
+
+/*
+ * Set IO clock frequency, in kHz
+ */
+void mx28_set_ioclk(enum mxs_ioclock io, uint32_t freq)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+	uint32_t div;
+
+	if (freq == 0)
+		return;
+
+	if (io > MXC_IOCLK1)
+		return;
+
+	div = (PLL_FREQ_KHZ * PLL_FREQ_COEF) / freq;
+
+	if (div < 18)
+		div = 18;
+
+	if (div > 35)
+		div = 35;
+
+	if (io == MXC_IOCLK0) {
+		writel(CLKCTRL_FRAC0_CLKGATEIO0,
+			&clkctrl_regs->hw_clkctrl_frac0_set);
+		clrsetbits_le32(&clkctrl_regs->hw_clkctrl_frac0,
+				CLKCTRL_FRAC0_IO0FRAC_MASK,
+				div << CLKCTRL_FRAC0_IO0FRAC_OFFSET);
+		writel(CLKCTRL_FRAC0_CLKGATEIO0,
+			&clkctrl_regs->hw_clkctrl_frac0_clr);
+	} else {
+		writel(CLKCTRL_FRAC0_CLKGATEIO1,
+			&clkctrl_regs->hw_clkctrl_frac0_set);
+		clrsetbits_le32(&clkctrl_regs->hw_clkctrl_frac0,
+				CLKCTRL_FRAC0_IO1FRAC_MASK,
+				div << CLKCTRL_FRAC0_IO1FRAC_OFFSET);
+		writel(CLKCTRL_FRAC0_CLKGATEIO1,
+			&clkctrl_regs->hw_clkctrl_frac0_clr);
+	}
+}
+
+/*
+ * Get IO clock, returns IO clock in kHz
+ */
+static uint32_t mx28_get_ioclk(enum mxs_ioclock io)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+	uint32_t tmp, ret;
+
+	if (io > MXC_IOCLK1)
+		return 0;
+
+	tmp = readl(&clkctrl_regs->hw_clkctrl_frac0);
+
+	if (io == MXC_IOCLK0)
+		ret = (tmp & CLKCTRL_FRAC0_IO0FRAC_MASK) >>
+			CLKCTRL_FRAC0_IO0FRAC_OFFSET;
+	else
+		ret = (tmp & CLKCTRL_FRAC0_IO1FRAC_MASK) >>
+			CLKCTRL_FRAC0_IO1FRAC_OFFSET;
+
+	return (PLL_FREQ_KHZ * PLL_FREQ_COEF) / ret;
+}
+
+/*
+ * Configure SSP clock frequency, in kHz
+ */
+void mx28_set_sspclk(enum mxs_sspclock ssp, uint32_t freq, int xtal)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+	uint32_t clk, clkreg;
+
+	if (ssp > MXC_SSPCLK3)
+		return;
+
+	clkreg = (uint32_t)(&clkctrl_regs->hw_clkctrl_ssp0) +
+			(ssp * sizeof(struct mx28_register));
+
+	clrbits_le32(clkreg, CLKCTRL_SSP_CLKGATE);
+	while (readl(clkreg) & CLKCTRL_SSP_CLKGATE)
+		;
+
+	if (xtal)
+		clk = XTAL_FREQ_KHZ;
+	else
+		clk = mx28_get_ioclk(ssp >> 1);
+
+	if (freq > clk)
+		return;
+
+	/* Calculate the divider and cap it if necessary */
+	clk /= freq;
+	if (clk > CLKCTRL_SSP_DIV_MASK)
+		clk = CLKCTRL_SSP_DIV_MASK;
+
+	clrsetbits_le32(clkreg, CLKCTRL_SSP_DIV_MASK, clk);
+	while (readl(clkreg) & CLKCTRL_SSP_BUSY)
+		;
+
+	if (xtal)
+		writel(CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp,
+			&clkctrl_regs->hw_clkctrl_clkseq_set);
+	else
+		writel(CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp,
+			&clkctrl_regs->hw_clkctrl_clkseq_clr);
+}
+
+/*
+ * Return SSP frequency, in kHz
+ */
+static uint32_t mx28_get_sspclk(enum mxs_sspclock ssp)
+{
+	struct mx28_clkctrl_regs *clkctrl_regs =
+		(struct mx28_clkctrl_regs *)MXS_CLKCTRL_BASE;
+	uint32_t clkreg;
+	uint32_t clk, tmp;
+
+	if (ssp > MXC_SSPCLK3)
+		return 0;
+
+	tmp = readl(&clkctrl_regs->hw_clkctrl_clkseq);
+	if (tmp & (CLKCTRL_CLKSEQ_BYPASS_SSP0 << ssp))
+		return XTAL_FREQ_KHZ;
+
+	clkreg = (uint32_t)(&clkctrl_regs->hw_clkctrl_ssp0) +
+			(ssp * sizeof(struct mx28_register));
+
+	tmp = readl(clkreg) & CLKCTRL_SSP_DIV_MASK;
+
+	if (tmp == 0)
+		return 0;
+
+	clk = mx28_get_ioclk(ssp >> 1);
+
+	return clk / tmp;
+}
+
+/*
+ * Set SSP/MMC bus frequency, in kHz)
+ */
+void mx28_set_ssp_busclock(unsigned int bus, uint32_t freq)
+{
+	struct mx28_ssp_regs *ssp_regs;
+	const uint32_t sspclk = mx28_get_sspclk(bus);
+	uint32_t reg;
+	uint32_t divide, rate, tgtclk;
+
+	ssp_regs = (struct mx28_ssp_regs *)(MXS_SSP0_BASE + (bus * 0x2000));
+
+	/*
+	 * SSP bit rate = SSPCLK / (CLOCK_DIVIDE * (1 + CLOCK_RATE)),
+	 * CLOCK_DIVIDE has to be an even value from 2 to 254, and
+	 * CLOCK_RATE could be any integer from 0 to 255.
+	 */
+	for (divide = 2; divide < 254; divide += 2) {
+		rate = sspclk / freq / divide;
+		if (rate <= 256)
+			break;
+	}
+
+	tgtclk = sspclk / divide / rate;
+	while (tgtclk > freq) {
+		rate++;
+		tgtclk = sspclk / divide / rate;
+	}
+	if (rate > 256)
+		rate = 256;
+
+	/* Always set timeout the maximum */
+	reg = SSP_TIMING_TIMEOUT_MASK |
+		(divide << SSP_TIMING_CLOCK_DIVIDE_OFFSET) |
+		((rate - 1) << SSP_TIMING_CLOCK_RATE_OFFSET);
+	writel(reg, &ssp_regs->hw_ssp_timing);
+
+	debug("SPI%d: Set freq rate to %d KHz (requested %d KHz)\n",
+		bus, tgtclk, freq);
+}
+
+uint32_t mxc_get_clock(enum mxc_clock clk)
+{
+	switch (clk) {
+	case MXC_ARM_CLK:
+		return mx28_get_pclk() * 1000000;
+	case MXC_GPMI_CLK:
+		return mx28_get_gpmiclk() * 1000000;
+	case MXC_AHB_CLK:
+	case MXC_IPG_CLK:
+		return mx28_get_hclk() * 1000000;
+	case MXC_EMI_CLK:
+		return mx28_get_emiclk();
+	case MXC_IO0_CLK:
+		return mx28_get_ioclk(MXC_IOCLK0);
+	case MXC_IO1_CLK:
+		return mx28_get_ioclk(MXC_IOCLK1);
+	case MXC_SSP0_CLK:
+		return mx28_get_sspclk(MXC_SSPCLK0);
+	case MXC_SSP1_CLK:
+		return mx28_get_sspclk(MXC_SSPCLK1);
+	case MXC_SSP2_CLK:
+		return mx28_get_sspclk(MXC_SSPCLK2);
+	case MXC_SSP3_CLK:
+		return mx28_get_sspclk(MXC_SSPCLK3);
+	}
+
+	return 0;
+}