diff options
Diffstat (limited to 'arch/arm/cpu/arm926ejs/mx28/clock.c')
| -rw-r--r-- | arch/arm/cpu/arm926ejs/mx28/clock.c | 355 |
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 000000000..f69850600 --- /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; +} |