diff options
Diffstat (limited to 'arch/arm/mach-imx')
| -rw-r--r-- | arch/arm/mach-imx/Makefile | 2 | ||||
| -rw-r--r-- | arch/arm/mach-imx/cpufreq.c | 287 |
2 files changed, 289 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile index 0b27d79f2ef..02272aa36e9 100644 --- a/arch/arm/mach-imx/Makefile +++ b/arch/arm/mach-imx/Makefile @@ -9,6 +9,8 @@ obj-y += irq.o time.o dma.o generic.o +obj-$(CONFIG_CPU_FREQ_IMX) += cpufreq.o + # Specific board support obj-$(CONFIG_ARCH_MX1ADS) += mx1ads.o diff --git a/arch/arm/mach-imx/cpufreq.c b/arch/arm/mach-imx/cpufreq.c new file mode 100644 index 00000000000..ac5f9989566 --- /dev/null +++ b/arch/arm/mach-imx/cpufreq.c @@ -0,0 +1,287 @@ +/* + * cpu.c: clock scaling for the iMX + * + * Copyright (C) 2000 2001, The Delft University of Technology + * Copyright (c) 2004 Sascha Hauer <sascha@saschahauer.de> + * Copyright (C) 2006 Inky Lung <ilung@cwlinux.com> + * Copyright (C) 2006 Pavel Pisa, PiKRON <ppisa@pikron.com> + * + * Based on SA1100 version written by: + * - Johan Pouwelse (J.A.Pouwelse@its.tudelft.nl): initial version + * - Erik Mouw (J.A.K.Mouw@its.tudelft.nl): + * + * 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 + * + */ + +/*#define DEBUG*/ + +#include <linux/kernel.h> +#include <linux/types.h> +#include <linux/init.h> +#include <linux/cpufreq.h> +#include <asm/system.h> + +#include <asm/hardware.h> + +#include "generic.h" + +#ifndef __val2mfld +#define __val2mfld(mask,val) (((mask)&~((mask)<<1))*(val)&(mask)) +#endif +#ifndef __mfld2val +#define __mfld2val(mask,val) (((val)&(mask))/((mask)&~((mask)<<1))) +#endif + +#define CR_920T_CLOCK_MODE 0xC0000000 +#define CR_920T_FASTBUS_MODE 0x00000000 +#define CR_920T_ASYNC_MODE 0xC0000000 + +static u32 mpctl0_at_boot; + +static void imx_set_async_mode(void) +{ + adjust_cr(CR_920T_CLOCK_MODE, CR_920T_ASYNC_MODE); +} + +static void imx_set_fastbus_mode(void) +{ + adjust_cr(CR_920T_CLOCK_MODE, CR_920T_FASTBUS_MODE); +} + +static void imx_set_mpctl0(u32 mpctl0) +{ + unsigned long flags; + + if (mpctl0 == 0) { + local_irq_save(flags); + CSCR &= ~CSCR_MPEN; + local_irq_restore(flags); + return; + } + + local_irq_save(flags); + MPCTL0 = mpctl0; + CSCR |= CSCR_MPEN; + local_irq_restore(flags); +} + +/** + * imx_compute_mpctl - compute new PLL parameters + * @new_mpctl: pointer to location assigned by new PLL control register value + * @cur_mpctl: current PLL control register parameters + * @freq: required frequency in Hz + * @relation: is one of %CPUFREQ_RELATION_L (supremum) + * and %CPUFREQ_RELATION_H (infimum) + */ +long imx_compute_mpctl(u32 *new_mpctl, u32 cur_mpctl, unsigned long freq, int relation) +{ + u32 f_ref = (CSCR & CSCR_SYSTEM_SEL) ? 16000000 : (CLK32 * 512); + u32 mfi; + u32 mfn; + u32 mfd; + u32 pd; + unsigned long long ll; + long l; + long quot; + + /* Fdppl=2*Fref*(MFI+MFN/(MFD+1))/(PD+1) */ + /* PD=<0,15>, MFD=<1,1023>, MFI=<5,15> MFN=<0,1022> */ + + if (cur_mpctl) { + mfd = ((cur_mpctl >> 16) & 0x3ff) + 1; + pd = ((cur_mpctl >> 26) & 0xf) + 1; + } else { + pd=2; mfd=313; + } + + /* pd=2; mfd=313; mfi=8; mfn=183; */ + /* (MFI+MFN/(MFD)) = Fdppl / (2*Fref) * (PD); */ + + quot = (f_ref + (1 << 9)) >> 10; + l = (freq * pd + quot) / (2 * quot); + mfi = l >> 10; + mfn = ((l & ((1 << 10) - 1)) * mfd + (1 << 9)) >> 10; + + mfd -= 1; + pd -= 1; + + *new_mpctl = ((mfi & 0xf) << 10) | (mfn & 0x3ff) | ((mfd & 0x3ff) << 16) + | ((pd & 0xf) << 26); + + ll = 2 * (unsigned long long)f_ref * ( (mfi<<16) + (mfn<<16) / (mfd+1) ); + quot = (pd+1) * (1<<16); + ll += quot / 2; + do_div(ll, quot); + freq = ll; + + pr_debug(KERN_DEBUG "imx: new PLL parameters pd=%d mfd=%d mfi=%d mfn=%d, freq=%ld\n", + pd, mfd, mfi, mfn, freq); + + return freq; +} + + +static int imx_verify_speed(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -EINVAL; + + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, policy->cpuinfo.max_freq); + + return 0; +} + +static unsigned int imx_get_speed(unsigned int cpu) +{ + unsigned int freq; + unsigned int cr; + unsigned int cscr; + unsigned int bclk_div; + + if (cpu) + return 0; + + cscr = CSCR; + bclk_div = __mfld2val(CSCR_BCLK_DIV, cscr) + 1; + cr = get_cr(); + + if((cr & CR_920T_CLOCK_MODE) == CR_920T_FASTBUS_MODE) { + freq = imx_get_system_clk(); + freq = (freq + bclk_div/2) / bclk_div; + } else { + freq = imx_get_mcu_clk(); + if (cscr & CSCR_MPU_PRESC) + freq /= 2; + } + + freq = (freq + 500) / 1000; + + return freq; +} + +static int imx_set_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + u32 mpctl0 = 0; + u32 cscr; + unsigned long flags; + long freq; + long sysclk; + unsigned int bclk_div = 1; + + freq = target_freq * 1000; + + pr_debug(KERN_DEBUG "imx: requested frequency %ld Hz, mpctl0 at boot 0x%08x\n", + freq, mpctl0_at_boot); + + sysclk = imx_get_system_clk(); + + if (freq > sysclk + 1000000) { + freq = imx_compute_mpctl(&mpctl0, mpctl0_at_boot, freq, relation); + if (freq < 0) { + printk(KERN_WARNING "imx: target frequency %ld Hz cannot be set\n", freq); + return -EINVAL; + } + } else { + if(freq + 1000 < sysclk) { + if (relation == CPUFREQ_RELATION_L) + bclk_div = (sysclk - 1000) / freq; + else + bclk_div = (sysclk + freq + 1000) / freq; + + if(bclk_div > 16) + bclk_div = 16; + } + freq = (sysclk + bclk_div / 2) / bclk_div; + } + + freqs.old = imx_get_speed(0); + freqs.new = (freq + 500) / 1000; + freqs.cpu = 0; + freqs.flags = 0; + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + local_irq_save(flags); + + imx_set_fastbus_mode(); + + imx_set_mpctl0(mpctl0); + + cscr = CSCR; + cscr &= ~CSCR_BCLK_DIV; + cscr |= __val2mfld(CSCR_BCLK_DIV, bclk_div - 1); + CSCR = cscr; + + if(mpctl0) { + CSCR |= CSCR_MPLL_RESTART; + + /* Wait until MPLL is stablized */ + while( CSCR & CSCR_MPLL_RESTART ); + + imx_set_async_mode(); + } + + local_irq_restore(flags); + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + pr_debug(KERN_INFO "imx: set frequency %ld Hz, running from %s\n", + freq, mpctl0? "MPLL": "SPLL"); + + return 0; +} + +static int __init imx_cpufreq_driver_init(struct cpufreq_policy *policy) +{ + printk(KERN_INFO "i.MX cpu freq change driver v1.0\n"); + + if (policy->cpu != 0) + return -EINVAL; + + policy->cur = policy->min = policy->max = imx_get_speed(0); + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + policy->cpuinfo.min_freq = 8000; + policy->cpuinfo.max_freq = 200000; + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + return 0; +} + +static struct cpufreq_driver imx_driver = { + .flags = CPUFREQ_STICKY, + .verify = imx_verify_speed, + .target = imx_set_target, + .get = imx_get_speed, + .init = imx_cpufreq_driver_init, + .name = "imx", +}; + +static int __init imx_cpufreq_init(void) +{ + + mpctl0_at_boot = 0; + + if((CSCR & CSCR_MPEN) && + ((get_cr() & CR_920T_CLOCK_MODE) != CR_920T_FASTBUS_MODE)) + mpctl0_at_boot = MPCTL0; + + return cpufreq_register_driver(&imx_driver); +} + +arch_initcall(imx_cpufreq_init); + |