--- /dev/null
+/*
+ * 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;
+
+ /*
+ * Some governors do not respects CPU and policy lower limits
+ * which leads to bad things (division by zero etc), ensure
+ * that such things do not happen.
+ */
+ if(target_freq < policy->cpuinfo.min_freq)
+ target_freq = policy->cpuinfo.min_freq;
+
+ if(target_freq < policy->min)
+ target_freq = policy->min;
+
+ 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;
+ /* Manual states, that PLL stabilizes in two CLK32 periods */
+ policy->cpuinfo.transition_latency = 4 * 1000000000LL / CLK32;
+ 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);
+
git://git.onelab.eu / linux-2.6.git / blobdiff