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Diffstat (limited to 'arch/arm/mach-sa1100/cpu-sa1100.c')
| -rw-r--r-- | arch/arm/mach-sa1100/cpu-sa1100.c | 249 |
1 files changed, 0 insertions, 249 deletions
diff --git a/arch/arm/mach-sa1100/cpu-sa1100.c b/arch/arm/mach-sa1100/cpu-sa1100.c deleted file mode 100644 index e8f4d1e19233..000000000000 --- a/arch/arm/mach-sa1100/cpu-sa1100.c +++ /dev/null @@ -1,249 +0,0 @@ -/* - * cpu-sa1100.c: clock scaling for the SA1100 - * - * Copyright (C) 2000 2001, The Delft University of Technology - * - * Authors: - * - Johan Pouwelse (J.A.Pouwelse@its.tudelft.nl): initial version - * - Erik Mouw (J.A.K.Mouw@its.tudelft.nl): - * - major rewrite for linux-2.3.99 - * - rewritten for the more generic power management scheme in - * linux-2.4.5-rmk1 - * - * This software has been developed while working on the LART - * computing board (http://www.lartmaker.nl/), which is - * sponsored by the Mobile Multi-media Communications - * (http://www.mobimedia.org/) and Ubiquitous Communications - * (http://www.ubicom.tudelft.nl/) projects. - * - * The authors can be reached at: - * - * Erik Mouw - * Information and Communication Theory Group - * Faculty of Information Technology and Systems - * Delft University of Technology - * P.O. Box 5031 - * 2600 GA Delft - * The Netherlands - * - * - * 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 - * - * - * Theory of operations - * ==================== - * - * Clock scaling can be used to lower the power consumption of the CPU - * core. This will give you a somewhat longer running time. - * - * The SA-1100 has a single register to change the core clock speed: - * - * PPCR 0x90020014 PLL config - * - * However, the DRAM timings are closely related to the core clock - * speed, so we need to change these, too. The used registers are: - * - * MDCNFG 0xA0000000 DRAM config - * MDCAS0 0xA0000004 Access waveform - * MDCAS1 0xA0000008 Access waveform - * MDCAS2 0xA000000C Access waveform - * - * Care must be taken to change the DRAM parameters the correct way, - * because otherwise the DRAM becomes unusable and the kernel will - * crash. - * - * The simple solution to avoid a kernel crash is to put the actual - * clock change in ROM and jump to that code from the kernel. The main - * disadvantage is that the ROM has to be modified, which is not - * possible on all SA-1100 platforms. Another disadvantage is that - * jumping to ROM makes clock switching unnecessary complicated. - * - * The idea behind this driver is that the memory configuration can be - * changed while running from DRAM (even with interrupts turned on!) - * as long as all re-configuration steps yield a valid DRAM - * configuration. The advantages are clear: it will run on all SA-1100 - * platforms, and the code is very simple. - * - * If you really want to understand what is going on in - * sa1100_update_dram_timings(), you'll have to read sections 8.2, - * 9.5.7.3, and 10.2 from the "Intel StrongARM SA-1100 Microprocessor - * Developers Manual" (available for free from Intel). - * - */ - -#include <linux/kernel.h> -#include <linux/types.h> -#include <linux/init.h> -#include <linux/cpufreq.h> -#include <linux/io.h> - -#include <asm/cputype.h> - -#include <mach/hardware.h> - -#include "generic.h" - -struct sa1100_dram_regs { - int speed; - u32 mdcnfg; - u32 mdcas0; - u32 mdcas1; - u32 mdcas2; -}; - - -static struct cpufreq_driver sa1100_driver; - -static struct sa1100_dram_regs sa1100_dram_settings[] = { - /*speed, mdcnfg, mdcas0, mdcas1, mdcas2, clock freq */ - { 59000, 0x00dc88a3, 0xcccccccf, 0xfffffffc, 0xffffffff},/* 59.0 MHz */ - { 73700, 0x011490a3, 0xcccccccf, 0xfffffffc, 0xffffffff},/* 73.7 MHz */ - { 88500, 0x014e90a3, 0xcccccccf, 0xfffffffc, 0xffffffff},/* 88.5 MHz */ - {103200, 0x01889923, 0xcccccccf, 0xfffffffc, 0xffffffff},/* 103.2 MHz */ - {118000, 0x01c29923, 0x9999998f, 0xfffffff9, 0xffffffff},/* 118.0 MHz */ - {132700, 0x01fb2123, 0x9999998f, 0xfffffff9, 0xffffffff},/* 132.7 MHz */ - {147500, 0x02352123, 0x3333330f, 0xfffffff3, 0xffffffff},/* 147.5 MHz */ - {162200, 0x026b29a3, 0x38e38e1f, 0xfff8e38e, 0xffffffff},/* 162.2 MHz */ - {176900, 0x02a329a3, 0x71c71c1f, 0xfff1c71c, 0xffffffff},/* 176.9 MHz */ - {191700, 0x02dd31a3, 0xe38e383f, 0xffe38e38, 0xffffffff},/* 191.7 MHz */ - {206400, 0x03153223, 0xc71c703f, 0xffc71c71, 0xffffffff},/* 206.4 MHz */ - {221200, 0x034fba23, 0xc71c703f, 0xffc71c71, 0xffffffff},/* 221.2 MHz */ - {235900, 0x03853a23, 0xe1e1e07f, 0xe1e1e1e1, 0xffffffe1},/* 235.9 MHz */ - {250700, 0x03bf3aa3, 0xc3c3c07f, 0xc3c3c3c3, 0xffffffc3},/* 250.7 MHz */ - {265400, 0x03f7c2a3, 0xc3c3c07f, 0xc3c3c3c3, 0xffffffc3},/* 265.4 MHz */ - {280200, 0x0431c2a3, 0x878780ff, 0x87878787, 0xffffff87},/* 280.2 MHz */ - { 0, 0, 0, 0, 0 } /* last entry */ -}; - -static void sa1100_update_dram_timings(int current_speed, int new_speed) -{ - struct sa1100_dram_regs *settings = sa1100_dram_settings; - - /* find speed */ - while (settings->speed != 0) { - if (new_speed == settings->speed) - break; - - settings++; - } - - if (settings->speed == 0) { - panic("%s: couldn't find dram setting for speed %d\n", - __func__, new_speed); - } - - /* No risk, no fun: run with interrupts on! */ - if (new_speed > current_speed) { - /* We're going FASTER, so first relax the memory - * timings before changing the core frequency - */ - - /* Half the memory access clock */ - MDCNFG |= MDCNFG_CDB2; - - /* The order of these statements IS important, keep 8 - * pulses!! - */ - MDCAS2 = settings->mdcas2; - MDCAS1 = settings->mdcas1; - MDCAS0 = settings->mdcas0; - MDCNFG = settings->mdcnfg; - } else { - /* We're going SLOWER: first decrease the core - * frequency and then tighten the memory settings. - */ - - /* Half the memory access clock */ - MDCNFG |= MDCNFG_CDB2; - - /* The order of these statements IS important, keep 8 - * pulses!! - */ - MDCAS0 = settings->mdcas0; - MDCAS1 = settings->mdcas1; - MDCAS2 = settings->mdcas2; - MDCNFG = settings->mdcnfg; - } -} - -static int sa1100_target(struct cpufreq_policy *policy, - unsigned int target_freq, - unsigned int relation) -{ - unsigned int cur = sa11x0_getspeed(0); - unsigned int new_ppcr; - struct cpufreq_freqs freqs; - - new_ppcr = sa11x0_freq_to_ppcr(target_freq); - switch (relation) { - case CPUFREQ_RELATION_L: - if (sa11x0_ppcr_to_freq(new_ppcr) > policy->max) - new_ppcr--; - break; - case CPUFREQ_RELATION_H: - if ((sa11x0_ppcr_to_freq(new_ppcr) > target_freq) && - (sa11x0_ppcr_to_freq(new_ppcr - 1) >= policy->min)) - new_ppcr--; - break; - } - - freqs.old = cur; - freqs.new = sa11x0_ppcr_to_freq(new_ppcr); - freqs.cpu = 0; - - cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); - - if (freqs.new > cur) - sa1100_update_dram_timings(cur, freqs.new); - - PPCR = new_ppcr; - - if (freqs.new < cur) - sa1100_update_dram_timings(cur, freqs.new); - - cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); - - return 0; -} - -static int __init sa1100_cpu_init(struct cpufreq_policy *policy) -{ - if (policy->cpu != 0) - return -EINVAL; - policy->cur = policy->min = policy->max = sa11x0_getspeed(0); - policy->cpuinfo.min_freq = 59000; - policy->cpuinfo.max_freq = 287000; - policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; - return 0; -} - -static struct cpufreq_driver sa1100_driver __refdata = { - .flags = CPUFREQ_STICKY, - .verify = sa11x0_verify_speed, - .target = sa1100_target, - .get = sa11x0_getspeed, - .init = sa1100_cpu_init, - .name = "sa1100", -}; - -static int __init sa1100_dram_init(void) -{ - if (cpu_is_sa1100()) - return cpufreq_register_driver(&sa1100_driver); - else - return -ENODEV; -} - -arch_initcall(sa1100_dram_init); |