From 4350147a816b9c5b40fa59e4fa23f17490630b79 Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Mon, 7 Nov 2005 14:27:33 +1100 Subject: [PATCH] ppc64: SMU based macs cpufreq support CPU freq support using 970FX powertune facility for iMac G5 and SMU based single CPU desktop. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/platforms/powermac/cpufreq_64.c | 323 +++++++++++++++++++++++++++ 1 file changed, 323 insertions(+) create mode 100644 arch/powerpc/platforms/powermac/cpufreq_64.c (limited to 'arch/powerpc/platforms/powermac/cpufreq_64.c') diff --git a/arch/powerpc/platforms/powermac/cpufreq_64.c b/arch/powerpc/platforms/powermac/cpufreq_64.c new file mode 100644 index 00000000000..39150342c6f --- /dev/null +++ b/arch/powerpc/platforms/powermac/cpufreq_64.c @@ -0,0 +1,323 @@ +/* + * Copyright (C) 2002 - 2005 Benjamin Herrenschmidt + * and Markus Demleitner + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This driver adds basic cpufreq support for SMU & 970FX based G5 Macs, + * that is iMac G5 and latest single CPU desktop. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#undef DEBUG + +#ifdef DEBUG +#define DBG(fmt...) printk(fmt) +#else +#define DBG(fmt...) +#endif + +/* see 970FX user manual */ + +#define SCOM_PCR 0x0aa001 /* PCR scom addr */ + +#define PCR_HILO_SELECT 0x80000000U /* 1 = PCR, 0 = PCRH */ +#define PCR_SPEED_FULL 0x00000000U /* 1:1 speed value */ +#define PCR_SPEED_HALF 0x00020000U /* 1:2 speed value */ +#define PCR_SPEED_QUARTER 0x00040000U /* 1:4 speed value */ +#define PCR_SPEED_MASK 0x000e0000U /* speed mask */ +#define PCR_SPEED_SHIFT 17 +#define PCR_FREQ_REQ_VALID 0x00010000U /* freq request valid */ +#define PCR_VOLT_REQ_VALID 0x00008000U /* volt request valid */ +#define PCR_TARGET_TIME_MASK 0x00006000U /* target time */ +#define PCR_STATLAT_MASK 0x00001f00U /* STATLAT value */ +#define PCR_SNOOPLAT_MASK 0x000000f0U /* SNOOPLAT value */ +#define PCR_SNOOPACC_MASK 0x0000000fU /* SNOOPACC value */ + +#define SCOM_PSR 0x408001 /* PSR scom addr */ +/* warning: PSR is a 64 bits register */ +#define PSR_CMD_RECEIVED 0x2000000000000000U /* command received */ +#define PSR_CMD_COMPLETED 0x1000000000000000U /* command completed */ +#define PSR_CUR_SPEED_MASK 0x0300000000000000U /* current speed */ +#define PSR_CUR_SPEED_SHIFT (56) + +/* + * The G5 only supports two frequencies (Quarter speed is not supported) + */ +#define CPUFREQ_HIGH 0 +#define CPUFREQ_LOW 1 + +static struct cpufreq_frequency_table g5_cpu_freqs[] = { + {CPUFREQ_HIGH, 0}, + {CPUFREQ_LOW, 0}, + {0, CPUFREQ_TABLE_END}, +}; + +static struct freq_attr* g5_cpu_freqs_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + +/* Power mode data is an array of the 32 bits PCR values to use for + * the various frequencies, retreived from the device-tree + */ +static u32 *g5_pmode_data; +static int g5_pmode_max; +static int g5_pmode_cur; + +static DECLARE_MUTEX(g5_switch_mutex); + + +static struct smu_sdbp_fvt *g5_fvt_table; /* table of op. points */ +static int g5_fvt_count; /* number of op. points */ +static int g5_fvt_cur; /* current op. point */ + +/* ----------------- real hardware interface */ + +static void g5_switch_volt(int speed_mode) +{ + struct smu_simple_cmd cmd; + + DECLARE_COMPLETION(comp); + smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete, + &comp, 'V', 'S', 'L', 'E', 'W', + 0xff, g5_fvt_cur+1, speed_mode); + wait_for_completion(&comp); +} + +static int g5_switch_freq(int speed_mode) +{ + struct cpufreq_freqs freqs; + int to; + + if (g5_pmode_cur == speed_mode) + return 0; + + down(&g5_switch_mutex); + + freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency; + freqs.new = g5_cpu_freqs[speed_mode].frequency; + freqs.cpu = 0; + + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); + + /* If frequency is going up, first ramp up the voltage */ + if (speed_mode < g5_pmode_cur) + g5_switch_volt(speed_mode); + + /* Clear PCR high */ + scom970_write(SCOM_PCR, 0); + /* Clear PCR low */ + scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0); + /* Set PCR low */ + scom970_write(SCOM_PCR, PCR_HILO_SELECT | + g5_pmode_data[speed_mode]); + + /* Wait for completion */ + for (to = 0; to < 10; to++) { + unsigned long psr = scom970_read(SCOM_PSR); + + if ((psr & PSR_CMD_RECEIVED) == 0 && + (((psr >> PSR_CUR_SPEED_SHIFT) ^ + (g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3) + == 0) + break; + if (psr & PSR_CMD_COMPLETED) + break; + udelay(100); + } + + /* If frequency is going down, last ramp the voltage */ + if (speed_mode > g5_pmode_cur) + g5_switch_volt(speed_mode); + + g5_pmode_cur = speed_mode; + ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul; + + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + up(&g5_switch_mutex); + + return 0; +} + +static int g5_query_freq(void) +{ + unsigned long psr = scom970_read(SCOM_PSR); + int i; + + for (i = 0; i <= g5_pmode_max; i++) + if ((((psr >> PSR_CUR_SPEED_SHIFT) ^ + (g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0) + break; + return i; +} + +/* ----------------- cpufreq bookkeeping */ + +static int g5_cpufreq_verify(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, g5_cpu_freqs); +} + +static int g5_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, unsigned int relation) +{ + unsigned int newstate = 0; + + if (cpufreq_frequency_table_target(policy, g5_cpu_freqs, + target_freq, relation, &newstate)) + return -EINVAL; + + return g5_switch_freq(newstate); +} + +static unsigned int g5_cpufreq_get_speed(unsigned int cpu) +{ + return g5_cpu_freqs[g5_pmode_cur].frequency; +} + +static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy) +{ + if (policy->cpu != 0) + return -ENODEV; + + policy->governor = CPUFREQ_DEFAULT_GOVERNOR; + policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL; + policy->cur = g5_cpu_freqs[g5_query_freq()].frequency; + cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu); + + return cpufreq_frequency_table_cpuinfo(policy, + g5_cpu_freqs); +} + + +static struct cpufreq_driver g5_cpufreq_driver = { + .name = "powermac", + .owner = THIS_MODULE, + .flags = CPUFREQ_CONST_LOOPS, + .init = g5_cpufreq_cpu_init, + .verify = g5_cpufreq_verify, + .target = g5_cpufreq_target, + .get = g5_cpufreq_get_speed, + .attr = g5_cpu_freqs_attr, +}; + + +static int __init g5_cpufreq_init(void) +{ + struct device_node *cpunode; + unsigned int psize, ssize; + struct smu_sdbp_header *shdr; + unsigned long max_freq; + u32 *valp; + int rc = -ENODEV; + + /* Look for CPU and SMU nodes */ + cpunode = of_find_node_by_type(NULL, "cpu"); + if (!cpunode) { + DBG("No CPU node !\n"); + return -ENODEV; + } + + /* Check 970FX for now */ + valp = (u32 *)get_property(cpunode, "cpu-version", NULL); + if (!valp) { + DBG("No cpu-version property !\n"); + goto bail_noprops; + } + if (((*valp) >> 16) != 0x3c) { + DBG("Wrong CPU version: %08x\n", *valp); + goto bail_noprops; + } + + /* Look for the powertune data in the device-tree */ + g5_pmode_data = (u32 *)get_property(cpunode, "power-mode-data",&psize); + if (!g5_pmode_data) { + DBG("No power-mode-data !\n"); + goto bail_noprops; + } + g5_pmode_max = psize / sizeof(u32) - 1; + + /* Look for the FVT table */ + shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL); + if (!shdr) + goto bail_noprops; + g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1]; + ssize = (shdr->len * sizeof(u32)) - sizeof(struct smu_sdbp_header); + g5_fvt_count = ssize / sizeof(struct smu_sdbp_fvt); + g5_fvt_cur = 0; + + /* Sanity checking */ + if (g5_fvt_count < 1 || g5_pmode_max < 1) + goto bail_noprops; + + /* + * From what I see, clock-frequency is always the maximal frequency. + * The current driver can not slew sysclk yet, so we really only deal + * with powertune steps for now. We also only implement full freq and + * half freq in this version. So far, I haven't yet seen a machine + * supporting anything else. + */ + valp = (u32 *)get_property(cpunode, "clock-frequency", NULL); + if (!valp) + return -ENODEV; + max_freq = (*valp)/1000; + g5_cpu_freqs[0].frequency = max_freq; + g5_cpu_freqs[1].frequency = max_freq/2; + + /* Check current frequency */ + g5_pmode_cur = g5_query_freq(); + if (g5_pmode_cur > 1) + /* We don't support anything but 1:1 and 1:2, fixup ... */ + g5_pmode_cur = 1; + + /* Force apply current frequency to make sure everything is in + * sync (voltage is right for example). Firmware may leave us with + * a strange setting ... + */ + g5_switch_freq(g5_pmode_cur); + + printk(KERN_INFO "Registering G5 CPU frequency driver\n"); + printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n", + g5_cpu_freqs[1].frequency/1000, + g5_cpu_freqs[0].frequency/1000, + g5_cpu_freqs[g5_pmode_cur].frequency/1000); + + rc = cpufreq_register_driver(&g5_cpufreq_driver); + + /* We keep the CPU node on hold... hopefully, Apple G5 don't have + * hotplug CPU with a dynamic device-tree ... + */ + return rc; + + bail_noprops: + of_node_put(cpunode); + + return rc; +} + +module_init(g5_cpufreq_init); + + +MODULE_LICENSE("GPL"); -- cgit v1.2.3