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kernel/drivers/cpufreq/pmac64-cpufreq.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
* and Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
*
* This driver adds basic cpufreq support for SMU & 970FX based G5 Macs,
* that is iMac G5 and latest single CPU desktop.
*/
#undef DEBUG
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/sections.h>
#include <asm/cputable.h>
#include <asm/time.h>
#include <asm/smu.h>
#include <asm/pmac_pfunc.h>
#define DBG(fmt...) pr_debug(fmt)
/* 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[] = {
{0, CPUFREQ_HIGH, 0},
{0, CPUFREQ_LOW, 0},
{0, 0, CPUFREQ_TABLE_END},
};
/* Power mode data is an array of the 32 bits PCR values to use for
* the various frequencies, retrieved from the device-tree
*/
static int g5_pmode_cur;
static void (*g5_switch_volt)(int speed_mode);
static int (*g5_switch_freq)(int speed_mode);
static int (*g5_query_freq)(void);
static unsigned long transition_latency;
#ifdef CONFIG_PMAC_SMU
static const u32 *g5_pmode_data;
static int g5_pmode_max;
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 */
/*
* SMU based voltage switching for Neo2 platforms
*/
static void g5_smu_switch_volt(int speed_mode)
{
struct smu_simple_cmd cmd;
DECLARE_COMPLETION_ONSTACK(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);
}
/*
* Platform function based voltage/vdnap switching for Neo2
*/
static struct pmf_function *pfunc_set_vdnap0;
static struct pmf_function *pfunc_vdnap0_complete;
static void g5_vdnap_switch_volt(int speed_mode)
{
struct pmf_args args;
u32 slew, done = 0;
unsigned long timeout;
slew = (speed_mode == CPUFREQ_LOW) ? 1 : 0;
args.count = 1;
args.u[0].p = &slew;
pmf_call_one(pfunc_set_vdnap0, &args);
/* It's an irq GPIO so we should be able to just block here,
* I'll do that later after I've properly tested the IRQ code for
* platform functions
*/
timeout = jiffies + HZ/10;
while(!time_after(jiffies, timeout)) {
args.count = 1;
args.u[0].p = &done;
pmf_call_one(pfunc_vdnap0_complete, &args);
if (done)
break;
usleep_range(1000, 1000);
}
if (done == 0)
pr_warn("Timeout in clock slewing !\n");
}
/*
* SCOM based frequency switching for 970FX rev3
*/
static int g5_scom_switch_freq(int speed_mode)
{
unsigned long flags;
int to;
/* If frequency is going up, first ramp up the voltage */
if (speed_mode < g5_pmode_cur)
g5_switch_volt(speed_mode);
local_irq_save(flags);
/* 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);
}
local_irq_restore(flags);
/* 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;
return 0;
}
static int g5_scom_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;
}
/*
* Fake voltage switching for platforms with missing support
*/
static void g5_dummy_switch_volt(int speed_mode)
{
}
#endif /* CONFIG_PMAC_SMU */
/*
* Platform function based voltage switching for PowerMac7,2 & 7,3
*/
static struct pmf_function *pfunc_cpu0_volt_high;
static struct pmf_function *pfunc_cpu0_volt_low;
static struct pmf_function *pfunc_cpu1_volt_high;
static struct pmf_function *pfunc_cpu1_volt_low;
static void g5_pfunc_switch_volt(int speed_mode)
{
if (speed_mode == CPUFREQ_HIGH) {
if (pfunc_cpu0_volt_high)
pmf_call_one(pfunc_cpu0_volt_high, NULL);
if (pfunc_cpu1_volt_high)
pmf_call_one(pfunc_cpu1_volt_high, NULL);
} else {
if (pfunc_cpu0_volt_low)
pmf_call_one(pfunc_cpu0_volt_low, NULL);
if (pfunc_cpu1_volt_low)
pmf_call_one(pfunc_cpu1_volt_low, NULL);
}
usleep_range(10000, 10000); /* should be faster , to fix */
}
/*
* Platform function based frequency switching for PowerMac7,2 & 7,3
*/
static struct pmf_function *pfunc_cpu_setfreq_high;
static struct pmf_function *pfunc_cpu_setfreq_low;
static struct pmf_function *pfunc_cpu_getfreq;
static struct pmf_function *pfunc_slewing_done;
static int g5_pfunc_switch_freq(int speed_mode)
{
struct pmf_args args;
u32 done = 0;
unsigned long timeout;
int rc;
DBG("g5_pfunc_switch_freq(%d)\n", speed_mode);
/* If frequency is going up, first ramp up the voltage */
if (speed_mode < g5_pmode_cur)
g5_switch_volt(speed_mode);
/* Do it */
if (speed_mode == CPUFREQ_HIGH)
rc = pmf_call_one(pfunc_cpu_setfreq_high, NULL);
else
rc = pmf_call_one(pfunc_cpu_setfreq_low, NULL);
if (rc)
pr_warn("pfunc switch error %d\n", rc);
/* It's an irq GPIO so we should be able to just block here,
* I'll do that later after I've properly tested the IRQ code for
* platform functions
*/
timeout = jiffies + HZ/10;
while(!time_after(jiffies, timeout)) {
args.count = 1;
args.u[0].p = &done;
pmf_call_one(pfunc_slewing_done, &args);
if (done)
break;
usleep_range(500, 500);
}
if (done == 0)
pr_warn("Timeout in clock slewing !\n");
/* 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;
return 0;
}
static int g5_pfunc_query_freq(void)
{
struct pmf_args args;
u32 val = 0;
args.count = 1;
args.u[0].p = &val;
pmf_call_one(pfunc_cpu_getfreq, &args);
return val ? CPUFREQ_HIGH : CPUFREQ_LOW;
}
/*
* Common interface to the cpufreq core
*/
static int g5_cpufreq_target(struct cpufreq_policy *policy, unsigned int index)
{
return g5_switch_freq(index);
}
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)
{
cpufreq_generic_init(policy, g5_cpu_freqs, transition_latency);
return 0;
}
static struct cpufreq_driver g5_cpufreq_driver = {
.name = "powermac",
.flags = CPUFREQ_CONST_LOOPS,
.init = g5_cpufreq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = g5_cpufreq_target,
.get = g5_cpufreq_get_speed,
.attr = cpufreq_generic_attr,
};
#ifdef CONFIG_PMAC_SMU
static int __init g5_neo2_cpufreq_init(struct device_node *cpunode)
{
unsigned int psize, ssize;
unsigned long max_freq;
char *freq_method, *volt_method;
const u32 *valp;
u32 pvr_hi;
int use_volts_vdnap = 0;
int use_volts_smu = 0;
int rc = -ENODEV;
/* Check supported platforms */
if (of_machine_is_compatible("PowerMac8,1") ||
of_machine_is_compatible("PowerMac8,2") ||
of_machine_is_compatible("PowerMac9,1") ||
of_machine_is_compatible("PowerMac12,1"))
use_volts_smu = 1;
else if (of_machine_is_compatible("PowerMac11,2"))
use_volts_vdnap = 1;
else
return -ENODEV;
/* Check 970FX for now */
valp = of_get_property(cpunode, "cpu-version", NULL);
if (!valp) {
DBG("No cpu-version property !\n");
goto bail_noprops;
}
pvr_hi = (*valp) >> 16;
if (pvr_hi != 0x3c && pvr_hi != 0x44) {
pr_err("Unsupported CPU version\n");
goto bail_noprops;
}
/* Look for the powertune data in the device-tree */
g5_pmode_data = of_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;
if (use_volts_smu) {
const struct smu_sdbp_header *shdr;
/* 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(*shdr);
g5_fvt_count = ssize / sizeof(*g5_fvt_table);
g5_fvt_cur = 0;
/* Sanity checking */
if (g5_fvt_count < 1 || g5_pmode_max < 1)
goto bail_noprops;
g5_switch_volt = g5_smu_switch_volt;
volt_method = "SMU";
} else if (use_volts_vdnap) {
struct device_node *root;
root = of_find_node_by_path("/");
if (root == NULL) {
pr_err("Can't find root of device tree\n");
goto bail_noprops;
}
pfunc_set_vdnap0 = pmf_find_function(root, "set-vdnap0");
pfunc_vdnap0_complete =
pmf_find_function(root, "slewing-done");
of_node_put(root);
if (pfunc_set_vdnap0 == NULL ||
pfunc_vdnap0_complete == NULL) {
pr_err("Can't find required platform function\n");
goto bail_noprops;
}
g5_switch_volt = g5_vdnap_switch_volt;
volt_method = "GPIO";
} else {
g5_switch_volt = g5_dummy_switch_volt;
volt_method = "none";
}
/*
* 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 = of_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;
/* Set callbacks */
transition_latency = 12000;
g5_switch_freq = g5_scom_switch_freq;
g5_query_freq = g5_scom_query_freq;
freq_method = "SCOM";
/* 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_volt(CPUFREQ_HIGH);
msleep(10);
g5_pmode_cur = -1;
g5_switch_freq(g5_query_freq());
pr_info("Registering G5 CPU frequency driver\n");
pr_info("Frequency method: %s, Voltage method: %s\n",
freq_method, volt_method);
pr_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;
}
#endif /* CONFIG_PMAC_SMU */
static int __init g5_pm72_cpufreq_init(struct device_node *cpunode)
{
struct device_node *cpuid = NULL, *hwclock = NULL;
const u8 *eeprom = NULL;
const u32 *valp;
u64 max_freq, min_freq, ih, il;
int has_volt = 1, rc = 0;
DBG("cpufreq: Initializing for PowerMac7,2, PowerMac7,3 and"
" RackMac3,1...\n");
/* Lookup the cpuid eeprom node */
cpuid = of_find_node_by_path("/u3@0,f8000000/i2c@f8001000/cpuid@a0");
if (cpuid != NULL)
eeprom = of_get_property(cpuid, "cpuid", NULL);
if (eeprom == NULL) {
pr_err("Can't find cpuid EEPROM !\n");
rc = -ENODEV;
goto bail;
}
/* Lookup the i2c hwclock */
for_each_node_by_name(hwclock, "i2c-hwclock") {
const char *loc = of_get_property(hwclock,
"hwctrl-location", NULL);
if (loc == NULL)
continue;
if (strcmp(loc, "CPU CLOCK"))
continue;
if (!of_get_property(hwclock, "platform-get-frequency", NULL))
continue;
break;
}
if (hwclock == NULL) {
pr_err("Can't find i2c clock chip !\n");
rc = -ENODEV;
goto bail;
}
DBG("cpufreq: i2c clock chip found: %pOF\n", hwclock);
/* Now get all the platform functions */
pfunc_cpu_getfreq =
pmf_find_function(hwclock, "get-frequency");
pfunc_cpu_setfreq_high =
pmf_find_function(hwclock, "set-frequency-high");
pfunc_cpu_setfreq_low =
pmf_find_function(hwclock, "set-frequency-low");
pfunc_slewing_done =
pmf_find_function(hwclock, "slewing-done");
pfunc_cpu0_volt_high =
pmf_find_function(hwclock, "set-voltage-high-0");
pfunc_cpu0_volt_low =
pmf_find_function(hwclock, "set-voltage-low-0");
pfunc_cpu1_volt_high =
pmf_find_function(hwclock, "set-voltage-high-1");
pfunc_cpu1_volt_low =
pmf_find_function(hwclock, "set-voltage-low-1");
/* Check we have minimum requirements */
if (pfunc_cpu_getfreq == NULL || pfunc_cpu_setfreq_high == NULL ||
pfunc_cpu_setfreq_low == NULL || pfunc_slewing_done == NULL) {
pr_err("Can't find platform functions !\n");
rc = -ENODEV;
goto bail;
}
/* Check that we have complete sets */
if (pfunc_cpu0_volt_high == NULL || pfunc_cpu0_volt_low == NULL) {
pmf_put_function(pfunc_cpu0_volt_high);
pmf_put_function(pfunc_cpu0_volt_low);
pfunc_cpu0_volt_high = pfunc_cpu0_volt_low = NULL;
has_volt = 0;
}
if (!has_volt ||
pfunc_cpu1_volt_high == NULL || pfunc_cpu1_volt_low == NULL) {
pmf_put_function(pfunc_cpu1_volt_high);
pmf_put_function(pfunc_cpu1_volt_low);
pfunc_cpu1_volt_high = pfunc_cpu1_volt_low = NULL;
}
/* Note: The device tree also contains a "platform-set-values"
* function for which I haven't quite figured out the usage. It
* might have to be called on init and/or wakeup, I'm not too sure
* but things seem to work fine without it so far ...
*/
/* Get max frequency from device-tree */
valp = of_get_property(cpunode, "clock-frequency", NULL);
if (!valp) {
pr_err("Can't find CPU frequency !\n");
rc = -ENODEV;
goto bail;
}
max_freq = (*valp)/1000;
/* Now calculate reduced frequency by using the cpuid input freq
* ratio. This requires 64 bits math unless we are willing to lose
* some precision
*/
ih = *((u32 *)(eeprom + 0x10));
il = *((u32 *)(eeprom + 0x20));
/* Check for machines with no useful settings */
if (il == ih) {
pr_warn("No low frequency mode available on this model !\n");
rc = -ENODEV;
goto bail;
}
min_freq = 0;
if (ih != 0 && il != 0)
min_freq = (max_freq * il) / ih;
/* Sanity check */
if (min_freq >= max_freq || min_freq < 1000) {
pr_err("Can't calculate low frequency !\n");
rc = -ENXIO;
goto bail;
}
g5_cpu_freqs[0].frequency = max_freq;
g5_cpu_freqs[1].frequency = min_freq;
/* Based on a measurement on Xserve G5, rounded up. */
transition_latency = 10 * NSEC_PER_MSEC;
/* Set callbacks */
g5_switch_volt = g5_pfunc_switch_volt;
g5_switch_freq = g5_pfunc_switch_freq;
g5_query_freq = g5_pfunc_query_freq;
/* 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_volt(CPUFREQ_HIGH);
msleep(10);
g5_pmode_cur = -1;
g5_switch_freq(g5_query_freq());
pr_info("Registering G5 CPU frequency driver\n");
pr_info("Frequency method: i2c/pfunc, Voltage method: %s\n",
has_volt ? "i2c/pfunc" : "none");
pr_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);
bail:
if (rc != 0) {
pmf_put_function(pfunc_cpu_getfreq);
pmf_put_function(pfunc_cpu_setfreq_high);
pmf_put_function(pfunc_cpu_setfreq_low);
pmf_put_function(pfunc_slewing_done);
pmf_put_function(pfunc_cpu0_volt_high);
pmf_put_function(pfunc_cpu0_volt_low);
pmf_put_function(pfunc_cpu1_volt_high);
pmf_put_function(pfunc_cpu1_volt_low);
}
of_node_put(hwclock);
of_node_put(cpuid);
of_node_put(cpunode);
return rc;
}
static int __init g5_cpufreq_init(void)
{
struct device_node *cpunode;
int rc = 0;
/* Get first CPU node */
cpunode = of_cpu_device_node_get(0);
if (cpunode == NULL) {
pr_err("Can't find any CPU node\n");
return -ENODEV;
}
if (of_machine_is_compatible("PowerMac7,2") ||
of_machine_is_compatible("PowerMac7,3") ||
of_machine_is_compatible("RackMac3,1"))
rc = g5_pm72_cpufreq_init(cpunode);
#ifdef CONFIG_PMAC_SMU
else
rc = g5_neo2_cpufreq_init(cpunode);
#endif /* CONFIG_PMAC_SMU */
return rc;
}
module_init(g5_cpufreq_init);
MODULE_LICENSE("GPL");
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