forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
464 lines
12 KiB
464 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
|
* cpuidle-pseries - idle state cpuidle driver. |
|
* Adapted from drivers/idle/intel_idle.c and |
|
* drivers/acpi/processor_idle.c |
|
* |
|
*/ |
|
|
|
#include <linux/kernel.h> |
|
#include <linux/module.h> |
|
#include <linux/init.h> |
|
#include <linux/moduleparam.h> |
|
#include <linux/cpuidle.h> |
|
#include <linux/cpu.h> |
|
#include <linux/notifier.h> |
|
|
|
#include <asm/paca.h> |
|
#include <asm/reg.h> |
|
#include <asm/machdep.h> |
|
#include <asm/firmware.h> |
|
#include <asm/runlatch.h> |
|
#include <asm/idle.h> |
|
#include <asm/plpar_wrappers.h> |
|
#include <asm/rtas.h> |
|
|
|
static struct cpuidle_driver pseries_idle_driver = { |
|
.name = "pseries_idle", |
|
.owner = THIS_MODULE, |
|
}; |
|
|
|
static int max_idle_state __read_mostly; |
|
static struct cpuidle_state *cpuidle_state_table __read_mostly; |
|
static u64 snooze_timeout __read_mostly; |
|
static bool snooze_timeout_en __read_mostly; |
|
|
|
static int snooze_loop(struct cpuidle_device *dev, |
|
struct cpuidle_driver *drv, |
|
int index) |
|
{ |
|
u64 snooze_exit_time; |
|
|
|
set_thread_flag(TIF_POLLING_NRFLAG); |
|
|
|
pseries_idle_prolog(); |
|
local_irq_enable(); |
|
snooze_exit_time = get_tb() + snooze_timeout; |
|
|
|
while (!need_resched()) { |
|
HMT_low(); |
|
HMT_very_low(); |
|
if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) { |
|
/* |
|
* Task has not woken up but we are exiting the polling |
|
* loop anyway. Require a barrier after polling is |
|
* cleared to order subsequent test of need_resched(). |
|
*/ |
|
clear_thread_flag(TIF_POLLING_NRFLAG); |
|
smp_mb(); |
|
break; |
|
} |
|
} |
|
|
|
HMT_medium(); |
|
clear_thread_flag(TIF_POLLING_NRFLAG); |
|
|
|
local_irq_disable(); |
|
|
|
pseries_idle_epilog(); |
|
|
|
return index; |
|
} |
|
|
|
static void check_and_cede_processor(void) |
|
{ |
|
/* |
|
* Ensure our interrupt state is properly tracked, |
|
* also checks if no interrupt has occurred while we |
|
* were soft-disabled |
|
*/ |
|
if (prep_irq_for_idle()) { |
|
cede_processor(); |
|
#ifdef CONFIG_TRACE_IRQFLAGS |
|
/* Ensure that H_CEDE returns with IRQs on */ |
|
if (WARN_ON(!(mfmsr() & MSR_EE))) |
|
__hard_irq_enable(); |
|
#endif |
|
} |
|
} |
|
|
|
/* |
|
* XCEDE: Extended CEDE states discovered through the |
|
* "ibm,get-systems-parameter" RTAS call with the token |
|
* CEDE_LATENCY_TOKEN |
|
*/ |
|
|
|
/* |
|
* Section 7.3.16 System Parameters Option of PAPR version 2.8.1 has a |
|
* table with all the parameters to ibm,get-system-parameters. |
|
* CEDE_LATENCY_TOKEN corresponds to the token value for Cede Latency |
|
* Settings Information. |
|
*/ |
|
#define CEDE_LATENCY_TOKEN 45 |
|
|
|
/* |
|
* If the platform supports the cede latency settings information system |
|
* parameter it must provide the following information in the NULL terminated |
|
* parameter string: |
|
* |
|
* a. The first byte is the length “N” of each cede latency setting record minus |
|
* one (zero indicates a length of 1 byte). |
|
* |
|
* b. For each supported cede latency setting a cede latency setting record |
|
* consisting of the first “N” bytes as per the following table. |
|
* |
|
* ----------------------------- |
|
* | Field | Field | |
|
* | Name | Length | |
|
* ----------------------------- |
|
* | Cede Latency | 1 Byte | |
|
* | Specifier Value | | |
|
* ----------------------------- |
|
* | Maximum wakeup | | |
|
* | latency in | 8 Bytes | |
|
* | tb-ticks | | |
|
* ----------------------------- |
|
* | Responsive to | | |
|
* | external | 1 Byte | |
|
* | interrupts | | |
|
* ----------------------------- |
|
* |
|
* This version has cede latency record size = 10. |
|
* |
|
* The structure xcede_latency_payload represents a) and b) with |
|
* xcede_latency_record representing the table in b). |
|
* |
|
* xcede_latency_parameter is what gets returned by |
|
* ibm,get-systems-parameter RTAS call when made with |
|
* CEDE_LATENCY_TOKEN. |
|
* |
|
* These structures are only used to represent the data obtained by the RTAS |
|
* call. The data is in big-endian. |
|
*/ |
|
struct xcede_latency_record { |
|
u8 hint; |
|
__be64 latency_ticks; |
|
u8 wake_on_irqs; |
|
} __packed; |
|
|
|
// Make space for 16 records, which "should be enough". |
|
struct xcede_latency_payload { |
|
u8 record_size; |
|
struct xcede_latency_record records[16]; |
|
} __packed; |
|
|
|
struct xcede_latency_parameter { |
|
__be16 payload_size; |
|
struct xcede_latency_payload payload; |
|
u8 null_char; |
|
} __packed; |
|
|
|
static unsigned int nr_xcede_records; |
|
static struct xcede_latency_parameter xcede_latency_parameter __initdata; |
|
|
|
static int __init parse_cede_parameters(void) |
|
{ |
|
struct xcede_latency_payload *payload; |
|
u32 total_xcede_records_size; |
|
u8 xcede_record_size; |
|
u16 payload_size; |
|
int ret, i; |
|
|
|
ret = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, |
|
NULL, CEDE_LATENCY_TOKEN, __pa(&xcede_latency_parameter), |
|
sizeof(xcede_latency_parameter)); |
|
if (ret) { |
|
pr_err("xcede: Error parsing CEDE_LATENCY_TOKEN\n"); |
|
return ret; |
|
} |
|
|
|
payload_size = be16_to_cpu(xcede_latency_parameter.payload_size); |
|
payload = &xcede_latency_parameter.payload; |
|
|
|
xcede_record_size = payload->record_size + 1; |
|
|
|
if (xcede_record_size != sizeof(struct xcede_latency_record)) { |
|
pr_err("xcede: Expected record-size %lu. Observed size %u.\n", |
|
sizeof(struct xcede_latency_record), xcede_record_size); |
|
return -EINVAL; |
|
} |
|
|
|
pr_info("xcede: xcede_record_size = %d\n", xcede_record_size); |
|
|
|
/* |
|
* Since the payload_size includes the last NULL byte and the |
|
* xcede_record_size, the remaining bytes correspond to array of all |
|
* cede_latency settings. |
|
*/ |
|
total_xcede_records_size = payload_size - 2; |
|
nr_xcede_records = total_xcede_records_size / xcede_record_size; |
|
|
|
for (i = 0; i < nr_xcede_records; i++) { |
|
struct xcede_latency_record *record = &payload->records[i]; |
|
u64 latency_ticks = be64_to_cpu(record->latency_ticks); |
|
u8 wake_on_irqs = record->wake_on_irqs; |
|
u8 hint = record->hint; |
|
|
|
pr_info("xcede: Record %d : hint = %u, latency = 0x%llx tb ticks, Wake-on-irq = %u\n", |
|
i, hint, latency_ticks, wake_on_irqs); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
#define NR_DEDICATED_STATES 2 /* snooze, CEDE */ |
|
static u8 cede_latency_hint[NR_DEDICATED_STATES]; |
|
|
|
static int dedicated_cede_loop(struct cpuidle_device *dev, |
|
struct cpuidle_driver *drv, |
|
int index) |
|
{ |
|
u8 old_latency_hint; |
|
|
|
pseries_idle_prolog(); |
|
get_lppaca()->donate_dedicated_cpu = 1; |
|
old_latency_hint = get_lppaca()->cede_latency_hint; |
|
get_lppaca()->cede_latency_hint = cede_latency_hint[index]; |
|
|
|
HMT_medium(); |
|
check_and_cede_processor(); |
|
|
|
local_irq_disable(); |
|
get_lppaca()->donate_dedicated_cpu = 0; |
|
get_lppaca()->cede_latency_hint = old_latency_hint; |
|
|
|
pseries_idle_epilog(); |
|
|
|
return index; |
|
} |
|
|
|
static int shared_cede_loop(struct cpuidle_device *dev, |
|
struct cpuidle_driver *drv, |
|
int index) |
|
{ |
|
|
|
pseries_idle_prolog(); |
|
|
|
/* |
|
* Yield the processor to the hypervisor. We return if |
|
* an external interrupt occurs (which are driven prior |
|
* to returning here) or if a prod occurs from another |
|
* processor. When returning here, external interrupts |
|
* are enabled. |
|
*/ |
|
check_and_cede_processor(); |
|
|
|
local_irq_disable(); |
|
pseries_idle_epilog(); |
|
|
|
return index; |
|
} |
|
|
|
/* |
|
* States for dedicated partition case. |
|
*/ |
|
static struct cpuidle_state dedicated_states[NR_DEDICATED_STATES] = { |
|
{ /* Snooze */ |
|
.name = "snooze", |
|
.desc = "snooze", |
|
.exit_latency = 0, |
|
.target_residency = 0, |
|
.enter = &snooze_loop }, |
|
{ /* CEDE */ |
|
.name = "CEDE", |
|
.desc = "CEDE", |
|
.exit_latency = 10, |
|
.target_residency = 100, |
|
.enter = &dedicated_cede_loop }, |
|
}; |
|
|
|
/* |
|
* States for shared partition case. |
|
*/ |
|
static struct cpuidle_state shared_states[] = { |
|
{ /* Snooze */ |
|
.name = "snooze", |
|
.desc = "snooze", |
|
.exit_latency = 0, |
|
.target_residency = 0, |
|
.enter = &snooze_loop }, |
|
{ /* Shared Cede */ |
|
.name = "Shared Cede", |
|
.desc = "Shared Cede", |
|
.exit_latency = 10, |
|
.target_residency = 100, |
|
.enter = &shared_cede_loop }, |
|
}; |
|
|
|
static int pseries_cpuidle_cpu_online(unsigned int cpu) |
|
{ |
|
struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); |
|
|
|
if (dev && cpuidle_get_driver()) { |
|
cpuidle_pause_and_lock(); |
|
cpuidle_enable_device(dev); |
|
cpuidle_resume_and_unlock(); |
|
} |
|
return 0; |
|
} |
|
|
|
static int pseries_cpuidle_cpu_dead(unsigned int cpu) |
|
{ |
|
struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu); |
|
|
|
if (dev && cpuidle_get_driver()) { |
|
cpuidle_pause_and_lock(); |
|
cpuidle_disable_device(dev); |
|
cpuidle_resume_and_unlock(); |
|
} |
|
return 0; |
|
} |
|
|
|
/* |
|
* pseries_cpuidle_driver_init() |
|
*/ |
|
static int pseries_cpuidle_driver_init(void) |
|
{ |
|
int idle_state; |
|
struct cpuidle_driver *drv = &pseries_idle_driver; |
|
|
|
drv->state_count = 0; |
|
|
|
for (idle_state = 0; idle_state < max_idle_state; ++idle_state) { |
|
/* Is the state not enabled? */ |
|
if (cpuidle_state_table[idle_state].enter == NULL) |
|
continue; |
|
|
|
drv->states[drv->state_count] = /* structure copy */ |
|
cpuidle_state_table[idle_state]; |
|
|
|
drv->state_count += 1; |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
static void __init fixup_cede0_latency(void) |
|
{ |
|
struct xcede_latency_payload *payload; |
|
u64 min_latency_us; |
|
int i; |
|
|
|
min_latency_us = dedicated_states[1].exit_latency; // CEDE latency |
|
|
|
if (parse_cede_parameters()) |
|
return; |
|
|
|
pr_info("cpuidle: Skipping the %d Extended CEDE idle states\n", |
|
nr_xcede_records); |
|
|
|
payload = &xcede_latency_parameter.payload; |
|
for (i = 0; i < nr_xcede_records; i++) { |
|
struct xcede_latency_record *record = &payload->records[i]; |
|
u64 latency_tb = be64_to_cpu(record->latency_ticks); |
|
u64 latency_us = DIV_ROUND_UP_ULL(tb_to_ns(latency_tb), NSEC_PER_USEC); |
|
|
|
if (latency_us == 0) |
|
pr_warn("cpuidle: xcede record %d has an unrealistic latency of 0us.\n", i); |
|
|
|
if (latency_us < min_latency_us) |
|
min_latency_us = latency_us; |
|
} |
|
|
|
/* |
|
* By default, we assume that CEDE(0) has exit latency 10us, |
|
* since there is no way for us to query from the platform. |
|
* |
|
* However, if the wakeup latency of an Extended CEDE state is |
|
* smaller than 10us, then we can be sure that CEDE(0) |
|
* requires no more than that. |
|
* |
|
* Perform the fix-up. |
|
*/ |
|
if (min_latency_us < dedicated_states[1].exit_latency) { |
|
/* |
|
* We set a minimum of 1us wakeup latency for cede0 to |
|
* distinguish it from snooze |
|
*/ |
|
u64 cede0_latency = 1; |
|
|
|
if (min_latency_us > cede0_latency) |
|
cede0_latency = min_latency_us - 1; |
|
|
|
dedicated_states[1].exit_latency = cede0_latency; |
|
dedicated_states[1].target_residency = 10 * (cede0_latency); |
|
pr_info("cpuidle: Fixed up CEDE exit latency to %llu us\n", |
|
cede0_latency); |
|
} |
|
|
|
} |
|
|
|
/* |
|
* pseries_idle_probe() |
|
* Choose state table for shared versus dedicated partition |
|
*/ |
|
static int pseries_idle_probe(void) |
|
{ |
|
|
|
if (cpuidle_disable != IDLE_NO_OVERRIDE) |
|
return -ENODEV; |
|
|
|
if (firmware_has_feature(FW_FEATURE_SPLPAR)) { |
|
/* |
|
* Use local_paca instead of get_lppaca() since |
|
* preemption is not disabled, and it is not required in |
|
* fact, since lppaca_ptr does not need to be the value |
|
* associated to the current CPU, it can be from any CPU. |
|
*/ |
|
if (lppaca_shared_proc(local_paca->lppaca_ptr)) { |
|
cpuidle_state_table = shared_states; |
|
max_idle_state = ARRAY_SIZE(shared_states); |
|
} else { |
|
fixup_cede0_latency(); |
|
cpuidle_state_table = dedicated_states; |
|
max_idle_state = NR_DEDICATED_STATES; |
|
} |
|
} else |
|
return -ENODEV; |
|
|
|
if (max_idle_state > 1) { |
|
snooze_timeout_en = true; |
|
snooze_timeout = cpuidle_state_table[1].target_residency * |
|
tb_ticks_per_usec; |
|
} |
|
return 0; |
|
} |
|
|
|
static int __init pseries_processor_idle_init(void) |
|
{ |
|
int retval; |
|
|
|
retval = pseries_idle_probe(); |
|
if (retval) |
|
return retval; |
|
|
|
pseries_cpuidle_driver_init(); |
|
retval = cpuidle_register(&pseries_idle_driver, NULL); |
|
if (retval) { |
|
printk(KERN_DEBUG "Registration of pseries driver failed.\n"); |
|
return retval; |
|
} |
|
|
|
retval = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, |
|
"cpuidle/pseries:online", |
|
pseries_cpuidle_cpu_online, NULL); |
|
WARN_ON(retval < 0); |
|
retval = cpuhp_setup_state_nocalls(CPUHP_CPUIDLE_DEAD, |
|
"cpuidle/pseries:DEAD", NULL, |
|
pseries_cpuidle_cpu_dead); |
|
WARN_ON(retval < 0); |
|
printk(KERN_DEBUG "pseries_idle_driver registered\n"); |
|
return 0; |
|
} |
|
|
|
device_initcall(pseries_processor_idle_init);
|
|
|