diff options
| -rw-r--r-- | drivers/idle/intel_idle.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index f64463e00df7..ab6b86ff9905 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -73,6 +73,10 @@ static unsigned int disabled_states_mask __read_mostly; static bool force_irq_on __read_mostly; static bool ibrs_off __read_mostly; +/* The maximum allowed length for the 'table' module parameter */ +#define MAX_CMDLINE_TABLE_LEN 256 +static char cmdline_table_str[MAX_CMDLINE_TABLE_LEN] __read_mostly; + static struct cpuidle_device __percpu *intel_idle_cpuidle_devices; static unsigned long auto_demotion_disable_flags; @@ -104,6 +108,9 @@ static struct device *sysfs_root __initdata; static const struct idle_cpu *icpu __initdata; static struct cpuidle_state *cpuidle_state_table __initdata; +/* C-states data from the 'intel_idle.table' cmdline parameter */ +static struct cpuidle_state cmdline_states[CPUIDLE_STATE_MAX] __initdata; + static unsigned int mwait_substates __initdata; /* @@ -2393,6 +2400,149 @@ static void __init intel_idle_sysfs_uninit(void) put_device(sysfs_root); } + /** + * get_cmdline_field - Get the current field from a cmdline string. + * @args: The cmdline string to get the current field from. + * @field: Pointer to the current field upon return. + * @sep: The fields separator character. + * + * Examples: + * Input: args="C1:1:1,C1E:2:10", sep=':' + * Output: field="C1", return "1:1,C1E:2:10" + * Input: args="C1:1:1,C1E:2:10", sep=',' + * Output: field="C1:1:1", return "C1E:2:10" + * Ipnut: args="::", sep=':' + * Output: field="", return ":" + * + * Return: The continuation of the cmdline string after the field or NULL. + */ +static char *get_cmdline_field(char *args, char **field, char sep) +{ + unsigned int i; + + for (i = 0; args[i] && !isspace(args[i]); i++) { + if (args[i] == sep) + break; + } + + *field = args; + + if (args[i] != sep) + return NULL; + + args[i] = '\0'; + return args + i + 1; +} + +/** + * cmdline_table_adjust - Adjust the C-states table with data from cmdline. + * @drv: cpuidle driver (assumed to point to intel_idle_driver). + * + * Adjust the C-states table with data from the 'intel_idle.table' module + * parameter (if specified). + */ +static void __init cmdline_table_adjust(struct cpuidle_driver *drv) +{ + char *args = cmdline_table_str; + struct cpuidle_state *state; + int i; + + if (args[0] == '\0') + /* The 'intel_idle.table' module parameter was not specified */ + return; + + /* Create a copy of the C-states table */ + for (i = 0; i < drv->state_count; i++) + cmdline_states[i] = drv->states[i]; + + /* + * Adjust the C-states table copy with data from the 'intel_idle.table' + * module parameter. + */ + while (args) { + char *fields, *name, *val; + + /* + * Get the next C-state definition, which is expected to be + * '<name>:<latency_us>:<target_residency_us>'. Treat "empty" + * fields as unchanged. For example, + * '<name>::<target_residency_us>' leaves the latency unchanged. + */ + args = get_cmdline_field(args, &fields, ','); + + /* name */ + fields = get_cmdline_field(fields, &name, ':'); + if (!fields) + goto error; + + if (!strcmp(name, "POLL")) { + pr_err("Cannot adjust POLL\n"); + continue; + } + + /* Find the C-state by its name */ + state = NULL; + for (i = 0; i < drv->state_count; i++) { + if (!strcmp(name, drv->states[i].name)) { + state = &cmdline_states[i]; + break; + } + } + + if (!state) { + pr_err("C-state '%s' was not found\n", name); + continue; + } + + /* Latency */ + fields = get_cmdline_field(fields, &val, ':'); + if (!fields) + goto error; + + if (*val) { + if (kstrtouint(val, 0, &state->exit_latency)) + goto error; + } + + /* Target residency */ + fields = get_cmdline_field(fields, &val, ':'); + + if (*val) { + if (kstrtouint(val, 0, &state->target_residency)) + goto error; + } + + /* + * Allow for 3 more fields, but ignore them. Helps to make + * possible future extensions of the cmdline format backward + * compatible. + */ + for (i = 0; fields && i < 3; i++) { + fields = get_cmdline_field(fields, &val, ':'); + if (!fields) + break; + } + + if (fields) { + pr_err("Too many fields for C-state '%s'\n", state->name); + goto error; + } + + pr_info("C-state from cmdline: name=%s, latency=%u, residency=%u\n", + state->name, state->exit_latency, state->target_residency); + } + + /* Copy the adjusted C-states table back */ + for (i = 1; i < drv->state_count; i++) + drv->states[i] = cmdline_states[i]; + + pr_info("Adjusted C-states with data from 'intel_idle.table'\n"); + return; + +error: + pr_info("Failed to adjust C-states with data from 'intel_idle.table'\n"); +} + static int __init intel_idle_init(void) { const struct x86_cpu_id *id; @@ -2456,6 +2606,7 @@ static int __init intel_idle_init(void) return -ENOMEM; intel_idle_cpuidle_driver_init(&intel_idle_driver); + cmdline_table_adjust(&intel_idle_driver); retval = intel_idle_sysfs_init(); if (retval) @@ -2519,3 +2670,21 @@ module_param(force_irq_on, bool, 0444); */ module_param(ibrs_off, bool, 0444); MODULE_PARM_DESC(ibrs_off, "Disable IBRS when idle"); + +/* + * Define the C-states table from a user input string. Expected format is + * 'name:latency:residency', where: + * - name: The C-state name. + * - latency: The C-state exit latency in us. + * - residency: The C-state target residency in us. + * + * Multiple C-states can be defined by separating them with commas: + * 'name1:latency1:residency1,name2:latency2:residency2' + * + * Example: intel_idle.table=C1:1:1,C1E:5:10,C6:100:600 + * + * To leave latency or residency unchanged, use an empty field, for example: + * 'C1:1:1,C1E::10' - leaves C1E latency unchanged. + */ +module_param_string(table, cmdline_table_str, MAX_CMDLINE_TABLE_LEN, 0444); +MODULE_PARM_DESC(table, "Build the C-states table from a user input string"); |