1 // SPDX-License-Identifier: GPL-2.0
3  *  cpuidle-pseries - idle state cpuidle driver.
78 	 * were soft-disabled  in check_and_cede_processor()
92  *        "ibm,get-systems-parameter" RTAS call with the token
98  * table with all the parameters to ibm,get-system-parameters.
99  * CEDE_LATENCY_TOKEN corresponds to the token value for Cede Latency
105  * If the platform supports the cede latency settings information system
109  * a. The first byte is the length “N” of each cede latency setting record minus
112  * b. For each supported cede latency setting a cede latency setting record
115  *    -----------------------------
118  *    -----------------------------
119  *    | Cede Latency    | 1 Byte  |
121  *    -----------------------------
123  *    | latency in      | 8 Bytes |
124  *    | tb-ticks        |         |
125  *    -----------------------------
129  *    -----------------------------
131  * This version has cede latency record size = 10.
137  * ibm,get-systems-parameter RTAS call when made with
141  * call. The data is in big-endian.
172 	ret = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1,  in parse_cede_parameters()
183 	xcede_record_size = payload->record_size + 1;  in parse_cede_parameters()
186 		pr_err("xcede: Expected record-size %lu. Observed size %u.\n",  in parse_cede_parameters()
188 		return -EINVAL;  in parse_cede_parameters()
198 	total_xcede_records_size = payload_size - 2;  in parse_cede_parameters()
202 		struct xcede_latency_record *record = &payload->records[i];  in parse_cede_parameters()
203 		u64 latency_ticks = be64_to_cpu(record->latency_ticks);  in parse_cede_parameters()
204 		u8 wake_on_irqs = record->wake_on_irqs;  in parse_cede_parameters()
205 		u8 hint = record->hint;  in parse_cede_parameters()
207 		pr_info("xcede: Record %d : hint = %u, latency = 0x%llx tb ticks, Wake-on-irq = %u\n",  in parse_cede_parameters()
224 	get_lppaca()->donate_dedicated_cpu = 1;  in dedicated_cede_loop()
225 	old_latency_hint = get_lppaca()->cede_latency_hint;  in dedicated_cede_loop()
226 	get_lppaca()->cede_latency_hint = cede_latency_hint[index];  in dedicated_cede_loop()
232 	get_lppaca()->donate_dedicated_cpu = 0;  in dedicated_cede_loop()
233 	get_lppaca()->cede_latency_hint = old_latency_hint;  in dedicated_cede_loop()
330 	drv->state_count = 0;  in pseries_cpuidle_driver_init()
337 		drv->states[drv->state_count] =	/* structure copy */  in pseries_cpuidle_driver_init()
340 		drv->state_count += 1;  in pseries_cpuidle_driver_init()
352 	min_latency_us = dedicated_states[1].exit_latency; // CEDE latency  in fixup_cede0_latency()
362 		struct xcede_latency_record *record = &payload->records[i];  in fixup_cede0_latency()
363 		u64 latency_tb = be64_to_cpu(record->latency_ticks);  in fixup_cede0_latency()
367 			pr_warn("cpuidle: xcede record %d has an unrealistic latency of 0us.\n", i);  in fixup_cede0_latency()
374 	 * By default, we assume that CEDE(0) has exit latency 10us,  in fixup_cede0_latency()
377 	 * However, if the wakeup latency of an Extended CEDE state is  in fixup_cede0_latency()
381 	 * Perform the fix-up.  in fixup_cede0_latency()
385 		 * We set a minimum of 1us wakeup latency for cede0 to  in fixup_cede0_latency()
391 			cede0_latency = min_latency_us - 1;  in fixup_cede0_latency()
395 		pr_info("cpuidle: Fixed up CEDE exit latency to %llu us\n",  in fixup_cede0_latency()
409 		return -ENODEV;  in pseries_idle_probe()
418 		if (lppaca_shared_proc(local_paca->lppaca_ptr)) {  in pseries_idle_probe()
423 			 * Use firmware provided latency values  in pseries_idle_probe()
431 			 * provided latency values. On such platforms,  in pseries_idle_probe()
441 		return -ENODEV;  in pseries_idle_probe()