1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2007 PA Semi, Inc
  4 *
  5 * Authors: Egor Martovetsky <egor@pasemi.com>
  6 *	    Olof Johansson <olof@lixom.net>
  7 *
  8 * Maintained by: Olof Johansson <olof@lixom.net>
  9 *
 10 * Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
 11 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 12 */
 13
 14#include <linux/cpufreq.h>
 15#include <linux/timer.h>
 16#include <linux/module.h>
 17#include <linux/of_address.h>
 18
 19#include <asm/hw_irq.h>
 20#include <asm/io.h>
 21#include <asm/prom.h>
 22#include <asm/time.h>
 23#include <asm/smp.h>
 24
 25#include <platforms/pasemi/pasemi.h>
 26
 27#define SDCASR_REG		0x0100
 28#define SDCASR_REG_STRIDE	0x1000
 29#define SDCPWR_CFGA0_REG	0x0100
 30#define SDCPWR_PWST0_REG	0x0000
 31#define SDCPWR_GIZTIME_REG	0x0440
 32
 33/* SDCPWR_GIZTIME_REG fields */
 34#define SDCPWR_GIZTIME_GR	0x80000000
 35#define SDCPWR_GIZTIME_LONGLOCK	0x000000ff
 36
 37/* Offset of ASR registers from SDC base */
 38#define SDCASR_OFFSET		0x120000
 39
 40static void __iomem *sdcpwr_mapbase;
 41static void __iomem *sdcasr_mapbase;
 42
 43/* Current astate, is used when waking up from power savings on
 44 * one core, in case the other core has switched states during
 45 * the idle time.
 46 */
 47static int current_astate;
 48
 49/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
 50static struct cpufreq_frequency_table pas_freqs[] = {
 51	{0, 0,	0},
 52	{0, 1,	0},
 53	{0, 2,	0},
 54	{0, 3,	0},
 55	{0, 4,	0},
 56	{0, 0,	CPUFREQ_TABLE_END},
 57};
 58
 59/*
 60 * hardware specific functions
 61 */
 62
 63static int get_astate_freq(int astate)
 64{
 65	u32 ret;
 66	ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
 67
 68	return ret & 0x3f;
 69}
 70
 71static int get_cur_astate(int cpu)
 72{
 73	u32 ret;
 74
 75	ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
 76	ret = (ret >> (cpu * 4)) & 0x7;
 77
 78	return ret;
 79}
 80
 81static int get_gizmo_latency(void)
 82{
 83	u32 giztime, ret;
 84
 85	giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
 86
 87	/* just provide the upper bound */
 88	if (giztime & SDCPWR_GIZTIME_GR)
 89		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
 90	else
 91		ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
 92
 93	return ret;
 94}
 95
 96static void set_astate(int cpu, unsigned int astate)
 97{
 98	unsigned long flags;
 99
100	/* Return if called before init has run */
101	if (unlikely(!sdcasr_mapbase))
102		return;
103
104	local_irq_save(flags);
105
106	out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
107
108	local_irq_restore(flags);
109}
110
111int check_astate(void)
112{
113	return get_cur_astate(hard_smp_processor_id());
114}
115
116void restore_astate(int cpu)
117{
118	set_astate(cpu, current_astate);
119}
120
121/*
122 * cpufreq functions
123 */
124
125static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
126{
127	struct cpufreq_frequency_table *pos;
128	const u32 *max_freqp;
129	u32 max_freq;
130	int cur_astate, idx;
131	struct resource res;
132	struct device_node *cpu, *dn;
133	int err = -ENODEV;
134
135	cpu = of_get_cpu_node(policy->cpu, NULL);
136	if (!cpu)
137		goto out;
138
139	max_freqp = of_get_property(cpu, "clock-frequency", NULL);
140	of_node_put(cpu);
141	if (!max_freqp) {
142		err = -EINVAL;
143		goto out;
144	}
145
146	/* we need the freq in kHz */
147	max_freq = *max_freqp / 1000;
148
149	dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
150	if (!dn)
151		dn = of_find_compatible_node(NULL, NULL,
152					     "pasemi,pwrficient-sdc");
153	if (!dn)
154		goto out;
155	err = of_address_to_resource(dn, 0, &res);
156	of_node_put(dn);
157	if (err)
158		goto out;
159	sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
160	if (!sdcasr_mapbase) {
161		err = -EINVAL;
162		goto out;
163	}
164
165	dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
166	if (!dn)
167		dn = of_find_compatible_node(NULL, NULL,
168					     "pasemi,pwrficient-gizmo");
169	if (!dn) {
170		err = -ENODEV;
171		goto out_unmap_sdcasr;
172	}
173	err = of_address_to_resource(dn, 0, &res);
174	of_node_put(dn);
175	if (err)
176		goto out_unmap_sdcasr;
177	sdcpwr_mapbase = ioremap(res.start, 0x1000);
178	if (!sdcpwr_mapbase) {
179		err = -EINVAL;
180		goto out_unmap_sdcasr;
181	}
182
183	pr_debug("init cpufreq on CPU %d\n", policy->cpu);
184	pr_debug("max clock-frequency is at %u kHz\n", max_freq);
185	pr_debug("initializing frequency table\n");
186
187	/* initialize frequency table */
188	cpufreq_for_each_entry_idx(pos, pas_freqs, idx) {
189		pos->frequency = get_astate_freq(pos->driver_data) * 100000;
190		pr_debug("%d: %d\n", idx, pos->frequency);
191	}
192
193	cur_astate = get_cur_astate(policy->cpu);
194	pr_debug("current astate is at %d\n",cur_astate);
195
196	policy->cur = pas_freqs[cur_astate].frequency;
197	ppc_proc_freq = policy->cur * 1000ul;
198
199	cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
200	return 0;
201
202out_unmap_sdcasr:
203	iounmap(sdcasr_mapbase);
204out:
205	return err;
206}
207
208static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
209{
210	/*
211	 * We don't support CPU hotplug. Don't unmap after the system
212	 * has already made it to a running state.
213	 */
214	if (system_state >= SYSTEM_RUNNING)
215		return 0;
216
217	if (sdcasr_mapbase)
218		iounmap(sdcasr_mapbase);
219	if (sdcpwr_mapbase)
220		iounmap(sdcpwr_mapbase);
221
222	return 0;
223}
224
225static int pas_cpufreq_target(struct cpufreq_policy *policy,
226			      unsigned int pas_astate_new)
227{
228	int i;
229
230	pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
231		 policy->cpu,
232		 pas_freqs[pas_astate_new].frequency,
233		 pas_freqs[pas_astate_new].driver_data);
234
235	current_astate = pas_astate_new;
236
237	for_each_online_cpu(i)
238		set_astate(i, pas_astate_new);
239
240	ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
241	return 0;
242}
243
244static struct cpufreq_driver pas_cpufreq_driver = {
245	.name		= "pas-cpufreq",
246	.flags		= CPUFREQ_CONST_LOOPS,
247	.init		= pas_cpufreq_cpu_init,
248	.exit		= pas_cpufreq_cpu_exit,
249	.verify		= cpufreq_generic_frequency_table_verify,
250	.target_index	= pas_cpufreq_target,
251	.attr		= cpufreq_generic_attr,
252};
253
254/*
255 * module init and destoy
256 */
257
258static int __init pas_cpufreq_init(void)
259{
260	if (!of_machine_is_compatible("PA6T-1682M") &&
261	    !of_machine_is_compatible("pasemi,pwrficient"))
262		return -ENODEV;
263
264	return cpufreq_register_driver(&pas_cpufreq_driver);
265}
266
267static void __exit pas_cpufreq_exit(void)
268{
269	cpufreq_unregister_driver(&pas_cpufreq_driver);
270}
271
272module_init(pas_cpufreq_init);
273module_exit(pas_cpufreq_exit);
274
275MODULE_LICENSE("GPL");
276MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");