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