1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * pervasive backend for the cbe_cpufreq driver
4 *
5 * This driver makes use of the pervasive unit to
6 * engage the desired frequency.
7 *
8 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005-2007
9 *
10 * Author: Christian Krafft <krafft@de.ibm.com>
11 */
12
13#include <linux/io.h>
14#include <linux/kernel.h>
15#include <linux/time.h>
16#include <asm/machdep.h>
17#include <asm/hw_irq.h>
18#include <asm/cell-regs.h>
19
20#include "ppc_cbe_cpufreq.h"
21
22/* to write to MIC register */
23static u64 MIC_Slow_Fast_Timer_table[] = {
24	[0 ... 7] = 0x007fc00000000000ull,
25};
26
27/* more values for the MIC */
28static u64 MIC_Slow_Next_Timer_table[] = {
29	0x0000240000000000ull,
30	0x0000268000000000ull,
31	0x000029C000000000ull,
32	0x00002D0000000000ull,
33	0x0000300000000000ull,
34	0x0000334000000000ull,
35	0x000039C000000000ull,
36	0x00003FC000000000ull,
37};
38
39
40int cbe_cpufreq_set_pmode(int cpu, unsigned int pmode)
41{
42	struct cbe_pmd_regs __iomem *pmd_regs;
43	struct cbe_mic_tm_regs __iomem *mic_tm_regs;
44	unsigned long flags;
45	u64 value;
46#ifdef DEBUG
47	long time;
48#endif
49
50	local_irq_save(flags);
51
52	mic_tm_regs = cbe_get_cpu_mic_tm_regs(cpu);
53	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
54
55#ifdef DEBUG
56	time = jiffies;
57#endif
58
59	out_be64(&mic_tm_regs->slow_fast_timer_0, MIC_Slow_Fast_Timer_table[pmode]);
60	out_be64(&mic_tm_regs->slow_fast_timer_1, MIC_Slow_Fast_Timer_table[pmode]);
61
62	out_be64(&mic_tm_regs->slow_next_timer_0, MIC_Slow_Next_Timer_table[pmode]);
63	out_be64(&mic_tm_regs->slow_next_timer_1, MIC_Slow_Next_Timer_table[pmode]);
64
65	value = in_be64(&pmd_regs->pmcr);
66	/* set bits to zero */
67	value &= 0xFFFFFFFFFFFFFFF8ull;
68	/* set bits to next pmode */
69	value |= pmode;
70
71	out_be64(&pmd_regs->pmcr, value);
72
73#ifdef DEBUG
74	/* wait until new pmode appears in status register */
75	value = in_be64(&pmd_regs->pmsr) & 0x07;
76	while (value != pmode) {
77		cpu_relax();
78		value = in_be64(&pmd_regs->pmsr) & 0x07;
79	}
80
81	time = jiffies  - time;
82	time = jiffies_to_msecs(time);
83	pr_debug("had to wait %lu ms for a transition using " \
84		 "pervasive unit\n", time);
85#endif
86	local_irq_restore(flags);
87
88	return 0;
89}
90
91
92int cbe_cpufreq_get_pmode(int cpu)
93{
94	int ret;
95	struct cbe_pmd_regs __iomem *pmd_regs;
96
97	pmd_regs = cbe_get_cpu_pmd_regs(cpu);
98	ret = in_be64(&pmd_regs->pmsr) & 0x07;
99
100	return ret;
101}
102
103