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 */
23 static u64 MIC_Slow_Fast_Timer_table[] = {
24 [0 ... 7] = 0x007fc00000000000ull,
25 };
26
27 /* more values for the MIC */
28 static 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
cbe_cpufreq_set_pmode(int cpu,unsigned int pmode)40 int 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
cbe_cpufreq_get_pmode(int cpu)92 int 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