1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2013 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7 #include <linux/bitfield.h>
8 #include <linux/errno.h>
9 #include <linux/percpu.h>
10 #include <linux/of.h>
11 #include <linux/of_address.h>
12 #include <linux/spinlock.h>
13
14 #include <asm/mips-cps.h>
15
16 void __iomem *mips_cpc_base;
17
18 static DEFINE_PER_CPU_ALIGNED(spinlock_t, cpc_core_lock);
19
20 static DEFINE_PER_CPU_ALIGNED(unsigned long, cpc_core_lock_flags);
21
mips_cpc_default_phys_base(void)22 phys_addr_t __weak mips_cpc_default_phys_base(void)
23 {
24 struct device_node *cpc_node;
25 struct resource res;
26 int err;
27
28 cpc_node = of_find_compatible_node(of_root, NULL, "mti,mips-cpc");
29 if (cpc_node) {
30 err = of_address_to_resource(cpc_node, 0, &res);
31 of_node_put(cpc_node);
32 if (!err)
33 return res.start;
34 }
35
36 return 0;
37 }
38
39 /**
40 * mips_cpc_phys_base - retrieve the physical base address of the CPC
41 *
42 * This function returns the physical base address of the Cluster Power
43 * Controller memory mapped registers, or 0 if no Cluster Power Controller
44 * is present.
45 */
mips_cpc_phys_base(void)46 static phys_addr_t mips_cpc_phys_base(void)
47 {
48 unsigned long cpc_base;
49
50 if (!mips_cm_present())
51 return 0;
52
53 if (!(read_gcr_cpc_status() & CM_GCR_CPC_STATUS_EX))
54 return 0;
55
56 /* If the CPC is already enabled, leave it so */
57 cpc_base = read_gcr_cpc_base();
58 if (cpc_base & CM_GCR_CPC_BASE_CPCEN)
59 return cpc_base & CM_GCR_CPC_BASE_CPCBASE;
60
61 /* Otherwise, use the default address */
62 cpc_base = mips_cpc_default_phys_base();
63 if (!cpc_base)
64 return cpc_base;
65
66 /* Enable the CPC, mapped at the default address */
67 write_gcr_cpc_base(cpc_base | CM_GCR_CPC_BASE_CPCEN);
68 return cpc_base;
69 }
70
mips_cpc_probe(void)71 int mips_cpc_probe(void)
72 {
73 phys_addr_t addr;
74 unsigned int cpu;
75
76 for_each_possible_cpu(cpu)
77 spin_lock_init(&per_cpu(cpc_core_lock, cpu));
78
79 addr = mips_cpc_phys_base();
80 if (!addr)
81 return -ENODEV;
82
83 mips_cpc_base = ioremap(addr, 0x8000);
84 if (!mips_cpc_base)
85 return -ENXIO;
86
87 return 0;
88 }
89
mips_cpc_lock_other(unsigned int core)90 void mips_cpc_lock_other(unsigned int core)
91 {
92 unsigned int curr_core;
93
94 if (mips_cm_revision() >= CM_REV_CM3)
95 /* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
96 return;
97
98 preempt_disable();
99 curr_core = cpu_core(¤t_cpu_data);
100 spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
101 per_cpu(cpc_core_lock_flags, curr_core));
102 write_cpc_cl_other(FIELD_PREP(CPC_Cx_OTHER_CORENUM, core));
103
104 /*
105 * Ensure the core-other region reflects the appropriate core &
106 * VP before any accesses to it occur.
107 */
108 mb();
109 }
110
mips_cpc_unlock_other(void)111 void mips_cpc_unlock_other(void)
112 {
113 unsigned int curr_core;
114
115 if (mips_cm_revision() >= CM_REV_CM3)
116 /* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
117 return;
118
119 curr_core = cpu_core(¤t_cpu_data);
120 spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
121 per_cpu(cpc_core_lock_flags, curr_core));
122 preempt_enable();
123 }
124