1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
commit 23d5de8efb9aed48074a72bf3d43841e1556ca42
Author: Paul Burton <paul.burton@imgtec.com>
Date: Tue Sep 22 11:12:16 2015 -0700
MIPS: CM: Introduce core-other locking functions
Introduce mips_cm_lock_other & mips_cm_unlock_other, mirroring the
existing CPC equivalents, in order to lock access from the current core
to another via the core-other GCR region. This hasn't been required in
the past but with CM3 the CPC starts using GCR_CL_OTHER rather than
CPC_CL_OTHER and this will be required for safety.
[ralf@linux-mips.org: Fix merge conflict.]
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Patchwork: https://patchwork.linux-mips.org/patch/11207/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
--- a/arch/mips/include/asm/mips-cm.h
+++ b/arch/mips/include/asm/mips-cm.h
@@ -334,6 +334,10 @@ BUILD_CM_Cx_R_(tcid_8_priority, 0x80)
/* GCR_Cx_OTHER register fields */
#define CM_GCR_Cx_OTHER_CORENUM_SHF 16
#define CM_GCR_Cx_OTHER_CORENUM_MSK (_ULCAST_(0xffff) << 16)
+#define CM3_GCR_Cx_OTHER_CORE_SHF 8
+#define CM3_GCR_Cx_OTHER_CORE_MSK (_ULCAST_(0x3f) << 8)
+#define CM3_GCR_Cx_OTHER_VP_SHF 0
+#define CM3_GCR_Cx_OTHER_VP_MSK (_ULCAST_(0x7) << 0)
/* GCR_Cx_RESET_BASE register fields */
#define CM_GCR_Cx_RESET_BASE_BEVEXCBASE_SHF 12
@@ -444,4 +448,32 @@ static inline unsigned int mips_cm_vp_id
return (core * mips_cm_max_vp_width()) + vp;
}
+#ifdef CONFIG_MIPS_CM
+
+/**
+ * mips_cm_lock_other - lock access to another core
+ * @core: the other core to be accessed
+ * @vp: the VP within the other core to be accessed
+ *
+ * Call before operating upon a core via the 'other' register region in
+ * order to prevent the region being moved during access. Must be followed
+ * by a call to mips_cm_unlock_other.
+ */
+extern void mips_cm_lock_other(unsigned int core, unsigned int vp);
+
+/**
+ * mips_cm_unlock_other - unlock access to another core
+ *
+ * Call after operating upon another core via the 'other' register region.
+ * Must be called after mips_cm_lock_other.
+ */
+extern void mips_cm_unlock_other(void);
+
+#else /* !CONFIG_MIPS_CM */
+
+static inline void mips_cm_lock_other(unsigned int core) { }
+static inline void mips_cm_unlock_other(void) { }
+
+#endif /* !CONFIG_MIPS_CM */
+
#endif /* __MIPS_ASM_MIPS_CM_H__ */
--- a/arch/mips/kernel/mips-cm.c
+++ b/arch/mips/kernel/mips-cm.c
@@ -9,6 +9,8 @@
*/
#include <linux/errno.h>
+#include <linux/percpu.h>
+#include <linux/spinlock.h>
#include <asm/mips-cm.h>
#include <asm/mipsregs.h>
@@ -136,6 +138,9 @@ static char *cm3_causes[32] = {
"0x19", "0x1a", "0x1b", "0x1c", "0x1d", "0x1e", "0x1f"
};
+static DEFINE_PER_CPU_ALIGNED(spinlock_t, cm_core_lock);
+static DEFINE_PER_CPU_ALIGNED(unsigned long, cm_core_lock_flags);
+
phys_addr_t __mips_cm_phys_base(void)
{
u32 config3 = read_c0_config3();
@@ -200,6 +205,7 @@ int mips_cm_probe(void)
{
phys_addr_t addr;
u32 base_reg;
+ unsigned cpu;
/*
* No need to probe again if we have already been
@@ -247,9 +253,42 @@ int mips_cm_probe(void)
/* determine register width for this CM */
mips_cm_is64 = config_enabled(CONFIG_64BIT) && (mips_cm_revision() >= CM_REV_CM3);
+ for_each_possible_cpu(cpu)
+ spin_lock_init(&per_cpu(cm_core_lock, cpu));
+
return 0;
}
+void mips_cm_lock_other(unsigned int core, unsigned int vp)
+{
+ unsigned curr_core;
+ u32 val;
+
+ preempt_disable();
+ curr_core = current_cpu_data.core;
+ spin_lock_irqsave(&per_cpu(cm_core_lock, curr_core),
+ per_cpu(cm_core_lock_flags, curr_core));
+
+ if (mips_cm_revision() >= CM_REV_CM3) {
+ val = core << CM3_GCR_Cx_OTHER_CORE_SHF;
+ val |= vp << CM3_GCR_Cx_OTHER_VP_SHF;
+ } else {
+ BUG_ON(vp != 0);
+ val = core << CM_GCR_Cx_OTHER_CORENUM_SHF;
+ }
+
+ write_gcr_cl_other(val);
+}
+
+void mips_cm_unlock_other(void)
+{
+ unsigned curr_core = current_cpu_data.core;
+
+ spin_unlock_irqrestore(&per_cpu(cm_core_lock, curr_core),
+ per_cpu(cm_core_lock_flags, curr_core));
+ preempt_enable();
+}
+
void mips_cm_error_report(void)
{
unsigned long revision = mips_cm_revision();
|
