1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright 2011 IBM Corporation.
4 */
5 #include <linux/types.h>
6 #include <linux/kernel.h>
7 #include <linux/irq.h>
8 #include <linux/smp.h>
9 #include <linux/interrupt.h>
10 #include <linux/irqdomain.h>
11 #include <linux/cpu.h>
12 #include <linux/of.h>
13
14 #include <asm/smp.h>
15 #include <asm/irq.h>
16 #include <asm/errno.h>
17 #include <asm/xics.h>
18 #include <asm/io.h>
19 #include <asm/hvcall.h>
20
21 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
22 {
23 unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
24 long rc;
25 unsigned int ret = XICS_IRQ_SPURIOUS;
26
27 rc = plpar_hcall(H_XIRR, retbuf, cppr);
28 if (rc == H_SUCCESS) {
29 ret = (unsigned int)retbuf[0];
30 } else {
31 pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
32 __func__, cppr, rc);
33 WARN_ON_ONCE(1);
34 }
35
36 return ret;
37 }
38
39 static inline void icp_hv_set_cppr(u8 value)
40 {
41 long rc = plpar_hcall_norets(H_CPPR, value);
42 if (rc != H_SUCCESS) {
43 pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
44 __func__, value, rc);
45 WARN_ON_ONCE(1);
46 }
47 }
48
49 static inline void icp_hv_set_xirr(unsigned int value)
50 {
51 long rc = plpar_hcall_norets(H_EOI, value);
52 if (rc != H_SUCCESS) {
53 pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
54 __func__, value, rc);
55 WARN_ON_ONCE(1);
56 icp_hv_set_cppr(value >> 24);
57 }
58 }
59
60 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
61 {
62 int hw_cpu = get_hard_smp_processor_id(n_cpu);
63 long rc;
64
65 /* Make sure all previous accesses are ordered before IPI sending */
66 mb();
67 rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
68 if (rc != H_SUCCESS) {
69 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
70 "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
71 WARN_ON_ONCE(1);
72 }
73 }
74
75 static void icp_hv_eoi(struct irq_data *d)
76 {
77 unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
78
79 iosync();
80 icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
81 }
82
83 static void icp_hv_teardown_cpu(void)
84 {
85 int cpu = smp_processor_id();
86
87 /* Clear any pending IPI */
88 icp_hv_set_qirr(cpu, 0xff);
89 }
90
91 static void icp_hv_flush_ipi(void)
92 {
93 /* We take the ipi irq but and never return so we
94 * need to EOI the IPI, but want to leave our priority 0
95 *
96 * should we check all the other interrupts too?
97 * should we be flagging idle loop instead?
98 * or creating some task to be scheduled?
99 */
100
101 icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
102 }
103
104 static unsigned int icp_hv_get_irq(void)
105 {
106 unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
107 unsigned int vec = xirr & 0x00ffffff;
108 unsigned int irq;
109
110 if (vec == XICS_IRQ_SPURIOUS)
111 return 0;
112
113 irq = irq_find_mapping(xics_host, vec);
114 if (likely(irq)) {
115 xics_push_cppr(vec);
116 return irq;
117 }
118
119 /* We don't have a linux mapping, so have rtas mask it. */
120 xics_mask_unknown_vec(vec);
121
122 /* We might learn about it later, so EOI it */
123 icp_hv_set_xirr(xirr);
124
125 return 0;
126 }
127
128 static void icp_hv_set_cpu_priority(unsigned char cppr)
129 {
130 xics_set_base_cppr(cppr);
131 icp_hv_set_cppr(cppr);
132 iosync();
133 }
134
135 #ifdef CONFIG_SMP
136
137 static void icp_hv_cause_ipi(int cpu)
138 {
139 icp_hv_set_qirr(cpu, IPI_PRIORITY);
140 }
141
142 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
143 {
144 int cpu = smp_processor_id();
145
146 icp_hv_set_qirr(cpu, 0xff);
147
148 return smp_ipi_demux();
149 }
150
151 #endif /* CONFIG_SMP */
152
153 static const struct icp_ops icp_hv_ops = {
154 .get_irq = icp_hv_get_irq,
155 .eoi = icp_hv_eoi,
156 .set_priority = icp_hv_set_cpu_priority,
157 .teardown_cpu = icp_hv_teardown_cpu,
158 .flush_ipi = icp_hv_flush_ipi,
159 #ifdef CONFIG_SMP
160 .ipi_action = icp_hv_ipi_action,
161 .cause_ipi = icp_hv_cause_ipi,
162 #endif
163 };
164
165 int __init icp_hv_init(void)
166 {
167 struct device_node *np;
168
169 np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
170 if (!np)
171 np = of_find_node_by_type(NULL,
172 "PowerPC-External-Interrupt-Presentation");
173 if (!np)
174 return -ENODEV;
175
176 icp_ops = &icp_hv_ops;
177
178 of_node_put(np);
179 return 0;
180 }
181
182
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