1 /*
2 * Copyright 2011 IBM Corporation.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
8 *
9 */
10 #include <linux/types.h>
11 #include <linux/kernel.h>
12 #include <linux/irq.h>
13 #include <linux/smp.h>
14 #include <linux/interrupt.h>
15 #include <linux/cpu.h>
16 #include <linux/of.h>
17
18 #include <asm/smp.h>
19 #include <asm/irq.h>
20 #include <asm/errno.h>
21 #include <asm/xics.h>
22 #include <asm/io.h>
23 #include <asm/hvcall.h>
24
icp_hv_get_xirr(unsigned char cppr)25 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
26 {
27 unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
28 long rc;
29 unsigned int ret = XICS_IRQ_SPURIOUS;
30
31 rc = plpar_hcall(H_XIRR, retbuf, cppr);
32 if (rc == H_SUCCESS) {
33 ret = (unsigned int)retbuf[0];
34 } else {
35 pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
36 __func__, cppr, rc);
37 WARN_ON_ONCE(1);
38 }
39
40 return ret;
41 }
42
icp_hv_set_cppr(u8 value)43 static inline void icp_hv_set_cppr(u8 value)
44 {
45 long rc = plpar_hcall_norets(H_CPPR, value);
46 if (rc != H_SUCCESS) {
47 pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
48 __func__, value, rc);
49 WARN_ON_ONCE(1);
50 }
51 }
52
icp_hv_set_xirr(unsigned int value)53 static inline void icp_hv_set_xirr(unsigned int value)
54 {
55 long rc = plpar_hcall_norets(H_EOI, value);
56 if (rc != H_SUCCESS) {
57 pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
58 __func__, value, rc);
59 WARN_ON_ONCE(1);
60 icp_hv_set_cppr(value >> 24);
61 }
62 }
63
icp_hv_set_qirr(int n_cpu,u8 value)64 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
65 {
66 int hw_cpu = get_hard_smp_processor_id(n_cpu);
67 long rc;
68
69 /* Make sure all previous accesses are ordered before IPI sending */
70 mb();
71 rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
72 if (rc != H_SUCCESS) {
73 pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
74 "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
75 WARN_ON_ONCE(1);
76 }
77 }
78
icp_hv_eoi(struct irq_data * d)79 static void icp_hv_eoi(struct irq_data *d)
80 {
81 unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
82
83 iosync();
84 icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
85 }
86
icp_hv_teardown_cpu(void)87 static void icp_hv_teardown_cpu(void)
88 {
89 int cpu = smp_processor_id();
90
91 /* Clear any pending IPI */
92 icp_hv_set_qirr(cpu, 0xff);
93 }
94
icp_hv_flush_ipi(void)95 static void icp_hv_flush_ipi(void)
96 {
97 /* We take the ipi irq but and never return so we
98 * need to EOI the IPI, but want to leave our priority 0
99 *
100 * should we check all the other interrupts too?
101 * should we be flagging idle loop instead?
102 * or creating some task to be scheduled?
103 */
104
105 icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
106 }
107
icp_hv_get_irq(void)108 static unsigned int icp_hv_get_irq(void)
109 {
110 unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
111 unsigned int vec = xirr & 0x00ffffff;
112 unsigned int irq;
113
114 if (vec == XICS_IRQ_SPURIOUS)
115 return NO_IRQ;
116
117 irq = irq_find_mapping(xics_host, vec);
118 if (likely(irq != NO_IRQ)) {
119 xics_push_cppr(vec);
120 return irq;
121 }
122
123 /* We don't have a linux mapping, so have rtas mask it. */
124 xics_mask_unknown_vec(vec);
125
126 /* We might learn about it later, so EOI it */
127 icp_hv_set_xirr(xirr);
128
129 return NO_IRQ;
130 }
131
icp_hv_set_cpu_priority(unsigned char cppr)132 static void icp_hv_set_cpu_priority(unsigned char cppr)
133 {
134 xics_set_base_cppr(cppr);
135 icp_hv_set_cppr(cppr);
136 iosync();
137 }
138
139 #ifdef CONFIG_SMP
140
icp_hv_cause_ipi(int cpu,unsigned long data)141 static void icp_hv_cause_ipi(int cpu, unsigned long data)
142 {
143 icp_hv_set_qirr(cpu, IPI_PRIORITY);
144 }
145
icp_hv_ipi_action(int irq,void * dev_id)146 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
147 {
148 int cpu = smp_processor_id();
149
150 icp_hv_set_qirr(cpu, 0xff);
151
152 return smp_ipi_demux();
153 }
154
155 #endif /* CONFIG_SMP */
156
157 static const struct icp_ops icp_hv_ops = {
158 .get_irq = icp_hv_get_irq,
159 .eoi = icp_hv_eoi,
160 .set_priority = icp_hv_set_cpu_priority,
161 .teardown_cpu = icp_hv_teardown_cpu,
162 .flush_ipi = icp_hv_flush_ipi,
163 #ifdef CONFIG_SMP
164 .ipi_action = icp_hv_ipi_action,
165 .cause_ipi = icp_hv_cause_ipi,
166 #endif
167 };
168
icp_hv_init(void)169 int icp_hv_init(void)
170 {
171 struct device_node *np;
172
173 np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
174 if (!np)
175 np = of_find_node_by_type(NULL,
176 "PowerPC-External-Interrupt-Presentation");
177 if (!np)
178 return -ENODEV;
179
180 icp_ops = &icp_hv_ops;
181
182 of_node_put(np);
183 return 0;
184 }
185
186