xref: /openbmc/linux/arch/powerpc/sysdev/xics/icp-hv.c (revision 6c552983)
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 
icp_hv_get_xirr(unsigned char cppr)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 
icp_hv_set_cppr(u8 value)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 
icp_hv_set_xirr(unsigned int value)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 
icp_hv_set_qirr(int n_cpu,u8 value)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 
icp_hv_eoi(struct irq_data * d)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 
icp_hv_teardown_cpu(void)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 
icp_hv_flush_ipi(void)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 
icp_hv_get_irq(void)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 
icp_hv_set_cpu_priority(unsigned char cppr)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 
icp_hv_cause_ipi(int cpu)137 static void icp_hv_cause_ipi(int cpu)
138 {
139 	icp_hv_set_qirr(cpu, IPI_PRIORITY);
140 }
141 
icp_hv_ipi_action(int irq,void * dev_id)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 
icp_hv_init(void)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