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