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
21static 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
39static 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
49static 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
60static 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
75static 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
83static 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
91static 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
104static 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
128static 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
137static void icp_hv_cause_ipi(int cpu)
138{
139	icp_hv_set_qirr(cpu, IPI_PRIORITY);
140}
141
142static 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
153static 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
165int __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