icp-hv.c

  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