1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * Copyright (C) 2019 Fraunhofer AISEC,
4 * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
5 */
6
7#include <cpu_func.h>
8#include <dm.h>
9#include <asm/barrier.h>
10#include <asm/global_data.h>
11#include <asm/smp.h>
12#include <linux/printk.h>
13
14DECLARE_GLOBAL_DATA_PTR;
15
16static int send_ipi_many(struct ipi_data *ipi, int wait)
17{
18	ofnode node, cpus;
19	u32 reg;
20	int ret, pending;
21
22	cpus = ofnode_path("/cpus");
23	if (!ofnode_valid(cpus)) {
24		pr_err("Can't find cpus node!\n");
25		return -EINVAL;
26	}
27
28	ofnode_for_each_subnode(node, cpus) {
29		/* skip if hart is marked as not available in the device tree */
30		if (!ofnode_is_enabled(node))
31			continue;
32
33		/* read hart ID of CPU */
34		ret = ofnode_read_u32(node, "reg", &reg);
35		if (ret)
36			continue;
37
38		/* skip if it is the hart we are running on */
39		if (reg == gd->arch.boot_hart)
40			continue;
41
42		if (reg >= CONFIG_NR_CPUS) {
43			pr_err("Hart ID %d is out of range, increase CONFIG_NR_CPUS\n",
44			       reg);
45			continue;
46		}
47
48#if !CONFIG_IS_ENABLED(XIP)
49#ifdef CONFIG_AVAILABLE_HARTS
50		/* skip if hart is not available */
51		if (!(gd->arch.available_harts & (1 << reg)))
52			continue;
53#endif
54#endif
55
56		gd->arch.ipi[reg].addr = ipi->addr;
57		gd->arch.ipi[reg].arg0 = ipi->arg0;
58		gd->arch.ipi[reg].arg1 = ipi->arg1;
59
60		/*
61		 * Ensure valid only becomes set when the IPI parameters are
62		 * set. An IPI may already be pending on other harts, so we
63		 * need a way to signal that the IPI device has been
64		 * initialized, and that it is ok to call the function.
65		 */
66		__smp_store_release(&gd->arch.ipi[reg].valid, 1);
67
68		ret = riscv_send_ipi(reg);
69		if (ret) {
70			pr_err("Cannot send IPI to hart %d\n", reg);
71			return ret;
72		}
73
74		if (wait) {
75			pending = 1;
76			while (pending) {
77				ret = riscv_get_ipi(reg, &pending);
78				if (ret)
79					return ret;
80			}
81		}
82	}
83
84	return 0;
85}
86
87void handle_ipi(ulong hart)
88{
89	int ret;
90	void (*smp_function)(ulong hart, ulong arg0, ulong arg1);
91
92	if (hart >= CONFIG_NR_CPUS)
93		return;
94
95	/*
96	 * If valid is not set, then U-Boot has not requested the IPI. The
97	 * IPI device may not be initialized, so all we can do is wait for
98	 * U-Boot to initialize it and send an IPI
99	 */
100	if (!__smp_load_acquire(&gd->arch.ipi[hart].valid))
101		return;
102
103	smp_function = (void (*)(ulong, ulong, ulong))gd->arch.ipi[hart].addr;
104	invalidate_icache_all();
105
106	/*
107	 * Clear the IPI to acknowledge the request before jumping to the
108	 * requested function.
109	 */
110	ret = riscv_clear_ipi(hart);
111	if (ret) {
112		pr_err("Cannot clear IPI of hart %ld (error %d)\n", hart, ret);
113		return;
114	}
115
116	smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1);
117}
118
119int smp_call_function(ulong addr, ulong arg0, ulong arg1, int wait)
120{
121	struct ipi_data ipi = {
122		.addr = addr,
123		.arg0 = arg0,
124		.arg1 = arg1,
125	};
126
127	return send_ipi_many(&ipi, wait);
128}
129