summaryrefslogtreecommitdiff
path: root/arch/riscv/cpu/cpu.c
blob: 296e458db4fe77f93ac9bb7318f95288e65589de (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
 */

#include <common.h>
#include <cpu.h>
#include <dm.h>
#include <init.h>
#include <log.h>
#include <asm/encoding.h>
#include <dm/uclass-internal.h>
#include <linux/bitops.h>

/*
 * The variables here must be stored in the data section since they are used
 * before the bss section is available.
 */
#ifdef CONFIG_OF_PRIOR_STAGE
phys_addr_t prior_stage_fdt_address __attribute__((section(".data")));
#endif
#ifndef CONFIG_XIP
u32 hart_lottery __attribute__((section(".data"))) = 0;

/*
 * The main hart running U-Boot has acquired available_harts_lock until it has
 * finished initialization of global data.
 */
u32 available_harts_lock = 1;
#endif

static inline bool supports_extension(char ext)
{
#ifdef CONFIG_CPU
	struct udevice *dev;
	char desc[32];

	uclass_find_first_device(UCLASS_CPU, &dev);
	if (!dev) {
		debug("unable to find the RISC-V cpu device\n");
		return false;
	}
	if (!cpu_get_desc(dev, desc, sizeof(desc))) {
		/* skip the first 4 characters (rv32|rv64) */
		if (strchr(desc + 4, ext))
			return true;
	}

	return false;
#else  /* !CONFIG_CPU */
#if CONFIG_IS_ENABLED(RISCV_MMODE)
	return csr_read(CSR_MISA) & (1 << (ext - 'a'));
#else  /* !CONFIG_IS_ENABLED(RISCV_MMODE) */
#warning "There is no way to determine the available extensions in S-mode."
#warning "Please convert your board to use the RISC-V CPU driver."
	return false;
#endif /* CONFIG_IS_ENABLED(RISCV_MMODE) */
#endif /* CONFIG_CPU */
}

static int riscv_cpu_probe(void)
{
#ifdef CONFIG_CPU
	int ret;

	/* probe cpus so that RISC-V timer can be bound */
	ret = cpu_probe_all();
	if (ret)
		return log_msg_ret("RISC-V cpus probe failed\n", ret);
#endif

	return 0;
}

/*
 * This is called on secondary harts just after the IPI is init'd. Currently
 * there's nothing to do, since we just need to clear any existing IPIs, and
 * that is handled by the sending of an ipi itself.
 */
#if CONFIG_IS_ENABLED(SMP)
static void dummy_pending_ipi_clear(ulong hart, ulong arg0, ulong arg1)
{
}
#endif

int arch_cpu_init_dm(void)
{
	int ret;

	ret = riscv_cpu_probe();
	if (ret)
		return ret;

	/* Enable FPU */
	if (supports_extension('d') || supports_extension('f')) {
		csr_set(MODE_PREFIX(status), MSTATUS_FS);
		csr_write(CSR_FCSR, 0);
	}

	if (CONFIG_IS_ENABLED(RISCV_MMODE)) {
		/*
		 * Enable perf counters for cycle, time,
		 * and instret counters only
		 */
#ifdef CONFIG_RISCV_PRIV_1_9
		csr_write(CSR_MSCOUNTEREN, GENMASK(2, 0));
		csr_write(CSR_MUCOUNTEREN, GENMASK(2, 0));
#else
		csr_write(CSR_MCOUNTEREN, GENMASK(2, 0));
#endif

		/* Disable paging */
		if (supports_extension('s'))
#ifdef CONFIG_RISCV_PRIV_1_9
			csr_read_clear(CSR_MSTATUS, SR_VM);
#else
			csr_write(CSR_SATP, 0);
#endif
	}

#if CONFIG_IS_ENABLED(SMP)
	ret = riscv_init_ipi();
	if (ret)
		return ret;

	/*
	 * Clear all pending IPIs on secondary harts. We don't do anything on
	 * the boot hart, since we never send an IPI to ourselves, and no
	 * interrupts are enabled
	 */
	ret = smp_call_function((ulong)dummy_pending_ipi_clear, 0, 0, 0);
	if (ret)
		return ret;
#endif

	return 0;
}

int arch_early_init_r(void)
{
	return riscv_cpu_probe();
}

/**
 * harts_early_init() - A callback function called by start.S to configure
 * feature settings of each hart.
 *
 * In a multi-core system, memory access shall be careful here, it shall
 * take care of race conditions.
 */
__weak void harts_early_init(void)
{
}