1// SPDX-License-Identifier: GPL-2.0
2/*
3 * R9A06G032 Second CA7 enabler.
4 *
5 * Copyright (C) 2018 Renesas Electronics Europe Limited
6 *
7 * Michel Pollet <michel.pollet@bp.renesas.com>, <buserror@gmail.com>
8 * Derived from actions,s500-smp
9 */
10
11#include <linux/io.h>
12#include <linux/of.h>
13#include <linux/of_address.h>
14#include <linux/smp.h>
15
16/*
17 * The second CPU is parked in ROM at boot time. It requires waking it after
18 * writing an address into the BOOTADDR register of sysctrl.
19 *
20 * So the default value of the "cpu-release-addr" corresponds to BOOTADDR...
21 *
22 * *However* the BOOTADDR register is not available when the kernel
23 * starts in NONSEC mode.
24 *
25 * So for NONSEC mode, the bootloader re-parks the second CPU into a pen
26 * in SRAM, and changes the "cpu-release-addr" of linux's DT to a SRAM address,
27 * which is not restricted.
28 */
29
30static void __iomem *cpu_bootaddr;
31
32static DEFINE_SPINLOCK(cpu_lock);
33
34static int
35r9a06g032_smp_boot_secondary(unsigned int cpu,
36 struct task_struct *idle)
37{
38 if (!cpu_bootaddr)
39 return -ENODEV;
40
41 spin_lock(lock: &cpu_lock);
42
43 writel(__pa_symbol(secondary_startup), cpu_bootaddr);
44 arch_send_wakeup_ipi_mask(cpumask_of(cpu));
45
46 spin_unlock(lock: &cpu_lock);
47
48 return 0;
49}
50
51static void __init r9a06g032_smp_prepare_cpus(unsigned int max_cpus)
52{
53 struct device_node *dn;
54 int ret = -EINVAL, dns;
55 u32 bootaddr;
56
57 dn = of_get_cpu_node(cpu: 1, NULL);
58 if (!dn) {
59 pr_err("CPU#1: missing device tree node\n");
60 return;
61 }
62 /*
63 * Determine the address from which the CPU is polling.
64 * The bootloader *does* change this property.
65 * Note: The property can be either 64 or 32 bits, so handle both cases
66 */
67 if (of_find_property(np: dn, name: "cpu-release-addr", lenp: &dns)) {
68 if (dns == sizeof(u64)) {
69 u64 temp;
70
71 ret = of_property_read_u64(np: dn,
72 propname: "cpu-release-addr", out_value: &temp);
73 bootaddr = temp;
74 } else {
75 ret = of_property_read_u32(np: dn,
76 propname: "cpu-release-addr",
77 out_value: &bootaddr);
78 }
79 }
80 of_node_put(node: dn);
81 if (ret) {
82 pr_err("CPU#1: invalid cpu-release-addr property\n");
83 return;
84 }
85 pr_info("CPU#1: cpu-release-addr %08x\n", bootaddr);
86
87 cpu_bootaddr = ioremap(offset: bootaddr, size: sizeof(bootaddr));
88}
89
90static const struct smp_operations r9a06g032_smp_ops __initconst = {
91 .smp_prepare_cpus = r9a06g032_smp_prepare_cpus,
92 .smp_boot_secondary = r9a06g032_smp_boot_secondary,
93};
94
95CPU_METHOD_OF_DECLARE(r9a06g032_smp,
96 "renesas,r9a06g032-smp", &r9a06g032_smp_ops);
97

source code of linux/drivers/soc/renesas/r9a06g032-smp.c