2 * Spin Table SMP initialisation
4 * Copyright (C) 2013 ARM Ltd.
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
19 #include <linux/delay.h>
20 #include <linux/init.h>
22 #include <linux/smp.h>
23 #include <linux/types.h>
25 #include <asm/cacheflush.h>
26 #include <asm/cpu_ops.h>
27 #include <asm/cputype.h>
29 #include <asm/smp_plat.h>
31 extern void secondary_holding_pen(void);
32 volatile unsigned long secondary_holding_pen_release = INVALID_HWID;
34 static phys_addr_t cpu_release_addr[NR_CPUS];
37 * Write secondary_holding_pen_release in a way that is guaranteed to be
38 * visible to all observers, irrespective of whether they're taking part
39 * in coherency or not. This is necessary for the hotplug code to work
42 static void write_pen_release(u64 val)
44 void *start = (void *)&secondary_holding_pen_release;
45 unsigned long size = sizeof(secondary_holding_pen_release);
47 secondary_holding_pen_release = val;
48 __flush_dcache_area(start, size);
52 static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu)
55 * Determine the address from which the CPU is polling.
57 if (of_property_read_u64(dn, "cpu-release-addr",
58 &cpu_release_addr[cpu])) {
59 pr_err("CPU %d: missing or invalid cpu-release-addr property\n",
68 static int smp_spin_table_cpu_prepare(unsigned int cpu)
70 __le64 __iomem *release_addr;
72 if (!cpu_release_addr[cpu])
76 * The cpu-release-addr may or may not be inside the linear mapping.
77 * As ioremap_cache will either give us a new mapping or reuse the
78 * existing linear mapping, we can use it to cover both cases. In
79 * either case the memory will be MT_NORMAL.
81 release_addr = ioremap_cache(cpu_release_addr[cpu],
82 sizeof(*release_addr));
87 * We write the release address as LE regardless of the native
88 * endianess of the kernel. Therefore, any boot-loaders that
89 * read this address need to convert this address to the
90 * boot-loader's endianess before jumping. This is mandated by
93 writeq_relaxed(__pa(secondary_holding_pen), release_addr);
94 __flush_dcache_area((__force void *)release_addr,
95 sizeof(*release_addr));
98 * Send an event to wake up the secondary CPU.
102 iounmap(release_addr);
107 static int smp_spin_table_cpu_boot(unsigned int cpu)
110 * Update the pen release flag.
112 write_pen_release(cpu_logical_map(cpu));
115 * Send an event, causing the secondaries to read pen_release.
122 const struct cpu_operations smp_spin_table_ops = {
123 .name = "spin-table",
124 .cpu_init = smp_spin_table_cpu_init,
125 .cpu_prepare = smp_spin_table_cpu_prepare,
126 .cpu_boot = smp_spin_table_cpu_boot,