| /* |
| * Spin Table SMP initialisation |
| * |
| * Copyright (C) 2013 ARM Ltd. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include <linux/delay.h> |
| #include <linux/init.h> |
| #include <linux/of.h> |
| #include <linux/smp.h> |
| |
| #include <asm/cacheflush.h> |
| #include <asm/cpu_ops.h> |
| #include <asm/cputype.h> |
| #include <asm/smp_plat.h> |
| |
| static phys_addr_t cpu_release_addr[NR_CPUS]; |
| |
| /* |
| * Write secondary_holding_pen_release in a way that is guaranteed to be |
| * visible to all observers, irrespective of whether they're taking part |
| * in coherency or not. This is necessary for the hotplug code to work |
| * reliably. |
| */ |
| static void write_pen_release(u64 val) |
| { |
| void *start = (void *)&secondary_holding_pen_release; |
| unsigned long size = sizeof(secondary_holding_pen_release); |
| |
| secondary_holding_pen_release = val; |
| __flush_dcache_area(start, size); |
| } |
| |
| |
| static int smp_spin_table_cpu_init(struct device_node *dn, unsigned int cpu) |
| { |
| /* |
| * Determine the address from which the CPU is polling. |
| */ |
| if (of_property_read_u64(dn, "cpu-release-addr", |
| &cpu_release_addr[cpu])) { |
| pr_err("CPU %d: missing or invalid cpu-release-addr property\n", |
| cpu); |
| |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| static int smp_spin_table_cpu_prepare(unsigned int cpu) |
| { |
| void **release_addr; |
| |
| if (!cpu_release_addr[cpu]) |
| return -ENODEV; |
| |
| release_addr = __va(cpu_release_addr[cpu]); |
| |
| /* |
| * We write the release address as LE regardless of the native |
| * endianess of the kernel. Therefore, any boot-loaders that |
| * read this address need to convert this address to the |
| * boot-loader's endianess before jumping. This is mandated by |
| * the boot protocol. |
| */ |
| release_addr[0] = (void *) cpu_to_le64(__pa(secondary_holding_pen)); |
| |
| __flush_dcache_area(release_addr, sizeof(release_addr[0])); |
| |
| /* |
| * Send an event to wake up the secondary CPU. |
| */ |
| sev(); |
| |
| return 0; |
| } |
| |
| static int smp_spin_table_cpu_boot(unsigned int cpu) |
| { |
| /* |
| * Update the pen release flag. |
| */ |
| write_pen_release(cpu_logical_map(cpu)); |
| |
| /* |
| * Send an event, causing the secondaries to read pen_release. |
| */ |
| sev(); |
| |
| return 0; |
| } |
| |
| static const struct cpu_operations smp_spin_table_ops = { |
| .name = "spin-table", |
| .cpu_init = smp_spin_table_cpu_init, |
| .cpu_prepare = smp_spin_table_cpu_prepare, |
| .cpu_boot = smp_spin_table_cpu_boot, |
| }; |
| CPU_METHOD_OF_DECLARE(spin_table, &smp_spin_table_ops); |