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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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90 lines
2.1 KiB
C
90 lines
2.1 KiB
C
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/*
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* linux/arch/arm/mach-axxia/platsmp.c
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*
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* Copyright (C) 2012 LSI Corporation
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/smp.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <asm/cacheflush.h>
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/* Syscon register offsets for releasing cores from reset */
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#define SC_CRIT_WRITE_KEY 0x1000
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#define SC_RST_CPU_HOLD 0x1010
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/*
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* Write the kernel entry point for secondary CPUs to the specified address
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*/
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static void write_release_addr(u32 release_phys)
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{
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u32 *virt = (u32 *) phys_to_virt(release_phys);
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writel_relaxed(virt_to_phys(secondary_startup), virt);
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/* Make sure this store is visible to other CPUs */
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smp_wmb();
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__cpuc_flush_dcache_area(virt, sizeof(u32));
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}
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static int axxia_boot_secondary(unsigned int cpu, struct task_struct *idle)
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{
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struct device_node *syscon_np;
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void __iomem *syscon;
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u32 tmp;
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syscon_np = of_find_compatible_node(NULL, NULL, "lsi,axxia-syscon");
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if (!syscon_np)
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return -ENOENT;
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syscon = of_iomap(syscon_np, 0);
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if (!syscon)
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return -ENOMEM;
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tmp = readl(syscon + SC_RST_CPU_HOLD);
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writel(0xab, syscon + SC_CRIT_WRITE_KEY);
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tmp &= ~(1 << cpu);
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writel(tmp, syscon + SC_RST_CPU_HOLD);
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return 0;
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}
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static void __init axxia_smp_prepare_cpus(unsigned int max_cpus)
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{
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int cpu_count = 0;
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int cpu;
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/*
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* Initialise the present map, which describes the set of CPUs actually
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* populated at the present time.
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*/
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for_each_possible_cpu(cpu) {
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struct device_node *np;
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u32 release_phys;
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np = of_get_cpu_node(cpu, NULL);
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if (!np)
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continue;
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if (of_property_read_u32(np, "cpu-release-addr", &release_phys))
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continue;
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if (cpu_count < max_cpus) {
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set_cpu_present(cpu, true);
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cpu_count++;
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}
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if (release_phys != 0)
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write_release_addr(release_phys);
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}
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}
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static struct smp_operations axxia_smp_ops __initdata = {
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.smp_prepare_cpus = axxia_smp_prepare_cpus,
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.smp_boot_secondary = axxia_boot_secondary,
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};
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CPU_METHOD_OF_DECLARE(axxia_smp, "lsi,syscon-release", &axxia_smp_ops);
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