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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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d686ce4204
Use WFI when putting CPU1 to sleep. Don't hold CPU1 in reset since that results in increased power consumption. Reset CPU1 briefly during CPU1 bootup. This has been tested for hotplug and suspend/resume and results in no increased power consumption. Signed-off-by: Alan Tull <atull@opensource.altera.com> Acked-by: Pavel Machek <pavel@denx.de> Signed-off-by: Dinh Nguyen <dinguyen@opensource.altera.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
106 lines
2.9 KiB
C
106 lines
2.9 KiB
C
/*
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* Copyright 2010-2011 Calxeda, Inc.
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* Copyright 2012 Pavel Machek <pavel@denx.de>
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* Based on platsmp.c, Copyright (C) 2002 ARM Ltd.
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* Copyright (C) 2012 Altera Corporation
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/delay.h>
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#include <linux/init.h>
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#include <linux/smp.h>
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#include <linux/io.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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#include <asm/smp_scu.h>
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#include <asm/smp_plat.h>
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#include "core.h"
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static int socfpga_boot_secondary(unsigned int cpu, struct task_struct *idle)
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{
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int trampoline_size = &secondary_trampoline_end - &secondary_trampoline;
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if (socfpga_cpu1start_addr) {
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/* This will put CPU #1 into reset. */
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writel(RSTMGR_MPUMODRST_CPU1,
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rst_manager_base_addr + SOCFPGA_RSTMGR_MODMPURST);
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memcpy(phys_to_virt(0), &secondary_trampoline, trampoline_size);
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writel(virt_to_phys(socfpga_secondary_startup),
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sys_manager_base_addr + (socfpga_cpu1start_addr & 0x000000ff));
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flush_cache_all();
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smp_wmb();
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outer_clean_range(0, trampoline_size);
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/* This will release CPU #1 out of reset. */
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writel(0, rst_manager_base_addr + SOCFPGA_RSTMGR_MODMPURST);
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}
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return 0;
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}
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/*
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* Initialise the CPU possible map early - this describes the CPUs
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* which may be present or become present in the system.
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*/
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static void __init socfpga_smp_init_cpus(void)
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{
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unsigned int i, ncores;
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ncores = scu_get_core_count(socfpga_scu_base_addr);
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for (i = 0; i < ncores; i++)
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set_cpu_possible(i, true);
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/* sanity check */
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if (ncores > num_possible_cpus()) {
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pr_warn("socfpga: no. of cores (%d) greater than configured"
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"maximum of %d - clipping\n", ncores, num_possible_cpus());
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ncores = num_possible_cpus();
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}
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for (i = 0; i < ncores; i++)
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set_cpu_possible(i, true);
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}
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static void __init socfpga_smp_prepare_cpus(unsigned int max_cpus)
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{
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scu_enable(socfpga_scu_base_addr);
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}
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/*
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* platform-specific code to shutdown a CPU
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*
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* Called with IRQs disabled
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*/
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static void socfpga_cpu_die(unsigned int cpu)
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{
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/* Do WFI. If we wake up early, go back into WFI */
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while (1)
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cpu_do_idle();
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}
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struct smp_operations socfpga_smp_ops __initdata = {
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.smp_init_cpus = socfpga_smp_init_cpus,
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.smp_prepare_cpus = socfpga_smp_prepare_cpus,
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.smp_boot_secondary = socfpga_boot_secondary,
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#ifdef CONFIG_HOTPLUG_CPU
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.cpu_die = socfpga_cpu_die,
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#endif
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};
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