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git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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aca95fb6bb
This adds support for Microwatt systems with more than one core, and updates the device tree for a 2-core version. The secondary CPUs are started and sent to spin in __secondary_hold very early on, in the platform probe function. The reason for doing this is so that they are there when smp_release_cpus() gets called, which is before the platform init_smp function or even the platform setup_arch function gets called. Note that having two CPUs in the device tree doesn't preclude operation with only one CPU. The SYSCON_CPU_CTRL register has a read-only field which indicates the number of CPU cores, so microwatt_init_smp() will only start as many CPU cores as are present in the system, and any extra CPU device-tree nodes will just be ignored. Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/Z5xt8aooKyXZv6Kf@thinks.paulus.ozlabs.org
61 lines
1.2 KiB
C
61 lines
1.2 KiB
C
/*
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* Microwatt FPGA-based SoC platform setup code.
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*
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* Copyright 2020 Paul Mackerras (paulus@ozlabs.org), IBM Corp.
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*/
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/stddef.h>
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#include <linux/init.h>
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#include <linux/of.h>
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#include <linux/of_platform.h>
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#include <asm/machdep.h>
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#include <asm/time.h>
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#include <asm/xics.h>
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#include <asm/udbg.h>
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#include "microwatt.h"
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static void __init microwatt_init_IRQ(void)
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{
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xics_init();
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}
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static int __init microwatt_populate(void)
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{
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return of_platform_default_populate(NULL, NULL, NULL);
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}
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machine_arch_initcall(microwatt, microwatt_populate);
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static int __init microwatt_probe(void)
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{
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/* Main reason for having this is to start the other CPU(s) */
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if (IS_ENABLED(CONFIG_SMP))
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microwatt_init_smp();
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return 1;
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}
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static void __init microwatt_setup_arch(void)
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{
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microwatt_rng_init();
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}
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static void microwatt_idle(void)
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{
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if (!prep_irq_for_idle_irqsoff())
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return;
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__asm__ __volatile__ ("wait");
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}
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define_machine(microwatt) {
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.name = "microwatt",
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.compatible = "microwatt-soc",
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.probe = microwatt_probe,
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.init_IRQ = microwatt_init_IRQ,
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.setup_arch = microwatt_setup_arch,
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.progress = udbg_progress,
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.power_save = microwatt_idle,
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};
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