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245a7868d2
When hotplug and/or a powered down idle state are supported cases will
arise where a non-zero VPE must be brought online without VPE 0, and it
where multiple VPEs must be onlined simultaneously. This patch prepares
for that by:
- Splitting struct boot_config into core & VPE boot config structures,
allocated one per core or VPE respectively. This allows for multiple
VPEs to be onlined simultaneously without clobbering each others
configuration.
- Indicating which VPEs should be online within a core at any given
time using a bitmap. This allows multiple VPEs to be brought online
simultaneously and also indicates to VPE 0 whether it should halt
after starting any non-zero VPEs that should be online within the
core. For example if all VPEs within a core are offlined via hotplug
and the user onlines the second VPE within that core:
1) The core will be powered up.
2) VPE 0 will run from the BEV (ie. mips_cps_core_entry) to
initialise the core.
3) VPE 0 will start VPE 1 because its bit is set in the cores
bitmap.
4) VPE 0 will halt itself because its bit is clear in the cores
bitmap.
- Moving the core & VPE initialisation to assembly code which does not
make any use of the stack. This is because if a non-zero VPE is to
be brought online in a powered down core then when VPE 0 of that
core runs it may not have a valid stack, and even if it did then
it's messy to run through parts of generic kernel code on VPE 0
before starting the correct VPE.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
81 lines
1.9 KiB
C
81 lines
1.9 KiB
C
/*
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* Copyright (C) 2013 Imagination Technologies
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* Author: Paul Burton <paul.burton@imgtec.com>
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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 of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/errno.h>
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#include <linux/percpu.h>
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#include <linux/spinlock.h>
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#include <asm/mips-cm.h>
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#include <asm/mips-cpc.h>
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void __iomem *mips_cpc_base;
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static DEFINE_PER_CPU_ALIGNED(spinlock_t, cpc_core_lock);
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static DEFINE_PER_CPU_ALIGNED(unsigned long, cpc_core_lock_flags);
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phys_t __weak mips_cpc_phys_base(void)
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{
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u32 cpc_base;
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if (!mips_cm_present())
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return 0;
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if (!(read_gcr_cpc_status() & CM_GCR_CPC_STATUS_EX_MSK))
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return 0;
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/* If the CPC is already enabled, leave it so */
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cpc_base = read_gcr_cpc_base();
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if (cpc_base & CM_GCR_CPC_BASE_CPCEN_MSK)
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return cpc_base & CM_GCR_CPC_BASE_CPCBASE_MSK;
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/* Otherwise, give it the default address & enable it */
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cpc_base = mips_cpc_default_phys_base();
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write_gcr_cpc_base(cpc_base | CM_GCR_CPC_BASE_CPCEN_MSK);
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return cpc_base;
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}
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int mips_cpc_probe(void)
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{
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phys_t addr;
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unsigned cpu;
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for_each_possible_cpu(cpu)
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spin_lock_init(&per_cpu(cpc_core_lock, cpu));
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addr = mips_cpc_phys_base();
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if (!addr)
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return -ENODEV;
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mips_cpc_base = ioremap_nocache(addr, 0x8000);
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if (!mips_cpc_base)
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return -ENXIO;
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return 0;
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}
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void mips_cpc_lock_other(unsigned int core)
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{
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unsigned curr_core;
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preempt_disable();
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curr_core = current_cpu_data.core;
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spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
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per_cpu(cpc_core_lock_flags, curr_core));
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write_cpc_cl_other(core << CPC_Cx_OTHER_CORENUM_SHF);
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}
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void mips_cpc_unlock_other(void)
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{
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unsigned curr_core = current_cpu_data.core;
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spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
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per_cpu(cpc_core_lock_flags, curr_core));
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preempt_enable();
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}
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