genode/repos/base-hw/src/core/spec/cortex_a9/kernel/cpu.cc

129 lines
3.0 KiB
C++

/*
* \brief Cpu class implementation specific to Cortex A9 SMP
* \author Stefan Kalkowski
* \date 2015-12-09
*/
/*
* Copyright (C) 2015-2016 Genode Labs GmbH
*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
/* core includes */
#include <kernel/lock.h>
#include <kernel/pd.h>
#include <pic.h>
#include <scu.h>
#include <board.h>
/* base-hw includes */
#include <kernel/perf_counter.h>
using namespace Kernel;
/* entrypoint for non-boot CPUs */
extern "C" void * _start_secondary_cpus;
/**
* SMP-safe simple counter
*/
class Counter
{
private:
Kernel::Lock _lock;
volatile int _value = 0;
public:
void inc()
{
Kernel::Lock::Guard guard(_lock);
Genode::memory_barrier();
_value++;
}
void wait_for(int const v) {
while (_value < v) ; }
};
static volatile bool primary_cpu = true; /* indicates boot cpu status */
static Counter data_cache_invalidated; /* counts cpus that invalidated
their data cache */
static Counter data_cache_enabled; /* counts cpus that enabled
their data cache */
static Counter smp_coherency_enabled; /* counts cpus that enabled
their SCU */
/*
* The initialization of Cortex A9 multicore systems implies a sophisticated
* algorithm in early revisions of this cpu.
*
* See ARM's Cortex-A9 MPCore TRM r2p0 in section 5.3.5 for more details
*/
void Kernel::Cpu::init(Kernel::Pic &pic, Kernel::Pd & core_pd, Genode::Board & board)
{
bool primary = primary_cpu;
if (primary) primary_cpu = false;
Sctlr::init();
Psr::write(Psr::init_kernel());
/* locally initialize interrupt controller */
pic.init_cpu_local();
invalidate_inner_data_cache();
data_cache_invalidated.inc();
/* primary cpu wakes up all others */
if (primary && NR_OF_CPUS > 1)
board.wake_up_all_cpus(&_start_secondary_cpus);
/* wait for other cores' data cache invalidation */
data_cache_invalidated.wait_for(NR_OF_CPUS);
if (primary) {
Genode::Scu scu(board);
scu.invalidate();
board.l2_cache().invalidate();
scu.enable();
}
/* secondary cpus wait for the primary's cache activation */
if (!primary) data_cache_enabled.wait_for(1);
enable_mmu_and_caches(core_pd);
data_cache_enabled.inc();
clean_invalidate_inner_data_cache();
/* wait for other cores' data cache activation */
data_cache_enabled.wait_for(NR_OF_CPUS);
if (primary) board.l2_cache().enable();
/* secondary cpus wait for the primary's coherency activation */
if (!primary) smp_coherency_enabled.wait_for(1);
Actlr::enable_smp();
smp_coherency_enabled.inc();
/* wait for other cores' coherency activation */
smp_coherency_enabled.wait_for(NR_OF_CPUS);
init_advanced_fp_simd();
{
Lock::Guard guard(data_lock());
/* enable performance counter */
perf_counter()->enable();
/* enable timer interrupt */
pic.unmask(Timer::interrupt_id(id()), id());
}
}