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#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/cpu.h>
#include <linux/percpu.h>
#include <linux/smp.h>
#include <mach/smp.h>
#include <mach/irqs.h>
#include <mach/fiq_smp_call.h>
#include <asm/cputype.h>
#if defined(CONFIG_FIQ_GLUE)
enum {
CSD_FLAG_LOCK = 0x01,
};
struct fiq_call_single_data {
struct list_head list;
smp_call_func_t func;
void *info;
cpumask_var_t cpumask;
u16 flags;
u16 priv;
};
struct call_function_data {
struct fiq_call_single_data csd;
fiq_smp_call_func_t func;
atomic_t refs;
cpumask_var_t cpumask;
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, fiq_cfd_data);
static struct call_function_data *current_cfd_data;
extern void irq_raise_softirq(const struct cpumask *mask, unsigned int irq);
static int __csd_lock_wait(struct fiq_call_single_data *data)
{
int cpu, nr_online_cpus = 0;
while (data->flags & CSD_FLAG_LOCK) {
for_each_cpu(cpu, data->cpumask) {
if (cpu_online(cpu)) {
nr_online_cpus++;
}
}
if (!nr_online_cpus)
return -ENXIO;
cpu_relax();
}
return 0;
}
static void __csd_lock(struct fiq_call_single_data *data)
{
__csd_lock_wait(data);
data->flags = CSD_FLAG_LOCK;
/*
* prevent CPU from reordering the above assignment
* to ->flags with any subsequent assignments to other
* fields of the specified fiq_call_single_data structure:
*/
smp_mb();
}
static void __csd_unlock(struct fiq_call_single_data *data)
{
WARN_ON(!(data->flags & CSD_FLAG_LOCK));
/*
* ensure we're all done before releasing data:
*/
smp_mb();
data->flags &= ~CSD_FLAG_LOCK;
}
/*
* fiq_smp_call_function: FIQ version of smp_call_function.
* @func:
* @info:
* @wait:
* Return 0 for success and error code for failure.
*
* This function is designed for the debugger only.
* Other kernel code or drivers should NOT use this function.
* This function can only be used in the FIQ-WDT handler.
*/
int fiq_smp_call_function(fiq_smp_call_func_t func, void *info, int wait)
{
struct cpumask *mask = (struct cpumask *)cpu_online_mask;
struct call_function_data *data;
int refs, install_csd, this_cpu = 0;
this_cpu = smp_processor_id();
data = this_cpu_ptr(&fiq_cfd_data);
__csd_lock(&data->csd);
atomic_set(&data->refs, 0);
data->func = func;
data->csd.info = info;
smp_wmb();
cpumask_and(data->cpumask, mask, cpu_online_mask);
cpumask_clear_cpu(this_cpu, data->cpumask);
refs = cpumask_weight(data->cpumask);
cpumask_and(data->csd.cpumask, data->cpumask, data->cpumask);
if (unlikely(!refs)) {
__csd_unlock(&data->csd);
goto fiq_smp_call_function_exit;
}
/* poll to install data on current_cfd_data */
install_csd = 0;
do {
#if 0 /* no need to protect due to FIQ-WDT */
spin_lock(&fiq_smp_call_lock);
#endif
if (!current_cfd_data) {
atomic_set(&data->refs, refs);
current_cfd_data = data;
install_csd = 1;
}
#if 0
spin_unlock(&fiq_smp_call_lock);
#endif
} while (!install_csd);
smp_mb();
/* send a message to all CPUs in the map */
irq_raise_softirq(data->cpumask, FIQ_SMP_CALL_SGI);
if (wait)
__csd_lock_wait(&data->csd);
fiq_smp_call_function_exit:
return 0;
}
static void fiq_smp_call_handler(void *arg, void *regs, void *svc_sp)
{
struct call_function_data *data;
int cpu = 0, refs;
fiq_smp_call_func_t func;
/* get the current cpu id */
asm volatile ("MRC p15, 0, %0, c0, c0, 5\n" "AND %0, %0, #0xf\n":"+r" (cpu)
: : "cc");
data = current_cfd_data;
if (data) {
func = data->func;
func(data->csd.info, regs, svc_sp);
cpumask_clear_cpu(cpu, data->csd.cpumask);
refs = atomic_dec_return(&data->refs);
if (refs == 0) {
__csd_unlock(&data->csd);
current_cfd_data = NULL;
}
}
}
static void __fiq_smp_call_init(void *info)
{
int err;
err = request_fiq(FIQ_SMP_CALL_SGI, fiq_smp_call_handler, 0, NULL);
if (err) {
pr_err("fail to request FIQ for FIQ_SMP_CALL_SGI\n");
} else {
pr_debug("Request FIQ for FIQ_SMP_CALL_SGI\n");
}
}
static int __init fiq_smp_call_init(void)
{
__fiq_smp_call_init(NULL);
smp_call_function(__fiq_smp_call_init, NULL, 1);
return 0;
}
arch_initcall(fiq_smp_call_init);
#endif /* CONFIG_FIQ_GLUE */
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