suspend.c

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#include <linux/init.h>

#include <asm/idmap.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/memory.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>

extern int __cpu_suspend(unsigned long, int (*)(unsigned long));
extern void cpu_resume_mmu(void);

/*
 * This is called by __cpu_suspend() to save the state, and do whatever
 * flushing is required to ensure that when the CPU goes to sleep we have
 * the necessary data available when the caches are not searched.
 */
void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
{
    u32 *ctx = ptr;

    *save_ptr = virt_to_phys(ptr);

    /* This must correspond to the LDM in cpu_resume() assembly */
    *ptr++ = virt_to_phys(idmap_pgd);
    *ptr++ = sp;
    *ptr++ = virt_to_phys(cpu_do_resume);

    cpu_do_suspend(ptr);

    flush_cache_louis();

    /*
     * flush_cache_louis does not guarantee that
     * save_ptr and ptr are cleaned to main memory,
     * just up to the Level of Unification Inner Shareable.
     * Since the context pointer and context itself
     * are to be retrieved with the MMU off that
     * data must be cleaned from all cache levels
     * to main memory using "area" cache primitives.
    */
    __cpuc_flush_dcache_area(ctx, ptrsz);
    __cpuc_flush_dcache_area(save_ptr, sizeof(*save_ptr));

    outer_clean_range(*save_ptr, *save_ptr + ptrsz);
    outer_clean_range(virt_to_phys(save_ptr),
              virt_to_phys(save_ptr) + sizeof(*save_ptr));
}

/*
 * Hide the first two arguments to __cpu_suspend - these are an implementation
 * detail which platform code shouldn't have to know about.
 */
int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
{
    struct mm_struct *mm = current->active_mm;
    int ret;

    if (!idmap_pgd)
        return -EINVAL;

    /*
     * Provide a temporary page table with an identity mapping for
     * the MMU-enable code, required for resuming.  On successful
     * resume (indicated by a zero return code), we need to switch
     * back to the correct page tables.
     */
    ret = __cpu_suspend(arg, fn);
    if (ret == 0) {
        cpu_switch_mm(mm->pgd, mm);
        local_flush_tlb_all();
    }

    return ret;
}