diff options
Diffstat (limited to 'arch/arm64/kernel/suspend.c')
-rw-r--r-- | arch/arm64/kernel/suspend.c | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c new file mode 100644 index 0000000..e074b1c --- /dev/null +++ b/arch/arm64/kernel/suspend.c @@ -0,0 +1,109 @@ +#include <linux/slab.h> +#include <asm/cacheflush.h> +#include <asm/cpu_ops.h> +#include <asm/debug-monitors.h> +#include <asm/pgtable.h> +#include <asm/memory.h> +#include <asm/smp_plat.h> +#include <asm/suspend.h> +#include <asm/tlbflush.h> + +extern int __cpu_suspend(unsigned long); +/* + * 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. + * + * @arg: Argument to pass to suspend operations + * @ptr: CPU context virtual address + * @save_ptr: address of the location where the context physical address + * must be saved + */ +int __cpu_suspend_finisher(unsigned long arg, struct cpu_suspend_ctx *ptr, + phys_addr_t *save_ptr) +{ + int cpu = smp_processor_id(); + + *save_ptr = virt_to_phys(ptr); + + cpu_do_suspend(ptr); + /* + * Only flush the context that must be retrieved with the MMU + * off. VA primitives ensure the flush is applied to all + * cache levels so context is pushed to DRAM. + */ + __flush_dcache_area(ptr, sizeof(*ptr)); + __flush_dcache_area(save_ptr, sizeof(*save_ptr)); + + return cpu_ops[cpu]->cpu_suspend(arg); +} + +/** + * cpu_suspend + * + * @arg: argument to pass to the finisher function + */ +int cpu_suspend(unsigned long arg) +{ + struct mm_struct *mm = current->active_mm; + int ret, cpu = smp_processor_id(); + unsigned long flags; + + /* + * If cpu_ops have not been registered or suspend + * has not been initialized, cpu_suspend call fails early. + */ + if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_suspend) + return -EOPNOTSUPP; + + /* + * From this point debug exceptions are disabled to prevent + * updates to mdscr register (saved and restored along with + * general purpose registers) from kernel debuggers. + */ + local_dbg_save(flags); + + /* + * mm context saved on the stack, it will be restored when + * the cpu comes out of reset through the identity mapped + * page tables, so that the thread address space is properly + * set-up on function return. + */ + ret = __cpu_suspend(arg); + if (ret == 0) { + cpu_switch_mm(mm->pgd, mm); + flush_tlb_all(); + } + + /* + * Restore pstate flags. OS lock and mdscr have been already + * restored, so from this point onwards, debugging is fully + * renabled if it was enabled when core started shutdown. + */ + local_dbg_restore(flags); + + return ret; +} + +extern struct sleep_save_sp sleep_save_sp; +extern phys_addr_t sleep_idmap_phys; + +static int cpu_suspend_init(void) +{ + void *ctx_ptr; + + /* ctx_ptr is an array of physical addresses */ + ctx_ptr = kcalloc(mpidr_hash_size(), sizeof(phys_addr_t), GFP_KERNEL); + + if (WARN_ON(!ctx_ptr)) + return -ENOMEM; + + sleep_save_sp.save_ptr_stash = ctx_ptr; + sleep_save_sp.save_ptr_stash_phys = virt_to_phys(ctx_ptr); + sleep_idmap_phys = virt_to_phys(idmap_pg_dir); + __flush_dcache_area(&sleep_save_sp, sizeof(struct sleep_save_sp)); + __flush_dcache_area(&sleep_idmap_phys, sizeof(sleep_idmap_phys)); + + return 0; +} +early_initcall(cpu_suspend_init); |