1 files changed, 130 insertions, 0 deletions
diff --git a/lib/psci/aarch64/psci_helpers.S b/lib/psci/aarch64/psci_helpers.S
new file mode 100644
index 0000000..add968a
--- /dev/null
+++ b/lib/psci/aarch64/psci_helpers.S
@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2014-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_macros.S>
+#include <assert_macros.S>
+#include <lib/psci/psci.h>
+#include <platform_def.h>
+
+	.globl	psci_do_pwrdown_cache_maintenance
+	.globl	psci_do_pwrup_cache_maintenance
+	.globl	psci_power_down_wfi
+
+/* -----------------------------------------------------------------------
+ * void psci_do_pwrdown_cache_maintenance(unsigned int power level);
+ *
+ * This function performs cache maintenance for the specified power
+ * level. The levels of cache affected are determined by the power
+ * level which is passed as the argument i.e. level 0 results
+ * in a flush of the L1 cache. Both the L1 and L2 caches are flushed
+ * for a higher power level.
+ *
+ * Additionally, this function also ensures that stack memory is correctly
+ * flushed out to avoid coherency issues due to a change in its memory
+ * attributes after the data cache is disabled.
+ * -----------------------------------------------------------------------
+ */
+func psci_do_pwrdown_cache_maintenance
+	stp     x29, x30, [sp,#-16]!
+	stp     x19, x20, [sp,#-16]!
+
+	/* ---------------------------------------------
+	 * Invoke CPU-specific power down operations for
+	 * the appropriate level
+	 * ---------------------------------------------
+	 */
+	bl	prepare_cpu_pwr_dwn
+
+	/* ---------------------------------------------
+	 * Do stack maintenance by flushing the used
+	 * stack to the main memory and invalidating the
+	 * remainder.
+	 * ---------------------------------------------
+	 */
+	bl	plat_get_my_stack
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the used
+	 * stack memory in x1.
+	 * ---------------------------------------------
+	 */
+	mov	x19, x0
+	mov	x1, sp
+	sub	x1, x0, x1
+	mov	x0, sp
+	bl	flush_dcache_range
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the unused
+	 * stack memory in x1. Calculate and store the
+	 * stack base address in x0.
+	 * ---------------------------------------------
+	 */
+	sub	x0, x19, #PLATFORM_STACK_SIZE
+	sub	x1, sp, x0
+	bl	inv_dcache_range
+
+	ldp	x19, x20, [sp], #16
+	ldp	x29, x30, [sp], #16
+	ret
+endfunc psci_do_pwrdown_cache_maintenance
+
+
+/* -----------------------------------------------------------------------
+ * void psci_do_pwrup_cache_maintenance(void);
+ *
+ * This function performs cache maintenance after this cpu is powered up.
+ * Currently, this involves managing the used stack memory before turning
+ * on the data cache.
+ * -----------------------------------------------------------------------
+ */
+func psci_do_pwrup_cache_maintenance
+	stp	x29, x30, [sp,#-16]!
+
+	/* ---------------------------------------------
+	 * Ensure any inflight stack writes have made it
+	 * to main memory.
+	 * ---------------------------------------------
+	 */
+	dmb	st
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the used
+	 * stack memory in x1. Calculate and store the
+	 * stack base address in x0.
+	 * ---------------------------------------------
+	 */
+	bl	plat_get_my_stack
+	mov	x1, sp
+	sub	x1, x0, x1
+	mov	x0, sp
+	bl	inv_dcache_range
+
+	/* ---------------------------------------------
+	 * Enable the data cache.
+	 * ---------------------------------------------
+	 */
+	mrs	x0, sctlr_el3
+	orr	x0, x0, #SCTLR_C_BIT
+	msr	sctlr_el3, x0
+	isb
+
+	ldp	x29, x30, [sp], #16
+	ret
+endfunc psci_do_pwrup_cache_maintenance
+
+/* -----------------------------------------------------------------------
+ * void psci_power_down_wfi(void);
+ * This function is called to indicate to the power controller that it
+ * is safe to power down this cpu. It should not exit the wfi and will
+ * be released from reset upon power up.
+ * -----------------------------------------------------------------------
+ */
+func psci_power_down_wfi
+	dsb	sy		// ensure write buffer empty
+	wfi
+	no_ret	plat_panic_handler
+endfunc psci_power_down_wfi