1 files changed, 148 insertions, 0 deletions
diff --git a/lib/psci/aarch32/psci_helpers.S b/lib/psci/aarch32/psci_helpers.S
new file mode 100644
index 0000000..5cc192e
--- /dev/null
+++ b/lib/psci/aarch32/psci_helpers.S
@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <asm_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
+	push	{r4, lr}
+
+	/* ----------------------------------------------
+	 * Turn OFF cache and do stack maintenance
+	 * prior to cpu operations . This sequence is
+	 * different from AArch64 because in AArch32 the
+	 * assembler routines for cpu operations utilize
+	 * the stack whereas in AArch64 it doesn't.
+	 * ----------------------------------------------
+	 */
+	mov	r4, r0
+	bl	do_stack_maintenance
+
+	/* ---------------------------------------------
+	 * Invoke CPU-specifc power down operations for
+	 * the appropriate level
+	 * ---------------------------------------------
+	 */
+	mov	r0, r4
+	pop	{r4, lr}
+	b	prepare_cpu_pwr_dwn
+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
+	/* r12 is pushed to meet the 8 byte stack alignment requirement */
+	push	{r12, lr}
+
+	/* ---------------------------------------------
+	 * Ensure any inflight stack writes have made it
+	 * to main memory.
+	 * ---------------------------------------------
+	 */
+	dmb	st
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the used
+	 * stack memory in r1. Calculate and store the
+	 * stack base address in r0.
+	 * ---------------------------------------------
+	 */
+	bl	plat_get_my_stack
+	mov	r1, sp
+	sub	r1, r0, r1
+	mov	r0, sp
+	bl	inv_dcache_range
+
+	/* ---------------------------------------------
+	 * Enable the data cache.
+	 * ---------------------------------------------
+	 */
+	ldcopr	r0, SCTLR
+	orr	r0, r0, #SCTLR_C_BIT
+	stcopr	r0, SCTLR
+	isb
+
+	pop	{r12, pc}
+endfunc psci_do_pwrup_cache_maintenance
+
+	/* ---------------------------------------------
+	 * void do_stack_maintenance(void)
+	 * Do stack maintenance by flushing the used
+	 * stack to the main memory and invalidating the
+	 * remainder.
+	 * ---------------------------------------------
+	 */
+func do_stack_maintenance
+	push	{r4, lr}
+	bl	plat_get_my_stack
+
+	/* Turn off the D-cache */
+	ldcopr	r1, SCTLR
+	bic	r1, #SCTLR_C_BIT
+	stcopr	r1, SCTLR
+	isb
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the used
+	 * stack memory in r1.
+	 * ---------------------------------------------
+	 */
+	mov	r4, r0
+	mov	r1, sp
+	sub	r1, r0, r1
+	mov	r0, sp
+	bl	flush_dcache_range
+
+	/* ---------------------------------------------
+	 * Calculate and store the size of the unused
+	 * stack memory in r1. Calculate and store the
+	 * stack base address in r0.
+	 * ---------------------------------------------
+	 */
+	sub	r0, r4, #PLATFORM_STACK_SIZE
+	sub	r1, sp, r0
+	bl	inv_dcache_range
+
+	pop	{r4, pc}
+endfunc do_stack_maintenance
+
+/* -----------------------------------------------------------------------
+ * 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