xilinx: common: Move ATF handover to common file

ATF handover can be used by Xilinx platforms, so move it to common
file from platform specific files.

Signed-off-by: Venkatesh Yadav Abbarapu <venkatesh.abbarapu@xilinx.com>
Change-Id: I5f0839351f534619de581d1953c8427a079487e0
diff --git a/plat/xilinx/common/plat_startup.c b/plat/xilinx/common/plat_startup.c
new file mode 100644
index 0000000..8c9a049
--- /dev/null
+++ b/plat/xilinx/common/plat_startup.c
@@ -0,0 +1,270 @@
+/*
+ * Copyright (c) 2014-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <plat_startup.h>
+
+
+/*
+ * ATFHandoffParams
+ * Parameter		bitfield	encoding
+ * -----------------------------------------------------------------------------
+ * Exec State		0		0 -> Aarch64, 1-> Aarch32
+ * endianness		1		0 -> LE, 1 -> BE
+ * secure (TZ)		2		0 -> Non secure, 1 -> secure
+ * EL			3:4		00 -> EL0, 01 -> EL1, 10 -> EL2, 11 -> EL3
+ * CPU#			5:6		00 -> A53_0, 01 -> A53_1, 10 -> A53_2, 11 -> A53_3
+ */
+
+#define FSBL_FLAGS_ESTATE_SHIFT		0
+#define FSBL_FLAGS_ESTATE_MASK		(1 << FSBL_FLAGS_ESTATE_SHIFT)
+#define FSBL_FLAGS_ESTATE_A64		0
+#define FSBL_FLAGS_ESTATE_A32		1
+
+#define FSBL_FLAGS_ENDIAN_SHIFT		1
+#define FSBL_FLAGS_ENDIAN_MASK		(1 << FSBL_FLAGS_ENDIAN_SHIFT)
+#define FSBL_FLAGS_ENDIAN_LE		0
+#define FSBL_FLAGS_ENDIAN_BE		1
+
+#define FSBL_FLAGS_TZ_SHIFT		2
+#define FSBL_FLAGS_TZ_MASK		(1 << FSBL_FLAGS_TZ_SHIFT)
+#define FSBL_FLAGS_NON_SECURE		0
+#define FSBL_FLAGS_SECURE		1
+
+#define FSBL_FLAGS_EL_SHIFT		3
+#define FSBL_FLAGS_EL_MASK		(3 << FSBL_FLAGS_EL_SHIFT)
+#define FSBL_FLAGS_EL0			0
+#define FSBL_FLAGS_EL1			1
+#define FSBL_FLAGS_EL2			2
+#define FSBL_FLAGS_EL3			3
+
+#define FSBL_FLAGS_CPU_SHIFT		5
+#define FSBL_FLAGS_CPU_MASK		(3 << FSBL_FLAGS_CPU_SHIFT)
+#define FSBL_FLAGS_A53_0		0
+#define FSBL_FLAGS_A53_1		1
+#define FSBL_FLAGS_A53_2		2
+#define FSBL_FLAGS_A53_3		3
+
+#define FSBL_MAX_PARTITIONS		8
+
+/* Structure corresponding to each partition entry */
+struct xfsbl_partition {
+	uint64_t entry_point;
+	uint64_t flags;
+};
+
+/* Structure for handoff parameters to ARM Trusted Firmware (ATF) */
+struct xfsbl_atf_handoff_params {
+	uint8_t magic[4];
+	uint32_t num_entries;
+	struct xfsbl_partition partition[FSBL_MAX_PARTITIONS];
+};
+
+/**
+ * @partition: Pointer to partition struct
+ *
+ * Get the target CPU for @partition.
+ *
+ * Return: FSBL_FLAGS_A53_0, FSBL_FLAGS_A53_1, FSBL_FLAGS_A53_2 or FSBL_FLAGS_A53_3
+ */
+static int get_fsbl_cpu(const struct xfsbl_partition *partition)
+{
+	uint64_t flags = partition->flags & FSBL_FLAGS_CPU_MASK;
+
+	return flags >> FSBL_FLAGS_CPU_SHIFT;
+}
+
+/**
+ * @partition: Pointer to partition struct
+ *
+ * Get the target exception level for @partition.
+ *
+ * Return: FSBL_FLAGS_EL0, FSBL_FLAGS_EL1, FSBL_FLAGS_EL2 or FSBL_FLAGS_EL3
+ */
+static int get_fsbl_el(const struct xfsbl_partition *partition)
+{
+	uint64_t flags = partition->flags & FSBL_FLAGS_EL_MASK;
+
+	return flags >> FSBL_FLAGS_EL_SHIFT;
+}
+
+/**
+ * @partition: Pointer to partition struct
+ *
+ * Get the target security state for @partition.
+ *
+ * Return: FSBL_FLAGS_NON_SECURE or FSBL_FLAGS_SECURE
+ */
+static int get_fsbl_ss(const struct xfsbl_partition *partition)
+{
+	uint64_t flags = partition->flags & FSBL_FLAGS_TZ_MASK;
+
+	return flags >> FSBL_FLAGS_TZ_SHIFT;
+}
+
+/**
+ * @partition: Pointer to partition struct
+ *
+ * Get the target endianness for @partition.
+ *
+ * Return: SPSR_E_LITTLE or SPSR_E_BIG
+ */
+static int get_fsbl_endian(const struct xfsbl_partition *partition)
+{
+	uint64_t flags = partition->flags & FSBL_FLAGS_ENDIAN_MASK;
+
+	flags >>= FSBL_FLAGS_ENDIAN_SHIFT;
+
+	if (flags == FSBL_FLAGS_ENDIAN_BE)
+		return SPSR_E_BIG;
+	else
+		return SPSR_E_LITTLE;
+}
+
+/**
+ * @partition: Pointer to partition struct
+ *
+ * Get the target execution state for @partition.
+ *
+ * Return: FSBL_FLAGS_ESTATE_A32 or FSBL_FLAGS_ESTATE_A64
+ */
+static int get_fsbl_estate(const struct xfsbl_partition *partition)
+{
+	uint64_t flags = partition->flags & FSBL_FLAGS_ESTATE_MASK;
+
+	return flags >> FSBL_FLAGS_ESTATE_SHIFT;
+}
+
+/**
+ * Populates the bl32 and bl33 image info structures
+ * @bl32:	BL32 image info structure
+ * @bl33:	BL33 image info structure
+ * atf_handoff_addr:  ATF handoff address
+ *
+ * Process the handoff paramters from the FSBL and populate the BL32 and BL33
+ * image info structures accordingly.
+ *
+ * Return: Return the status of the handoff. The value will be from the
+ *         fsbl_handoff enum.
+ */
+enum fsbl_handoff fsbl_atf_handover(entry_point_info_t *bl32,
+					entry_point_info_t *bl33,
+					uint64_t atf_handoff_addr)
+{
+	const struct xfsbl_atf_handoff_params *ATFHandoffParams;
+	assert((atf_handoff_addr < BL31_BASE) ||
+	       (atf_handoff_addr > (uint64_t)&__BL31_END__));
+	if (!atf_handoff_addr) {
+		WARN("BL31: No ATF handoff structure passed\n");
+		return FSBL_HANDOFF_NO_STRUCT;
+	}
+
+	ATFHandoffParams = (struct xfsbl_atf_handoff_params *)atf_handoff_addr;
+	if ((ATFHandoffParams->magic[0] != 'X') ||
+	    (ATFHandoffParams->magic[1] != 'L') ||
+	    (ATFHandoffParams->magic[2] != 'N') ||
+	    (ATFHandoffParams->magic[3] != 'X')) {
+		ERROR("BL31: invalid ATF handoff structure at %llx\n",
+		      atf_handoff_addr);
+		return FSBL_HANDOFF_INVAL_STRUCT;
+	}
+
+	VERBOSE("BL31: ATF handoff params at:0x%llx, entries:%u\n",
+		atf_handoff_addr, ATFHandoffParams->num_entries);
+	if (ATFHandoffParams->num_entries > FSBL_MAX_PARTITIONS) {
+		ERROR("BL31: ATF handoff params: too many partitions (%u/%u)\n",
+		      ATFHandoffParams->num_entries, FSBL_MAX_PARTITIONS);
+		return FSBL_HANDOFF_TOO_MANY_PARTS;
+	}
+
+	/*
+	 * we loop over all passed entries but only populate two image structs
+	 * (bl32, bl33). I.e. the last applicable images in the handoff
+	 * structure will be used for the hand off
+	 */
+	for (size_t i = 0; i < ATFHandoffParams->num_entries; i++) {
+		entry_point_info_t *image;
+		int target_estate, target_secure;
+		int target_cpu, target_endianness, target_el;
+
+		VERBOSE("BL31: %zd: entry:0x%llx, flags:0x%llx\n", i,
+			ATFHandoffParams->partition[i].entry_point,
+			ATFHandoffParams->partition[i].flags);
+
+		target_cpu = get_fsbl_cpu(&ATFHandoffParams->partition[i]);
+		if (target_cpu != FSBL_FLAGS_A53_0) {
+			WARN("BL31: invalid target CPU (%i)\n", target_cpu);
+			continue;
+		}
+
+		target_el = get_fsbl_el(&ATFHandoffParams->partition[i]);
+		if ((target_el == FSBL_FLAGS_EL3) ||
+		    (target_el == FSBL_FLAGS_EL0)) {
+			WARN("BL31: invalid exception level (%i)\n", target_el);
+			continue;
+		}
+
+		target_secure = get_fsbl_ss(&ATFHandoffParams->partition[i]);
+		if (target_secure == FSBL_FLAGS_SECURE &&
+		    target_el == FSBL_FLAGS_EL2) {
+			WARN("BL31: invalid security state (%i) for exception level (%i)\n",
+			     target_secure, target_el);
+			continue;
+		}
+
+		target_estate = get_fsbl_estate(&ATFHandoffParams->partition[i]);
+		target_endianness = get_fsbl_endian(&ATFHandoffParams->partition[i]);
+
+		if (target_secure == FSBL_FLAGS_SECURE) {
+			image = bl32;
+
+			if (target_estate == FSBL_FLAGS_ESTATE_A32)
+				bl32->spsr = SPSR_MODE32(MODE32_svc, SPSR_T_ARM,
+							 target_endianness,
+							 DISABLE_ALL_EXCEPTIONS);
+			else
+				bl32->spsr = SPSR_64(MODE_EL1, MODE_SP_ELX,
+						     DISABLE_ALL_EXCEPTIONS);
+		} else {
+			image = bl33;
+
+			if (target_estate == FSBL_FLAGS_ESTATE_A32) {
+				if (target_el == FSBL_FLAGS_EL2)
+					target_el = MODE32_hyp;
+				else
+					target_el = MODE32_sys;
+
+				bl33->spsr = SPSR_MODE32(target_el, SPSR_T_ARM,
+							 target_endianness,
+							 DISABLE_ALL_EXCEPTIONS);
+			} else {
+				if (target_el == FSBL_FLAGS_EL2)
+					target_el = MODE_EL2;
+				else
+					target_el = MODE_EL1;
+
+				bl33->spsr = SPSR_64(target_el, MODE_SP_ELX,
+						     DISABLE_ALL_EXCEPTIONS);
+			}
+		}
+
+		VERBOSE("Setting up %s entry point to:%llx, el:%x\n",
+			target_secure == FSBL_FLAGS_SECURE ? "BL32" : "BL33",
+			ATFHandoffParams->partition[i].entry_point,
+			target_el);
+		image->pc = ATFHandoffParams->partition[i].entry_point;
+
+		if (target_endianness == SPSR_E_BIG)
+			EP_SET_EE(image->h.attr, EP_EE_BIG);
+		else
+			EP_SET_EE(image->h.attr, EP_EE_LITTLE);
+	}
+
+	return FSBL_HANDOFF_SUCCESS;
+}