juno: Add a handler for 'ARM Architecture' SMC calls

Currently UEFI and Linux are using SMC calls in the 'ARM Architecture'
Owning Entity range so lets implement these to get things working.

UEFI probably doesn't actually need to issue the ID_PRESENCE and ID_UID
calls it does, and the device-tree used by Linux could specify the PSCI
identifiers instead. After those changes, this patch isn't required.
Signed-off-by: Jon Medhurst <tixy@linaro.org>

plat/juno/platform.mk

@@ -93,6 +93,7 @@ BL31_SOURCES		+=	bl31_plat_setup.c			\
 				plat_topology.c				\
 				plat_gic.c				\
 				scpi.c					\
+				smc_arm.c				\
 				cci400.c				\
 				gic_v2.c				\
 				gic_v3.c

plat/juno/smc_arm.c

+/*
+ * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <stdint.h>
+#include <context.h>
+#include <runtime_svc.h>
+#include <psci_private.h>
+
+
+#define ARM_SMC_ARM_CPU_SUSPEND   0x80100001
+#define ARM_SMC_ARM_CPU_OFF       0x80100002
+#define ARM_SMC_ARM_CPU_ON        0x80100003
+#define ARM_SMC_ARM_MIGRATE       0x80100004
+
+#define ARM_TRUSTZONE_ARM_FAST_SMC_ID_PRESENCE	0x80FFFF00
+#define ARM_TRUSTZONE_ARM_FAST_SMC_ID_UID	0x80FFFF10
+
+#define ARM_TRUSTZONE_UID_4LETTERID	0x1
+#define ARM_TRUSTZONE_ARM_UID		0x40524d48 /* "ARMH" */
+
+
+static uint64_t smc_arm_handler(uint32_t smc_fid, uint64_t x1, uint64_t x2,
+				uint64_t x3, uint64_t x4, void *cookie,
+				void *handle, uint64_t flags)
+{
+	switch (smc_fid) {
+
+	/*
+	 * HACK WARNING: Below we use SMC_RET4 to return the original contents
+	 * of x1-x3. We do this because UEFI is expecting these values to be
+	 * preserved across the SMC call.
+	 */
+
+	case ARM_TRUSTZONE_ARM_FAST_SMC_ID_PRESENCE:
+		SMC_RET4(handle, 1, x1, x2, x3);
+		break;
+
+	case ARM_TRUSTZONE_ARM_FAST_SMC_ID_UID + 0:
+		SMC_RET4(handle, ARM_TRUSTZONE_UID_4LETTERID, x1, x2, x3);
+		break;
+
+	case ARM_TRUSTZONE_ARM_FAST_SMC_ID_UID + 1:
+		SMC_RET4(handle, ARM_TRUSTZONE_ARM_UID, x1, x2, x3);
+		break;
+
+	/* The following 3 cases translate functions into the PSCI equivalent */
+
+	case ARM_SMC_ARM_CPU_OFF:
+		smc_fid = PSCI_CPU_OFF;
+		break;
+
+	case ARM_SMC_ARM_CPU_SUSPEND:
+		smc_fid = PSCI_CPU_SUSPEND_AARCH64;
+		break;
+
+	case ARM_SMC_ARM_CPU_ON:
+		smc_fid = PSCI_CPU_ON_AARCH64;
+		break;
+
+	}
+
+	return psci_smc_handler(smc_fid, x1, x2, x3, x4, cookie, handle, flags);
+}
+
+static int32_t smc_arm_setup(void)
+{
+	return 0;
+}
+
+DECLARE_RT_SVC(arm, OEN_ARM_START, OEN_ARM_END, SMC_TYPE_FAST,
+			smc_arm_setup, smc_arm_handler);