feat(msm8916): initial platform port

Introduce the bare mimimum base of the msm8916 BL31 port. This is
pretty much just a standard platform "skeleton" with CPU/memory
initialization and an UART driver. This allows booting into
e.g. U-Boot with working UART output.

Note that the plat/qti/msm8916 port is completely separate and does not
make use of anything in plat/qti/common at the moment. The main reason
for that is that plat/qti/common is heavily focused around having a
binary "qtiseclib" component, while the MSM8916 port is fully
open-source (and therefore somewhat limited to publicly documented
functionality).

In the future it might be possible to re-use some of the open-source
parts in plat/qti/common (e.g. spmi_arb.c or pm_ps_hold.c) but it's
not strictly required for the basic functionality supported so far.

Change-Id: I7b4375df0f947b3bd1e55b0b52b21edb6e6d175b
Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
diff --git a/plat/qti/msm8916/include/platform_def.h b/plat/qti/msm8916/include/platform_def.h
new file mode 100644
index 0000000..4ad26dd
--- /dev/null
+++ b/plat/qti/msm8916/include/platform_def.h
@@ -0,0 +1,50 @@
+/*
+ * Copyright (c) 2021, Stephan Gerhold <stephan@gerhold.net>
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef PLATFORM_DEF_H
+#define PLATFORM_DEF_H
+
+#include <plat/common/common_def.h>
+
+/*
+ * There is at least 1 MiB available for BL31. However, at the moment the
+ * "msm8916_entry_point" variable in the data section is read through the
+ * 64 KiB region of the "boot remapper" after reset. For simplicity, limit
+ * the end of the data section (BL31_PROGBITS_LIMIT) to 64 KiB for now and
+ * the overall limit to 128 KiB. This could be increased if needed by placing
+ * the "msm8916_entry_point" variable explicitly in the first 64 KiB of BL31.
+ */
+#define BL31_LIMIT			(BL31_BASE + 0x20000)	/* 128 KiB */
+#define BL31_PROGBITS_LIMIT		(BL31_BASE + 0x10000)	/* 64 KiB */
+
+#define CACHE_WRITEBACK_GRANULE		U(64)
+#define PLATFORM_STACK_SIZE		U(0x1000)
+
+/* CPU topology: single cluster with 4 cores */
+#define PLATFORM_CLUSTER_COUNT		U(1)
+#define PLATFORM_MAX_CPUS_PER_CLUSTER	U(4)
+#define PLATFORM_CORE_COUNT		(PLATFORM_CLUSTER_COUNT * \
+					 PLATFORM_MAX_CPUS_PER_CLUSTER)
+
+/* Power management */
+#define PLATFORM_SYSTEM_COUNT		U(1)
+#define PLAT_NUM_PWR_DOMAINS		(PLATFORM_SYSTEM_COUNT + \
+					 PLATFORM_CLUSTER_COUNT + \
+					 PLATFORM_CORE_COUNT)
+#define PLAT_MAX_PWR_LVL		MPIDR_AFFLVL2
+#define PLAT_MAX_RET_STATE		U(2)
+#define PLAT_MAX_OFF_STATE		U(3)
+
+/* Translation tables */
+#define MAX_MMAP_REGIONS		8
+#define MAX_XLAT_TABLES			4
+
+#define PLAT_PHY_ADDR_SPACE_SIZE	(ULL(1) << 32)
+#define PLAT_VIRT_ADDR_SPACE_SIZE	(ULL(1) << 32)
+
+/* Timer frequency */
+#define PLAT_SYSCNT_FREQ		19200000
+
+#endif /* PLATFORM_DEF_H */