platform: Add Andes AE350 initial support

This commit provides basic support for the AE350 platform.

Signed-off-by: Zong Li <zongbox@gmail.com>
Signed-off-by: Nylon Chen <nylon7@andestech.com>

platform/andes/ae350/plmt.c

@@ -0,0 +1,97 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2019 Andes Technology Corporation
+ *
+ * Authors:
+ *   Zong Li <zong@andestech.com>
+ *   Nylon Chen <nylon7@andestech.com>
+ */
+
+#include <sbi/riscv_io.h>
+#include <sbi/sbi_hart.h>
+
+static u32 plmt_time_hart_count;
+static volatile void *plmt_time_base;
+static volatile u64 *plmt_time_val;
+static volatile u64 *plmt_time_cmp;
+
+u64 plmt_timer_value(void)
+{
+#if __riscv_xlen == 64
+	return readq_relaxed(plmt_time_val);
+#else
+	u32 lo, hi;
+
+	do {
+		hi = readl_relaxed((void *)plmt_time_val + 0x04);
+		lo = readl_relaxed(plmt_time_val);
+	} while (hi != readl_relaxed((void *)plmt_time_val + 0x04));
+
+	return ((u64)hi << 32) | (u64)lo;
+#endif
+}
+
+void plmt_timer_event_stop(void)
+{
+	u32 target_hart = sbi_current_hartid();
+
+	if (plmt_time_hart_count <= target_hart)
+		return;
+
+	/* Clear PLMT Time Compare */
+#if __riscv_xlen == 64
+	writeq_relaxed(-1ULL, &plmt_time_cmp[target_hart]);
+#else
+	writel_relaxed(-1UL, &plmt_time_cmp[target_hart]);
+	writel_relaxed(-1UL, (void *)(&plmt_time_cmp[target_hart]) + 0x04);
+#endif
+}
+
+void plmt_timer_event_start(u64 next_event)
+{
+	u32 target_hart = sbi_current_hartid();
+
+	if (plmt_time_hart_count <= target_hart)
+		return;
+
+	/* Program PLMT Time Compare */
+#if __riscv_xlen == 64
+	writeq_relaxed(next_event, &plmt_time_cmp[target_hart]);
+#else
+	u32 mask = -1UL;
+
+	writel_relaxed(next_event & mask, &plmt_time_cmp[target_hart]);
+	writel_relaxed(next_event >> 32,
+		       (void *)(&plmt_time_cmp[target_hart]) + 0x04);
+#endif
+
+}
+
+int plmt_warm_timer_init(void)
+{
+	u32 target_hart = sbi_current_hartid();
+
+	if (plmt_time_hart_count <= target_hart || !plmt_time_base)
+		return -1;
+
+	/* Clear PLMT Time Compare */
+#if __riscv_xlen == 64
+	writeq_relaxed(-1ULL, &plmt_time_cmp[target_hart]);
+#else
+	writel_relaxed(-1UL, &plmt_time_cmp[target_hart]);
+	writel_relaxed(-1UL, (void *)(&plmt_time_cmp[target_hart]) + 0x04);
+#endif
+
+	return 0;
+}
+
+int plmt_cold_timer_init(unsigned long base, u32 hart_count)
+{
+	plmt_time_hart_count = hart_count;
+	plmt_time_base	     = (void *)base;
+	plmt_time_val        = (u64 *)(plmt_time_base);
+	plmt_time_cmp        = (u64 *)(plmt_time_base + 0x8);
+
+	return 0;
+}