GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/riscv/cpu/generic/Kconfig

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+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+config GENERIC_RISCV
+	bool
+	select ARCH_EARLY_INIT_R
+	imply CPU
+	imply CPU_RISCV
+	imply RISCV_TIMER
+	imply SIFIVE_CLINT if (RISCV_MMODE || SPL_RISCV_MMODE)
+	imply CMD_CPU
+	imply SPL_CPU_SUPPORT
+	imply SPL_OPENSBI
+	imply SPL_LOAD_FIT

source/bootloader/u-boot-2020.01/arch/riscv/cpu/generic/Makefile

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+# SPDX-License-Identifier: GPL-2.0+
+#
+# Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+
+obj-y += dram.o
+obj-y += cpu.o

source/bootloader/u-boot-2020.01/arch/riscv/cpu/generic/cpu.c

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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <irq_func.h>
+
+/*
+ * cleanup_before_linux() is called just before we call linux
+ * it prepares the processor for linux
+ *
+ * we disable interrupt and caches.
+ */
+int cleanup_before_linux(void)
+{
+	disable_interrupts();
+
+	cache_flush();
+
+	return 0;
+}
+
+/* To enumerate devices on the /soc/ node, create a "simple-bus" driver */
+static const struct udevice_id riscv_virtio_soc_ids[] = {
+	{ .compatible = "riscv-virtio-soc" },
+	{ }
+};
+
+U_BOOT_DRIVER(riscv_virtio_soc) = {
+	.name = "riscv_virtio_soc",
+	.id = UCLASS_SIMPLE_BUS,
+	.of_match = riscv_virtio_soc_ids,
+	.flags = DM_FLAG_PRE_RELOC,
+};

source/bootloader/u-boot-2020.01/arch/riscv/cpu/generic/dram.c

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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
+ */
+
+#include <common.h>
+#include <fdtdec.h>
+#include <init.h>
+#include <linux/sizes.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	return fdtdec_setup_mem_size_base();
+}
+
+int dram_init_banksize(void)
+{
+	return fdtdec_setup_memory_banksize();
+}
+
+ulong board_get_usable_ram_top(ulong total_size)
+{
+#ifdef CONFIG_64BIT
+	/*
+	 * Ensure that we run from first 4GB so that all
+	 * addresses used by U-Boot are 32bit addresses.
+	 *
+	 * This in-turn ensures that 32bit DMA capable
+	 * devices work fine because DMA mapping APIs will
+	 * provide 32bit DMA addresses only.
+	 */
+	if (gd->ram_top > SZ_4G)
+		return SZ_4G;
+#endif
+	return gd->ram_top;
+}