avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/arch/arm/lib/semihosting.c

@@ -0,0 +1,216 @@
+/*
+ * Copyright 2014 Broadcom Corporation
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+/*
+ * Minimal semihosting implementation for reading files into memory. If more
+ * features like writing files or console output are required they can be
+ * added later. This code has been tested on arm64/aarch64 fastmodel only.
+ * An untested placeholder exists for armv7 architectures, but since they
+ * are commonly available in silicon now, fastmodel usage makes less sense
+ * for them.
+ */
+#include <common.h>
+#include <command.h>
+
+#define SYSOPEN		0x01
+#define SYSCLOSE	0x02
+#define SYSREAD		0x06
+#define SYSFLEN		0x0C
+
+#define MODE_READ	0x0
+#define MODE_READBIN	0x1
+
+/*
+ * Call the handler
+ */
+static noinline long smh_trap(unsigned int sysnum, void *addr)
+{
+	register long result asm("r0");
+#if defined(CONFIG_ARM64)
+	asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
+#elif defined(CONFIG_CPU_V7M)
+	asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
+#else
+	/* Note - untested placeholder */
+	asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));
+#endif
+	return result;
+}
+
+/*
+ * Open a file on the host. Mode is "r" or "rb" currently. Returns a file
+ * descriptor or -1 on error.
+ */
+static long smh_open(const char *fname, char *modestr)
+{
+	long fd;
+	unsigned long mode;
+	struct smh_open_s {
+		const char *fname;
+		unsigned long mode;
+		size_t len;
+	} open;
+
+	debug("%s: file \'%s\', mode \'%s\'\n", __func__, fname, modestr);
+
+	/* Check the file mode */
+	if (!(strcmp(modestr, "r"))) {
+		mode = MODE_READ;
+	} else if (!(strcmp(modestr, "rb"))) {
+		mode = MODE_READBIN;
+	} else {
+		printf("%s: ERROR mode \'%s\' not supported\n", __func__,
+		       modestr);
+		return -1;
+	}
+
+	open.fname = fname;
+	open.len = strlen(fname);
+	open.mode = mode;
+
+	/* Open the file on the host */
+	fd = smh_trap(SYSOPEN, &open);
+	if (fd == -1)
+		printf("%s: ERROR fd %ld for file \'%s\'\n", __func__, fd,
+		       fname);
+
+	return fd;
+}
+
+/*
+ * Read 'len' bytes of file into 'memp'. Returns 0 on success, else failure
+ */
+static long smh_read(long fd, void *memp, size_t len)
+{
+	long ret;
+	struct smh_read_s {
+		long fd;
+		void *memp;
+		size_t len;
+	} read;
+
+	debug("%s: fd %ld, memp %p, len %zu\n", __func__, fd, memp, len);
+
+	read.fd = fd;
+	read.memp = memp;
+	read.len = len;
+
+	ret = smh_trap(SYSREAD, &read);
+	if (ret < 0) {
+		/*
+		 * The ARM handler allows for returning partial lengths,
+		 * but in practice this never happens so rather than create
+		 * hard to maintain partial read loops and such, just fail
+		 * with an error message.
+		 */
+		printf("%s: ERROR ret %ld, fd %ld, len %zu memp %p\n",
+		       __func__, ret, fd, len, memp);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Close the file using the file descriptor
+ */
+static long smh_close(long fd)
+{
+	long ret;
+
+	debug("%s: fd %ld\n", __func__, fd);
+
+	ret = smh_trap(SYSCLOSE, &fd);
+	if (ret == -1)
+		printf("%s: ERROR fd %ld\n", __func__, fd);
+
+	return ret;
+}
+
+/*
+ * Get the file length from the file descriptor
+ */
+static long smh_len_fd(long fd)
+{
+	long ret;
+
+	debug("%s: fd %ld\n", __func__, fd);
+
+	ret = smh_trap(SYSFLEN, &fd);
+	if (ret == -1)
+		printf("%s: ERROR ret %ld, fd %ld\n", __func__, ret, fd);
+
+	return ret;
+}
+
+static int smh_load_file(const char * const name, ulong load_addr,
+			 ulong *end_addr)
+{
+	long fd;
+	long len;
+	long ret;
+
+	fd = smh_open(name, "rb");
+	if (fd == -1)
+		return -1;
+
+	len = smh_len_fd(fd);
+	if (len < 0) {
+		smh_close(fd);
+		return -1;
+	}
+
+	ret = smh_read(fd, (void *)load_addr, len);
+	smh_close(fd);
+
+	if (ret == 0) {
+		*end_addr = load_addr + len - 1;
+		printf("loaded file %s from %08lX to %08lX, %08lX bytes\n",
+		       name,
+		       load_addr,
+		       *end_addr,
+		       len);
+	} else {
+		printf("read failed\n");
+		return 0;
+	}
+
+	return 0;
+}
+
+static int do_smhload(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	if (argc == 3 || argc == 4) {
+		ulong load_addr;
+		ulong end_addr = 0;
+		ulong ret;
+		char end_str[64];
+
+		load_addr = simple_strtoul(argv[2], NULL, 16);
+		if (!load_addr)
+			return -1;
+
+		ret = smh_load_file(argv[1], load_addr, &end_addr);
+		if (ret < 0)
+			return 1;
+
+		/* Optionally save returned end to the environment */
+		if (argc == 4) {
+			sprintf(end_str, "0x%08lx", end_addr);
+			setenv(argv[3], end_str);
+		}
+	} else {
+		return CMD_RET_USAGE;
+	}
+	return 0;
+}
+
+U_BOOT_CMD(smhload, 4, 0, do_smhload, "load a file using semihosting",
+	   "<file> 0x<address> [end var]\n"
+	   "    - load a semihosted file to the address specified\n"
+	   "      if the optional [end var] is specified, the end\n"
+	   "      address of the file will be stored in this environment\n"
+	   "      variable.\n");