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/sh/cpu/sh4/Makefile

@@ -0,0 +1,12 @@
+#
+# (C) Copyright 2000-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# (C) Copyright 2007
+# Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+extra-y	= start.o
+obj-y	= cpu.o interrupts.o watchdog.o cache.o

u-boot/arch/sh/cpu/sh4/cache.c

@@ -0,0 +1,114 @@
+/*
+ * (C) Copyright 2007
+ * Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <asm/processor.h>
+#include <asm/io.h>
+
+/*
+ * Jump to P2 area.
+ * When handling TLB or caches, we need to do it from P2 area.
+ */
+#define jump_to_P2()			\
+  do {					\
+    unsigned long __dummy;		\
+    __asm__ __volatile__(		\
+		"mov.l	1f, %0\n\t"	\
+		"or	%1, %0\n\t"	\
+		"jmp	@%0\n\t"	\
+		" nop\n\t"		\
+		".balign 4\n"		\
+		"1:	.long 2f\n"	\
+		"2:"			\
+		: "=&r" (__dummy)	\
+		: "r" (0x20000000));	\
+  } while (0)
+
+/*
+ * Back to P1 area.
+ */
+#define back_to_P1()					\
+  do {							\
+    unsigned long __dummy;				\
+    __asm__ __volatile__(				\
+		"nop;nop;nop;nop;nop;nop;nop\n\t"	\
+		"mov.l	1f, %0\n\t"			\
+		"jmp	@%0\n\t"			\
+		" nop\n\t"				\
+		".balign 4\n"				\
+		"1:	.long 2f\n"			\
+		"2:"					\
+		: "=&r" (__dummy));			\
+  } while (0)
+
+#define CACHE_VALID       1
+#define CACHE_UPDATED     2
+
+static inline void cache_wback_all(void)
+{
+	unsigned long addr, data, i, j;
+
+	jump_to_P2();
+	for (i = 0; i < CACHE_OC_NUM_ENTRIES; i++){
+		for (j = 0; j < CACHE_OC_NUM_WAYS; j++) {
+			addr = CACHE_OC_ADDRESS_ARRAY | (j << CACHE_OC_WAY_SHIFT)
+				| (i << CACHE_OC_ENTRY_SHIFT);
+			data = inl(addr);
+			if (data & CACHE_UPDATED) {
+				data &= ~CACHE_UPDATED;
+				outl(data, addr);
+			}
+		}
+	}
+	back_to_P1();
+}
+
+
+#define CACHE_ENABLE      0
+#define CACHE_DISABLE     1
+
+int cache_control(unsigned int cmd)
+{
+	unsigned long ccr;
+
+	jump_to_P2();
+	ccr = inl(CCR);
+
+	if (ccr & CCR_CACHE_ENABLE)
+		cache_wback_all();
+
+	if (cmd == CACHE_DISABLE)
+		outl(CCR_CACHE_STOP, CCR);
+	else
+		outl(CCR_CACHE_INIT, CCR);
+	back_to_P1();
+
+	return 0;
+}
+
+void flush_dcache_range(unsigned long start, unsigned long end)
+{
+	u32 v;
+
+	start &= ~(L1_CACHE_BYTES - 1);
+	for (v = start; v < end; v += L1_CACHE_BYTES) {
+		asm volatile ("ocbwb     %0" :	/* no output */
+			      : "m" (__m(v)));
+	}
+}
+
+void invalidate_dcache_range(unsigned long start, unsigned long end)
+{
+	u32 v;
+
+	start &= ~(L1_CACHE_BYTES - 1);
+	for (v = start; v < end; v += L1_CACHE_BYTES) {
+		asm volatile ("ocbi     %0" :	/* no output */
+			      : "m" (__m(v)));
+	}
+}

u-boot/arch/sh/cpu/sh4/config.mk

@@ -0,0 +1,11 @@
+#
+# (C) Copyright 2000-2004
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# (C) Copyright 2007
+# Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+#
+PLATFORM_CPPFLAGS += -m4-nofpu

u-boot/arch/sh/cpu/sh4/cpu.c

@@ -0,0 +1,83 @@
+/*
+ * (C) Copyright 2007
+ * Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <command.h>
+#include <netdev.h>
+#include <asm/processor.h>
+#include <asm/cache.h>
+
+int checkcpu(void)
+{
+	puts("CPU: SH4\n");
+	return 0;
+}
+
+int cpu_init (void)
+{
+	return 0;
+}
+
+int cleanup_before_linux (void)
+{
+	disable_interrupts();
+	return 0;
+}
+
+int do_reset (cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+	disable_interrupts();
+	reset_cpu (0);
+	return 0;
+}
+
+void flush_cache (unsigned long addr, unsigned long size)
+{
+	invalidate_dcache_range(addr , addr + size);
+}
+
+void icache_enable (void)
+{
+	cache_control(0);
+}
+
+void icache_disable (void)
+{
+	cache_control(1);
+}
+
+int icache_status (void)
+{
+	return 0;
+}
+
+void dcache_enable (void)
+{
+}
+
+void dcache_disable (void)
+{
+}
+
+int dcache_status (void)
+{
+	return 0;
+}
+
+int cpu_eth_init(bd_t *bis)
+{
+#ifdef CONFIG_SH_ETHER
+	sh_eth_initialize(bis);
+#endif
+	return 0;
+}
+
+void relocate_code(ulong start_addr_sp, gd_t *new_gd, ulong relocaaddr)
+{
+	/* TODO(sh maintainer): Implement this */
+	while (1);
+}

u-boot/arch/sh/cpu/sh4/interrupts.c

@@ -0,0 +1,22 @@
+/*
+ * (C) Copyright 2007
+ * Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+
+int interrupt_init (void)
+{
+	return 0;
+}
+
+void enable_interrupts (void)
+{
+
+}
+
+int disable_interrupts (void){
+	return 0;
+}

u-boot/arch/sh/cpu/sh4/start.S

@@ -0,0 +1,62 @@
+/*
+ * (C) Copyright 2007, 2010
+ * Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <asm-offsets.h>
+#include <config.h>
+
+	.text
+	.align	2
+
+	.global	_start
+_sh_start:
+	mov.l	._lowlevel_init, r0
+100:	bsrf	r0
+	nop
+
+	bsr	1f
+	nop
+1:	sts	pr, r5
+	mov.l	._reloc_dst, r4
+	add	#(_sh_start-1b), r5
+	mov.l	._reloc_dst_end, r6
+
+2:	mov.l	@r5+, r1
+	mov.l	r1, @r4
+	add	#4, r4
+	cmp/hs	r6, r4
+	bf	2b
+
+	mov.l	._bss_start, r4
+	mov.l	._bss_end, r5
+	mov	#0, r1
+
+3:	mov.l	r1, @r4			/* bss clear */
+	add	#4, r4
+	cmp/hs	r5, r4
+	bf	3b
+
+	mov.l	._gd_init, r13		/* global data */
+	mov.l	._stack_init, r15	/* stack */
+
+	#TODO(sh maintainer): Fix this up to call the correct code
+	#mov.l	._sh_generic_init, r0
+	#jsr	@r0
+	nop
+
+loop:
+	bra	loop
+
+	.align	2
+
+._lowlevel_init:	.long	(lowlevel_init - (100b + 4))
+._reloc_dst:		.long	reloc_dst
+._reloc_dst_end:	.long	reloc_dst_end
+._bss_start:		.long	bss_start
+._bss_end:		.long	bss_end
+._gd_init:		.long	(_sh_start - GENERATED_GBL_DATA_SIZE)
+._stack_init:		.long	(_sh_start - GENERATED_GBL_DATA_SIZE - CONFIG_SYS_MALLOC_LEN - 16)
+#._sh_generic_init:	.long	sh_generic_init

u-boot/arch/sh/cpu/sh4/watchdog.c

@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/processor.h>
+#include <asm/system.h>
+#include <asm/io.h>
+
+#define WDT_BASE	WTCNT
+
+#define WDT_WD		(1 << 6)
+#define WDT_RST_P	(0)
+#define WDT_RST_M	(1 << 5)
+#define WDT_ENABLE	(1 << 7)
+
+#if defined(CONFIG_WATCHDOG)
+static unsigned char csr_read(void)
+{
+	return inb(WDT_BASE + 0x04);
+}
+
+static void cnt_write(unsigned char value)
+{
+	outl((unsigned short)value | 0x5A00, WDT_BASE + 0x00);
+}
+
+static void csr_write(unsigned char value)
+{
+	outl((unsigned short)value | 0xA500, WDT_BASE + 0x04);
+}
+
+void watchdog_reset(void)
+{
+	outl(0x55000000, WDT_BASE + 0x08);
+}
+
+int watchdog_init(void)
+{
+	/* Set overflow time*/
+	cnt_write(0);
+	/* Power on reset */
+	csr_write(WDT_WD|WDT_RST_P|WDT_ENABLE);
+
+	return 0;
+}
+
+int watchdog_disable(void)
+{
+	csr_write(csr_read() & ~WDT_ENABLE);
+	return 0;
+}
+#endif
+
+void reset_cpu(unsigned long ignored)
+{
+	/* Address error with SR.BL=1 first. */
+	trigger_address_error();
+
+	while (1)
+		;
+}