Add a simple hello_world example that also echos input

Signed-off-by: Anton Blanchard <anton@linux.ibm.com>
4 years ago · 8bc3e8ea0a
6 changed files with 879 additions and 0 deletions
--- a/fpga/hello_world.hex
+++ b/fpga/hello_world.hex
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--- a/hello_world/Makefile
+++ b/hello_world/Makefile
@ -0,0 +1,22 @@
				@@ -0,0 +1,22 @@
+CROSS_COMPILE = powerpc64le-linux-
+CC = $(CROSS_COMPILE)gcc
+LD = $(CROSS_COMPILE)ld
+OBJCOPY = $(CROSS_COMPILE)objcopy
+
+CFLAGS = -Os -g -Wall -std=c99 -msoft-float -mno-string -mno-multiple -mno-vsx -mno-altivec -mlittle-endian -fno-stack-protector -mstrict-align -ffreestanding -fdata-sections -ffunction-sections 
+ASFLAGS = $(CFLAGS)
+LDFLAGS = -T powerpc.lds
+
+all: hello_world.hex
+
+hello_world.elf: hello_world.o head.o
+	$(LD) $(LDFLAGS) -o hello_world.elf hello_world.o head.o
+
+hello_world.bin: hello_world.elf
+	$(OBJCOPY) -O binary hello_world.elf hello_world.bin
+
+hello_world.hex: hello_world.bin
+	./bin2hex.py hello_world.bin > hello_world.hex
+
+clean:
+	@rm -f *.o hello_world.elf hello_world.bin hello_world.hex
--- a/hello_world/bin2hex.py
+++ b/hello_world/bin2hex.py
@ -0,0 +1,17 @@
				@@ -0,0 +1,17 @@
+#!/usr/bin/python3
+
+import sys
+import subprocess
+import struct
+
+with open(sys.argv[1], "rb") as f:
+        while True:
+            word = f.read(8)
+            if len(word) == 8:
+                print("%016x" % struct.unpack('Q', word));
+            elif len(word) == 4:
+                print("00000000%08x" % struct.unpack('I', word));
+            elif len(word) == 0:
+                exit(0);
+            else:
+                raise Exception("Bad length")
--- a/hello_world/head.S
+++ b/hello_world/head.S
@ -0,0 +1,95 @@
				@@ -0,0 +1,95 @@
+/* Copyright 2013-2014 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * 	http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
+ * implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define STACK_TOP 0x3000
+
+#define FIXUP_ENDIAN						   \
+	tdi   0,0,0x48;	  /* Reverse endian of b . + 8		*/ \
+	b     191f;	  /* Skip trampoline if endian is good	*/ \
+	.long 0xa600607d; /* mfmsr r11				*/ \
+	.long 0x01006b69; /* xori r11,r11,1			*/ \
+	.long 0x05009f42; /* bcl 20,31,$+4			*/ \
+	.long 0xa602487d; /* mflr r10				*/ \
+	.long 0x14004a39; /* addi r10,r10,20			*/ \
+	.long 0xa64b5a7d; /* mthsrr0 r10			*/ \
+	.long 0xa64b7b7d; /* mthsrr1 r11			*/ \
+	.long 0x2402004c; /* hrfid				*/ \
+191:
+
+
+/* Load an immediate 64-bit value into a register */
+#define LOAD_IMM64(r, e)			\
+	lis     r,(e)@highest;			\
+	ori     r,r,(e)@higher;			\
+	rldicr  r,r, 32, 31;			\
+	oris    r,r, (e)@h;			\
+	ori     r,r, (e)@l;
+
+	.section ".head","ax"
+
+	. = 0
+.global _start
+_start:
+	FIXUP_ENDIAN
+	b	boot_entry
+
+.global boot_entry
+boot_entry:
+	/* setup stack */
+	LOAD_IMM64(%r1, STACK_TOP - 0x100)
+	LOAD_IMM64(%r12, main)
+	mtctr	%r12,
+	bctrl
+	b .
+
+#define EXCEPTION(nr)		\
+	.= nr			;\
+	b	.
+
+	/* More exception stubs */
+	EXCEPTION(0x300)
+	EXCEPTION(0x380)
+	EXCEPTION(0x400)
+	EXCEPTION(0x480)
+	EXCEPTION(0x500)
+	EXCEPTION(0x600)
+	EXCEPTION(0x700)
+	EXCEPTION(0x800)
+	EXCEPTION(0x900)
+	EXCEPTION(0x980)
+	EXCEPTION(0xa00)
+	EXCEPTION(0xb00)
+	EXCEPTION(0xc00)
+	EXCEPTION(0xd00)
+	EXCEPTION(0xe00)
+	EXCEPTION(0xe20)
+	EXCEPTION(0xe40)
+	EXCEPTION(0xe60)
+	EXCEPTION(0xe80)
+	EXCEPTION(0xf00)
+	EXCEPTION(0xf20)
+	EXCEPTION(0xf40)
+	EXCEPTION(0xf60)
+	EXCEPTION(0xf80)
+#if 0
+	EXCEPTION(0x1000)
+	EXCEPTION(0x1100)
+	EXCEPTION(0x1200)
+	EXCEPTION(0x1300)
+	EXCEPTION(0x1400)
+	EXCEPTION(0x1500)
+	EXCEPTION(0x1600)
+#endif
--- a/hello_world/hello_world.c
+++ b/hello_world/hello_world.c
@ -0,0 +1,146 @@
				@@ -0,0 +1,146 @@
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdbool.h>
+
+/*
+ * Core UART functions to implement for a port
+ */
+
+static uint64_t potato_uart_base;
+
+#define PROC_FREQ 100000000
+#define UART_FREQ 115200
+#define UART_BASE 0xc0002000
+
+#define POTATO_CONSOLE_TX		0x00
+#define POTATO_CONSOLE_RX		0x08
+#define POTATO_CONSOLE_STATUS		0x10
+#define   POTATO_CONSOLE_STATUS_RX_EMPTY		0x01
+#define   POTATO_CONSOLE_STATUS_TX_EMPTY		0x02
+#define   POTATO_CONSOLE_STATUS_RX_FULL			0x04
+#define   POTATO_CONSOLE_STATUS_TX_FULL			0x08
+#define POTATO_CONSOLE_CLOCK_DIV	0x18
+#define POTATO_CONSOLE_IRQ_EN		0x20
+
+static uint64_t potato_uart_reg_read(int offset)
+{
+	uint64_t addr;
+	uint64_t val;
+
+	addr = potato_uart_base + offset;
+
+	val = *(volatile uint64_t *)addr;
+
+	return val;
+}
+
+static void potato_uart_reg_write(int offset, uint64_t val)
+{
+	uint64_t addr;
+
+	addr = potato_uart_base + offset;
+
+	*(volatile uint64_t *)addr = val;
+}
+
+static int potato_uart_rx_empty(void)
+{
+	uint64_t val;
+
+	val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
+
+	if (val & POTATO_CONSOLE_STATUS_RX_EMPTY)
+		return 1;
+
+	return 0;
+}
+
+static int potato_uart_tx_full(void)
+{
+	uint64_t val;
+
+	val = potato_uart_reg_read(POTATO_CONSOLE_STATUS);
+
+	if (val & POTATO_CONSOLE_STATUS_TX_FULL)
+		return 1;
+
+	return 0;
+}
+
+static char potato_uart_read(void)
+{
+	uint64_t val;
+
+	val = potato_uart_reg_read(POTATO_CONSOLE_RX);
+
+	return (char)(val & 0x000000ff);
+}
+
+static void potato_uart_write(char c)
+{
+	uint64_t val;
+
+	val = c;
+
+	potato_uart_reg_write(POTATO_CONSOLE_TX, val);
+}
+
+static unsigned long potato_uart_divisor(unsigned long proc_freq, unsigned long uart_freq)
+{
+	return proc_freq / (uart_freq * 16) - 1;
+}
+
+void potato_uart_init(void)
+{
+	potato_uart_base = UART_BASE;
+
+	potato_uart_reg_write(POTATO_CONSOLE_CLOCK_DIV, potato_uart_divisor(PROC_FREQ, UART_FREQ));
+}
+
+int getchar(void)
+{
+	while (potato_uart_rx_empty())
+		/* Do nothing */ ;
+
+	return potato_uart_read();
+}
+
+void putchar(unsigned char c)
+{
+	while (potato_uart_tx_full())
+		/* Do Nothing */;
+
+	potato_uart_write(c);
+}
+
+void putstr(const char *str, unsigned long len)
+{
+	for (unsigned long i = 0; i < len; i++) {
+		putchar(str[i]);
+	}
+}
+
+size_t strlen(const char *s)
+{
+	size_t len = 0;
+
+	while (*s++)
+		len++;
+
+	return len;
+}
+
+#define HELLO_WORLD "Hello World\r\n"
+
+int main(void)
+{
+	potato_uart_init();
+
+	putstr(HELLO_WORLD, strlen(HELLO_WORLD));
+
+	while (1) {
+		unsigned char c = getchar();
+		putchar(c);
+	}
+}
--- a/hello_world/powerpc.lds
+++ b/hello_world/powerpc.lds
@ -0,0 +1,13 @@
				@@ -0,0 +1,13 @@
+SECTIONS
+{
+	_start = .;
+	. = 0;
+	.head : {
+		KEEP(*(.head))
+ 	}
+	. = 0x1000;
+	.text : { *(.text) }
+	. = 0x2000;
+	.data : { *(.data) }
+	.bss : { *(.bss) }
+}