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authorLey Foon Tan <lftan@altera.com>2015-02-10 23:21:08 +0800
committerLey Foon Tan <lftan@altera.com>2015-02-10 23:21:08 +0800
commite8bf5bc776edef44777b13b2eb4461d653519bae (patch)
tree91626d85686ba2938f0c1fa76633b790a76c3cfc /arch/nios2
parent96f3a5cc33baede169e0d330119090789e97e86b (diff)
downloadkernel-e8bf5bc776edef44777b13b2eb4461d653519bae.tar.gz
nios2: add early printk support
Signed-off-by: Ley Foon Tan <lftan@altera.com>
Diffstat (limited to 'arch/nios2')
-rw-r--r--arch/nios2/Kconfig.debug11
-rw-r--r--arch/nios2/include/asm/prom.h22
-rw-r--r--arch/nios2/kernel/Makefile1
-rw-r--r--arch/nios2/kernel/early_printk.c118
-rw-r--r--arch/nios2/kernel/prom.c52
-rw-r--r--arch/nios2/kernel/setup.c4
6 files changed, 207 insertions, 1 deletions
diff --git a/arch/nios2/Kconfig.debug b/arch/nios2/Kconfig.debug
index 8d4e6bacd997..2fd08cbfdddb 100644
--- a/arch/nios2/Kconfig.debug
+++ b/arch/nios2/Kconfig.debug
@@ -14,4 +14,15 @@ config DEBUG_STACK_USAGE
This option will slow down process creation somewhat.
+config EARLY_PRINTK
+ bool "Activate early kernel debugging"
+ default y
+ select SERIAL_CORE_CONSOLE
+ depends on SERIAL_ALTERA_JTAGUART_CONSOLE || SERIAL_ALTERA_UART_CONSOLE
+ help
+ Enable early printk on console
+ This is useful for kernel debugging when your machine crashes very
+ early before the console code is initialized.
+ You should normally say N here, unless you want to debug such a crash.
+
endmenu
diff --git a/arch/nios2/include/asm/prom.h b/arch/nios2/include/asm/prom.h
new file mode 100644
index 000000000000..75fffb42cfa5
--- /dev/null
+++ b/arch/nios2/include/asm/prom.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright Altera Corporation (C) <2015>. All rights reserved
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_NIOS2_PROM_H__
+#define __ASM_NIOS2_PROM_H__
+
+extern unsigned long __init of_early_console(void);
+
+#endif
diff --git a/arch/nios2/kernel/Makefile b/arch/nios2/kernel/Makefile
index 8ae76823ff93..eaaa894c432f 100644
--- a/arch/nios2/kernel/Makefile
+++ b/arch/nios2/kernel/Makefile
@@ -20,5 +20,6 @@ obj-y += syscall_table.o
obj-y += time.o
obj-y += traps.o
+obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-$(CONFIG_MODULES) += module.o
obj-$(CONFIG_NIOS2_ALIGNMENT_TRAP) += misaligned.o
diff --git a/arch/nios2/kernel/early_printk.c b/arch/nios2/kernel/early_printk.c
new file mode 100644
index 000000000000..c08e4c1486fc
--- /dev/null
+++ b/arch/nios2/kernel/early_printk.c
@@ -0,0 +1,118 @@
+/*
+ * Early printk for Nios2.
+ *
+ * Copyright (C) 2015, Altera Corporation
+ * Copyright (C) 2010, Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2009, Wind River Systems Inc
+ * Implemented by fredrik.markstrom@gmail.com and ivarholmqvist@gmail.com
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/console.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/io.h>
+
+#include <asm/prom.h>
+
+static unsigned long base_addr;
+
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE)
+
+#define ALTERA_JTAGUART_DATA_REG 0
+#define ALTERA_JTAGUART_CONTROL_REG 4
+#define ALTERA_JTAGUART_CONTROL_WSPACE_MSK 0xFFFF0000
+#define ALTERA_JTAGUART_CONTROL_AC_MSK 0x00000400
+
+#define JUART_GET_CR() \
+ __builtin_ldwio((void *)(base_addr + ALTERA_JTAGUART_CONTROL_REG))
+#define JUART_SET_CR(v) \
+ __builtin_stwio((void *)(base_addr + ALTERA_JTAGUART_CONTROL_REG), v)
+#define JUART_SET_TX(v) \
+ __builtin_stwio((void *)(base_addr + ALTERA_JTAGUART_DATA_REG), v)
+
+static void early_console_write(struct console *con, const char *s, unsigned n)
+{
+ unsigned long status;
+
+ while (n-- && *s) {
+ while (((status = JUART_GET_CR())
+ & ALTERA_JTAGUART_CONTROL_WSPACE_MSK) == 0) {
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
+ if ((status & ALTERA_JTAGUART_CONTROL_AC_MSK) == 0)
+ return; /* no connection activity */
+#endif
+ }
+ JUART_SET_TX(*s);
+ s++;
+ }
+}
+
+#elif defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
+
+#define ALTERA_UART_TXDATA_REG 4
+#define ALTERA_UART_STATUS_REG 8
+#define ALTERA_UART_STATUS_TRDY 0x0040
+
+#define UART_GET_SR() \
+ __builtin_ldwio((void *)(base_addr + ALTERA_UART_STATUS_REG))
+#define UART_SET_TX(v) \
+ __builtin_stwio((void *)(base_addr + ALTERA_UART_TXDATA_REG), v)
+
+static void early_console_putc(char c)
+{
+ while (!(UART_GET_SR() & ALTERA_UART_STATUS_TRDY))
+ ;
+
+ UART_SET_TX(c);
+}
+
+static void early_console_write(struct console *con, const char *s, unsigned n)
+{
+ while (n-- && *s) {
+ early_console_putc(*s);
+ if (*s == '\n')
+ early_console_putc('\r');
+ s++;
+ }
+}
+
+#else
+# error Neither SERIAL_ALTERA_JTAGUART_CONSOLE nor SERIAL_ALTERA_UART_CONSOLE \
+selected
+#endif
+
+static struct console early_console_prom = {
+ .name = "early",
+ .write = early_console_write,
+ .flags = CON_PRINTBUFFER | CON_BOOT,
+ .index = -1
+};
+
+void __init setup_early_printk(void)
+{
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE) || \
+ defined(CONFIG_SERIAL_ALTERA_UART_CONSOLE)
+ base_addr = of_early_console();
+#else
+ base_addr = 0;
+#endif
+
+ if (!base_addr)
+ return;
+
+#if defined(CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE_BYPASS)
+ /* Clear activity bit so BYPASS doesn't stall if we've used JTAG for
+ * downloading the kernel. This might cause early data to be lost even
+ * if the JTAG terminal is running.
+ */
+ JUART_SET_CR(JUART_GET_CR() | ALTERA_JTAGUART_CONTROL_AC_MSK);
+#endif
+
+ early_console = &early_console_prom;
+ register_console(early_console);
+ pr_info("early_console initialized at 0x%08lx\n", base_addr);
+}
diff --git a/arch/nios2/kernel/prom.c b/arch/nios2/kernel/prom.c
index 0522d3378e3f..718dd197909f 100644
--- a/arch/nios2/kernel/prom.c
+++ b/arch/nios2/kernel/prom.c
@@ -1,7 +1,7 @@
/*
* Device tree support
*
- * Copyright (C) 2013 Altera Corporation
+ * Copyright (C) 2013, 2015 Altera Corporation
* Copyright (C) 2010 Thomas Chou <thomas@wytron.com.tw>
*
* Based on MIPS support for CONFIG_OF device tree support
@@ -30,6 +30,7 @@
#include <linux/of_fdt.h>
#include <linux/io.h>
+#include <asm/prom.h>
#include <asm/sections.h>
void __init early_init_dt_add_memory_arch(u64 base, u64 size)
@@ -63,3 +64,52 @@ void __init early_init_devtree(void *params)
early_init_dt_scan(params);
}
+
+#ifdef CONFIG_EARLY_PRINTK
+static int __init early_init_dt_scan_serial(unsigned long node,
+ const char *uname, int depth, void *data)
+{
+ u64 *addr64 = (u64 *) data;
+ const char *p;
+
+ /* only consider serial nodes */
+ if (strncmp(uname, "serial", 6) != 0)
+ return 0;
+
+ p = of_get_flat_dt_prop(node, "compatible", NULL);
+ if (!p)
+ return 0;
+
+ /*
+ * We found an altera_jtaguart but it wasn't configured for console, so
+ * skip it.
+ */
+#ifndef CONFIG_SERIAL_ALTERA_JTAGUART_CONSOLE
+ if (strncmp(p, "altr,juart", 10) == 0)
+ return 0;
+#endif
+
+ /*
+ * Same for altera_uart.
+ */
+#ifndef CONFIG_SERIAL_ALTERA_UART_CONSOLE
+ if (strncmp(p, "altr,uart", 9) == 0)
+ return 0;
+#endif
+
+ *addr64 = fdt_translate_address((const void *)initial_boot_params,
+ node);
+
+ return *addr64 == OF_BAD_ADDR ? 0 : 1;
+}
+
+unsigned long __init of_early_console(void)
+{
+ u64 base = 0;
+
+ if (of_scan_flat_dt(early_init_dt_scan_serial, &base))
+ return (u32)ioremap(base, 32);
+ else
+ return 0;
+}
+#endif /* CONFIG_EARLY_PRINTK */
diff --git a/arch/nios2/kernel/setup.c b/arch/nios2/kernel/setup.c
index cb3121f975d4..b101a43d3c5a 100644
--- a/arch/nios2/kernel/setup.c
+++ b/arch/nios2/kernel/setup.c
@@ -139,6 +139,10 @@ void __init setup_arch(char **cmdline_p)
console_verbose();
+#ifdef CONFIG_EARLY_PRINTK
+ setup_early_printk();
+#endif
+
memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;