From e8bf5bc776edef44777b13b2eb4461d653519bae Mon Sep 17 00:00:00 2001 From: Ley Foon Tan Date: Tue, 10 Feb 2015 23:21:08 +0800 Subject: nios2: add early printk support Signed-off-by: Ley Foon Tan --- arch/nios2/kernel/early_printk.c | 118 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 118 insertions(+) create mode 100644 arch/nios2/kernel/early_printk.c (limited to 'arch/nios2/kernel/early_printk.c') 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 + * 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 +#include +#include +#include + +#include + +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); +} -- cgit