[deliverable/linux.git] / arch / microblaze / kernel / early_printk.c

/*
 * Early printk support for Microblaze.
 *
 * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
 * Copyright (C) 2007-2009 PetaLogix
 * Copyright (C) 2003-2006 Yasushi SHOJI <yashi@atmark-techno.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/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/tty.h>
#include <linux/io.h>
#include <asm/processor.h>
#include <linux/fcntl.h>
#include <asm/setup.h>
#include <asm/prom.h>

static u32 base_addr;

#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
static void early_printk_uartlite_putc(char c)
{
	/*
	 * Limit how many times we'll spin waiting for TX FIFO status.
	 * This will prevent lockups if the base address is incorrectly
	 * set, or any other issue on the UARTLITE.
	 * This limit is pretty arbitrary, unless we are at about 10 baud
	 * we'll never timeout on a working UART.
	 */

	unsigned retries = 1000000;
	/* read status bit - 0x8 offset */
	while (--retries && (in_be32(base_addr + 8) & (1 << 3)))
		;

	/* Only attempt the iowrite if we didn't timeout */
	/* write to TX_FIFO - 0x4 offset */
	if (retries)
		out_be32(base_addr + 4, c & 0xff);
}

static void early_printk_uartlite_write(struct console *unused,
					const char *s, unsigned n)
{
	while (*s && n-- > 0) {
		if (*s == '\n')
			early_printk_uartlite_putc('\r');
		early_printk_uartlite_putc(*s);
		s++;
	}
}

static struct console early_serial_uartlite_console = {
	.name = "earlyser",
	.write = early_printk_uartlite_write,
	.flags = CON_PRINTBUFFER | CON_BOOT,
	.index = -1,
};
#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */

#ifdef CONFIG_SERIAL_8250_CONSOLE
static void early_printk_uart16550_putc(char c)
{
	/*
	 * Limit how many times we'll spin waiting for TX FIFO status.
	 * This will prevent lockups if the base address is incorrectly
	 * set, or any other issue on the UARTLITE.
	 * This limit is pretty arbitrary, unless we are at about 10 baud
	 * we'll never timeout on a working UART.
	 */

	#define UART_LSR_TEMT	0x40 /* Transmitter empty */
	#define UART_LSR_THRE	0x20 /* Transmit-hold-register empty */
	#define BOTH_EMPTY (UART_LSR_TEMT | UART_LSR_THRE)

	unsigned retries = 10000;

	while (--retries &&
		!((in_be32(base_addr + 0x14) & BOTH_EMPTY) == BOTH_EMPTY))
		;

	if (retries)
		out_be32(base_addr, c & 0xff);
}

static void early_printk_uart16550_write(struct console *unused,
					const char *s, unsigned n)
{
	while (*s && n-- > 0) {
		if (*s == '\n')
			early_printk_uart16550_putc('\r');
		early_printk_uart16550_putc(*s);
		s++;
	}
}

static struct console early_serial_uart16550_console = {
	.name = "earlyser",
	.write = early_printk_uart16550_write,
	.flags = CON_PRINTBUFFER | CON_BOOT,
	.index = -1,
};
#endif /* CONFIG_SERIAL_8250_CONSOLE */

int __init setup_early_printk(char *opt)
{
	int version = 0;

	if (early_console)
		return 1;

	base_addr = of_early_console(&version);
	if (base_addr) {
#ifdef CONFIG_MMU
		early_console_reg_tlb_alloc(base_addr);
#endif
		switch (version) {
#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
		case UARTLITE:
			pr_info("Early console on uartlite at 0x%08x\n",
								base_addr);
			early_console = &early_serial_uartlite_console;
			break;
#endif
#ifdef CONFIG_SERIAL_8250_CONSOLE
		case UART16550:
			pr_info("Early console on uart16650 at 0x%08x\n",
								base_addr);
			early_console = &early_serial_uart16550_console;
			break;
#endif
		default:
			pr_info("Unsupported early console %d\n",
								version);
			return 1;
		}

		register_console(early_console);
		return 0;
	}
	return 1;
}

/* Remap early console to virtual address and do not allocate one TLB
 * only for early console because of performance degression */
void __init remap_early_printk(void)
{
	if (!early_console)
		return;
	pr_info("early_printk_console remapping from 0x%x to ", base_addr);
	base_addr = (u32) ioremap(base_addr, PAGE_SIZE);
	pr_cont("0x%x\n", base_addr);

#ifdef CONFIG_MMU
	/*
	 * Early console is on the top of skipped TLB entries
	 * decrease tlb_skip size ensure that hardcoded TLB entry will be
	 * used by generic algorithm
	 * FIXME check if early console mapping is on the top by rereading
	 * TLB entry and compare baseaddr
	 *  mts  rtlbx, (tlb_skip - 1)
	 *  nop
	 *  mfs  rX, rtlblo
	 *  nop
	 *  cmp rX, orig_base_addr
	 */
	tlb_skip -= 1;
#endif
}

void __init disable_early_printk(void)
{
	if (!early_console)
		return;
	pr_warn("disabling early console\n");
	unregister_console(early_console);
	early_console = NULL;
}
Commit	Line	Data
	1	/*
	2	* Early printk support for Microblaze.
	3	*
	4	* Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
	5	* Copyright (C) 2007-2009 PetaLogix
	6	* Copyright (C) 2003-2006 Yasushi SHOJI <yashi@atmark-techno.com>
	7	*
	8	* This file is subject to the terms and conditions of the GNU General Public
	9	* License. See the file "COPYING" in the main directory of this archive
	10	* for more details.
	11	*/
	12
	13	#include <linux/console.h>
	14	#include <linux/kernel.h>
	15	#include <linux/init.h>
	16	#include <linux/string.h>
	17	#include <linux/tty.h>
	18	#include <linux/io.h>
	19	#include <asm/processor.h>
	20	#include <linux/fcntl.h>
	21	#include <asm/setup.h>
	22	#include <asm/prom.h>
	23
	24	static u32 base_addr;
	25
	26	#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
	27	static void early_printk_uartlite_putc(char c)
	28	{
	29	/*
	30	* Limit how many times we'll spin waiting for TX FIFO status.
	31	* This will prevent lockups if the base address is incorrectly
	32	* set, or any other issue on the UARTLITE.
	33	* This limit is pretty arbitrary, unless we are at about 10 baud
	34	* we'll never timeout on a working UART.
	35	*/
	36
	37	unsigned retries = 1000000;
	38	/* read status bit - 0x8 offset */
	39	while (--retries && (in_be32(base_addr + 8) & (1 << 3)))
	40	;
	41
	42	/* Only attempt the iowrite if we didn't timeout */
	43	/* write to TX_FIFO - 0x4 offset */
	44	if (retries)
	45	out_be32(base_addr + 4, c & 0xff);
	46	}
	47
	48	static void early_printk_uartlite_write(struct console *unused,
	49	const char *s, unsigned n)
	50	{
	51	while (*s && n-- > 0) {
	52	if (*s == '\n')
	53	early_printk_uartlite_putc('\r');
	54	early_printk_uartlite_putc(*s);
	55	s++;
	56	}
	57	}
	58
	59	static struct console early_serial_uartlite_console = {
	60	.name = "earlyser",
	61	.write = early_printk_uartlite_write,
	62	.flags = CON_PRINTBUFFER \| CON_BOOT,
	63	.index = -1,
	64	};
	65	#endif /* CONFIG_SERIAL_UARTLITE_CONSOLE */
	66
	67	#ifdef CONFIG_SERIAL_8250_CONSOLE
	68	static void early_printk_uart16550_putc(char c)
	69	{
	70	/*
	71	* Limit how many times we'll spin waiting for TX FIFO status.
	72	* This will prevent lockups if the base address is incorrectly
	73	* set, or any other issue on the UARTLITE.
	74	* This limit is pretty arbitrary, unless we are at about 10 baud
	75	* we'll never timeout on a working UART.
	76	*/
	77
	78	#define UART_LSR_TEMT 0x40 /* Transmitter empty */
	79	#define UART_LSR_THRE 0x20 /* Transmit-hold-register empty */
	80	#define BOTH_EMPTY (UART_LSR_TEMT \| UART_LSR_THRE)
	81
	82	unsigned retries = 10000;
	83
	84	while (--retries &&
	85	!((in_be32(base_addr + 0x14) & BOTH_EMPTY) == BOTH_EMPTY))
	86	;
	87
	88	if (retries)
	89	out_be32(base_addr, c & 0xff);
	90	}
	91
	92	static void early_printk_uart16550_write(struct console *unused,
	93	const char *s, unsigned n)
	94	{
	95	while (*s && n-- > 0) {
	96	if (*s == '\n')
	97	early_printk_uart16550_putc('\r');
	98	early_printk_uart16550_putc(*s);
	99	s++;
	100	}
	101	}
	102
	103	static struct console early_serial_uart16550_console = {
	104	.name = "earlyser",
	105	.write = early_printk_uart16550_write,
	106	.flags = CON_PRINTBUFFER \| CON_BOOT,
	107	.index = -1,
	108	};
	109	#endif /* CONFIG_SERIAL_8250_CONSOLE */
	110
	111	int __init setup_early_printk(char *opt)
	112	{
	113	int version = 0;
	114
	115	if (early_console)
	116	return 1;
	117
	118	base_addr = of_early_console(&version);
	119	if (base_addr) {
	120	#ifdef CONFIG_MMU
	121	early_console_reg_tlb_alloc(base_addr);
	122	#endif
	123	switch (version) {
	124	#ifdef CONFIG_SERIAL_UARTLITE_CONSOLE
	125	case UARTLITE:
	126	pr_info("Early console on uartlite at 0x%08x\n",
	127	base_addr);
	128	early_console = &early_serial_uartlite_console;
	129	break;
	130	#endif
	131	#ifdef CONFIG_SERIAL_8250_CONSOLE
	132	case UART16550:
	133	pr_info("Early console on uart16650 at 0x%08x\n",
	134	base_addr);
	135	early_console = &early_serial_uart16550_console;
	136	break;
	137	#endif
	138	default:
	139	pr_info("Unsupported early console %d\n",
	140	version);
	141	return 1;
	142	}
	143
	144	register_console(early_console);
	145	return 0;
	146	}
	147	return 1;
	148	}
	149
	150	/* Remap early console to virtual address and do not allocate one TLB
	151	* only for early console because of performance degression */
	152	void __init remap_early_printk(void)
	153	{
	154	if (!early_console)
	155	return;
	156	pr_info("early_printk_console remapping from 0x%x to ", base_addr);
	157	base_addr = (u32) ioremap(base_addr, PAGE_SIZE);
	158	pr_cont("0x%x\n", base_addr);
	159
	160	#ifdef CONFIG_MMU
	161	/*
	162	* Early console is on the top of skipped TLB entries
	163	* decrease tlb_skip size ensure that hardcoded TLB entry will be
	164	* used by generic algorithm
	165	* FIXME check if early console mapping is on the top by rereading
	166	* TLB entry and compare baseaddr
	167	* mts rtlbx, (tlb_skip - 1)
	168	* nop
	169	* mfs rX, rtlblo
	170	* nop
	171	* cmp rX, orig_base_addr
	172	*/
	173	tlb_skip -= 1;
	174	#endif
	175	}
	176
	177	void __init disable_early_printk(void)
	178	{
	179	if (!early_console)
	180	return;
	181	pr_warn("disabling early console\n");
	182	unregister_console(early_console);
	183	early_console = NULL;
	184	}