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/*
* 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;
}
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