| /* |
| * 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; |
| } |