diff options
Diffstat (limited to 'arch/sh/kernel/sh_bios.c')
| -rw-r--r-- | arch/sh/kernel/sh_bios.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/arch/sh/kernel/sh_bios.c b/arch/sh/kernel/sh_bios.c new file mode 100644 index 000000000..250dbdf3f --- /dev/null +++ b/arch/sh/kernel/sh_bios.c @@ -0,0 +1,169 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * C interface for trapping into the standard LinuxSH BIOS. + * + * Copyright (C) 2000 Greg Banks, Mitch Davis + * Copyright (C) 1999, 2000 Niibe Yutaka + * Copyright (C) 2002 M. R. Brown + * Copyright (C) 2004 - 2010 Paul Mundt + */ +#include <linux/module.h> +#include <linux/console.h> +#include <linux/tty.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/delay.h> +#include <asm/sh_bios.h> + +#define BIOS_CALL_CONSOLE_WRITE 0 +#define BIOS_CALL_ETH_NODE_ADDR 10 +#define BIOS_CALL_SHUTDOWN 11 +#define BIOS_CALL_GDB_DETACH 0xff + +void *gdb_vbr_vector = NULL; + +static inline long sh_bios_call(long func, long arg0, long arg1, long arg2, + long arg3) +{ + register long r0 __asm__("r0") = func; + register long r4 __asm__("r4") = arg0; + register long r5 __asm__("r5") = arg1; + register long r6 __asm__("r6") = arg2; + register long r7 __asm__("r7") = arg3; + + if (!gdb_vbr_vector) + return -ENOSYS; + + __asm__ __volatile__("trapa #0x3f":"=z"(r0) + :"0"(r0), "r"(r4), "r"(r5), "r"(r6), "r"(r7) + :"memory"); + return r0; +} + +void sh_bios_console_write(const char *buf, unsigned int len) +{ + sh_bios_call(BIOS_CALL_CONSOLE_WRITE, (long)buf, (long)len, 0, 0); +} + +void sh_bios_gdb_detach(void) +{ + sh_bios_call(BIOS_CALL_GDB_DETACH, 0, 0, 0, 0); +} +EXPORT_SYMBOL_GPL(sh_bios_gdb_detach); + +void sh_bios_get_node_addr(unsigned char *node_addr) +{ + sh_bios_call(BIOS_CALL_ETH_NODE_ADDR, 0, (long)node_addr, 0, 0); +} +EXPORT_SYMBOL_GPL(sh_bios_get_node_addr); + +void sh_bios_shutdown(unsigned int how) +{ + sh_bios_call(BIOS_CALL_SHUTDOWN, how, 0, 0, 0); +} + +/* + * Read the old value of the VBR register to initialise the vector + * through which debug and BIOS traps are delegated by the Linux trap + * handler. + */ +void sh_bios_vbr_init(void) +{ + unsigned long vbr; + + if (unlikely(gdb_vbr_vector)) + return; + + __asm__ __volatile__ ("stc vbr, %0" : "=r" (vbr)); + + if (vbr) { + gdb_vbr_vector = (void *)(vbr + 0x100); + printk(KERN_NOTICE "Setting GDB trap vector to %p\n", + gdb_vbr_vector); + } else + printk(KERN_NOTICE "SH-BIOS not detected\n"); +} + +/** + * sh_bios_vbr_reload - Re-load the system VBR from the BIOS vector. + * + * This can be used by save/restore code to reinitialize the system VBR + * from the fixed BIOS VBR. A no-op if no BIOS VBR is known. + */ +void sh_bios_vbr_reload(void) +{ + if (gdb_vbr_vector) + __asm__ __volatile__ ( + "ldc %0, vbr" + : + : "r" (((unsigned long) gdb_vbr_vector) - 0x100) + : "memory" + ); +} + +#ifdef CONFIG_EARLY_PRINTK +/* + * Print a string through the BIOS + */ +static void sh_console_write(struct console *co, const char *s, + unsigned count) +{ + sh_bios_console_write(s, count); +} + +/* + * Setup initial baud/bits/parity. We do two things here: + * - construct a cflag setting for the first rs_open() + * - initialize the serial port + * Return non-zero if we didn't find a serial port. + */ +static int __init sh_console_setup(struct console *co, char *options) +{ + int cflag = CREAD | HUPCL | CLOCAL; + + /* + * Now construct a cflag setting. + * TODO: this is a totally bogus cflag, as we have + * no idea what serial settings the BIOS is using, or + * even if its using the serial port at all. + */ + cflag |= B115200 | CS8 | /*no parity*/0; + + co->cflag = cflag; + + return 0; +} + +static struct console bios_console = { + .name = "bios", + .write = sh_console_write, + .setup = sh_console_setup, + .flags = CON_PRINTBUFFER, + .index = -1, +}; + +static int __init setup_early_printk(char *buf) +{ + int keep_early = 0; + + if (!buf) + return 0; + + if (strstr(buf, "keep")) + keep_early = 1; + + if (!strncmp(buf, "bios", 4)) + early_console = &bios_console; + + if (likely(early_console)) { + if (keep_early) + early_console->flags &= ~CON_BOOT; + else + early_console->flags |= CON_BOOT; + register_console(early_console); + } + + return 0; +} +early_param("earlyprintk", setup_early_printk); +#endif |