android_kernel_xiaomi_sm8350/arch/sparc64/prom/printf.c
David S. Miller bff06d5522 [SPARC64]: Rewrite bootup sequence.
Instead of all of this cpu-specific code to remap the kernel
to the correct location, use portable firmware calls to do
this instead.

What we do now is the following in position independant
assembler:

	chosen_node = prom_finddevice("/chosen");
	prom_mmu_ihandle_cache = prom_getint(chosen_node, "mmu");
	vaddr = 4MB_ALIGN(current_text_addr());
	prom_translate(vaddr, &paddr_high, &paddr_low, &mode);
	prom_boot_mapping_mode = mode;
	prom_boot_mapping_phys_high = paddr_high;
	prom_boot_mapping_phys_low = paddr_low;
	prom_map(-1, 8 * 1024 * 1024, KERNBASE, paddr_low);

and that replaces the massive amount of by-hand TLB probing and
programming we used to do here.

The new code should also handle properly the case where the kernel
is mapped at the correct address already (think: future kexec
support).

Consequently, the bulk of remap_kernel() dies as does the entirety
of arch/sparc64/prom/map.S

We try to share some strings in the PROM library with the ones used
at bootup, and while we're here mark input strings to oplib.h routines
with "const" when appropriate.

There are many more simplifications now possible.  For one thing, we
can consolidate the two copies we now have of a lot of cpu setup code
sitting in head.S and trampoline.S.

This is a significant step towards CONFIG_DEBUG_PAGEALLOC support.

Signed-off-by: David S. Miller <davem@davemloft.net>
2005-09-22 20:11:33 -07:00

48 lines
1.0 KiB
C

/*
* printf.c: Internal prom library printf facility.
*
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1997 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
* Copyright (c) 2002 Pete Zaitcev (zaitcev@yahoo.com)
*
* We used to warn all over the code: DO NOT USE prom_printf(),
* and yet people do. Anton's banking code was outputting banks
* with prom_printf for most of the 2.4 lifetime. Since an effective
* stick is not available, we deployed a carrot: an early printk
* through PROM by means of -p boot option. This ought to fix it.
* USE printk; if you need, deploy -p.
*/
#include <linux/kernel.h>
#include <asm/openprom.h>
#include <asm/oplib.h>
static char ppbuf[1024];
void
prom_write(const char *buf, unsigned int n)
{
char ch;
while (n != 0) {
--n;
if ((ch = *buf++) == '\n')
prom_putchar('\r');
prom_putchar(ch);
}
}
void
prom_printf(const char *fmt, ...)
{
va_list args;
int i;
va_start(args, fmt);
i = vscnprintf(ppbuf, sizeof(ppbuf), fmt, args);
va_end(args);
prom_write(ppbuf, i);
}