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/*
* sc-rm7k.c: RM7000 cache management functions.
*
* Copyright (C) 1997, 2001, 2003, 2004 Ralf Baechle (ralf@linux-mips.org)
*/
#undef DEBUG
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <asm/addrspace.h>
#include <asm/bcache.h>
#include <asm/cacheops.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
/* Primary cache parameters. */
#define sc_lsize 32
#define tc_pagesize (32*128)
/* Secondary cache parameters. */
#define scache_size (256*1024) /* Fixed to 256KiB on RM7000 */
extern unsigned long icache_way_size, dcache_way_size;
#include <asm/r4kcache.h>
int rm7k_tcache_enabled;
/*
* Writeback and invalidate the primary cache dcache before DMA.
* (XXX These need to be fixed ...)
*/
static void rm7k_sc_wback_inv(unsigned long addr, unsigned long size)
{
unsigned long end, a;
pr_debug("rm7k_sc_wback_inv[%08lx,%08lx]", addr, size);
/* Catch bad driver code */
BUG_ON(size == 0);
a = addr & ~(sc_lsize - 1);
end = (addr + size - 1) & ~(sc_lsize - 1);
while (1) {
flush_scache_line(a); /* Hit_Writeback_Inv_SD */
if (a == end)
break;
a += sc_lsize;
}
if (!rm7k_tcache_enabled)
return;
a = addr & ~(tc_pagesize - 1);
end = (addr + size - 1) & ~(tc_pagesize - 1);
while(1) {
invalidate_tcache_page(a); /* Page_Invalidate_T */
if (a == end)
break;
a += tc_pagesize;
}
}
static void rm7k_sc_inv(unsigned long addr, unsigned long size)
{
unsigned long end, a;
pr_debug("rm7k_sc_inv[%08lx,%08lx]", addr, size);
/* Catch bad driver code */
BUG_ON(size == 0);
a = addr & ~(sc_lsize - 1);
end = (addr + size - 1) & ~(sc_lsize - 1);
while (1) {
invalidate_scache_line(a); /* Hit_Invalidate_SD */
if (a == end)
break;
a += sc_lsize;
}
if (!rm7k_tcache_enabled)
return;
a = addr & ~(tc_pagesize - 1);
end = (addr + size - 1) & ~(tc_pagesize - 1);
while(1) {
invalidate_tcache_page(a); /* Page_Invalidate_T */
if (a == end)
break;
a += tc_pagesize;
}
}
/*
* This function is executed in the uncached segment CKSEG1.
* It must not touch the stack, because the stack pointer still points
* into CKSEG0.
*
* Three options:
* - Write it in assembly and guarantee that we don't use the stack.
* - Disable caching for CKSEG0 before calling it.
* - Pray that GCC doesn't randomly start using the stack.
*
* This being Linux, we obviously take the least sane of those options -
* following DaveM's lead in c-r4k.c
*
* It seems we get our kicks from relying on unguaranteed behaviour in GCC
*/
static __init void __rm7k_sc_enable(void)
{
int i;
set_c0_config(1 << 3); /* CONF_SE */
write_c0_taglo(0);
write_c0_taghi(0);
for (i = 0; i < scache_size; i += sc_lsize) {
__asm__ __volatile__ (
".set noreorder\n\t"
".set mips3\n\t"
"cache %1, (%0)\n\t"
".set mips0\n\t"
".set reorder"
:
: "r" (KSEG0ADDR(i)), "i" (Index_Store_Tag_SD));
}
}
static __init void rm7k_sc_enable(void)
{
void (*func)(void) = (void *) KSEG1ADDR(&__rm7k_sc_enable);
if (read_c0_config() & 0x08) /* CONF_SE */
return;
printk(KERN_INFO "Enabling secondary cache...");
func();
}
static void rm7k_sc_disable(void)
{
clear_c0_config(1<<3); /* CONF_SE */
}
struct bcache_ops rm7k_sc_ops = {
.bc_enable = rm7k_sc_enable,
.bc_disable = rm7k_sc_disable,
.bc_wback_inv = rm7k_sc_wback_inv,
.bc_inv = rm7k_sc_inv
};
void __init rm7k_sc_init(void)
{
unsigned int config = read_c0_config();
if ((config >> 31) & 1) /* Bit 31 set -> no S-Cache */
return;
printk(KERN_INFO "Secondary cache size %dK, linesize %d bytes.\n",
(scache_size >> 10), sc_lsize);
if (!((config >> 3) & 1)) /* CONF_SE */
rm7k_sc_enable();
/*
* While we're at it let's deal with the tertiary cache.
*/
if (!((config >> 17) & 1)) {
/*
* We can't enable the L3 cache yet. There may be board-specific
* magic necessary to turn it on, and blindly asking the CPU to
* start using it would may give cache errors.
*
* Also, board-specific knowledge may allow us to use the
* CACHE Flash_Invalidate_T instruction if the tag RAM supports
* it, and may specify the size of the L3 cache so we don't have
* to probe it.
*/
printk(KERN_INFO "Tertiary cache present, %s enabled\n",
config&(1<<12) ? "already" : "not (yet)");
if ((config >> 12) & 1)
rm7k_tcache_enabled = 1;
}
bcops = &rm7k_sc_ops;
}
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