u-boot-brain/arch/mips/lib/cache.c
Paul Burton d8b326976a MIPS: Clear instruction hazards in flush_cache()
When writing code, for example during relocation, we ensure that the
icache has a coherent view of the new instructions with a call to
flush_cache(). This handles the bulk of the work to ensure the new
instructions will execute as expected, however it does not ensure that
the CPU pipeline doesn't already contain instructions taken from a stale
view of the affected memory. This could theoretically be a problem for
relocation, but in practice typically isn't because we sync caches for
enough code after the entry point of the newly written code that by the
time the CPU pipeline might possibly fetch any of it we'll have long ago
written it back & invalidated any stale icache entries. This is however
a problem for shorter regions of code.

In preparation for later patches which write shorter segments of code,
ensure any instruction hazards are cleared by flush_cache() by
introducing & using a new instruction_hazard_barrier() function which
makes use of the jr.hb instruction to clear the hazard.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
Cc: u-boot@lists.denx.de
2017-11-28 21:59:30 +01:00

180 lines
4.1 KiB
C

/*
* (C) Copyright 2003
* Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <asm/cacheops.h>
#ifdef CONFIG_MIPS_L2_CACHE
#include <asm/cm.h>
#endif
#include <asm/io.h>
#include <asm/mipsregs.h>
#include <asm/system.h>
DECLARE_GLOBAL_DATA_PTR;
static void probe_l2(void)
{
#ifdef CONFIG_MIPS_L2_CACHE
unsigned long conf2, sl;
bool l2c = false;
if (!(read_c0_config1() & MIPS_CONF_M))
return;
conf2 = read_c0_config2();
if (__mips_isa_rev >= 6) {
l2c = conf2 & MIPS_CONF_M;
if (l2c)
l2c = read_c0_config3() & MIPS_CONF_M;
if (l2c)
l2c = read_c0_config4() & MIPS_CONF_M;
if (l2c)
l2c = read_c0_config5() & MIPS_CONF5_L2C;
}
if (l2c && config_enabled(CONFIG_MIPS_CM)) {
gd->arch.l2_line_size = mips_cm_l2_line_size();
} else if (l2c) {
/* We don't know how to retrieve L2 config on this system */
BUG();
} else {
sl = (conf2 & MIPS_CONF2_SL) >> MIPS_CONF2_SL_SHF;
gd->arch.l2_line_size = sl ? (2 << sl) : 0;
}
#endif
}
void mips_cache_probe(void)
{
#ifdef CONFIG_SYS_CACHE_SIZE_AUTO
unsigned long conf1, il, dl;
conf1 = read_c0_config1();
il = (conf1 & MIPS_CONF1_IL) >> MIPS_CONF1_IL_SHF;
dl = (conf1 & MIPS_CONF1_DL) >> MIPS_CONF1_DL_SHF;
gd->arch.l1i_line_size = il ? (2 << il) : 0;
gd->arch.l1d_line_size = dl ? (2 << dl) : 0;
#endif
probe_l2();
}
static inline unsigned long icache_line_size(void)
{
#ifdef CONFIG_SYS_CACHE_SIZE_AUTO
return gd->arch.l1i_line_size;
#else
return CONFIG_SYS_ICACHE_LINE_SIZE;
#endif
}
static inline unsigned long dcache_line_size(void)
{
#ifdef CONFIG_SYS_CACHE_SIZE_AUTO
return gd->arch.l1d_line_size;
#else
return CONFIG_SYS_DCACHE_LINE_SIZE;
#endif
}
static inline unsigned long scache_line_size(void)
{
#ifdef CONFIG_MIPS_L2_CACHE
return gd->arch.l2_line_size;
#else
return 0;
#endif
}
#define cache_loop(start, end, lsize, ops...) do { \
const void *addr = (const void *)(start & ~(lsize - 1)); \
const void *aend = (const void *)((end - 1) & ~(lsize - 1)); \
const unsigned int cache_ops[] = { ops }; \
unsigned int i; \
\
for (; addr <= aend; addr += lsize) { \
for (i = 0; i < ARRAY_SIZE(cache_ops); i++) \
mips_cache(cache_ops[i], addr); \
} \
} while (0)
void flush_cache(ulong start_addr, ulong size)
{
unsigned long ilsize = icache_line_size();
unsigned long dlsize = dcache_line_size();
unsigned long slsize = scache_line_size();
/* aend will be miscalculated when size is zero, so we return here */
if (size == 0)
return;
if ((ilsize == dlsize) && !slsize) {
/* flush I-cache & D-cache simultaneously */
cache_loop(start_addr, start_addr + size, ilsize,
HIT_WRITEBACK_INV_D, HIT_INVALIDATE_I);
goto ops_done;
}
/* flush D-cache */
cache_loop(start_addr, start_addr + size, dlsize, HIT_WRITEBACK_INV_D);
/* flush L2 cache */
if (slsize)
cache_loop(start_addr, start_addr + size, slsize,
HIT_WRITEBACK_INV_SD);
/* flush I-cache */
cache_loop(start_addr, start_addr + size, ilsize, HIT_INVALIDATE_I);
ops_done:
/* ensure cache ops complete before any further memory accesses */
sync();
/* ensure the pipeline doesn't contain now-invalid instructions */
instruction_hazard_barrier();
}
void flush_dcache_range(ulong start_addr, ulong stop)
{
unsigned long lsize = dcache_line_size();
unsigned long slsize = scache_line_size();
/* aend will be miscalculated when size is zero, so we return here */
if (start_addr == stop)
return;
cache_loop(start_addr, stop, lsize, HIT_WRITEBACK_INV_D);
/* flush L2 cache */
if (slsize)
cache_loop(start_addr, stop, slsize, HIT_WRITEBACK_INV_SD);
/* ensure cache ops complete before any further memory accesses */
sync();
}
void invalidate_dcache_range(ulong start_addr, ulong stop)
{
unsigned long lsize = dcache_line_size();
unsigned long slsize = scache_line_size();
/* aend will be miscalculated when size is zero, so we return here */
if (start_addr == stop)
return;
/* invalidate L2 cache */
if (slsize)
cache_loop(start_addr, stop, slsize, HIT_INVALIDATE_SD);
cache_loop(start_addr, stop, lsize, HIT_INVALIDATE_D);
/* ensure cache ops complete before any further memory accesses */
sync();
}