u-boot/arch/arm/lib/cache.c
Stephen Warren 5e0404ff85 board_f: fix noncached reservation calculation
The current code in reserve_noncached() has two issues:

1) The first update of gd->start_addr_sp always rounds down to a section
start. However, the equivalent calculation in cache.c:noncached_init()
always first rounds up to a section start, then subtracts a section size.
These two calculations differ if the initial value is already rounded to
section alignment.

2) The second update of gd->start_addr_sp subtracts exactly
CONFIG_SYS_NONCACHED_MEMORY, whereas the equivalent calculation in
cache.c:noncached_init() rounds the noncached size up to section
alignment before subtracting it. The two calculations differ if the
noncached region size is not a multiple of the MMU section size.

In practice, one/both of those issues causes a practical problem on
Jetson TX1; U-Boot triggers a synchronous abort during initialization,
likely due to overlapping use of some memory region.

This change fixes both these issues by duplicating the exact calculations
from noncached_init() into reserve_noncached().

However, this fix assumes that gd->start_addr_sp on entry to
reserve_noncached() exactly matches mem_malloc_start on entry to
noncached_init(). I haven't traced the code to see whether it absolutely
guarantees this in all (or indeed any!) cases. Consequently, I added some
comments in the hope that this condition will continue to be true.

Fixes: 5f7adb5b1c ("board_f: reserve noncached space below malloc area")
Cc: Vikas Manocha <vikas.manocha@st.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
2019-08-30 14:17:11 -04:00

120 lines
2.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2002
* Wolfgang Denk, DENX Software Engineering, wd@denx.de.
*/
/* for now: just dummy functions to satisfy the linker */
#include <common.h>
#include <malloc.h>
/*
* Flush range from all levels of d-cache/unified-cache.
* Affects the range [start, start + size - 1].
*/
__weak void flush_cache(unsigned long start, unsigned long size)
{
flush_dcache_range(start, start + size);
}
/*
* Default implementation:
* do a range flush for the entire range
*/
__weak void flush_dcache_all(void)
{
flush_cache(0, ~0);
}
/*
* Default implementation of enable_caches()
* Real implementation should be in platform code
*/
__weak void enable_caches(void)
{
puts("WARNING: Caches not enabled\n");
}
__weak void invalidate_dcache_range(unsigned long start, unsigned long stop)
{
/* An empty stub, real implementation should be in platform code */
}
__weak void flush_dcache_range(unsigned long start, unsigned long stop)
{
/* An empty stub, real implementation should be in platform code */
}
int check_cache_range(unsigned long start, unsigned long stop)
{
int ok = 1;
if (start & (CONFIG_SYS_CACHELINE_SIZE - 1))
ok = 0;
if (stop & (CONFIG_SYS_CACHELINE_SIZE - 1))
ok = 0;
if (!ok) {
warn_non_spl("CACHE: Misaligned operation at range [%08lx, %08lx]\n",
start, stop);
}
return ok;
}
#ifdef CONFIG_SYS_NONCACHED_MEMORY
/*
* Reserve one MMU section worth of address space below the malloc() area that
* will be mapped uncached.
*/
static unsigned long noncached_start;
static unsigned long noncached_end;
static unsigned long noncached_next;
void noncached_init(void)
{
phys_addr_t start, end;
size_t size;
/* If this calculation changes, update board_f.c:reserve_noncached() */
end = ALIGN(mem_malloc_start, MMU_SECTION_SIZE) - MMU_SECTION_SIZE;
size = ALIGN(CONFIG_SYS_NONCACHED_MEMORY, MMU_SECTION_SIZE);
start = end - size;
debug("mapping memory %pa-%pa non-cached\n", &start, &end);
noncached_start = start;
noncached_end = end;
noncached_next = start;
#if !CONFIG_IS_ENABLED(SYS_DCACHE_OFF)
mmu_set_region_dcache_behaviour(noncached_start, size, DCACHE_OFF);
#endif
}
phys_addr_t noncached_alloc(size_t size, size_t align)
{
phys_addr_t next = ALIGN(noncached_next, align);
if (next >= noncached_end || (noncached_end - next) < size)
return 0;
debug("allocated %zu bytes of uncached memory @%pa\n", size, &next);
noncached_next = next + size;
return next;
}
#endif /* CONFIG_SYS_NONCACHED_MEMORY */
#if CONFIG_IS_ENABLED(SYS_THUMB_BUILD)
void invalidate_l2_cache(void)
{
unsigned int val = 0;
asm volatile("mcr p15, 1, %0, c15, c11, 0 @ invl l2 cache"
: : "r" (val) : "cc");
isb();
}
#endif