Mirrors/u-boot
2
0
Fork 0
mirror of https://github.com/AsahiLinux/u-boot synced 2024-11-10 23:24:38 +00:00
Code Issues Projects Releases Packages Wiki Activity

board_f: fix noncached reservation calculation

Browse source 
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>
This commit is contained in:
Stephen Warren 2019-08-27 11:54:31 -06:00 committed by Tom Rini
parent 877294b56a
commit 5e0404ff85
3 changed files with 17 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

1
arch/arm/lib/cache.c
View file

@ -77,6 +77,7 @@ 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;

15
common/board_f.c
View file

@ -470,9 +470,18 @@ static int reserve_uboot(void)
#ifdef CONFIG_SYS_NONCACHED_MEMORY
static int reserve_noncached(void)
{
/* round down to SECTION SIZE (typicaly 1MB) limit */
gd->start_addr_sp &= ~(MMU_SECTION_SIZE - 1);
gd->start_addr_sp -= CONFIG_SYS_NONCACHED_MEMORY;
/*
* The value of gd->start_addr_sp must match the value of malloc_start
* calculated in boatrd_f.c:initr_malloc(), which is passed to
* board_r.c:mem_malloc_init() and then used by
* cache.c:noncached_init()
*
* These calculations must match the code in cache.c:noncached_init()
*/
gd->start_addr_sp = ALIGN(gd->start_addr_sp, MMU_SECTION_SIZE) -
MMU_SECTION_SIZE;
gd->start_addr_sp -= ALIGN(CONFIG_SYS_NONCACHED_MEMORY,
MMU_SECTION_SIZE);
debug("Reserving %dM for noncached_alloc() at: %08lx\n",
CONFIG_SYS_NONCACHED_MEMORY >> 20, gd->start_addr_sp);

4
common/board_r.c
View file

@ -247,6 +247,10 @@ static int initr_malloc(void)
gd->malloc_ptr / 1024);
#endif
/* The malloc area is immediately below the monitor copy in DRAM */
/*
* This value MUST match the value of gd->start_addr_sp in board_f.c:
* reserve_noncached().
*/
malloc_start = gd->relocaddr - TOTAL_MALLOC_LEN;
mem_malloc_init((ulong)map_sysmem(malloc_start, TOTAL_MALLOC_LEN),
TOTAL_MALLOC_LEN);