diff options
| author | Marek Vasut <[email protected]> | 2026-06-03 16:17:55 +0200 |
|---|---|---|
| committer | Tom Rini <[email protected]> | 2026-06-04 08:26:41 -0600 |
| commit | af4aad1f0a0beba82d2015d79b450b59bf34d2bc (patch) | |
| tree | 07504357be5476d8d334c80476cf144cc9c3598d /lib | |
| parent | 4065ee552b8e975e73b90c5b57f00af6ca0c5d65 (diff) | |
lmb: Optionally limit available memory to 4 GiB on limited systems
Some architectures can not DMA above 4 GiB boundary,
limit available memory to memory below 4 GiB boundary.
Signed-off-by: Marek Vasut <[email protected]>
Reviewed-by: Ilias Apalodimas <[email protected]>
Tested-by: Ilias Apalodimas <[email protected]> #rpi4 8GiB
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig | 8 | ||||
| -rw-r--r-- | lib/lmb.c | 20 |
2 files changed, 27 insertions, 1 deletions
diff --git a/lib/Kconfig b/lib/Kconfig index 77ebc79e1db..29911068a69 100644 --- a/lib/Kconfig +++ b/lib/Kconfig @@ -1295,6 +1295,14 @@ config SPL_LMB_ARCH_MEM_MAP memory map. Enable this config in such scenarios which allow architectures and boards to define their own memory map. +config LMB_LIMIT_DMA_BELOW_4G + bool + depends on LMB + default y if ARCH_BCM283X + help + Some architectures can not DMA above 4 GiB boundary, + limit available memory to memory below 4 GiB boundary. + config PHANDLE_CHECK_SEQ bool "Enable phandle check while getting sequence number" help diff --git a/lib/lmb.c b/lib/lmb.c index 8f12c6ad8e5..a2aeb526e29 100644 --- a/lib/lmb.c +++ b/lib/lmb.c @@ -611,6 +611,7 @@ static __maybe_unused void lmb_reserve_common_spl(void) static void lmb_add_memory(void) { int i; + phys_addr_t bank_end; phys_size_t size; u64 ram_top = gd->ram_top; struct bd_info *bd = gd->bd; @@ -625,8 +626,25 @@ static void lmb_add_memory(void) for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) { size = bd->bi_dram[i].size; - if (size) + if (size) { lmb_add(bd->bi_dram[i].start, size); + if (!IS_ENABLED(CONFIG_LMB_LIMIT_DMA_BELOW_4G)) + continue; + + bank_end = bd->bi_dram[i].start + size; + + /* + * Reserve memory above ram_top as + * no-overwrite so that it cannot be + * allocated + */ + if (bd->bi_dram[i].start >= ram_top) + lmb_reserve(bd->bi_dram[i].start, size, + LMB_NOOVERWRITE); + else if (bank_end > ram_top) + lmb_reserve(ram_top, bank_end - ram_top, + LMB_NOOVERWRITE); + } } } |