On 5/22/25 04:33, Jamin Lin wrote:
On big-endian hosts, the aspeed_ram_capacity_write() function previously passed
the address of a 64-bit "data" variable directly to address_space_write(),
assuming host and guest endianness matched.

However, the data is expected to be written in little-endian format to DRAM.
On big-endian hosts, this led to incorrect data being written into DRAM,
which caused the guest firmware to misdetect the DRAM size.

As a result, U-Boot fails to boot and hangs.

- Replaces the "address_space_write()" call with "address_space_stl_le()",
   which performs an explicit 32-bit little-endian write.
- Updating the MemoryRegionOps to restrict access to exactly 4 bytes
   using .valid.{min,max}_access_size = 4 and .impl.min_access_size = 4.

Signed-off-by: Jamin Lin <jamin_...@aspeedtech.com>
Fixes: 7436db1 ("aspeed/soc: fix incorrect dram size for AST2700")


Reviewed-by: Cédric Le Goater <c...@redhat.com>

Thanks,

C.


---
  hw/arm/aspeed_ast27x0.c | 10 ++++++----
  1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/arm/aspeed_ast27x0.c b/hw/arm/aspeed_ast27x0.c
index 1974a25766..82a5ecff04 100644
--- a/hw/arm/aspeed_ast27x0.c
+++ b/hw/arm/aspeed_ast27x0.c
@@ -346,8 +346,9 @@ static void aspeed_ram_capacity_write(void *opaque, hwaddr 
addr, uint64_t data,
       * If writes the data to the address which is beyond the ram size,
       * it would write the data to the "address % ram_size".
       */
-    result = address_space_write(&s->dram_as, addr % ram_size,
-                                 MEMTXATTRS_UNSPECIFIED, &data, 4);
+    address_space_stl_le(&s->dram_as, addr % ram_size, data,
+                         MEMTXATTRS_UNSPECIFIED, &result);
+
      if (result != MEMTX_OK) {
          qemu_log_mask(LOG_GUEST_ERROR,
                        "%s: DRAM write failed, addr:0x%" HWADDR_PRIx
@@ -360,9 +361,10 @@ static const MemoryRegionOps aspeed_ram_capacity_ops = {
      .read = aspeed_ram_capacity_read,
      .write = aspeed_ram_capacity_write,
      .endianness = DEVICE_LITTLE_ENDIAN,
+    .impl.min_access_size = 4,
      .valid = {
-        .min_access_size = 1,
-        .max_access_size = 8,
+        .min_access_size = 4,
+        .max_access_size = 4,
      },
  };


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