On 16/10/2026 12:40 pm, Chen Huei Lok wrote:
DDR retention lets N5X skip a full DDR re-calibration across a
configuration reset by reusing previously calibrated PHY data, which
significantly shortens bring-up time. To do this the SPL must, early in
boot and before DRAM is usable, locate a known-good backup of the
calibration data, verify it, and replay it into the DDR PHY before
handoff. Enable the configs that this restore path depends on:
- CONFIG_FS_LOADER / CONFIG_SPL_FS_LOADER: the generic firmware loader is
used by the DDR driver (request_firmware_into_buf()) to pull the backup
calibration header and data from the QSPI/NAND RAW partition into the
OCRAM scratch buffer (SOC64_OCRAM_PHY_BACKUP_BASE). The loader device is
resolved through the "firmware-loader" phandle on the DDR node, falling
back to /chosen. SPL_FS_LOADER is required because the restore runs in
SPL, before DRAM is available. The N5X RAW path binds SPI flash from DT
(sfconfig), so CONFIG_SPL_ENV_SUPPORT is not required.
- CONFIG_SPL_CRC32: the retention path checksums the calibration payload
with crc32_wd_buf() when storing and validating the QSPI backup. SPL
must build lib/crc32.c (obj-$(CONFIG_SPL_CRC32)), which is not selected
by SHA384.
- CONFIG_SHA384: the calibration backup is bound to the current DDR
configuration with a SHA-384 digest (sha384_csum_wd() over the DDR
handoff image and the mem-clk table). On store the digest is written
into the backup header; on restore it is recomputed and compared
(is_ddrconfig_hash_match()), so a backup that no longer matches the
running DDR / mem-clk configuration is rejected. Enabling SHA384 selects
the SHA-512 implementation it is built on, so CONFIG_SHA512_ALGO does
not need to be listed explicitly.
Init order and failure modes: the restore is best-effort and fully
guarded. The buffer load is bounds-checked against the HPS handoff region
(SOC64_HANDOFF_BASE) to prevent overflow, the header magic must match, a
CRC32 over the data must match, and finally the SHA-384 config hash must
match. If any check fails (missing loader, read error, bad magic, CRC or
hash mismatch) the backup is discarded and DDR falls back to a normal
full calibration, so an invalid or stale backup never corrupts bring-up.
These symbols are enabled only after the fs_loader RAW-partition support
and the N5X self-refresh / retention restore code that consume them, so
the series stays bisectable. The defconfig is kept in canonical
savedefconfig order.
Signed-off-by: Tien Fong Chee <[email protected]>
Signed-off-by: Chen Huei Lok <[email protected]>
---
configs/socfpga_n5x_defconfig | 3 +++
1 file changed, 3 insertions(+)
diff --git a/configs/socfpga_n5x_defconfig b/configs/socfpga_n5x_defconfig
index 2d9456ef435..2119d8f4f4f 100644
--- a/configs/socfpga_n5x_defconfig
+++ b/configs/socfpga_n5x_defconfig
@@ -72,6 +72,8 @@ CONFIG_SPL_DM_SEQ_ALIAS=y
CONFIG_DWAPB_GPIO=y
CONFIG_DM_I2C=y
CONFIG_SYS_I2C_DW=y
+CONFIG_FS_LOADER=y
+CONFIG_SPL_FS_LOADER=y
CONFIG_SYS_MMC_MAX_BLK_COUNT=256
CONFIG_MMC_DW=y
CONFIG_SPI_FLASH_ISSI=y
@@ -93,4 +95,5 @@ CONFIG_WDT=y
# CONFIG_SPL_USE_TINY_PRINTF is not set
CONFIG_PANIC_HANG=y
CONFIG_SPL_CRC32=y
+CONFIG_SHA384=y
# CONFIG_TOOLS_MKEFICAPSULE is not set
Reviewed-by: Tien Fong Chee <[email protected]>
Best regards,
Tien Fong
