xm: openipc.c as on openipc-hisilicon; drop the SPI NAND images

CLAUDE.md

@@ -42,16 +42,14 @@ git diff --diff-filter=M v2022.10 HEAD         # the mainline files we patched
 | SoC: PLL and DDR bring-up, timer, reset, DRAM size, SDHCI glue | `arch/arm/mach-xm/` (`ARCH_XM`; `TARGET_XM510`/`XM530`/`XM550`; register map in `include/mach/xm.h`) |
 | Boards: `board_init`, `misc_init_r` → `openipc_helper()`, `board_eth_init` with the PHY reset / MAC glue | `board/xiongmai/{xm510,xm530}/`. XM550 uses the xm530 board with `XM_DDR3` |
 | Memory map, console, timer | `include/configs/{xm510,xm530}.h`, each ending in `#include "openipc-common.h"` |
-| SPI NAND on the v2 controller (XM530/550): raw NAND, full-ID table, on-die ECC status through `ecc.read_page` | `drivers/mtd/nand/raw/xmsfc_nand.c` (`NAND_XMSFC`) |
 | SPI NOR controller, v1 (XM510) and v2 (XM530/550), non-DM | `drivers/mtd/spi/xmsfc.c`. It provides `spi_flash_probe()` and fills `mtd->_read/_write/_erase`, so mainline's non-DM `spi_flash_*()` wrappers, `sf` and env-in-SPI-flash work without the SPI and spi-nor layers |
-| OpenIPC boot layer | `common/openipc.c` and `include/openipc.h` (copied from `openipc-hisilicon`, NAND gate rekeyed to `CONFIG_ENV_IS_IN_NAND`), `include/configs/openipc-common.h` (XM-only rewrite, same env commands) |
+| OpenIPC boot layer | `common/openipc.c` and `include/openipc.h` (identical to `openipc-hisilicon`'s), `include/configs/openipc-common.h` (XM-only rewrite, same env commands) |
 | Kconfig fragments and the build | `openipc/`, `build.sh` |
 
 **Patched mainline files**, each small:
 
 - `arch/arm/{Kconfig,Makefile}`: the `ARCH_XM` hook.
 - `common/{Kconfig,Makefile}`: `OPENIPC`, `PRODUCT_SOC`, `PRODUCT_SOCMODEL`.
-- `drivers/mtd/nand/raw/{Kconfig,Makefile}`: the `NAND_XMSFC` hook.
 - `drivers/mtd/spi/{Kconfig,Makefile}`, `cmd/Kconfig` (`CMD_SF`) and
   `env/Kconfig` (`ENV_IS_IN_SPI_FLASH`): accept `XMSFC_SPI_NOR`.
 - `drivers/net/Kconfig`: `NETDEVICES` selects `DM_ETH` only when `DM` is on.
@@ -96,33 +94,11 @@ position-independent fixups. The only RAM before DDR is a 4 KiB SRAM at
   driver restores it (`xmsfc_bus_mode()`) after every v2 operation, and only
   ever runs after relocation, from DDR.
 
-## SPI NAND (XM530/XM550): built on a guess
+## No SPI NAND
 
-Xiongmai never shipped a NAND U-Boot from this SDK. There is a
-`CONFIG_SYS_USE_SPI_NAND` block in the vendor `xm530.h`, but no board target,
-and nothing documents how the boot ROM starts from SPI NAND.
-
-**What the NAND image assumes:**
-
-- the controller's window serves the NAND page data linearly, as in NOR
-  bus-read mode;
-- U-Boot is linked at 0x60001000 (the vendor's NAND `TEXT_BASE`), behind a
-  4 KiB header;
-- the header's first word is `ldr pc, [pc, #-4]` followed by that address, so
-  it reaches U-Boot whether the ROM starts at the window or the 0x08000000
-  alias (`build.sh`).
-
-**What it carries:**
-
-- layout `768k(boot),256k(env),-(ubi)`;
-- the environment at 0xc0000;
-- the kernel at `/boot/uImage` inside the UBIFS `rootfs` volume;
-- the same recovery as on `openipc-hisilicon` NAND.
-
-Only qemu-hisilicon's NAND model, which implements the same guess, has run
-it. The OpenIPC XM530 kernel has no SPI NAND driver either, so a NAND image
-loads and starts the kernel, which then cannot mount its root. Treat NAND as
-unverified on silicon, and say so wherever it is offered.
+There are only NOR images. No XM530/XM550 board with SPI NAND has turned
+up, and the OpenIPC XM530 kernel has no SPI NAND driver. `openipc.c`'s NAND
+paths (`CONFIG_FMC_SPI_NAND`) are never built here.
 
 ## Build
 
@@ -131,10 +107,10 @@ bash build.sh               # xm510 xm530 xm550; continues past failures, exits
 bash build.sh xm530         # one or more SoCs (CROSS_COMPILE defaults to arm-linux-gnueabi-)
 ```
 
-- Output: `output/u-boot-<soc>-nor.bin`, plus `-nand.bin` for xm530/xm550,
-  built out of tree in `output/build-<soc>-<nor|nand>/`.
+- Output: `output/u-boot-<soc>-nor.bin`, built out of tree in
+  `output/build-<soc>-nor/`.
 - `.config` is `openipc/openipc_config`, then `openipc/<soc>_config`, then
-  `openipc/nand_config` for NAND images, then `olddefconfig`. A later line
+  `olddefconfig`. A later line
   wins. The "override" warnings are that layering.
 - There are no `configs/*_defconfig` for these targets.
 - The host toolchain must match CI (Ubuntu `gcc-arm-linux-gnueabi`). A Docker
@@ -162,12 +138,10 @@ with the reset vector at the window or alias, exactly as silicon does.
   bootloaders leave it, with per-block locks on. `xmsfc_unprotect()` must clear
   it before writes land.
 
-- **NAND:** `-global xm-sfc.nand-file=<raw image>`, with no `flash-file`.
-  - The raw image is pages of 2048 + 64 bytes, U-Boot at page 0, and
-    `ubinize`'s output at 1 MiB.
-  - It must reach the prompt, save the env, mount the rootfs and start the
-    kernel.
-  - From an erased NAND, TFTP recovery must create the UBI volumes and boot.
+- **SD recovery:** a FAT card (`-drive if=sd,file=<image>,format=raw`) with
+  `*.img` files: each valid uImage whose load address and size fit the flash
+  has its payload written there unless it is already on the flash; the
+  boot then goes on.
 
 **What qemu does not check:** DDR training values, the v2 bus-read restore and
 PHY/MDIO timing are acked instantly. A change to those needs a real board.

build.sh

@@ -31,39 +31,20 @@ build_xm() {
     builddir=${BOOT_SRCDIR}/output/build-${soc}-${kind}
     make_opts="-C ${BOOT_SRCDIR} O=${builddir} -j$(nproc)"
     fragments="openipc/openipc_config openipc/${soc}_config"
-    [ "${kind}" = nand ] && fragments="${fragments} openipc/nand_config"
 
     rm -rf "${builddir}"
     mkconfig "${builddir}" ${fragments} && \
     make ${make_opts} olddefconfig </dev/null >/dev/null && \
     make ${make_opts} </dev/null || return 1
 
-    if [ "${kind}" = nor ]; then
-        cp "${builddir}/u-boot.bin" "output/u-boot-${soc}-nor.bin" || return 1
-    else
-        # SPI NAND: a 4 KiB header, then U-Boot linked at the window + 4 KiB
-        # (CONFIG_SYS_TEXT_BASE in nand_config). Nothing documents what the
-        # boot ROM expects here; the header's first word jumps to U-Boot
-        # wherever the ROM starts it (ldr pc, [pc, #-4] and the address).
-        text=$(sed -n 's/^CONFIG_SYS_TEXT_BASE=//p' "${builddir}/.config")
-        python3 - "${builddir}/u-boot.bin" "output/u-boot-${soc}-nand.bin" \
-            "${text}" <<'PY' || return 1
-import struct, sys
-src, dst, text = sys.argv[1], sys.argv[2], int(sys.argv[3], 0)
-hdr = bytearray(b'\xff' * 0x1000)
-hdr[0:8] = struct.pack('<II', 0xe51ff004, text)
-open(dst, 'wb').write(bytes(hdr) + open(src, 'rb').read())
-PY
-    fi
+    cp "${builddir}/u-boot.bin" "output/u-boot-${soc}-nor.bin"
 }
 
 build_soc() {
     soc=$1
     case "${soc}" in
-        xm510)
+        xm510|xm530|xm550)
             build_xm "${soc}" nor ;;
-        xm530|xm550)
-            build_xm "${soc}" nor && build_xm "${soc}" nand ;;
         *)
             echo "unsupported SoC: ${soc}" >&2
             return 1 ;;