[ 物联网篇 ] 09 - Buildroot中构建NXP IMX8MM

make freescale_imx8mmevk_defconfig 
make 
// buildroot-2019.05-rc2/output/images 目录得到固件
├── bl31.bin
├── boot.vfat
├── fsl-imx8mm-evk.dtb
├── Image
├── imx8-boot-sd.bin
├── imx-boot-imx8mmevk-sd.bin-flash_evk
├── lpddr4_pmu_train_fw.bin
├── rootfs.ext2
├── rootfs.ext4 -> rootfs.ext2
├── rootfs.tar
├── sdcard.img
├── signed_hdmi_imx8m.bin
├── u-boot.bin
├── u-boot.imx
├── u-boot.itb
├── u-boot-nodtb.bin
├── u-boot-spl.bin
└── u-boot-spl-ddr.bin

buildroot-2019.05-rc2/board/freescale/common/imx/genimage.cfg.template_imx8
image sdcard.img {
  hdimage {
  }

  partition imx-boot {
    in-partition-table = "no"
     # image = "imx8-boot-sd.bin"
     # 这里是重点
    image = "imx-boot-imx8mmevk-sd.bin-flash_evk"
    offset = %IMXOFFSET%
  }

  partition boot {
    partition-type = 0xC
    bootable = "true"
    image = "boot.vfat"
    offset = 8M
  }

  partition rootfs {
    partition-type = 0x83
    image = "rootfs.ext2"
  }
}

[    4.194949] VSD_3V3: disabling
[    4.199098] ALSA device list:
[    4.202081]   #0: wm8524-audio
[    4.205139]   #1: imx-spdif
[    4.207946]   #2: imx-audio-micfil
[    4.229743] EXT4-fs (mmcblk2p2): recovery complete
[    4.235308] EXT4-fs (mmcblk2p2): mounted filesystem with ordered data mode. Opts: (null)
[    4.243484] VFS: Mounted root (ext4 filesystem) on device 179:2.
[    4.251138] devtmpfs: mounted
[    4.254447] Freeing unused kernel memory: 1280K
[    4.274522] EXT4-fs (mmcblk2p2): re-mounted. Opts: data=ordered
Starting syslogd: OK
Starting klogd: OK
Initializing random number generator... [    4.310549] random: dd: uninitialized urandom read (512 bytes read)
done.
Starting network: OK

// 起初以为是这里问题，没有加载音频相关的固件，后来想明白了，固件加载不成功，卡住也不合理。
[    4.383016] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!
[    4.389557] imx-uart 30860000.serial:    
[    4.446690] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!
[    4.453230] imx-uart 30860000.serial: Prepare for the RX slave dma failed!
[    4.560810] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!
[    4.567366] imx-uart 30860000.serial: We cannot prepare for the TX slave dma!
[    4.577798] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!
[    4.584355] imx-uart 30860000.serial: We cannot prepare for the TX slave dma!
[    4.591517] imx-sdma 30bd0000.dma-controller: sdma firmware not ready!
[    4.598071] imx-uart 30860000.serial: We cannot prepare for the TX slave dma!
[   62.567126] imx-sdma 30bd0000.dma-controller: external firmware not found, using ROM firmware
[   62.567554] imx-sdma 302c0000.dma-controller: external firmware not found, using ROM firmware
[   62.584223] imx-sdma 302b0000.dma-controller: external firmware not found, using ROM firmware

BR2_TARGET_GENERIC_GETTY_PORT="ttymxc0"
改为
BR2_TARGET_GENERIC_GETTY_PORT="ttymxc1"
对应的是串口登录
target/etc/ inittab 
ttymxc1::respawn:/sbin/getty -L  ttymxc1 0 vt100 # GENERIC_SERIAL

Incorrect selection of kernel headers: expected 4.14, got 4.9