RT1052 首次运行ucLinux

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这次试用的RT1052处理器被称为跨界处理器，因为其不仅有MCU的价格而且具有MPU的高性能。今天要使用的ucLinux操作系统也是一个跨界的产物。

        在嵌入式系统里由于资源有限，所以MCU一般都是踝机运行，一方面其占用的资源较少；另一方面MCU的也的确仅仅运行单一处理事务，不需要复杂的综合处理；在高级应用里开源的操作系统就当属linux了，可是此linux偏偏需要一个MMU的东西——内存管理单元，在MMU的管理下，linux可以正常运行处理复杂逻辑与多种应用，声音与图像齐具。现在问题就来了，RT1052这类的MCU是没有MMU的，于是ucLinux就出现了。

        ucLinux的启动是需要较复杂与庞大的BSP支持的，飞凌公司已经在官方为我们编译好了，所以我们只需要下载并运行之。

        与其它linux系统一下，我们可以使用串口来打印出来系统启动的系统，我这次使用了xshell软件记录了启动信息，如下：

1. U-Boot 2017.09-rc1-g597daa3 (Aug 06 2018 - 14:56:38 +0800)
   
2. 
   
3. CPU: i.MX RT105x at 528MHz
   
4. Model: NXP i.RT1050 EVK
   
5. DRAM:  32 MiB
   
6. MMC:   FSL_SDHC: 0
   
7. SF: Detected w25q128bv with page size 256 Bytes, erase size 64 KiB, total 16 MiB
   
8. *** Warning - bad CRC, using default environment
   
9. 
   
10. Video: 480x272x24
    
11. In:    serial@40184000
    
12. Out:   serial@40184000
    
13. Err:   serial@40184000
    
14. Net:   eth0: ethernet@402D8000
    
15. Hit any key to stop autoboot:  0
    
16. SF: Detected w25q128bv with page size 256 Bytes, erase size 64 KiB, total 16 MiB
    
17. device 0 offset 0x80000, size 0x400000
    
18. SF: 4194304 bytes @ 0x80000 Read: OK
    
19. device 0 offset 0x70000, size 0x10000
    
20. SF: 65536 bytes @ 0x70000 Read: OK
    
21. ## Booting kernel from Legacy Image at 80007fc0 ...
    
22.    Image Name:   Linux-4.5.0-g50baef1-dirty
    
23.    Image Type:   ARM Linux Kernel Image (uncompressed)
    
24.    Data Size:    3032352 Bytes = 2.9 MiB
    
25.    Load Address: 80008000
    
26.    Entry Point:  80008001
    
27.    Verifying Checksum ... OK
    
28. ## Flattened Device Tree blob at 81000000
    
29.    Booting using the fdt blob at 0x81000000
    
30.    XIP Kernel Image ... OK
    
31.    Loading Device Tree to 81e67000, end 81e6cbb2 ... OK
    
32. 
    
33. Starting kernel ...
    
34. 
    
35. Booting Linux on physical CPU 0x0
    
36. Linux version 4.5.0-g50baef1-dirty (bluesky@developer-RH2485-V2) (gcc version 4.7.4 20130508 (prerelease) (20170818-165657- build on build.emcraft by build) ) #76 Mon Aug 6 15:12:10 CST 2018
    
37. CPU: ARMv7-M [411fc271] revision 1 (ARMv7M), cr=00000000
    
38. CPU: WBA data cache, WBA instruction cache
    
39. Machine model: NXP IMXRT1050 board
    
40. Built 1 zonelists in Zone order, mobility grouping off.  Total pages: 8128
    
41. Kernel command line: rootfstype=jffs2 root=/dev/mtdblock4 rw
    
42. PID hash table entries: 128 (order: -3, 512 bytes)
    
43. Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
    
44. Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
    
45. Memory: 28324K/32768K available (2343K kernel code, 113K rwdata, 432K rodata, 72K init, 94K bss, 4444K reserved, 0K cma-reserved)
    
46. Virtual kernel memory layout:
    
47.     vector  : 0x00000000 - 0x00001000   (   4 kB)
    
48.     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
    
49.     vmalloc : 0x00000000 - 0xffffffff   (4095 MB)
    
50.     lowmem  : 0x80000000 - 0x82000000   (  32 MB)
    
51.       .text : 0x80008000 - 0x802bdde8   (2776 kB)
    
52.       .init : 0x802be000 - 0x802d0000   (  72 kB)
    
53.       .data : 0x802d0000 - 0x802ec520   ( 114 kB)
    
54.        .bss : 0x802ec520 - 0x80303f7c   (  95 kB)
    
55. NR_IRQS:16 nr_irqs:16 16
    
56. sched_clock: 32 bits at 75MHz, resolution 13ns, wraps every 28633115129ns
    
57. clocksource: vf-pit: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 25483472618 ns
    
58. Calibrating delay loop... 1196.85 BogoMIPS (lpj=5984256)
    
59. pid_max: default: 4096 minimum: 301
    
60. Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
    
61. Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
    
62. devtmpfs: initialized
    
63. clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
    
64. pinctrl core: initialized pinctrl subsystem
    
65. NET: Registered protocol family 16
    
66. imxrt105x-pinctrl 40a8000.iomuxc_snvs: initialized IMX pinctrl driver
    
67. imxrt105x-pinctrl 401f8000.iomuxc: initialized IMX pinctrl driver
    
68. SCSI subsystem initialized
    
69. usbcore: registered new interface driver usbfs
    
70. usbcore: registered new interface driver hub
    
71. usbcore: registered new device driver usb
    
72. pps_core: LinuxPPS API ver. 1 registered
    
73. pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
    
74. PTP clock support registered
    
75. clocksource: Switched to clocksource vf-pit
    
76. NET: Registered protocol family 2
    
77. TCP established hash table entries: 1024 (order: 0, 4096 bytes)
    
78. TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
    
79. TCP: Hash tables configured (established 1024 bind 1024)
    
80. UDP hash table entries: 256 (order: 0, 4096 bytes)
    
81. UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
    
82. NET: Registered protocol family 1
    
83. RPC: Registered named UNIX socket transport module.
    
84. RPC: Registered udp transport module.
    
85. RPC: Registered tcp transport module.
    
86. RPC: Registered tcp NFSv4.1 backchannel transport module.
    
87. futex hash table entries: 16 (order: -5, 192 bytes)
    
88. jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
    
89. fuse init (API version 7.24)
    
90. Block layer SCSI generic (bsg) driver version 0.4 loaded (major 251)
    
91. io scheduler noop registered
    
92. io scheduler cfq registered (default)
    
93. mxsfb 402b8000.lcdif: initialized
    
94. 40184000.serial: ttyLP0 at MMIO 0x40184000 (irq = 44, base_baud = 375000) is a FSL_LPUART
    
95. Serial: Console lpuart rounded baud ratefrom 187500 to 115200
    
96. console [ttyLP0] enabled
    
97. 40188000.serial: ttyLP1 at MMIO 0x40188000 (irq = 45, base_baud = 375000) is a FSL_LPUART
    
98. Serial: VF610 driver
    
99. fsl-flexspi 402a8000.flexspi: w25q128 (16384 Kbytes)
    
100. 5 ofpart partitions found on MTD device 402a8000.flexspi
     
101. Creating 5 MTD partitions on "402a8000.flexspi":
     
102. 0x000000000000-0x000000050000 : "uboot"
     
103. 0x000000050000-0x000000070000 : "uboot_env"
     
104. 0x000000070000-0x000000080000 : "dtb"
     
105. 0x000000080000-0x000000480000 : "kernel"
     
106. 0x000000480000-0x000001000000 : "rootfs"
     
107. libphy: fec_enet_mii_bus: probed
     
108. PPP generic driver version 2.4.2
     
109. PPP BSD Compression module registered
     
110. PPP Deflate Compression module registered
     
111. ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
     
112. ehci-mxc: Freescale On-Chip EHCI Host driver
     
113. usbcore: registered new interface driver cdc_acm
     
114. cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
     
115. usbcore: registered new interface driver uas
     
116. usbcore: registered new interface driver usb-storage
     
117. ci_hdrc ci_hdrc.0: doesn't support gadget
     
118. ci_hdrc ci_hdrc.0: EHCI Host Controller
     
119. ci_hdrc ci_hdrc.0: new USB bus registered, assigned bus number 1
     
120. ci_hdrc ci_hdrc.0: USB 2.0 started, EHCI 1.00
     
121. hub 1-0:1.0: USB hub found
     
122. hub 1-0:1.0: 1 port detected
     
123. ci_hdrc ci_hdrc.1: EHCI Host Controller
     
124. ci_hdrc ci_hdrc.1: new USB bus registered, assigned bus number 2
     
125. ci_hdrc ci_hdrc.1: USB 2.0 started, EHCI 1.00
     
126. hub 2-0:1.0: USB hub found
     
127. hub 2-0:1.0: 1 port detected
     
128. i2c /dev entries driver
     
129. input: TSC2007 Touchscreen as /devices/platform/soc/soc:aips-bus@40000000/403f0000.lpci2c/i2c-0/0-0048/input/input0
     
130. rtc-rx8010 0-0032: rtc core: registered rx8010 as rtc0
     
131. i2c i2c-0: LPI2C adapter registered
     
132. sdhci: Secure Digital Host Controller Interface driver
     
133. sdhci: Copyright(c) Pierre Ossman
     
134. sdhci-pltfm: SDHCI platform and OF driver helper
     
135. sdhci-esdhc-imx 402c0000.esdhc: could not get default state
     
136. /soc/aips-bus@40000000/esdhc@402c0000: voltage-ranges unspecified
     
137. mmc0: SDHCI controller on 402c0000.esdhc [402c0000.esdhc] using DMA
     
138. usbcore: registered new interface driver usbhid
     
139. usbhid: USB HID core driver
     
140. NET: Registered protocol family 17
     
141. input: gpio-keys as /devices/platform/gpio-keys/input/input1
     
142. rtc-rx8010 0-0032: setting system clock to 2018-10-22 22:41:44 UTC (1540248104)
     
143. VFS: Mounted root (jffs2 filesystem) on device 31:4.
     
144. devtmpfs: mounted
     
145. Freeing unused kernel memory: 72K (802be000 - 802d0000)
     
146. init started: BusyBox v1.24.2 (2018-08-06 15:10:58 CST)
     

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        从启动信息我们可以看到，首先调用了uboot，然后启动Kernel。从启动信息也看到，此次使用的kernel也是emcraft提供的。不得不感叹一下emcraft对于ucLinux的支持力度之大。

        之后我又试用了一些命令，此版本的ucLinux所支持的指令还是非常多的，此后的试用将基于ucLinux而开展，好有期待~~

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