从本小节开始,讲着重介绍Zedboard上的嵌入式linux应用,包括使用SDK设计最简单的linux应用程序、linux交叉编译环境搭建、设备驱动编写等内容。
本小节使用的linux系统是Digilent官方提供的OOB设计,它是Digilent官网给出的一个完整的、Zedboard可运行的linux系统,包含了Zedboard上的几个重要的设备驱动如串口、USB、以太网、OLED、HDMI等。当linux在Zedboard上运行起来后,Zedboard就是一个小型的嵌入式系统,使用SDK及Xilinx
ARM Linux工具链(arm-xilinx-linux-gnueabi)编译生成的可执行文件可以在这个系统执行。
本小节介绍的是使用SDK开发应用程序,并非在linux系统下使用arm-xilinx-linux-gnueabi。如果需要在linux系统下开发Zedboard上可执行程序,需要安装用arm-xilinx-linux-gnueabi编译环境。
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硬件平台:Digilent ZedBoard
开发环境:Windows XP 32 bit
软件: SDK 14.2
一、获取Zedboard可运行的linux
Digilent官网给出Zedboard的可运行linux设计ZedBoard_OOB_Design包,可从http://www.digilentinc.com/Data/Documents/Other/ZedBoard_OOB_Design.zip获取,下载后解压,可以看到包的结构和内容:
boot_image目录:
--
system.bit – 配置FPGA的bit文件
--
u-boot.elf – 引导linux需要的Second-Stage boot loader
--
zynq_fsbl.elf – 配置ARM PS系统的First-Stage boot loader(FSBL)
doc目录:
--
README.txt – 说明文件
hw目录:
-- EDK 14.1版本的
XPS工程,用来生成硬件文件和bit文件
linux目录:
--
devicetree_ramdisk.dts – 设备树源代码
--
.config – Linux内核配置文件,用来生成zImage
sd_image目录:
--
BOOT.BIN – 使用
boot_images中的三个文件生成的Zynq配置文件
--
devicetree_ramdisk.dtb – 编译后的设备树文件
--
ramdisk8M.image.gz – 编译后的文件系统
--
README – 介绍如何运行OOB设计的说明文档
--
zImage – 编译后的内核
sw目录:--硬件配置--FSBL源代码
其中sd_image目录中包含了ZedBoard上能够运行linux的所有文件。将SD卡格式化为Fat32,把sd_image目录文件拷贝到SD卡根目录下;然后将JP7~JP11设置为SD卡启动模式,将JP2短路,JP3断开,这样可以下一步我们可以把U盘作为USB 从设备挂载到Zedboard上。
Zedboard的连接和短路块设置
上电后,等待ARM PS的配置、FPGA的配置(蓝 {MOD}LED DONE 亮起),之后开始引导Linux系统了。可以从超级终端上看到一系列的引导信息:
1 U-Boot 2012.04.01-00297-gc319bf9-dirty (Sep 13 2012 - 09:30:49)
2
3 DRAM: 512 MiB
4 WARNING: Caches not enabled
5 MMC: SDHCI: 0
6 Using default environment
7
8 In: serial
9 Out: serial
10 Err: serial
11 Net: zynq_gemHit any key to stop autoboot: 0
12 Copying Linux from SD to RAM...
13 Device: SDHCI
14 Manufacturer ID: 1b
15 OEM: 534d
16 Name: 00000
17 Tran Speed: 25000000
18 Rd Block Len: 512
19 SD version 1.0
20 High Capacity: Yes
21 Capacity: 3.7 GiB
22 Bus Width: 1-bit
23 reading zImage
24
25 2479640 bytes read
26 reading devicetree_ramdisk.dtb
27
28 5817 bytes read
29 reading ramdisk8M.image.gz
30
31 3694108 bytes read
32 ## Starting application at 0x00008000 ...
33 Uncompressing Linux... done, booting the kernel.
34 [ 0.000000] Booting Linux on physical CPU 0
35 [ 0.000000] Linux version 3.3.0-digilent-12.07-zed-beta (tinghui.wang@DIGILENT_LINUX) (gcc version 4.6.1 (Sourcery CodeBench Lite 2011.09-50) ) #2 SMP PREEMPT Thu Jul 12 21:01:42 PDT 2012
36 [ 0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c5387d
37 [ 0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
38 [ 0.000000] Machine: Xilinx Zynq Platform, model: Xilinx Zynq ZED
39 [ 0.000000] bootconsole [earlycon0] enabled
40 [ 0.000000] Memory policy: ECC disabled, Data cache writealloc
41 [ 0.000000] BUG: mapping for 0xf8f00000 at 0xfe00c000 out of vmalloc space
42 [ 0.000000] BUG: mapping for 0xe0000000 at 0xfe000000 out of vmalloc space
43 [ 0.000000] BUG: mapping for 0xffff1000 at 0xfe200000 out of vmalloc space
44 [ 0.000000] PERCPU: Embedded 7 pages/cpu @c1489000 s5696 r8192 d14784 u32768
45 [ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 125824
46 [ 0.000000] Kernel command line: console=ttyPS0,115200 root=/dev/ram rw initrd=0x800000,8M earlyprintk rootfstype=ext4 rootwait devtmpfs.mount=0
47 [ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
48 [ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
49 [ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
50 [ 0.000000] Memory: 240MB 256MB = 496MB total
51 [ 0.000000] Memory: 489856k/489856k available, 34432k reserved, 0K highmem
52 [ 0.000000] Virtual kernel memory layout:
53 [ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
54 [ 0.000000] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
55 [ 0.000000] vmalloc : 0xe0800000 - 0xfd000000 ( 456 MB)
56 [ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
57 [ 0.000000] pkmap : 0xbfe00000 - 0xc0000000 ( 2 MB)
58 [ 0.000000] modules : 0xbf000000 - 0xbfe00000 ( 14 MB)
59 [ 0.000000] .text : 0xc0008000 - 0xc042f040 (4253 kB)
60 [ 0.000000] .init : 0xc0430000 - 0xc0456640 ( 154 kB)
61 [ 0.000000] .data : 0xc0458000 - 0xc0485dc0 ( 184 kB)
62 [ 0.000000] .bss : 0xc0485de4 - 0xc049d734 ( 95 kB)
63 [ 0.000000] Preemptible hierarchical RCU implementation.
64 [ 0.000000] Verbose stalled-CPUs detection is disabled.
65 [ 0.000000] NR_IRQS:128
66 [ 0.000000] xlnx,ps7-ttc-1.00.a #0 at 0xe0800000, irq=43
67 [ 0.000000] Console: colour dummy device 80x30
68 [ 0.000000] Calibrating delay loop... 1594.16 BogoMIPS (lpj=7970816)
69 [ 0.090000] pid_max: default: 32768 minimum: 301
70 [ 0.090000] Mount-cache hash table entries: 512
71 [ 0.090000] CPU: Testing write buffer coherency: ok
72 [ 0.090000] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
73 [ 0.100000] smp_twd: clock not found: -2
74 [ 0.100000] Calibrating local timer... 399.36MHz.
75 [ 0.170000] hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, 7 counters available
76 [ 0.170000] Setting up static identity map for 0x2f8d48 - 0x2f8d7c
77 [ 0.270000] CPU1: Booted secondary processor
78 [ 0.310000] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
79 [ 0.310000] Brought up 2 CPUs
80 [ 0.310000] SMP: Total of 2 processors activated (3188.32 BogoMIPS).
81 [ 0.320000] devtmpfs: initialized
82 [ 0.320000] ------------[ cut here ]------------
83 [ 0.320000] WARNING: at arch/arm/mm/dma-mapping.c:198 consistent_init+0x70/0x104()
84 [ 0.330000] Modules linked in:
85 [ 0.330000] [] (unwind_backtrace+0x0/0xe0) from [] (warn_slowpath_common+0x4c/0x64)
86 [ 0.340000] [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c)
87 [ 0.350000] [] (warn_slowpath_null+0x18/0x1c) from [] (consistent_init+0x70/0x104)
88 [ 0.360000] [] (consistent_init+0x70/0x104) from [] (do_one_initcall+0x90/0x160)
89 [ 0.360000] [] (do_one_initcall+0x90/0x160) from [] (kernel_init+0x84/0x128)
90 [ 0.370000] [] (kernel_init+0x84/0x128) from [] (kernel_thread_exit+0x0/0x8)
91 [ 0.380000] ---[ end trace 1b75b31a2719ed1c ]---
92 [ 0.380000] ------------[ cut here ]------------
93 [ 0.390000] WARNING: at arch/arm/mm/dma-mapping.c:198 consistent_init+0x70/0x104()
94 [ 0.390000] Modules linked in:
95 [ 0.390000] [] (unwind_backtrace+0x0/0xe0) from [] (warn_slowpath_common+0x4c/0x64)
96 [ 0.400000] [] (warn_slowpath_common+0x4c/0x64) from [] (warn_slowpath_null+0x18/0x1c)
97 [ 0.410000] [] (warn_slowpath_null+0x18/0x1c) from [] (consistent_init+0x70/0x104)
98 [ 0.420000] [] (consistent_init+0x70/0x104) from [] (do_one_initcall+0x90/0x160)
99 [ 0.430000] [] (do_one_initcall+0x90/0x160) from [] (kernel_init+0x84/0x128)
100 [ 0.430000] [] (kernel_init+0x84/0x128) from [] (kernel_thread_exit+0x0/0x8)
101 [ 0.440000] ---[ end trace 1b75b31a2719ed1d ]---
102 [ 0.440000] NET: Registered protocol family 16
103 [ 0.460000] L310 cache controller enabled
104 [ 0.460000] l2x0: 8 ways, CACHE_ID 0x410000c8, AUX_CTRL 0x72060000, Cache size: 524288 B
105 [ 0.460000] registering platform device 'pl330' id 0
106 [ 0.470000] registering platform device 'arm-pmu' id 0
107 [ 0.470000]
108 [ 0.470000] ###############################################
109 [ 0.480000] # #
110 [ 0.480000] # Board ZED Init #
111 [ 0.480000] # #
112 [ 0.490000] ###############################################
113 [ 0.490000]
114 [ 0.500000] hw-breakpoint: found 5 (+1 reserved) breakpoint and 1 watchpointregisters.
115 [ 0.500000] hw-breakpoint: maximum watchpoint size is 4 bytes.
116 [ 0.530000] xslcr xslcr.0: at 0xF8000000 mapped to 0xE0808000
117 [ 0.540000] bio: create slab 0> at
0
118 [
0.540000] gpiochip_add: registered GPIOs
0 to
245 on device:
xgpiops
119 [
0.540000] xgpiops e000a000.gpio: gpio at
0xe000a000 mapped to
0xe080a000
120 [
0.550000] SCSI subsystem initialized
121 [
0.550000] usbcore:
registered new interface driver usbfs
122 [
0.560000] usbcore:
registered new interface driver hub
123 [
0.560000] usbcore:
registered new device driver usb
124 [
0.570000] Advanced Linux Sound Architecture Driver Version
1.0.
24.
125 [
0.570000] Switching to clocksource xttcpss_timer1
126 [
0.590000] NET: Registered protocol family
2
127 [
0.590000] IP route cache hash table entries:
4096 (order:
2,
16384 bytes)
128 [
0.590000] TCP established hash table entries:
16384 (order:
5,
131072 bytes)
129 [
0.600000] TCP
bind hash table entries:
16384 (order:
5,
196608 bytes)
130 [
0.600000] TCP: Hash tables configured (established
16384 bind 16384)
131 [
0.610000] TCP reno registered
132 [
0.610000] UDP hash table entries:
256 (order:
1,
8192 bytes)
133 [
0.620000] UDP-Lite hash table entries:
256 (order:
1,
8192 bytes)
134 [
0.620000] NET: Registered protocol family
1
135 [
0.630000] Trying to
unpack rootfs image as initramfs...
136 [
0.630000] rootfs image is not initramfs (
no cpio magic); looks like an initrd
137 [
0.670000] Freeing initrd memory:
8192K
138 [
0.670000] xscugtimer xscugtimer.
0: ioremap fe00c200 to e0810200 with size
400
139 [
0.670000] pl330 dev
0 probe success
140 [
0.680000] msgmni has been set to
972
141 [
0.680000] io scheduler noop registered
142 [
0.680000] io scheduler deadline registered
143 [
0.680000] io scheduler cfq registered (default)
144 [
0.690000] e00
0.690000] console [ttyPS0] enabled,
bootconsole disabled
145 [
0.690000] console [ttyPS0] enabled,