来源: 互联网  发布时间: 2014-02-18

LPC17XX串口接收数据死机现象解决办法

写了段串口接收的函数gprs_callback放到串口中断中，如下：

void gprs_callback(void)
{
 if(GprsCnt<GRLEN)
  GprsReceive[GprsCnt++] = LPC_UART2->RBR;
}

其中变量都是定义volatile的公共变量，但是发现程序极不稳定，常常运行一会就死机。

 

后来发现先把RBR送给一个局部变量，再送给公共变量就没问题了，如下：

void gprs_callback(void)
{
 char b;
 b = LPC_UART2->RBR;
 if(GprsCnt<GRLEN)
  GprsReceive[GprsCnt++] = b;
}

具体原因还不清楚。

    

    来源: 互联网  发布时间: 2014-02-18

内核：一个中断如何对应多个句柄

input子系统

input子系统代码位置：kernel/drivers/input/input.c

这个文件完成input系统最原始的初始化，subsys_initcall开始子系统的初始化，并封装EXPORT_SYMBOL给其他驱动调用的接口

在input_init中，三件事：

err = class_register(&input_class); if (err) { pr_err("unable to register input_dev class\n"); return err; } err = input_proc_init(); if (err) goto fail1; err = register_chrdev(INPUT_MAJOR, "input", &input_fops); if (err) { pr_err("unable to register char major %d", INPUT_MAJOR); goto fail2; }
创建一个class，proc目录下节点，和注册input的方法集

对开发很有用的是proc的节点，我们看下代码，才能更好地利用它

static int __init input_proc_init(void) { struct proc_dir_entry *entry; proc_bus_input_dir = proc_mkdir("bus/input", NULL); if (!proc_bus_input_dir) return -ENOMEM; entry = proc_create("devices", 0, proc_bus_input_dir, &input_devices_fileops); if (!entry) goto fail1; entry = proc_create("handlers", 0, proc_bus_input_dir, &input_handlers_fileops); if (!entry) goto fail2; return 0; fail2: remove_proc_entry("devices", proc_bus_input_dir); fail1: remove_proc_entry("bus/input", NULL); return -ENOMEM; }
分如下步骤：

1. "bus/input"目录创建

2. 在"bus/input"目录下创建proc目录devices，它的方法集有

static const struct file_operations input_devices_fileops = { .owner = THIS_MODULE, .open = input_proc_devices_open, .poll = input_proc_devices_poll, .read = seq_read, .llseek = seq_lseek, .release = seq_release, };
这里要高度重视这些方法集，因为方法集才是创建这些节点的目的，内核很多的调用都是通过方法集调用，所以即使用sourceinsight也很难直接找到注册位置和调用位置

static const struct seq_operations input_devices_seq_ops = { .start = input_devices_seq_start, .next = input_devices_seq_next, .stop = input_seq_stop, .show = input_devices_seq_show, }; static int input_proc_devices_open(struct inode *inode, struct file *file) { return seq_open(file, &input_devices_seq_ops); }
open方法就完成一件事：open这个节点的文件，这个节点又对应着一系列的调用，分别有start next stop show；看方法的名字也能知道，这些方法的调用是先start，再next，最后stop，可以通过show，用cat查看一些信息。明白这些，就可以理解，这些方法里面，是一些句柄的链表，每次调用device的open，都会把devices的所有句柄，按照start-next-next-...-stop的方式，这就实现了一个open，能够有多个功能。

“handlers”节点和“devieces”节点注册方式类似，里面关联的是很多的中断句柄

static const struct seq_operations input_handlers_seq_ops = { .start = input_handlers_seq_start, .next = input_handlers_seq_next, .stop = input_seq_stop, .show = input_handlers_seq_show, }; static int input_proc_handlers_open(struct inode *inode, struct file *file) { return seq_open(file, &input_handlers_seq_ops); } static const struct file_operations input_handlers_fileops = { .owner = THIS_MODULE, .open = input_proc_handlers_open, .read = seq_read, .llseek = seq_lseek, .release = seq_release, };
我们实际用下这些节点

shell@android:/proc/bus/input # ls devices handlers shell@android:/proc/bus/input #
shell@android:/proc/bus/input # cat devices I: Bus=0000 Vendor=0001 Product=0001 Version=0100 N: Name="headsetdet" P: Phys= S: Sysfs=/devices/platform/headsetdet.0/input/input0 U: Uniq= H: Handlers=event0 B: PROP=0 B: EV=3 B: KEY=1 I: Bus=0019 Vendor=0001 Product=0001 Version=0100 N: Name="keypad" P: Phys=gpio-keys/input0 S: Sysfs=/devices/platform/keypad/input/input1 U: Uniq= H: Handlers=kbd event1 keychord B: PROP=0 B: EV=3 B: KEY=8000 100000 0 0 0 I: Bus=0000 Vendor=0000 Product=0000 Version=0000 N: Name="ft5x0x_ts" P: Phys= S: Sysfs=/devices/virtual/input/input2 U: Uniq= H: Handlers=cpufreq_interactive event2 B: PROP=2 B: EV=9 B: ABS=2658000 0 I: Bus=0000 Vendor=0000 Product=0000 Version=0000 N: Name="lightsensor-level" P: Phys= S: Sysfs=/devices/virtual/input/input3 U: Uniq= H: Handlers=event3 B: PROP=0 B: EV=9 B: ABS=100 10000000 shell@android:/proc/bus/input #
shell@android:/proc/bus/input # cat handlers N: Number=0 Name=kbd N: Number=1 Name=cpufreq_interactive N: Number=2 Name=sysrq (filter) N: Number=3 Name=evdev Minor=64 N: Number=4 Name=keychord shell@android:/proc/bus/input #
cpufreq_interactive就是interactive策略，增加对input及时响应的一个句柄。

    

    来源: 互联网  发布时间: 2014-02-18

ubuntu下commonlisp配置

ubuntu 12.04 的Commonlisp实现

ubuntu 12.04 下commonlisp的实现很多，有clisp ，gcl和sbcl三个。你可以按照自己的需求安装对于的实现。我安装的是sbcl。这三个实现都可以通过softwareCenter 安装。如果你使用的是Windows，我建议还是使用lispbox网址http://common-lisp.net/project/lispbox/下载解压即可运行了。不需要关注各个软件的安装。

什么是CommonLisp

在讲解一样东西前先对它进行一番介绍是个好习惯，所以本文的第一个内容便是对CommonLisp的介绍。

CommonLisp是一中编程语言，它是Lisp的诸多方言中的一种。

Lisp的原始写法似乎应该是LISP，即LIStProcessor的缩写，不过Lisp这种写法似乎比LISP更常见（而且，在我看来，也更可爱= =）。Lisp是JohnMcCarthy在1960年左右创造的一种基于λ演算的函数式编程语言，可以说是历史悠久、源远流长（其古老程度和FORTRAN老哥有一拼）。当然在初期由于没有什么统一的规范或者标准，不同的人采用了不同的方式对Lisp进行实现，也就出现了许多方言，CommonLisp便是其中一种（另一个主要的Lisp方言是Scheme，此外还有一个和Emacs一起的EmacsLisp）。

Common Lisp实现区别和介绍

Common-lisp的实现有很多，下面我介绍几种。

CLISP GNU CLISP, a Common Lisp implementation Common Lisp is a high-level,general-purpose programming language.A bytecode-compilingimplementation, portable and runs on a number of Unix and Unix-likesystems (including MacOS X), as well as Microsoft Windows and several other systems.GPL license. GNU CLISP is a Common Lisp implementation by BrunoHaible of Karlsruhe University and Michael Stoll of MunichUniversity, both in Germany. It mostly supports the Lisp describedin the ANSI Common Lisp standard. It runs on microcomputers (OS /2,Windows NT/2000, Windows 95/98, Amiga 500-4000, Acorn RISC PC) aswell as on Unix workstations (Linux, SVR4, Sun4, DEC Alpha OSF,HP-UX, BeOS, NeXTstep, SGI, AIX, Sun3 and others) and needs only 2MB of RAM. The user interface comes in German, English, French,Spanish and Dutch. GNU CLISP includes an interpreter,a compiler, a large subset of CLOS, a foreign languageinterface and a socket interface. An X11 interface is availablethrough CLX and Garnet. GNU CLISP 后来贡献给了gnu项目，所以叫做GNUCLISP 。GNUCLISP 实现包括解释器，编译器，CLOS的大部分子集，以及外部语言接口和socket接口。
GNU CommonLisp (GCL)  The GNU Project'sLisp compiler. It producesnative object code by first generating Ccode and then calling a C compiler. Not yet fully ANSI-compliant,GCL is however the implementation of choice for several largeprojects including the mathematical tools Maxima,AXIOM and(historically) ACL2.GCL runs on Linuxunder eleven different architectures, and also under Windows,Solaris, and FreeBSD.GPL license.GCL 是一个Lisp编译器。它首先根据lisp代码生成c代码之后调用c编译器生成机器代码。只是实现了大部分ansicommon lisp标准。
Clozure CL(CCL)  Clozure CL (CCL) is a CommonLisp implementation. It implements the full ANSI Common Lispstandard with several extensions (CLOS MOP, threads, CLOSconditions, CLOS streams, ...). It contains a command linedevelopment environment, an experimental integrated developmentenvironment (IDE) for Mac OS X using the Hemlockeditor, and can also be used with SLIME(a Common Lisp development environment for GNUEmacs). Clozure CL is opensource and the project is hosted by Clozure Associates.Originally a freeand open source fork of Macintosh Common Lisp. As that historyimplies, CCL was written for the Macintosh, but Clozure CL now runson Mac OS X,FreeBSD, Linux,Solarisand Windows.32 and 64 bit x86ports are supported on each platform. Additionally there are PowerPC ports for Mac OS and Linux. CCL was previously known as OpenMCL,but that name is no longer used, to avoid confusion with the opensource version of Macintosh Common Lisp. LGPL license. Clozure CL (CCL)完全实现了ANSICommon Lisp 标准和某些重要的扩展。它包含一个命令行的开发环境和一个集成的ide，可以使用hemlock editor或者emacs。最初由Macintosh Common Lisp分化而来。CMUCL Originally from CarnegieMellon University, now maintained as freeand open source software by a group of volunteers. CMUCL uses afast native-code compiler. It is available on Linuxand BSDfor Intel x86; Linuxfor Alpha; Mac OS Xfor Intel x86 and PowerPC; and Solaris, IRIX, and HP-UX on theirnative platforms. Public domain (some parts BSD license) SteelBank Common Lisp is derived from CMUCL. The ScieneerCommon Lisp is a commercial derivative from CMUCL.
SteelBank Common Lisp (SBCL)  A branch from CMUCL."Broadly speaking, SBCL is distinguished from CMU CL by agreater emphasis on maintainability."[10]SBCL runs on the platforms CMUCL does, except HP/UX; in addition, itruns on Linux for AMD64, PowerPC, SPARC, MIPS, Windows x86[11]and has experimental support for running on Windows AMD64. SBCL doesnot use an interpreter by default; all expressions are compiled tonative code unless the user switches the interpreter on. The SBCLcompiler generates fast native code.[12]Public domain (some parts BSD license).Steel Bank Common Lisp (SBCL) is a freeCommon Lispimplementation that features a high performance native compiler,Unicode supportand threading.

The name "Steel Bank Common Lisp" is a reference toCarnegie MellonUniversity Common Lisp from which SBCL forked: AndrewCarnegie made his fortune in the steel industry and AndrewMellon was a successful banker.

上面只是介绍lisp最受关注的几个开源实现，lisp还有许多商用的实现比如说AllegroCommon Lisp和LispWorks等，都提供了很好的集成IDE开发环境。

具体可以参阅：http://en.wikipedia.org/wiki/Common_Lisp#Implementations

Common Lisp开发工具

有了上面的commonlisp实现，也就是有了sdk，对于开发来说，必不可少的一个工具就是一个编辑器，好的编辑器可以让你的开发事半功倍。CommonLisp 最常用的编辑器就算emacs。

另外使用emacs需要安装SLIME

SLIME The Superior Lisp Interaction Mode forEmacs从它的名字上你就能知道它是干什么的，简单来说，使用它我们可以非常轻松地体验CommonLisp编程的REPL（Read-Eval-PrintLoop）旅程。

SLIME is a Emacs mode for Common Lisp development. Inspired byexisting systems such Emacs Lisp and ILISP,we are working to create an environment for hacking Common Lisp in.

SLIME works with GNU Emacs versions 21 and later, and with XEmacsversion 21 on Unix, , and .

The currently supported Common Lisp implementations are:

• CMU Common Lisp (CMUCL)

• Steel Bank Common Lisp (SBCL)

• Clozure CL (a.k.a. OpenMCL)

• LispWorks

• Allegro CL

• CLISP

• Scieneer CL

• ECL

• Corman CL

• ABCL

Ubuntu下Common Lisp的安装

一篇好文：http://www.liyaos.com/blog/common-lisp-notes-0/

下文来自：http://blog.csdn.net/zheda3072211120/article/details/6953303

binghe学长的译作<<实用CommonLisp编程>>出版了..买了一本回来准备学习CL..

貌似在win下没有好的环境..所以只好在虚拟机下跑ubuntu来学习CL了..

下面是我个人的安装过程..

1.安装emacs

sudo apt-get install emacs

目前最新的emacs貌似是23.多了..

说实话一直对emacs没爱..常年使用vim..但这次貌似只能学习下传说中的神器了..

2.安装lisp环境

同书上一样..选择了sbcl

sudo apt-get install sbcl clisp

sbcl的具体执行程序位置是/usr/bin/sbcl..这个后面配置emacs时会用

3.安装slime

sudo apt-get install slime

slime的位置在/usr/share/common-lisp/source/slime..这个后面也会用

4.配置emacs

在~/.emacs中对emacs进行配置..我没什么经验..所以只好照抄网上的配置了..如下

(tool-bar-mode -1) ;这个关闭工具栏

(menu-bar-mode -1) ;这个关闭菜单栏

(setq inferior-lisp-program"/usr/bin/sbcl") ;sbcl的路径

(add-to-list 'load-path"/usr/share/common-lisp/source/slime") ;slime的路径

(require 'slime)

(slime-setup) ;slime安装

我已经习惯了vim那样啥也没有的纯键盘操作了..所以关掉了tool/menu..大家自己看着办

5.进入CL交互环境

启动emacs..并按Alt+x(术语貌似是M-x)..输入slime..然后就等待一会儿.出现CL-USER>..就表示OK了..

好吧..接下来就是学习CL了..