以下为本人学习笔记，如有转载请注明出处，谢谢
1. service用法 oneshot
DEFINE_MUTEX(buzzer_mutex);
mutex_lock(&buzzer_mutex);
mutex_unlock(&buzzer_mutex);
static void WriteNumber(const char *fileName, int number)
{
FILE *fp;
fp = fopen(fileName, "w");
if (fp == NULL) {
LCD_DEBUG("open %s error, errno %d\n", fileName, errno);
return;
}
fprintf(fp, "%d", number);
fclose(fp);
}
service aa /usr/bin/aa
class core
user root
group root
critical
onrestart restart aa
onrestart restart tt
#service bbd /usr/bin/bb
service bb /usr/bin/app_bbl_read
user root
group root
oneshot
2.【Shell脚本】怎样表示一个for循环
作者：gnuhpc
出处：http://www.cnblogs.com/gnuhpc/
在此说一下我常用的两个结构：
1.
for i in $(seq 1 100); do
echo $i
done
2.
for (( i = 1 ; $i <= 100; i++ )) ；do
echo $i;
done
3.对于关闭抢占的内核接口
看内核接口是同步还是异步，比方说msleep就是异步接口，会休眠让出cpu
mdelay是忙等待，不会让出cpu
如果是同步接口的话，对于单核cpu，就不会出现多进程同时调用同一个接口出错的情况
如果是异步接口的话，就得具体问题具体分析，如果是仅仅避免多个进程调度同一个接口的情况的话，加信号量或者普通的锁就可以，不一定要加互斥锁，
如果是又有中间层调度接口，又有用户态上层调度接口，那么就另当别论了
spin_lock这种锁是用来多核cpu共同调用同个接口的问题，
mutex_lock这种是会休眠，同个cpu的互斥锁，如果是进程上下文就可以用，如果是中断上下文就不能用这种锁，因为这种锁会休眠，中断中是不允许休眠的
local_irq_save(flags);
local_irq_restore(flags);
spin_lock_irqsave(&iproc_bbl->lock, flags);
spin_unlock_irqrestore(&iproc_bbl->lock, flags);
4.网上大家经常碰到的不能连接问题:
请在运行-cmd输入netstat -n 查看5222端口是否在建立状态 ESTABLISHED,这个方法来源自网络,部落没有遇到过.另外,还有一个,就是清空本地本地DNS缓存,具体步骤如下:
在windows下运行运行菜单,开始->运行,输入"CMD"进行命令行窗口,然后输入 ipconfig/flushdns 按回车键
5.休眠唤醒调试
kernel/power/main.c中可以通过打印链表的信息，在休眠唤醒的时候将每个唤醒的源消耗的时间打印出来
dpm_run_callback（） ----》drivers/base/power
6.中断中不可以加入打印
中断处理函数应该避免调用不可重入函数, 因为新的中断可能发生并打断正在执行任务中，如果当前任务调用了一些不可重入的函数,将会产生错误。
一些常用库函数如printf，malloc，free等都是不可重入函数,因为在函数中引用了全局变量, 这个道理因该很容易明白了吧?
例如, printf会引用全局变量stdout，malloc，free会引用全局的内存分配表。
arch/arm/kernel/debug.S:157: Error: too many positional arguments
7.sys文件节点要注意返回值
static inline ssize_t show_counter_sysfs(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct asiu_pwm_chip *asiu_pwm = dev_get_drvdata(dev);
int i, n;
long value;
n=0;
if(asiu_pwm) {
for (i=0; i<6; i++) {
value = __onepulse_pwm_counter_extend(i);
n += sprintf(buf + n, "pwm_id(%d)----0x%x \n", i, value);
}
return n;
}
else
return -1;
}
static struct device_attribute sysfs_misc_list[] = {
__ATTR(onepluse_counter,S_IRUGO , show_counter_sysfs, NULL),
};
/* tp info show include tp sw version, fw version, cfg csum, hw version */
static ssize_t tp_show(struct kobject *kobj, struct kobj_attribute *attr,
char *buf)
{
struct synaptics_rmi4_data *rmi4_data = exp_data.rmi4_data;
int len = 0;
int retval;
unsigned char config_id[4];
if (NULL == rmi4_data || !f34_ctrl_base_addr)
return -1;
/* Get device config ID */
retval = synaptics_rmi4_reg_read(rmi4_data,
f34_ctrl_base_addr,
config_id, sizeof(config_id));
if (retval < 0) {
dev_err(rmi4_data->pdev,
"%s: Failed to read device config ID\n", __func__);
return -1;
}
len =
scnprintf(buf + len, PAGE_SIZE, "SW:%s\n",
SYNAPTICS_DSX_DRV_VERSION);
/* combine FW and CFG CSUM */
#define SPLIT_TAG "_CFGID"
len +=
scnprintf(buf + len, PAGE_SIZE, "FW:%u%s%02x%02x%02x%02x\n", rmi4_data->firmware_id,
SPLIT_TAG,
config_id[0],
config_id[1],
config_id[2],
config_id[3]);
/*
len +=
scnprintf(buf + len, PAGE_SIZE,
"CFG ID:0x%02x 0x%02x 0x%02x 0x%02x\n", config_id[0],
config_id[1], config_id[2], config_id[3]);
*/
/* add for chipset name */
len += scnprintf(buf + len, PAGE_SIZE, "CHIP NAME:%s\n", "synaptics");
return len;
}
sys 文件节点写函数的时候，sh: write error: Bad address，这种错误一般是return没有返回正确的值，
什么值是正确的呢？那就是count，长度这些才可以，那么系统是怎么识别的呢？要取决于文件系统和echo的实现
static ssize_t test_sysfs_get_report_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
int retval;
unsigned char command;
unsigned long setting;
struct synaptics_rmi4_data *rmi4_data = f54->rmi4_data;
retval = sstrtoul(buf, 10, &setting);
if (retval)
return retval;
printk("zbh 111 \r\n");
if (setting != 1) {
printk("zbh %s(): ---> %d\r\n", __func__, __LINE__);
return -EINVAL;
}
mutex_lock(&f54->status_mutex);
retval = test_check_for_idle_status();
if (retval < 0) {
printk("zbh %s(): ---> %d\r\n", __func__, __LINE__);
goto exit;
}
if (!test_report_type_valid(f54->report_type)) {
dev_err(rmi4_data->pdev,
"%s: Invalid report type\n",
__func__);
retval = -EINVAL;
printk("zbh %s(): ---> %d\r\n", __func__, __LINE__);
goto exit;
}
test_set_interrupt(true);
command = (unsigned char)COMMAND_GET_REPORT;
retval = synaptics_rmi4_reg_write(rmi4_data,
f54->command_base_addr,
&command,
sizeof(command));
if (retval < 0) {
dev_err(rmi4_data->pdev,
"%s: Failed to write get report command\n",
__func__);
goto exit;
}
/* tddi f54 test reporting + */
#ifdef F54_POLLING_GET_REPORT
retval = test_sysfs_get_report_polling();
if (retval < 0) {
dev_err(rmi4_data->pdev,
"%s: Failed to get report image\n",
__func__);
printk("zbh 222 \r\n");
goto exit;
}
#else
/* tddi f54 test reporting - */
f54->status = STATUS_BUSY;
f54->report_size = 0;
f54->data_pos = 0;
hrtimer_start(&f54->watchdog,
ktime_set(GET_REPORT_TIMEOUT_S, 0),
HRTIMER_MODE_REL);
retval = count;
#endif
retval = count; // ===》如果去掉这一行的话，那么echo 1 > get_report 的话就会出现错误 sh: write error: Bad address
exit:
mutex_unlock(&f54->status_mutex);
printk("zbh %s(): retval=%d---> %d\r\n", __func__, retval, __LINE__);
return retval;
}
因为bbl会影响打印机，1s=1000000us
Bbl的时钟是32.768kHz，
所以1000000/32768=30us左右
也就是这个时钟的精度是30us，而bbl寄存器读status状态是延时10us，太短了，至少要在一个clock完成后再读，所以改成延时35us，
8.shell脚本循环
#!/bin/sh
while true
do
let "i++"
echo "is $i"
done
9.查看这些宏CONFIG_SMP在linux内核中是否有定义
#ifndef CONFIG_SMP
要去linux3.6.5目录下.config文件
10.书写代码框架注意：
goto 和return
static int asiu_pwmc_config(struct pwm_chip *chip, struct pwm_device *pwm,
int duty_ns, int period_ns)
{
struct asiu_pwm_chip *asiu_pwm = to_asiu_pwm_chip(chip);
struct asiu_pwm_cfg *pwm_cfg;
unsigned long period_counts, dutyhi_counts;
unsigned long prescale = 0;
unsigned long long ticks;
if (pwm_cfg->enabled) {
/* Change the PWM output with the new config */
asiu_pwmc_disable(chip, pwm);
//asiu_pwmc_enable(chip, pwm);
}
#ifdef PWMC_DEBUG
dev_info(chip->dev, "%s : [pwm-%d] duty_ns = %d, period_ns = %d\n",
__FUNCTION__, pwm->hwpwm, duty_ns, period_ns);
#endif
if (duty_ns == 0 && period_ns ==0) {
/* PWM stay low, duty cycle = 0% */
prescale = 0;
period_counts = 0;
dutyhi_counts = 0;
}
else if (duty_ns >= period_ns) {
/* PWM stay high, duty cycle = 100% */
prescale = 0;
period_counts = ASIU_PWM_PERIOD_MASK;
dutyhi_counts = ASIU_PWM_DUTYHI_MASK;
}
else {
ticks = (unsigned long long)period_ns * asiu_pwm->tick_hz;
do_div(ticks, NSEC_PER_SEC);
period_counts = ticks;
prescale = period_counts >> ASIU_PWM_PEROID_WIDTH;
if(prescale & ~ASIU_PWM_PRESCALE_MASK) {
dev_warn(chip->dev, "%s(%d) : period_counts = %d, prescale = 0x%x\n",
__FUNCTION__, __LINE__, period_counts, prescale);
return -EINVAL;
}
ticks = (unsigned long long)duty_ns * asiu_pwm->tick_hz;
do_div(ticks, NSEC_PER_SEC);
dutyhi_counts = ticks;
}
pwm_cfg = pwm_get_chip_data(pwm);
if (!pwm_cfg) {
dev_warn(chip->dev, "fail to get pwm config data\n");
return -ENOMEM;
}
pwm_cfg->prescale = prescale;
pwm_cfg->period_cnt = period_counts;
pwm_cfg->dutyhi_cnt = dutyhi_counts;
if (pwm_cfg->enabled) {
/* Change the PWM output with the new config */
//asiu_pwmc_disable(chip, pwm);
asiu_pwmc_enable(chip, pwm);
}
#ifdef PWMC_DEBUG
dev_info(chip->dev, "%s : pwm_cfg->prescale = %d, period_cnt = %d, dutyhi_cnt = %d\n",
__FUNCTION__, pwm_cfg->prescale, pwm_cfg->period_cnt, pwm_cfg->dutyhi_cnt);
#endif
return 0;
}
对于如上框架：
进入config函数时先pwm_disable, 然后中间计算，最后enable
但是中间有很多return，我们做接口的目的有个宗旨：
函数是为了改变原来的状态的，如果此函数运行失败返回，那么就要还原原来的场景，不要改变原来的场景。
如上例子如果用中间用return，一开始执行了disable，那么中间如果执行失败return了，后面就不会执行enable，那么pwm状态就会变了，那么对于这种情况我们要使用goto到后面，然后再进行enable，就算失败了，也要还原之前的场景去enable，所以需要把上一次的值保存起来。
11.vim快捷键
vi -d a.c b.c，可以对比
对比过程中，如果拷贝的话，可以用快捷键dp
12.对触摸屏中断的理解
触摸屏与cpu是由一个gpio中断口线相连，所有的中断都是由tp那端抛给cpu的，
Tp通过设定各种参数，刷新频率，扫描频率，电容值（即基准点），tp通过计算触摸屏上的点来决定是否发送中断给cpu，如果计算到没点，就不发送中断给cpu，如果计算到有点，那么就会发送中断给cpu，（注意：tp只要上电启动了那么就会一直进行运算），每次触摸屏上只要有按下，不管几个手指都会产生一个中断，抬起又产生一个中断，最小单位产生两个中断，如果是电平中断，一直按着手指，会不停的产生中断，产生中断的时间和次数由tp的运算速度决定，很难去量化，按下的手指越多，tp运算时间越长，至于有时候发现log有10个finger，和10个status状态，那是驱动代码在一个中断产生时遍历了report动作10次，这些finger和status是通过tp寄存器读取到再由驱动上报内核空间，最终通过input子系统发送给用户空间
===========================================================================================
13.怎么样让编译器对某些函数不再抱怨warning: unused parameter ‘xxx’？
转自：https://segmentfault.com/q/1010000002395334
#define UNUSED_PARAMETER(x) (void)x
int main(int argc, char **argv)
{
// 这两行是为了避免编译报警告
UNUSED_PARAMETER(argc);
UNUSED_PARAMETER(argv);
}
如果可能，请务必用正常方法消除 warning，真的多余就去掉吧
方法一：
void foo(int a) {
(void)a;
// ...
}
方法二：
#ifdef __GNUC__
# define UNUSED(x) UNUSED_ ## x __attribute__((__unused__))
#else
# define UNUSED(x) UNUSED_ ## x
#endif
void foo(int UNUSED(a)) {
// ...
}
参考：http://stackoverflow.com/a/12891181
===========================================================================================
字符串比较时，strncmp strcmp 需要注意的地方，要注意比较长度
if ((strlen(ts_keyword) != strlen(fw_ugd->ts_keyid)) ||
strcasecmp(ts_keyword, fw_ugd->ts_keyid)) {
printf("%s: check ts_keyword[%s],fw_ugd->ts_keyid[%s]\n",
__FUNCTION__, ts_keyword, fw_ugd->ts_keyid);
retval = TP_FW_ERR_TS_KEYID_COMPARE;
goto error;
}
中断 IRQF_ONESHOT 与 IRQF_SHARED 不能同时使用 当多个设备共享中断时，由于IRQF_ONESHOT会关闭中断线程的中断，而线程一般执行时间会比较长，所以是不允许的 当hardirq函数为NULL时，必须声明IRQF_ONESHOT, 表示threadirq线程中关闭该中断,在某些情况下，这个标志会非常有用 例如：设备是低电平产生中断，而硬中断函数为NULL，如果不使用IRQF_ONESHOT,就会一直产生中断执行NULL函数，中断线程 得不到执行，声明IRQF_ONESHOT后，会执行完线程才使能该中断
14.devm_request_irq---- 这种架构会自己释放资源，不需要自己释放，交由devr内核链表管理
http://lxr.free-electrons.com/ident?i=devm_request_irq
15.这个网址可以查询内核源码
16.rm命令
删除除了 tt.c的所有文件，只保留tt.c不被删除
rm -rf !(tt.c)
17.查看当前项目有哪些远程仓库
$ git remote
bixiaopeng@bixiaopengtekiMacBook-Pro wirelessqa$ git remote origin
查看远程仓库
$ git remote -v
bixiaopeng@bixiaopengtekiMacBook-Pro wirelessqa$ git remote -v origin git@gitlab.***.com:xiaopeng.bxp/wirelessqa.git (fetch) origin git@gitlab.***.com:xiaopeng.bxp/wirelessqa.git (push)
0x1000 16*16*16=4096bit = 4KB
18.堆栈的限制
堆栈空间的最大值是由setrlimit系统调用确定的，也可以通过bash内建的ulimit命令来设定和查看.
例如:
查看当前可使用的最大堆栈(以KB为单位)
ulimit -s
8192 //栈的大小默认是8M
设定为最大的使用堆栈为15KB
ulimit -s 15
此时执行ls将会得到一个段错误.
ls -l /etc/
total 1040
Segmentation fault
通过用strace跟踪ls命令,将发现有如下的系统调用
getrlimit(RLIMIT_STACK, {rlim_cur=15*1024, rlim_max=15*1024}) = 0
说明当前可用的堆栈空间,已经不足以运行strace命令了.
19.Linux驱动调试中的Debugfs的使用简介
http://blog.csdn.net/wealoong/article/details/7992071
Linux DebugFS 子目录也是用debugfs_create_dir来实现
http://blog.csdn.net/superkris/article/details/8626517
mount来调试文件节点， sysfs节点调试方法
make menuconfig ----
Global build settings ------
Compile the kernel with Debug FileSystem enabled
Make kernel_menuconfig --------------
Kernel hacking --------
Debug Filesystem
mount -t debugfs none /sys/kernel/debug
20.grep 命令
grep -run "\< abc \>"
21.检测内存泄露的方法
Make kernel_menuconfig
Kernel hacking =======>
[*] Kernel memory leak detector
(40000) Maximum kmemleak early log entries
[*] Compile the kernel with debug info
make menuconfig
[*] Compile the kernel with Debug FileSystem enabled
[*] Compile the kernel with debug information
开机后
mount -t debugfs none /sys/kernel/debug
cd /sys/kernel/debug
cat kmemleak
make kernel_menuconfig
这个选项是说明
General setup ================>
Choose SLAB allocator (SLUB (Unqueued Allocator))
(X) SLUB (Unqueued Allocator)
[*] Enable SLUB debugging support
22.这里使用slub分配内存比slab更高效
我们在调试内核时，如果出现系统响应非常慢的情况
先看有没有死锁，用lockdep来检测
检测出来后再用ftrace来跟踪函数
如果出现kernel内存泄露，可以 用kmemleak来查看，查看前要确认内核使用哪个分配器，一般是slab或者slub
cat /proc/meminfo 查看内存泄露
23.Linux设备驱动之semaphore机制
static noinline void __down(struct semaphore *sem);
static noinline int __down_interruptible(struct semaphore *sem);
static noinline int __down_killable(struct semaphore *sem);
static noinline int __down_timeout(struct semaphore *sem, long jiffies);
static noinline void __up(struct semaphore *sem);
#define DEFINE_SEMAPHORE(name) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
static inline void sema_init(struct semaphore *sem, int val)
{
static struct lock_class_key __key;
*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
}
一个核，执行了两个死循环进程，那么这两个进程是通过内核的调度算法去选择要执行哪个进程的，最终会执行arm的指令，这两个进程在单和上是永远不可能同时执行的，MMU里面会有进程id寄存器
24.获得内核函数地址的四种方法
本文以获取内核函数 sys_open()的地址为例。
1）从System.map文件中直接得到地址：
$ grep sys_open /usr/src/linux/System.map
2)使用 nm 命令：
$ nm vmlinuz | grep sys_open
3)从 /proc/kallsyms 文件获得地址：
$ cat /proc/kallsyms | grep sys_open
4)使用 kallsyms_lookup_name() 函数：
是在kernel/kallsyms.c文件中定义的，要使用它必须启用CONFIG_KALLSYMS编译内核。
kallsyms_lookup_name()接受一个字符串格式内核函数名，返回那个内核函数的地址。
kallsyms_lookup_name("sys_open");
方法一、
通过打印函数地址，可以查看函数在哪里调用
例如：
Core.c drivers\pwm
int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns)
{
if (!pwm || period_ns == 0 || duty_ns > period_ns)
return -EINVAL;
printk("%s drivers\pwm Core.c----(%d)\r\n", __func__, __LINE__);
printk("pwm->chip->ops->config=%p----(%d)\r\n", pwm->chip->ops->config, __LINE__);
return pwm->chip->ops->config(pwm->chip, pwm, duty_ns, period_ns);
}
终端显示如下：
[ 42.550000] pwm->chip->ops->config=c001b0c0----(378)
然后可以在
如下目录
Z:\linux-3.6.5
中的System.map中找到
c001b0c0 t asiu_pwmc_config
就调用的是这个函数asiu_pwmc_config
方法二、
dump_stack()函数
25.打印语句的使用，带颜色的打印
#define RESETCOLOR "\033[0m"
#define GREEN "\033[0;32m"
#define RED "\033[0;31m"
#define LIGHT_RED "\033[1;31m"
#define YELLOW "\033[1;33m"
#define BLUE "\033[0;34m"
#define LIGHT_BLUE "\033[1;34m"
#define CYAN "\033[0;36m"
#define PURPLE "\033[0;35m"
#define LIGHT_PURPLE "\033[1;35m"
#define BROWN "\033[0;33m"
#define WHITE "\033[1;37m"
#define LIGHT_GRAY "\033[0;37m"
#define DARY_GRAY "\033[1;30m"
printf(YELLOW"** 10. set asiu_pwm while **"RESETCOLOR"\r\n");
printf(YELLOW"**"LIGHT_RED" 4. onepluse pwm disable "YELLOW"**"RESETCOLOR"\r\n");
RC文件延时方法：
wait /dev/zhangb 随便一个不存在的节点都可以，固定为延时5s
如何增加打印信息---灵活使用宏定义：
#include <stdio.h>
#include <stdlib.h>
#define qWiFiDebug(format, ...) printf("[WiFi] "format" File:%s, Line:%d, Function:%s \r\n", ##__VA_ARGS__, __FILE__, __LINE__ , __FUNCTION__);
int main(void)
-{
| qWiFiDebug("aaaaaa -----");
|
| return 0;
|}
打印输出：
./a.out
[WiFi] aaaaaa ----- File:a.c, Line:9, Function:main
#define RESETCOLOR "\033[0m" #define GREEN "\033[0;32m" #define RED "\033[0;31m" #define LIGHT_RED "\033[1;31m" #define YELLOW "\033[1;33m" #define BLUE "\033[0;34m" #define LIGHT_BLUE "\033[1;34m" #define CYAN "\033[0;36m" #define PURPLE "\033[0;35m" #define LIGHT_PURPLE "\033[1;35m" #define BROWN "\033[0;33m" #define WHITE "\033[1;37m" #define LIGHT_GRAY "\033[0;37m" #define DARY_GRAY "\033[1;30m" #define ZBH_TRACE_DEBUG (1 << 0) #define ZBH_TRACE_INIT (1 << 1) #define ZBH_TRACE_INT (1 << 2) #define ZBH_TRACE_X_Y_COORDINATE (1 << 3) #define ZBH_TRACE_FINGER_UP (1 << 4) #ifdef __BASE_FILE_NAME__ #define printk_get_basename(x) __BASE_FILE_NAME__ #else static char *printk_get_basename(char *path) { char *p1 = path, *p2 = p1; while (*p1 != '\0') { if (*p1 == '/') p2 = p1 + 1; p1++; } return (p2); } #endif //printk(KERN_INFO "[%s]"format"File:%s, Line:%d, Function:%s \r\n", \ // ##__VA_ARGS__, printk_get_basename(__FILE__), __LINE__, __FUNCTION__); \ //printk(KERN_INFO "[%s%4d@%18s] "format, GT1X_PREFIX, __LINE__, printk_get_basename(__FILE__), ##arg); \ //printk(KERN_INFO "[%s]"format"[File:%s, Line:%d, Function:%s] \r\n", ZBH_PREFIX, ##arg, printk_get_basename(__FILE__), __LINE__, __FUNCTION__); \ #define ZBH_PREFIX "ZBH: " #define zbh_trace(flag, format, arg...) \ do { \ if (zbh_trace_param & flag) \ printk(KERN_INFO "[%s%4d@ %s] %s(): "format, ZBH_PREFIX, __LINE__, \ printk_get_basename(__FILE__), __FUNCTION__, ##arg); \ } while (0) #define zbh_printk(format, arg...) \ printk(KERN_INFO "%s"format, ZBH_PREFIX, ##arg)
26.linux用户栈和内核栈的设置
http://stackoverflow.com/questions/2562602/how-does-fork-return-for-child-process
http://blog.csdn.net/u011279649/article/details/18795547
copy_thread(unsigned long clone_flags, unsigned long sp, unsigned long unused, struct task_struct * p, struct pt_regs * regs)
How to set the new process entry
int
copy_thread(unsigned long clone_flags, unsigned long stack_start,
unsigned long stk_sz, struct task_struct *p, struct pt_regs *regs)
{
struct thread_info *thread = task_thread_info(p);
struct pt_regs *childregs = task_pt_regs(p);
*childregs = *regs;
childregs->ARM_r0 = 0;
childregs->ARM_sp = stack_start;
memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save));
thread->cpu_context.sp = (unsigned long)childregs;
thread->cpu_context.pc = (unsigned long)ret_from_fork;
27.makefile编写注意：
EXTRA_CFLAGS += -DDO_TEST_REPORTING
ifeq ($(CONFIG_ENABLE_PCI),y)
EXTRA_CPPFLAGS += -DCONFIG_ENABLE_PCI
endif
28.好的网址
http://web.mit.edu/gnu/www/index.html -------》麻省理工大学的校网，gnu ， automake , autoconf
www.yoctoproject.org --------》飞思卡尔搞的非常强大的linux开发环境
29.文件系统操作，查看内核一些信息
cat /proc/meminfo
/data/app # cat /proc/meminfo
MemTotal: 60488 kB
MemFree: 19200 kB
Buffers: 0 kB
Cached: 27028 kB
SwapCached: 0 kB
Active: 11276 kB
Inactive: 22708 kB
Active(anon): 11256 kB
Inactive(anon): 13432 kB
Active(file): 20 kB
Inactive(file): 9276 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 0 kB
Writeback: 0 kB
AnonPages: 6976 kB
Mapped: 2832 kB
Shmem: 17732 kB
Slab: 3448 kB
SReclaimable: 668 kB
SUnreclaim: 2780 kB
KernelStack: 496 kB
PageTables: 312 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 30244 kB
Committed_AS: 46220 kB
VmallocTotal: 319488 kB
VmallocUsed: 21720 kB
VmallocChunk: 294908 kB
/data/app # cat /proc/mtd
dev: size erasesize name
mtd0: 000c0000 00020000 "boot"
mtd1: 00080000 00020000 "nvram_fac"
mtd2: 000c0000 00020000 "boot_res"
mtd3: 00400000 00020000 "kernel"
mtd4: 00600000 00020000 "ramdisk"
mtd5: 00600000 00020000 "base"
mtd6: 06e00000 00020000 "data"
30.find 命令和grep命令
find . "*sdio*" -maxdepth 2
find . README -maxdepth 1 | xargs grep -nri "a"
find target/linux/brcm5830/files/arch/arm/mach-iproc/pm_iproc/ -name "*.c" -print | xargs grep "USB"
find ./package/kmod-prolin/bbl/ -maxdepth 1 -print | xargs grep -rni "PCI"
find ./ -name "synaptics_dsx_core.h" | xargs grep -rwi "reset_device"
find ./package/kmod-brcm5830x/input/keypad_matrix/src/keypad_matrix.c -print0 |xargs grep -run -B8 -A2 "buzzer_level"
find ./ -name "*.c" |xargs grep --colour -run printf
dev_dbg(rmi4_data->pdev,
"%s: rmi4_data->report_type = %d\n"
"rmi4_data->finger_limit = %d\n"
"fhandler->num_of_data_points = %d\n",
__func__, rmi4_data->report_type,
rmi4_data->finger_limit, fhandler->num_of_data_points);
这是个小技巧，grep的A(after，后)选项和B(before，前)选项可以同时输出其匹配行的前后几行。 比如包含有如下文本的message.txt： Aug 5 02:43:12 zion kernel: [ 0.000000] Zone PFN ranges: Aug 5 02:43:12 zion kernel: [ 0.000000] DMA 0 -> 4096 Aug 5 02:43:12 zion kernel: [ 0.000000] Normal 4096 -> 130730 Aug 5 02:43:12 zion kernel: [ 0.000000] HighMem 130730 -> 130730 Aug 5 02:43:12 zion kernel: [ 0.000000] early_node_map[1] active PFN ranges Aug 5 02:43:12 zion kernel: [ 0.000000] 0: 0 -> 130730 Aug 5 02:43:12 zion kernel: [ 0.000000] DMI 2.3 present. 用带-B1和-A2选项的grep匹配搜索"DMA"。 grep -B1 -A2 "DMA" message.txt 输出： Aug 5 02:43:12 zion kernel: [ 0.000000] Zone PFN ranges: Aug 5 02:43:12 zion kernel: [ 0.000000] DMA 0 -> 4096 Aug 5 02:43:12 zion kernel: [ 0.000000] Normal 4096 -> 130730 Aug 5 02:43:12 zion kernel: [ 0.000000] HighMem 130730 -> 130730 grep匹配一个结果，输出多行的功能，在搜索日志文件时很有用。
Linux下find一次查找多个指定文件或者排除某类文件，在 GREP 中匹配多个关键字的方法 （1）Linux下find一次查找多个指定文件: 查找a.html和b.html find . -name "a.html" -name "b.html" find . -regex '.*\.txt\|.*\.doc\|.*\.mp3' find . -regex '.*\.txt\|.*\.doc\|.*\.mp3' ./a.txt ./a.doc ./a.mp3 (2)排除某些文件类型： 排除目录下所有以html结尾的文件： find . -type f ! -name "*.html" find . -type f ! -name "*.html" ./ge.bak.02.09 ./ge.html.changed.by.jack ./a.txt ./a.doc ./a.mp3 （3）排除多种文件类型的示例： find . -type f ! -name "*.html" -type f ! -name "*.php" -type f ! -name "*.svn-base" -type f ! -name "*.js" -type f ! -name "*.gif" -type f ! -name "*.png" -type f ! -name "*.cpp" -type f ! -name "*.h" -type f ! -name "*.o" -type f ! -name "*.jpg" -type f ! -name "*.so" -type f ! -name "*.bak" -type f ! -name "*.log" （3）在 GREP 中匹配多个关键字的方法： grep查找多个数字的文件： -r 递归，-E：正则 -l：只显示文件名 root@116.255.139.240:~/a# grep -r -E '0341028|100081|10086|10001' * a.txt:100081 b.txt:10086 c/cc.txt:0341028 c/cc.txt:100081 c/cc.txt:10086 c/cc.txt:10001 c.txt:10001 d.txt:0341028 grep -r -E -l '0341028|100081|10086|10001' * a.txt b.txt c/cc.txt c.txt d.txt 多种类型文件示例： view plainprint? find . -name "*.html" -o -name "*.js"|xargs grep -r "BusiTree"
31.printk 调试方法
内核中打印回调函数的名称
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/current.h>
#include <linux/utsname.h>
#include <asm/cacheflush.h>
#include <asm/processor.h>
#include <asm/thread_notify.h>
#include <asm/stacktrace.h>
#include <asm/mach/time.h>
// add by zbh
int get_func_name(void *ip)
{
printk("[<%p>] %pS\n", (void *) ip, (void *) ip);
printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n",
KERN_DEFAULT, raw_smp_processor_id(),
current->pid, current->comm,
print_tainted(), init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
return 0;
}
void *ip = NULL;
ip = keydata->buzzer->enable; printk("[<%p>] %pS\n", (void *) ip, (void *) ip); printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", KERN_DEFAULT, raw_smp_processor_id(), current->pid, current->comm, print_tainted(), init_utsname()->release, (int)strcspn(init_utsname()->version, " "), init_utsname()->version); keydata->buzzer->enable(keydata,freq,duty);
再在panic.c中 找到print_tainted
EXPORT_SYMBOL(print_tainted);
这样可以给其他驱动调用此函数
print_hex_dump ===>内核一个不错的打印方式
此网址是我记录的一个printk 打印函数地址的方法
http://www.cnblogs.com/sky-heaven/p/7161373.html
unsigned char input[0x28];
unsigned char output[0x28];
print_hex_dump(KERN_CRIT, "bbl_ram@ ", DUMP_PREFIX_OFFSET,
16, 1, output, sizeof(output), true);
printk("\n");
__builtin_return_address
http://www.cnblogs.com/sky-heaven/p/7161404.html
printk("\033[1;31m %p---%pS \033[0m\r\n", __builtin_return_address(0), __builtin_return_address(0));
sprint_symbol也可以通过函数地址打印函数名字
https://www.cnblogs.com/sky-heaven/p/14977059.html
printk("\033[1;33m of_reserved_mem.c zbh %s(%d):\033[0m\r\n", __func__, __LINE__); void *ip = NULL; ip = (unsigned long)rmem->ops->device_init; printk("\033[1;33m of_reserved_mem.c zbh rmem->ops->device_init: [<%p>] %pS \033[0m\r\n", (void *) ip, (void *) ip); printk("\033[1;33m of_reserved_mem.c zbh %s(%d):sprint_symbol start \033[0m\r\n", __func__, __LINE__); char my_buf[KSYM_SYMBOL_LEN]; unsigned long my_address; my_address = (unsigned long)rmem->ops->device_init; sprint_symbol(my_buf, my_address); printk("\033[1;33m of_reserved_mem.c zbh %s(%d):sprint_symbol my_buf=%s \033[0m\r\n", __func__, __LINE__, my_buf); printk("\033[1;33m of_reserved_mem.c zbh %s(%d):sprint_symbol my_address=0x%08x \033[0m\r\n", __func__, __LINE__, my_address); ret = rmem->ops->device_init(rmem, dev);
CONFIG_KALLSYMS 这个要定义
int my_get_function_name(unsigned long *addr) { void *ip = NULL; char my_buf[KSYM_SYMBOL_LEN]; unsigned long my_address; ip = addr; printk("\033[1;33m zbh %s(%d) [<%p>] %pS \033[0m\r\n", __func__, __LINE__, (void *) ip, (void *) ip); my_address = addr; sprint_symbol(my_buf, my_address); printk("\033[1;33m zbh %s(%d):sprint_symbol my_buf=%s my_address=0x%08x\033[0m\r\n", __func__, __LINE__, my_buf, my_address); return 0; } my_get_function_name((unsigned long)rmem->ops->device_init); ret = rmem->ops->device_init(rmem, dev);
#define BF3005_PREFIX "bf3005: " #define bf3005_trace(flag, format, arg...) \ do { \ if (bf3005_trace_param & flag) \ printk(KERN_ERR "[%s%4d@%18s] "format, BF3005_PREFIX, __LINE__, printk_get_basename(__FILE__), ##arg); \ } while (0) #define bf3005_printk(format, arg...) \ printk(KERN_ERR "%s"format, BF3005_PREFIX, ##arg) bf3005_trace(BF3005_TRACE_DESCR, "enter %s(initialized = %d)\n", __func__, bf3005->initialized);
方法1：
//#define MY_DEBUG
#ifdef MY_DEBUG
#define MY_DBG(x...) do{printk(x);}while(0)
#else
#define MY_DBG(x...)
#endif
方法2：
驱动可以如下写：
#define MY_LEVEL1 (1 << 0)
#define MY_LEVEL2 (1 << 1)
unsigned int my_trace_param=0;
module_param_named(trace, my_trace_param, uint, S_IRUGO|S_IWUSR);
#define MY_DBG(flag, msg...) \
do { \
if (my_trace_param & flag) \
printk(KERN_ERR "zbh-debug: " msg); \
} while (0)
MY_DBG(MY_LEVEL1, "Goodbye module exit1.\r\n");
MY_DBG(MY_LEVEL2, "Goodbye module exit2.\r\n");
MY_DBG(MY_LEVEL2, "Goodbye module exit3.\r\n");
测试：
insmod my_printk_driver.ko
echo 2 > /sys/module/my_printk_driver/parameters/trace
这样就可以选择到底打印哪一条语句，用来动态调试开关，默认关打印
code:
#include <linux/init.h> #include <linux/module.h> #include <linux/fs.h> #include <linux/kernel.h> #include<linux/slab.h> //kmalloc #include<asm/io.h> //ioremap #include<linux/device.h> //class_create/device_create #include <asm/uaccess.h> #include <linux/pwm.h> #include <linux/cdev.h> #include <pax/gpio_cfg.h> #include <pax/bcm5830x_gpio_def.h> #include <mach/iproc_regs.h> #include <mach/memory.h> #include <mach/iomux.h> #include <linux/delay.h> #include <linux/gpio.h> #include <linux/timer.h> #include <linux/hrtimer.h> #include <linux/ktime.h> #define PWM_IOC_MAGIC 'n' #define PWM_CONFIG _IOW(PWM_IOC_MAGIC, 1, int) #define PWM_DISABLE _IOW(PWM_IOC_MAGIC, 2, int) #define ONE_PWM_CONFIG _IOW(PWM_IOC_MAGIC, 3, int) #define ONE_PWM_DISABLE _IOW(PWM_IOC_MAGIC, 4, int) #define ONE_PWM_WHILE_10000 _IOW(PWM_IOC_MAGIC, 5, int) #define SET_PWM_GPIO _IOW(PWM_IOC_MAGIC, 6, int) #define SET_PWM_POLATIRY _IOW(PWM_IOC_MAGIC, 7, int) #define READ_ONEPLUSE_COUNTER _IOW(PWM_IOC_MAGIC, 8, int) #define SET_PWM_FUNC _IOW(PWM_IOC_MAGIC, 9, int) #define SET_PWM_WHILE _IOW(PWM_IOC_MAGIC, 10, int) #define ONE_PWM_DOORBELL _IOW(PWM_IOC_MAGIC, 11, int) #define MY_LEVEL1 (1 << 0) #define MY_LEVEL2 (1 << 1) unsigned int my_trace_param = 0; module_param_named(trace, my_trace_param, uint, S_IRUGO|S_IWUSR); #define MY_DBG(flag, msg...) \ do { \ if (my_trace_param & flag) \ printk(KERN_ERR "zbh-bbl: " msg); \ } while (0) static int ttime = 0; static int pmode = 0; // pmode=0 ----> asiu_pwmc , pmode=1 ----> onepluse module_param(ttime, int, 0); module_param(pmode, int, 0); //module_param(period, int, 0); #define HELLO_MAJOR 230 int hello_major = HELLO_MAJOR; module_param(hello_major, int, 0); static struct cdev *hello_cdev = NULL; static struct class *dev_class = NULL; static struct device *dev_device = NULL; static int hello_open(struct inode *inode, struct file *filp); static int hello_release(struct inode *inode, struct file *filp); static int hello_open(struct inode *inode, struct file *filp) { printk("hello_open is OK\r\n"); return 0; } static int hello_release(struct inode *inode, struct file *filp) { printk("hello_release is OK\r\n"); printk("pwm disable and free\r\n"); return 0; } struct file_operations hello_ops = { .owner = THIS_MODULE, .open = hello_open, .release = hello_release, //.unlocked_ioctl = hello_ioctl, }; static int __init hello_init(void) { dev_t devno; int ret; devno = MKDEV(hello_major, 0); ret = register_chrdev_region(devno, 1, "zbh_hello"); if (!ret) { printk("register dev OK.\r\n"); } else { printk("register dev failed.\r\n"); } hello_cdev = cdev_alloc(); cdev_init(hello_cdev, &hello_ops); cdev_add(hello_cdev, devno, 1); hello_cdev->owner = THIS_MODULE; hello_cdev->ops = &hello_ops; dev_class = class_create(THIS_MODULE, "dev_class"); if (IS_ERR(dev_class)) { printk(KERN_ERR "class_create() failed for dev_class\n"); ret = -EINVAL; goto out_err_1; } dev_device = device_create(dev_class, NULL, devno, NULL, "zbh_hello"); if (IS_ERR(dev_device)) { printk(KERN_ERR "device_create failed.\r\n"); ret = -ENODEV; goto out_err_2; } printk("Hello module init OK.\r\n"); return 0; out_err_2: class_destroy(dev_class); out_err_1: unregister_chrdev_region(MKDEV(hello_major, 0), 1); cdev_del(hello_cdev); return ret; } static void __exit hello_exit(void) { cdev_del(hello_cdev); device_destroy(dev_class, MKDEV(hello_major, 0)); class_destroy(dev_class); unregister_chrdev_region(MKDEV(hello_major, 0), 1); MY_DBG(MY_LEVEL1, "Goodbye module exit1.\r\n"); MY_DBG(MY_LEVEL2, "Goodbye module exit2.\r\n"); MY_DBG(MY_LEVEL2, "Goodbye module exit3.\r\n"); } module_init(hello_init); module_exit(hello_exit); MODULE_LICENSE("Dual BSD/GPL"); MODULE_AUTHOR("zhangbinghua"); MODULE_DESCRIPTION("zhangbh debug driver");