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#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/spinlock.h>
#include <linux/smp.h>
#include <linux/poll.h>
#include <linux/uaccess.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/ktime.h>
#include <mach/mt_ccci_common.h>
#include "ccci_util_log.h"
#define CCCI_LOG_BUF_SIZE 4096 // must be power of 2
#define CCCI_LOG_MAX_WRITE 512
//extern u64 local_clock(void);
struct ccci_ring_buffer {
void *buffer;
unsigned int size;
unsigned int read_pos;
unsigned int write_pos;
atomic_t last_ops; // 0 for write; 1 for read
atomic_t reader_cnt;
wait_queue_head_t log_wq;
spinlock_t write_lock;
};
struct ccci_ring_buffer ccci_log_buf;
int ccci_log_write(const char *fmt, ...)
{
va_list args;
int write_len,first_half;
unsigned long flags;
char temp_log[CCCI_LOG_MAX_WRITE];
int this_cpu;
char state = irqs_disabled()?'-':' ';
u64 ts_nsec = local_clock();
unsigned long rem_nsec = do_div(ts_nsec, 1000000000);
if(unlikely(ccci_log_buf.buffer == NULL))
return -ENODEV;
preempt_disable();
this_cpu = smp_processor_id();
preempt_enable();
write_len = snprintf(temp_log, sizeof(temp_log), "[%5lu.%06lu]%c(%x)[%d:%s]",
(unsigned long)ts_nsec, rem_nsec/1000, state, this_cpu,
current->pid, current->comm);
va_start(args, fmt);
write_len += vsnprintf(temp_log+write_len, sizeof(temp_log)-write_len, fmt, args);
va_end(args);
//printk("[cclog]write %d\n", write_len);
spin_lock_irqsave(&ccci_log_buf.write_lock, flags);
if(ccci_log_buf.write_pos+write_len > CCCI_LOG_BUF_SIZE) {
first_half = CCCI_LOG_BUF_SIZE-ccci_log_buf.write_pos;
memcpy(ccci_log_buf.buffer+ccci_log_buf.write_pos, temp_log, first_half);
memcpy(ccci_log_buf.buffer, temp_log+first_half, write_len-first_half);
} else {
memcpy(ccci_log_buf.buffer+ccci_log_buf.write_pos, temp_log, write_len);
}
ccci_log_buf.write_pos = (ccci_log_buf.write_pos+write_len) & (CCCI_LOG_BUF_SIZE-1);
atomic_set(&ccci_log_buf.last_ops, 0);
spin_unlock_irqrestore(&ccci_log_buf.write_lock, flags);
wake_up_all(&ccci_log_buf.log_wq);
return write_len;
}
EXPORT_SYMBOL(ccci_log_write);
static ssize_t ccci_log_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
unsigned int available,read_len,first_half;
unsigned long flags;
int ret;
retry:
spin_lock_irqsave(&ccci_log_buf.write_lock, flags);
available = (ccci_log_buf.write_pos-ccci_log_buf.read_pos) & (CCCI_LOG_BUF_SIZE-1);
if(available==0 && !atomic_read(&ccci_log_buf.last_ops))
available = CCCI_LOG_BUF_SIZE;
if(!available) {
spin_unlock_irqrestore(&ccci_log_buf.write_lock, flags);
if(!(file->f_flags & O_NONBLOCK)) {
ret = wait_event_interruptible(ccci_log_buf.log_wq, !atomic_read(&ccci_log_buf.last_ops));
if(ret == -ERESTARTSYS)
return -EINTR;
else
goto retry;
} else {
return -EAGAIN;
}
}
read_len = size<available?size:available;
//printk("[cclog]read %d\n", read_len);
if(ccci_log_buf.read_pos+read_len > CCCI_LOG_BUF_SIZE) {
first_half = CCCI_LOG_BUF_SIZE-ccci_log_buf.read_pos;
ret = copy_to_user(buf, ccci_log_buf.buffer+ccci_log_buf.read_pos, first_half);
ret = copy_to_user(buf+first_half, ccci_log_buf.buffer, read_len-first_half);
} else {
ret = copy_to_user(buf, ccci_log_buf.buffer+ccci_log_buf.read_pos, read_len);
}
ccci_log_buf.read_pos = (ccci_log_buf.read_pos+read_len) & (CCCI_LOG_BUF_SIZE-1);
atomic_set(&ccci_log_buf.last_ops, 1);
spin_unlock_irqrestore(&ccci_log_buf.write_lock, flags);
return read_len;
}
unsigned int ccci_log_poll(struct file *fp, struct poll_table_struct *poll)
{
unsigned int mask = 0;
poll_wait(fp, &ccci_log_buf.log_wq, poll);
if(!atomic_read(&ccci_log_buf.last_ops))
mask |= POLLIN|POLLRDNORM;
return mask;
}
static int ccci_log_open(struct inode *inode, struct file *file)
{
if(atomic_read(&ccci_log_buf.reader_cnt))
return -EBUSY;
atomic_inc(&ccci_log_buf.reader_cnt);
return 0;
}
static int ccci_log_close(struct inode *inode, struct file *file)
{
atomic_dec(&ccci_log_buf.reader_cnt);
return 0;
}
static const struct file_operations ccci_log_fops = {
.read = ccci_log_read,
.open = ccci_log_open,
.release = ccci_log_close,
.poll = ccci_log_poll,
};
void ccci_log_init(void)
{
struct proc_dir_entry *ccci_log_proc;
ccci_log_proc = proc_create("ccci_log", 0664, NULL, &ccci_log_fops);
if(ccci_log_proc == NULL) {
CCCI_UTIL_INF_MSG("fail to create proc entry for log\n");
return;
}
ccci_log_buf.buffer = kmalloc(CCCI_LOG_BUF_SIZE, GFP_KERNEL);
spin_lock_init(&ccci_log_buf.write_lock);
init_waitqueue_head(&ccci_log_buf.log_wq);
atomic_set(&ccci_log_buf.last_ops, 1);
atomic_set(&ccci_log_buf.reader_cnt, 0);
}
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