摘要：

相对于上一篇測试程序CMA连续物理内存用户空间映射---(一)

添加功能：

1、分配和映射统一放在IOCTL，一次完毕，能够连续多次分配并映射到用户空间，提高操作性；

2、驱动添加链表，使分配的多块内存在链表中管理，方便加入删除；

3、添加内存释放和解除映射；

4、使用rmmod删除驱动模块时。将释放全部内存。

映射流程：

1、用户通过IOCTL分配大小传给驱动ioctl------------------------------------->

2、驱动依据用户是否使用 writebuffer。来使用dma_alloc_writecombine或者dma_alloc_coherent。物理内存---------------------------->

3、通过vm_mmap，在用户空间找一块空暇空间来供映射使用-------------------------------->

vm_mmap在大于linux3.7内核版本号中才干使用。在老内核中能够使用sys_mmap

參考mmap的call stack

[  409.762850] [<c00184c4>] (unwind_backtrace+0x0/0xf8) from [<bf000020>] (cmamem_mmap+0x20/0xd0 [cma_mem])

[  409.774141] [<bf000020>] (cmamem_mmap+0x20/0xd0 [cma_mem]) from [<c0095ab8>] (mmap_region+0x310/0x540)

[  409.774771] [<c0095ab8>] (mmap_region+0x310/0x540) from [<c0095f80>] (do_mmap_pgoff+0x298/0x330)

[  409.784230] [<c0095f80>] (do_mmap_pgoff+0x298/0x330) from [<c00886d0>] (vm_mmap_pgoff+0x64/0x94)

[  409.792291] [<c00886d0>] (vm_mmap_pgoff+0x64/0x94) from [<c00947a8>] (sys_mmap_pgoff+0x54/0xa8)

[  409.800962] [<c00947a8>] (sys_mmap_pgoff+0x54/0xa8) from [<c0013940>] (ret_fast_syscall+0x0/0x30)

4、vm_mmap将会调用驱动中的mmap接口函数

在mmap中通过remap_pfn_range实现物理内存到用户空间的映射.；

5、讲映射好的用户空间及内核空间虚拟内核和物理内存保存到链表中；

6、删除操作时，查询链表，解除映射，释放内存。从链表移除；

7、驱动模块释放时，释放全部内存；

源代码：

驱动：

cma_mem.c

#include <linux/miscdevice.h>

#include <linux/platform_device.h>

#include <linux/fs.h>

#include <linux/file.h>

#include <linux/mm.h>

#include <linux/list.h>

#include <linux/mutex.h>

#include <linux/debugfs.h>

#include <linux/mempolicy.h>

#include <linux/sched.h>

#include <linux/module.h>

#include <asm/io.h>

#include <asm/uaccess.h>

#include <asm/cacheflush.h>

#include <linux/dma-mapping.h>

#include <linux/export.h>

#include <linux/syscalls.h>

#include <linux/mman.h>

#include "cma_mem.h"

#define DEVICE_NAME "cma_mem" 

#define MEM_DEBUG 1

enum cma_status{

	UNKNOW_STATUS = 0,

	HAVE_ALLOCED = 1,

	HAVE_MMAPED =2,

};

struct cmamem_dev {

	unsigned int count;

	struct miscdevice dev;

	struct mutex cmamem_lock;

};

struct cmamem_block {

	char name[10];

	char is_use_buffer;

	char is_free;

	int id;

	unsigned long offset;

	unsigned long len;

	unsigned long phy_base;

	unsigned long mem_base;

	void *kernel_base;

	struct list_head memqueue_list;

};

struct current_status{

		int status;

		int id_count;

		dma_addr_t phy_base;

};

static struct current_status cmamem_status;

static struct cmamem_dev cmamem_dev;

static struct cmamem_block *cmamem_block_head;

static int mem_block_count = 0;

static void dump_mem(struct cmamem_block *memory_block)

{

	printk("%s:CMA name:%s\n",__func__,  memory_block->name);

	printk("%s:CMA id:%d\n",__func__,  memory_block->id);

	printk("%s:Is usebuf:%d\n",__func__,  memory_block->is_use_buffer);

	printk("%s:PHY Base:0x%08lx\n",__func__,  memory_block->phy_base);

	printk("%s:KER Base:0x%08x\n",__func__,  (unsigned int)(memory_block->kernel_base));

	printk("%s:USR Base:0x%08lx\n",__func__,  memory_block->mem_base);

}

static long cmamem_alloc(struct file *file, unsigned long arg)

{

	struct cmamem_block *memory_block;

	struct mem_block cma_info_temp;

	int size;

	int ret;

	if ((ret = copy_from_user(&cma_info_temp, (void __user *)arg,

	sizeof(struct mem_block))))

	{

		printk(KERN_ERR"cmamem_alloc:copy_from_user error:%d\n", ret);

		return -1;

	}

	if(cma_info_temp.name[0] == '\0')

	{

		printk(KERN_ERR "%s, no set mem name, please set\n", __func__);

		return -1;

	}

	if(cma_info_temp.len){

		size = PAGE_ALIGN(cma_info_temp.len);

		cma_info_temp.len = size;

#ifdef	MEM_DEBUG

	//	printk(KERN_INFO "%s len:%ld, is_use_buffer:%d\n", __func__, cma_info_temp.len, cma_info_temp.is_use_buffer);

#endif

		if(cma_info_temp.is_use_buffer)

			cma_info_temp.kernel_base = dma_alloc_writecombine(NULL, size, (dma_addr_t *)(&(cma_info_temp.phy_base)), GFP_KERNEL);

		else

			cma_info_temp.kernel_base = dma_alloc_coherent(NULL, size, (dma_addr_t *)(&(cma_info_temp.phy_base)), GFP_KERNEL);

		if (!cma_info_temp.phy_base){

				printk(KERN_ERR "dma alloc fail:%d!\n", __LINE__);

				return -ENOMEM;

			}

		cma_info_temp.id = ++mem_block_count;

		cmamem_status.phy_base = 	cma_info_temp.phy_base;

		cmamem_status.id_count =  	cma_info_temp.id;

		cmamem_status.status = HAVE_ALLOCED;

		cma_info_temp.mem_base = vm_mmap(file, 0, size, PROT_READ | PROT_WRITE, MAP_SHARED, 0);

		if(cma_info_temp.mem_base < 0)

		{

				printk(KERN_ERR "do_mmap fail:%d!\n", __LINE__);

				cma_info_temp.id = --mem_block_count;

				return -ENOMEM;

		}

		printk(KERN_INFO "cma_info_temp.mem_base:0x%lx\n", cma_info_temp.mem_base);

		//mem_block_count ++;

	}

	else{

		printk(KERN_ERR"cmamem_alloc: the len is NULL\n");

		return -1;

	}	

	if(copy_to_user((void __user *)arg, (void *)(&cma_info_temp), sizeof(struct mem_block)))

		return -EFAULT;

	/* setup the memory block */

	memory_block = (struct cmamem_block *)kmalloc(sizeof(struct cmamem_block), GFP_KERNEL);

	if(memory_block == NULL)

	{

		printk(KERN_ERR "%s error line:%d\n", __func__, __LINE__);

		mem_block_count --;

		return -1;

	}

	if(cma_info_temp.name[0] != '\0')

		memcpy(memory_block->name, cma_info_temp.name, 10);

	memory_block->id		=	cma_info_temp.id;

	memory_block->is_free	=	0;

	memory_block->is_use_buffer	=	cma_info_temp.is_use_buffer;

	memory_block->mem_base 	=	cma_info_temp.mem_base;

	memory_block->kernel_base 	=	cma_info_temp.kernel_base;

	memory_block->phy_base 	=	cma_info_temp.phy_base;

	memory_block->len		=	cma_info_temp.len;

#ifdef	MEM_DEBUG

	dump_mem(memory_block);

#endif

#ifdef CMA_TEST

	int i;

	for(i = 0; i < 10; i++)

		((char *)(cma_info_temp.kernel_base))[i] = (cma_info_temp.id * i);

#endif

	/* add to memory block queue */

	list_add_tail(&memory_block->memqueue_list, &cmamem_block_head->memqueue_list);

	return 0;

}

static int cmamem_free(struct file *file, unsigned long arg)

{

	struct cmamem_block *memory_block;

	struct mem_block cma_info_temp;

	int ret;

	if ((ret = copy_from_user(&cma_info_temp, (void __user *)arg,

	sizeof(struct mem_block))))

	{

		printk(KERN_ERR"cmamem_alloc:copy_from_user error:%d\n", ret);

		return -1;

	}

	printk(KERN_INFO "will delete the mem name:%s\n", cma_info_temp.name);

	list_for_each_entry(memory_block, &cmamem_block_head->memqueue_list, memqueue_list)

	{

		if(memory_block){

			//if(memory_block->id == cma_info_temp.id || !strcmp(cma_info_temp.name, memory_block->name)){

			if(!strcmp(cma_info_temp.name, memory_block->name)){

				if(memory_block->is_free == 0){

					printk(KERN_INFO "delete the mem id:%d, name:%s\n", cma_info_temp.id, cma_info_temp.name);

					vm_munmap(memory_block->mem_base, memory_block->len);

					if(memory_block->is_use_buffer)

						dma_free_coherent(NULL,	memory_block->len, memory_block->kernel_base, memory_block->phy_base);

					else

						dma_free_writecombine(NULL, memory_block->len, memory_block->kernel_base, memory_block->phy_base);

					memory_block->is_free = 1;

					list_del(&memory_block->memqueue_list);

					break;

				}

			}

		}

	}  

	return 0;

}

static int cmamem_freeall(void)

{

	struct cmamem_block *memory_block;

	printk(KERN_INFO "will delete all cma mem\n");

	list_for_each_entry(memory_block, &cmamem_block_head->memqueue_list, memqueue_list)

	{

		if(memory_block && memory_block->id > 0){

				if(memory_block->is_free == 0){

					printk(KERN_INFO "delete the mem id:%d, name:%s\n", memory_block->id, memory_block->name);

					if(memory_block->is_use_buffer)

						dma_free_coherent(NULL, memory_block->len, memory_block->kernel_base, memory_block->phy_base);

					else

						dma_free_writecombine(NULL, memory_block->len, memory_block->kernel_base, memory_block->phy_base);

					memory_block->is_free = 1;

				}

		}

	}  

	return 0;

}

static long cmamem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	int ret = 0;

	switch(cmd){

		case CMEM_ALLOCATE:

		{

			printk(KERN_ERR"cmamem_ioctl:CMEM_ALLOCATE\n");

			mutex_lock(&cmamem_dev.cmamem_lock);

			cmamem_alloc(file, arg);

			if(ret < 0)

				goto alloc_err;

			mutex_unlock(&cmamem_dev.cmamem_lock);

			break;

		}

		case CMEM_UNMAP:

		{

			printk(KERN_ERR"cmamem_ioctl:CMEM_UNMAP\n");

			mutex_lock(&cmamem_dev.cmamem_lock);

			ret = cmamem_free(file, arg);

			if(ret < 0)

				goto free_err;

			mutex_unlock(&cmamem_dev.cmamem_lock);

			break;

		}

		default:

		{

			printk(KERN_INFO "cma mem not support command\n");

			break;

		}

	}

	return 0;

	alloc_err:

		mutex_unlock(&cmamem_dev.cmamem_lock);

		printk(KERN_ERR "%s alloc error\n", __func__);

		return ret;

	free_err:

		mutex_unlock(&cmamem_dev.cmamem_lock);

		printk(KERN_ERR "%s free error\n", __func__);

	return ret;

}

static int cmamem_mmap(struct file *filp, struct vm_area_struct *vma)

{

	unsigned long start = vma->vm_start;

	unsigned long size = vma->vm_end - vma->vm_start;

	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;

	unsigned long page, pos;

	//if(size > MMAP_MEM_SIZE)

	//	return -EINVAL;

	if(cmamem_status.status != HAVE_ALLOCED)

	{

		printk(KERN_ERR"%s, you should allocted memory firstly\n", __func__);

		return -EINVAL;

	}

//	printk( "cmamem_mmap:vma:start=0x%08x offset=0x%08x\n", (unsigned int)start, (unsigned int)offset );

	pos = (unsigned long)cmamem_status.phy_base + offset;

	page = pos >> PAGE_SHIFT ;

//	printk( "cmamem_status.phy_base:0x%08x\n", (unsigned int)cmamem_status.phy_base);

	if( remap_pfn_range( vma, start, page, size, PAGE_SHARED )) {

		return -EAGAIN;

	}

	else{

	//	printk( "remap_pfn_range %u\n success\n", (unsigned int)page );

	}

	vma->vm_flags &= ~VM_IO;

	vma->vm_flags |=  (VM_DONTEXPAND | VM_DONTDUMP);

	cmamem_status.status = HAVE_MMAPED;

	return 0;

}

static struct file_operations dev_fops = {

    .owner          = THIS_MODULE,

    .unlocked_ioctl = cmamem_ioctl,

	.mmap = cmamem_mmap,

};

static int __init cmamem_init(void)

{

	printk(KERN_INFO "%s\n", __func__);

	mutex_init(&cmamem_dev.cmamem_lock);

//NIT_LIST_HEAD(&cmamem_dev.info_list);

	cmamem_dev.count = 0;

	cmamem_dev.dev.name = DEVICE_NAME;

	cmamem_dev.dev.minor = MISC_DYNAMIC_MINOR;

	cmamem_dev.dev.fops = &dev_fops;

	cmamem_block_head = (struct cmamem_block *)kmalloc(sizeof(struct cmamem_block), GFP_KERNEL);

	cmamem_block_head->id = -1;

	mem_block_count = 0;

	INIT_LIST_HEAD(&cmamem_block_head->memqueue_list);

/*

	cmamem_status.status = UNKNOW_STATUS;

	cmamem_status.id_count = -1;

	cmamem_status.phy_base = 0;

*/

	return misc_register(&cmamem_dev.dev);

}

static void __exit cmamem_exit(void)

{

    printk(KERN_ERR"%s\n", __func__);

	cmamem_freeall();

	misc_deregister(&cmamem_dev.dev);

} 

module_init(cmamem_init);

module_exit(cmamem_exit);

MODULE_LICENSE("GPL");

cma_mem.h

#ifndef _CMA_MEM_H_

#define _CMA_MEM_H_

#define CMEM_IOCTL_MAGIC 'm'

#define CMEM_GET_PHYS		_IOW(CMEM_IOCTL_MAGIC, 1, unsigned int)

#define CMEM_MAP		_IOW(CMEM_IOCTL_MAGIC, 2, unsigned int)

#define CMEM_GET_SIZE		_IOW(CMEM_IOCTL_MAGIC, 3, unsigned int)

#define CMEM_UNMAP		_IOW(CMEM_IOCTL_MAGIC, 4, unsigned int)

#define CMEM_ALLOCATE		_IOW(CMEM_IOCTL_MAGIC, 5, unsigned int)

#define CMEM_CONNECT		_IOW(CMEM_IOCTL_MAGIC, 6, unsigned int)

#define CMEM_GET_TOTAL_SIZE	_IOW(CMEM_IOCTL_MAGIC, 7, unsigned int)

#define CMEM_CACHE_FLUSH	_IOW(CMEM_IOCTL_MAGIC, 8, unsigned int)

struct mem_block {

	char name[10];

	char is_use_buffer;

	int id;

	unsigned long offset;

	unsigned long len;

	unsigned long phy_base;

	unsigned long mem_base;

	void *kernel_base;

};

#endif

用户測试程序：

#include <stdio.h>

#include <stdarg.h>

#include <string.h>

#include <errno.h>

#include <stdlib.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <time.h>

#include <sys/mman.h>

#include <assert.h>

#include <linux/videodev2.h>

#include <linux/fb.h>

#include <pthread.h>

#include <poll.h>

#include <semaphore.h>

#define CMEM_IOCTL_MAGIC 'm'

#define CMEM_GET_PHYS		_IOW(CMEM_IOCTL_MAGIC, 1, unsigned int)

#define CMEM_MAP		_IOW(CMEM_IOCTL_MAGIC, 2, unsigned int)

#define CMEM_GET_SIZE		_IOW(CMEM_IOCTL_MAGIC, 3, unsigned int)

#define CMEM_UNMAP		_IOW(CMEM_IOCTL_MAGIC, 4, unsigned int)

#define CMEM_ALLOCATE		_IOW(CMEM_IOCTL_MAGIC, 5, unsigned int)

#define CMEM_CONNECT		_IOW(CMEM_IOCTL_MAGIC, 6, unsigned int)

#define CMEM_GET_TOTAL_SIZE	_IOW(CMEM_IOCTL_MAGIC, 7, unsigned int)

#define CMEM_CACHE_FLUSH	_IOW(CMEM_IOCTL_MAGIC, 8, unsigned int)

struct cmamem_info {

	char name[10];

	char is_use_buffer;

	int id;

	unsigned long offset;

	unsigned long len;

	unsigned long phy_base;

	unsigned long mem_base;

	void *kernel_base;

};

struct mem_block {

	char name[10];

	char is_use_buffer;

	int id;

	unsigned long offset;

	unsigned long len;

	unsigned long phy_base;

	unsigned long mem_base;

	void *kernel_base;

};

int main()

{

	int cmem_fd;

	void *cmem_base;

	unsigned int size;

	struct mem_block region;

	int i,j;

	char str[10];

	memset(&region, 0x00, sizeof(struct mem_block));

	cmem_fd = open("/dev/cma_mem", O_RDWR, 0);//打开设备，为了操作硬件引擎。要noncache的

	printf("cmem_fd:%d\n", cmem_fd);

	j = 0;

	if (cmem_fd >= 0)

	while(j <= 2)

	{

		j++;

		sprintf(str, "mem%d", j);

		memset(&region, 0x00, sizeof(struct mem_block));

		region.len = 800 * 480 * 4;

		region.is_use_buffer = 1;

		memcpy(region.name, str, strlen(str));

		printf("sizeof(struct mem_block):%d\n", sizeof(struct mem_block));

		printf("region.mem_base:0x%08x\n", region.mem_base);

		if (ioctl(cmem_fd, CMEM_ALLOCATE, &region) < 0) //获取所有空间

		{

			perror("PMEM_GET_TOTAL_SIZE failed\n");

			return -1;

		}

		//size = region.len;

		printf("region.len:0x%08x offset:0x%08x\n",region.len, region.offset);

		printf("region.mem_base:0x%08x\n", region.mem_base);

		for(i = 0; i < 10; i++)

		printf("%d\n", ((char *)(region.mem_base))[i]);

	/*	cmem_base = mmap(0, size, PROT_READ|PROT_WRITE, MAP_SHARED, cmem_fd, 0);//mmap操作

		if (cmem_base == MAP_FAILED)

		{	cmem_base = 0;

            close(cmem_fd);

            cmem_fd = -1;

			perror("mmap pmem error!\n");

		}

		for(i = 0; i < 10; i++)

		((unsigned int *)cmem_base)[i] = i;

		printf("pmem_base:0x%08x\n", cmem_base);

		for(i = 0; i < 10; i++)

		printf("%d\n", ((unsigned int *)cmem_base)[i]);

		*/

		printf("\n\n ********************* \n\n");

    }

	printf("free the mem\n");

	getchar();

	j = 0;

/*	while(j <= 2)//释放測试

	{

		j++;

		sprintf(str, "mem%d", j);

		memset(&region, 0x00, sizeof(struct mem_block));

		region.id = j;

		region.is_use_buffer = 1;

		memcpy(region.name, str, strlen(str));

		printf("user will del:%s, id = %d\n", str, region.id);

		if (ioctl(cmem_fd, CMEM_UNMAP, &region) < 0) //获取所有空间

		{

			perror("PMEM_GET_TOTAL_SIZE failed\n");

			return -1;

		}

	}

	getchar();*/

	close(cmem_fd);

	return 0;

}

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