ls dev/block/mtdblock
ls dev/mtd/mtd

cat proc/mtd                                                 
dev:    size   erasesize  name
mtd0: 00001000 00001000 "JEDEC"
mtd1: 003ff000 00001000 "user"

接下来是在应用中操作/dev/mtd/mtd1节点。linux程序网上有很多，这里只给出android应用如何操作的具体代码

首先是jni里的

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <mtd/mtd-user.h>
#include <jni.h>#include "android/log.h"
static const char *TAG="25q32";
#define LOGI(fmt, args...) __android_log_print(ANDROID_LOG_INFO,  TAG, fmt, ##args)
#define LOGD(fmt, args...) __android_log_print(ANDROID_LOG_DEBUG, TAG, fmt, ##args)
#define LOGE(fmt, args...) __android_log_print(ANDROID_LOG_ERROR, TAG, fmt, ##args)int fd=-1;JNIEXPORT void JNICALL Java_w25q32_open(JNIEnv *env, jclass thiz)
{/* Opening device */const char *path_utf = "/dev/mtd/mtd1";LOGD("Opening %s with flags 0x%x", path_utf, O_SYNC | O_RDWR);fd = open(path_utf, O_SYNC | O_RDWR);LOGD("open() fd = %d", fd);if (fd == -1){/* Throw an exception */LOGE("Cannot open 25q32");/* TODO: throw an exception */}
}JNIEXPORT void JNICALL Java_w25q32_close
(JNIEnv *env, jobject thiz)
{LOGD("close(fd = %d)", fd);if (fd != -1){close(fd);}
}#define BUF_SIZE   (64 * 1024)JNIEXPORT jint JNICALL JNICALL Java_w25q32_eraseFlash
(JNIEnv *env, jclass thiz, jint offset, jint bytes)
{int err;struct erase_info_user erase;erase.start = offset;erase.length = bytes;err = ioctl (fd,MEMERASE,&erase);if (err < 0){LOGE ("MEMERASE");return 1;}LOGD ("Erased %d bytes from address 0x%.8x in flash\n",bytes,offset);return 0;
}JNIEXPORT jbyteArray JNICALL JNICALL Java_w25q32_readFlash(JNIEnv *env, jclass thiz, jint offset, jint len)
{jbyte *buf = NULL;int size = len;int err;jbyteArray result;retry:if ((buf = (jbyte *) malloc (size)) == NULL){LOGD ("%s: malloc(%#x)\n", __FUNCTION__, size);if (size != BUF_SIZE) {size = BUF_SIZE;LOGE ("%s: trying buffer size %#x\n", __FUNCTION__, size);goto retry;}LOGE ("malloc()");goto err0;}if (offset != lseek (fd,offset,SEEK_SET)){LOGE ("lseek()");goto err1;}err = read (fd,buf,len);LOGD ("read %d", err);if (err < 0){goto err1;}result = (*env)->NewByteArray(env, err);if (result == NULL){LOGE ("NewByteArray()");goto err1;}(*env)->SetByteArrayRegion(env, result, 0, err, buf);LOGD ("Copied %zu bytes from address 0x%.8x in flash\n",err,offset);free (buf);return result;err1:if (buf != NULL)free (buf);err0:return NULL;
}JNIEXPORT jint JNICALL JNICALL Java_w25q32_writeFlash
(JNIEnv *env, jclass thiz, jint offset, jbyteArray array, jint len)
{jbyte *buf = NULL;int err;int size = len;if (offset != lseek (fd,offset,SEEK_SET)){LOGE ("lseek()");goto err0;}buf = (*env)->GetByteArrayElements(env, array, NULL);err = write (fd,buf,len);if (err < 0){LOGE ("%s: write, size %#x\n", __FUNCTION__, err);LOGE ("write()");goto err1;}LOGD ("Copied %d bytes to address 0x%.8x in flash\n", err, offset);(*env)->ReleaseByteArrayElements(env, array, buf, 0);return err;err1:(*env)->ReleaseByteArrayElements(env, array, buf, 0);
err0:return -1;
}

然后是java里的

public class w25q32 {/** Do not remove or rename the field mFd: it is used by native method* close();*/final int ROM_SIZE = 4190208;//0x3ff000final int PAGE_SIZE = 4096;//0x1000public w25q32() throws SecurityException{open();}public int w25q32_erase(String addr, int len){String hex = addr.replace("0x", "");int offset = Integer.parseInt(hex, 16);if(offset+len > ROM_SIZE)return -1;int times = len/PAGE_SIZE + (len%PAGE_SIZE>0?1:0);int erase_size = times*PAGE_SIZE;return eraseFlash(offset, erase_size);}public byte[] w25q32_read(String addr, int len){if(len<1)return null;String hex = addr.replace("0x", "");int offset = Integer.parseInt(hex, 16);int size = len;if(offset+size > ROM_SIZE) {size = ROM_SIZE - offset;}return readFlash(offset, size);}public int w25q32_write(String addr, byte[] buf, int len){if(buf == null)return -1;int ret = w25q32_erase(addr, len);if(ret != 0)return ret;String hex = addr.replace("0x", "");int offset = Integer.parseInt(hex, 16);return writeFlash(offset, buf, len);}public void releasePort(){close();}// JNIprivate native void open();private native void close();private native int eraseFlash(int offset, int bytes);private native byte[] readFlash(int offset, int len);private native int writeFlash(int offset, byte[] buf, int len);static {System.loadLibrary("xx");}
}

在应用中使用

w25q32 w25qxx = new w25q32();
w25qxx.w25q32_erase("0x0", 0x3ff000);
byte[] BUFFER1 = {0x0c,0x00,0x29,0x0b,0x01,0x00,(byte)0xfc,(byte)0xff,(byte)0xfa,0x00,(byte)0xff,(byte)0xff,(byte)0xff,(byte)0xff,0x0d,0x0a};
w25qxx.w25q32_write("0x1000", BUFFER1, BUFFER1.length);
byte[] BUFFER2 = w25qxx.w25q32_read("0x1000", BUFFER1.length);
w25qxx.releasePort();

以上。