ZigBee学习笔记_osal_nv_init()

新年过完了，又可以继续学习了，进度好慢那感觉，今天看哈osal_nv_init()函数，代码很简单如下，

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• void osal_nv_init( void *p )
• {
• (void)p; // Suppress Lint warning.
• (void)initNV(); // Always returns TRUE after pages have been erased.
• }
  

明明没有用到参数，还给传递进来一个参数，不晓得在搞什么，其中重点函数式initNVIDIA()函数，

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• static uint8 initNV( void )
• {
• osalNvPgHdr_t pgHdr;
• uint8 oldPg = OSAL_NV_PAGE_NULL;
• uint8 newPg = OSAL_NV_PAGE_NULL;
• uint8 findDups = FALSE;
• uint8 pg;
• pgRes = OSAL_NV_PAGE_NULL;
• for ( pg = OSAL_NV_PAGE_BEG; pg <= OSAL_NV_PAGE_END; pg++ )
• {
• HalFlashRead(pg, OSAL_NV_PAGE_HDR_OFFSET, (uint8 *)(&pgHdr), OSAL_NV_HDR_SIZE);
• if ( pgHdr.active == OSAL_NV_ERASED_ID )
• {
• if ( pgRes == OSAL_NV_PAGE_NULL )
• {
• pgRes = pg;
• }
• else
• {
• setPageUse( pg, TRUE );
• }
• }
• else // Page is active.
• {
• // If the page is not yet in use, it is the tgt of items from an xfer.
• if ( pgHdr.inUse == OSAL_NV_ERASED_ID )
• {
• newPg = pg;
• }
• // An Xfer from this page was in progress.
• else if ( pgHdr.xfer != OSAL_NV_ERASED_ID )
• {
• oldPg = pg;
• }
• }
• // Calculate page offset and lost bytes - any "old" item triggers an N^2 re-scan from start.
• if ( initPage( pg, OSAL_NV_ITEM_NULL, findDups ) != OSAL_NV_ITEM_NULL )
• {
• findDups = TRUE;
• pg = OSAL_NV_PAGE_BEG-1;
• continue;
• }
• } // for ( pg = OSAL_NV_PAGE_BEG; pg <= OSAL_NV_PAGE_END; pg++ )
• /* First the old page is erased, and then the new page is put into use.
• * So if a transfer was in progress, the new page will always not yet be
• * marked as in use, since that is the last step to ending a transfer.
• */
• if ( newPg != OSAL_NV_PAGE_NULL )
• {
• /* If there is already a fallow page reserved, keep it and put the newPg in use.
• * An unfinished compaction will finish to the new reserve page and the old page
• * will be erased and reserved.
• */
• if ( pgRes != OSAL_NV_PAGE_NULL )
• {
• setPageUse( newPg, TRUE );
• }
• /* If setting old page to 'xfer' failed or board reset before it was effected, there is no way
• * to know which page was the 'old page' - so just reset all NV pages to start clean.
• */
• else if ( oldPg != OSAL_NV_PAGE_NULL )
• {
• pgRes = newPg;
• }
• /* If a page compaction was interrupted and the page being compacted is not
• * yet erased, then there may be items remaining to xfer before erasing.
• */
• if ( oldPg != OSAL_NV_PAGE_NULL )
• {
• compactPage( oldPg );
• }
• }
• /* If no page met the criteria to be the reserve page:
• * - A compactPage() failed or board reset before doing so.
• * - Perhaps the user changed which Flash pages are dedicated to NV and downloaded the code
• * without erasing Flash？
• */
• if ( pgRes == OSAL_NV_PAGE_NULL )
• {
• for ( pg = OSAL_NV_PAGE_BEG; pg <= OSAL_NV_PAGE_END; pg++ )
• {
• erasePage( pg );
• }
• initNV();
• }
• return TRUE;
• }
  

看注释是擦除非易失性存储器页，总是返回TRUE，首先用到osalNvPgHdr_t结构变量，定义如下

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• typedef struct
• {
• uint16 active;
• uint16 inUse;
• uint16 xfer;
• uint16 spare;
• } osalNvPgHdr_t;
  

用于指示存储器页面的一些信息

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• #define OSAL_NV_PAGE_NULL 0
  

oldPg以及newPg均初始化为0，

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• #define OSAL_NV_PAGES_USED HAL_NV_PAGE_CNT
• #define OSAL_NV_PAGE_BEG HAL_NV_PAGE_BEG
• #define OSAL_NV_PAGE_END (OSAL_NV_PAGE_BEG + OSAL_NV_PAGES_USED - 1)
• #define HAL_NV_PAGE_CNT 6
• #define HAL_NV_PAGE_BEG (HAL_NV_PAGE_END-HAL_NV_PAGE_CNT+1)
• #define HAL_FLASH_LOCK_BITS 16
• #define HAL_NV_PAGE_END 126
  

这个宏定义看着挺绕的，结果是OSAL_NV_PAGE_BEG为121，OSAL_NV_PAGE_END为126，在CC2530中有128个页，最后一个页的最后16个字节是用来flash lock bits，这里用的的是121-126不晓得为啥，再循环中调用了HalFlashRead()函数，其中参数定义如下

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• #define OSAL_NV_PAGE_HDR_OFFSET 0
• #define OSAL_NV_HDR_SIZE 8
  

osalNvPgHdr_t结构体占据了8个字节的大小，

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• void HalFlashRead(uint8 pg, uint16 offset, uint8 *buf, uint16 cnt)
• {
• // Calculate the offset into the containing flash bank as it gets mapped into XDATA.
• uint8 *ptr = (uint8 *)(offset + HAL_FLASH_PAGE_MAP) +
• ((pg % HAL_FLASH_PAGE_PER_BANK) * HAL_FLASH_PAGE_SIZE);
• uint8 memctr = MEMCTR; // Save to restore.
• #if !defined HAL_OAD_BOOT_CODE
• halIntState_t is;
• #endif
• pg /= HAL_FLASH_PAGE_PER_BANK; // Calculate the flash bank from the flash page.
• #if !defined HAL_OAD_BOOT_CODE
• HAL_ENTER_CRITICAL_SECTION(is);
• #endif
• // Calculate and map the containing flash bank into XDATA.
• MEMCTR = (MEMCTR & 0xF8) | pg;
• while (cnt--)
• {
• *buf++ = *ptr++;
• }
• MEMCTR = memctr;
• #if !defined HAL_OAD_BOOT_CODE
• HAL_EXIT_CRITICAL_SECTION(is);
• #endif
• }
  

该函数是从flash中读取cnt个字节，访问flash数据用的是XDATA地址空间，flash映射到XDATA的高32KB地址空间中，因此，需要计算是flash哪个区映射到该地址空间，用到的宏定义如下

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• #define HAL_FLASH_PAGE_MAP 0x8000
• #define HAL_FLASH_PAGE_PER_BANK 16
• #define HAL_FLASH_PAGE_SIZE 2048
  

通过计算最终得到地址，并保存MEMCTR的值，将pg赋值为所映射额区号，保存EA的值关闭中断，为MEMCTR赋新值，就可以开始字节拷贝了，cnt个字节拷贝完成之后恢复MEMCTR的值，重新开中断恢复EA的值，该函数就完成了。

返回到initNV()函数中，读取的8个字节的数据存放在了pgHdr中，

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• #define OSAL_NV_ERASED_ID 0xFFFF
  

接下来判断active的值是否是0xFFFF，如果是继而判断pgRes是否等于OSAL_NV_PAGE_NULL，在第一次进来时pgRes是等于OSAL_NV_PAGE_NULL的，将pgRes赋值为pg，当第二次进入循环中则会进入setPageUse()函数如下

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• static void setPageUse( uint8 pg, uint8 inUse )
• {
• osalNvPgHdr_t pgHdr;
• pgHdr.active = OSAL_NV_ZEROED_ID;
• if ( inUse )
• {
• pgHdr.inUse = OSAL_NV_ZEROED_ID;
• }
• else
• {
• pgHdr.inUse = OSAL_NV_ERASED_ID;
• }
• writeWord( pg, OSAL_NV_PAGE_HDR_OFFSET, (uint8*)(&pgHdr) );
• }
  

该函数是设置page header的active/inUse状态，

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• #define OSAL_NV_ZEROED_ID 0x0000
  

设置active为OSAL_NV_ZEROED_ID，然后判断inUse参数，如果为TRUE则设置inUse为OSAL_NV_ZEROED_ID，为FALSE设置inUse为OSAL_NV_ZERASED_ID,最后调用writeWord()函数保存pgHdr的值，

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• static void writeWord( uint8 pg, uint16 offset, uint8 *buf )
• {
• offset = (offset >> 2) + ((uint16)pg << 9);
• if ( OSAL_NV_CHECK_BUS_VOLTAGE )
• {
• HalFlashWrite(offset, buf, 1);
• }
• else
• {
• failF = TRUE;
• }
• }
  

这个地址的计算可以从手册中看出

手册中说道32位字是可以写入的闪存的最小可写单元，闪存页面是存储器内科擦除的最小单元，因此对flash的写是写4个字节，这样这个地址的计算就可以容易明白了。

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• #define OSAL_NV_CHECK_BUS_VOLTAGE (HalAdcCheckVdd( HAL_ADC_VDD_LIMIT_4 ))
  

在if中去检测了供电电压，HalFlashWrite()函数式利用DMA操作将数据写入flash中，不多说了就。

回到initNV()函数中，当所读取的active不是OSAL_NV_ERASED_ID时，(如果清楚osalNvPgHdr_t结构体的各个变量的意义就能清晰明白这里的逻辑了)即页面没有被擦除，判断inUse是否为OSAL_NV_ERASED_ID,是则将newPg赋值为pg，xfer貌似是指明是否有传输在进行，当有传输在发生时将oldPg赋值为pg。之后有个initPage()函数，是浏览页面项，计算校验和以及丢失的字节和页面偏移量，

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• #define OSAL_NV_ITEM_NULL 0
  

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• static uint16 initPage( uint8 pg, uint16 id, uint8 findDups )
• {
• uint16 offset = OSAL_NV_PAGE_HDR_SIZE;
• uint16 sz, lost = 0;
• osalNvHdr_t hdr;
• do
• {
• HalFlashRead(pg, offset, (uint8 *)(&hdr), OSAL_NV_HDR_SIZE);
• if ( hdr.id == OSAL_NV_ERASED_ID )
• {
• break;
• }
• offset += OSAL_NV_HDR_SIZE;
• sz = OSAL_NV_DATA_SIZE( hdr.len );
• // A bad 'len' write has blown away the rest of the page.
• if ( (offset + sz) > OSAL_NV_PAGE_FREE )
• {
• lost += (OSAL_NV_PAGE_FREE - offset + OSAL_NV_HDR_SIZE);
• offset = OSAL_NV_PAGE_FREE;
• break;
• }
• if ( hdr.id != OSAL_NV_ZEROED_ID )
• {
• /* This trick allows function to do double duty for findItem() without
• * compromising its essential functionality at powerup initialization.
• */
• if ( id != OSAL_NV_ITEM_NULL )
• {
• /* This trick allows asking to find the old/transferred item in case
• * of a successful new item write that gets interrupted before the
• * old item can be zeroed out.
• */
• if ( (id & 0x7fff) == hdr.id )
• {
• if ( (((id & OSAL_NV_SOURCE_ID) == 0) && (hdr.stat == OSAL_NV_ERASED_ID)) ||
• (((id & OSAL_NV_SOURCE_ID) != 0) && (hdr.stat != OSAL_NV_ERASED_ID)) )
• {
• return offset;
• }
• }
• }
• // When invoked from the osal_nv_init(), verify checksums and find & zero any duplicates.
• else
• {
• if ( hdr.chk == calcChkF( pg, offset, hdr.len ) )
• {
• if ( findDups )
• {
• if ( hdr.stat == OSAL_NV_ERASED_ID )
• {
• /* The trick of setting the MSB of the item Id causes the logic
• * immediately above to return a valid page only if the header 'stat'
• * indicates that it was the older item being transferred.
• */
• uint16 off = findItem( (hdr.id | OSAL_NV_SOURCE_ID) );
• if ( off != OSAL_NV_ITEM_NULL )
• {
• setItem( findPg, off, eNvZero ); // Mark old duplicate as invalid.
• }
• }
• }
• // Any "old" item immediately exits and triggers the N^2 exhaustive initialization.
• else if ( hdr.stat != OSAL_NV_ERASED_ID )
• {
• return OSAL_NV_ERASED_ID;
• }
• }
• else
• {
• setItem( pg, offset, eNvZero ); // Mark bad checksum as invalid.
• lost += (OSAL_NV_HDR_SIZE + sz);
• }
• }
• }
• else
• {
• lost += (OSAL_NV_HDR_SIZE + sz);
• }
• offset += sz;
• } while ( TRUE );
• pgOff[pg - OSAL_NV_PAGE_BEG] = offset;
• pgLost[pg - OSAL_NV_PAGE_BEG] = lost;
• return OSAL_NV_ITEM_NULL;
• }
  

挺长的一大坨，

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• typedef struct
• {
• uint16 id;
• uint16 len; // Enforce Flash-WORD size on len.
• uint16 chk; // Byte-wise checksum of the 'len' data bytes of the item.
• uint16 stat; // Item status.
• } osalNvHdr_t;
• #define OSAL_NV_HDR_SIZE 8
• #define OSAL_NV_PAGE_FREE HAL_FLASH_PAGE_SIZE
• #define HAL_FLASH_PAGE_SIZE 2048
• #define OSAL_NV_SOURCE_ID 0x8000
• #define OSAL_NV_DATA_SIZE( LEN ) \
• ((((LEN) + OSAL_NV_WORD_SIZE - 1) / OSAL_NV_WORD_SIZE) * OSAL_NV_WORD_SIZE)
• #define OSAL_NV_WORD_SIZE HAL_FLASH_WORD_SIZE
• #define HAL_FLASH_WORD_SIZE 4
  

进来之后先是读取8个字节数据到hdr结构变量中，当读取的id变量为OSAL_NV_ERASED_ID时跳出循环，偏移量增加OSAL_NV_HDR_SIZE大小，OSAL_NV_DATA_SIZE()宏定义感觉应该是为了实现4个字节对齐才这样写的，最后得出的sz和len的关系应该是（len+4）> sz >= len，当offset+sz的和大于页面的最大字节即2048时，超出本页面了就，len的值就是错的，lost的值更新，offset赋值为OSAL_NV_PAGE_FREE，退出循环。当offset+sz的和是合理的值时，检测id属性，当hdr.id不等于OSAL_NV_ZEROED_ID且传递进来的id不等于OSAL_NV_ITEM_NULL时，这次调用传递进来的id是OSAL_NV_ITEM_NULL，不符合条件，就不看了先，跳过去看else里面的内容，上面的注释也说了，当该函数是被osal_nv_init()函数调用时，是在这里处理的，调用了calcChkF()函数计算校验和，就不多介绍了，当计算的校验和与hdr.chk相等时，进而判断findDups，参数传递进来的是FALSE，当stat不等于OSAL_NV_ERASED_ID时返回OSAL_NV_ERASED_ID，当校验和不相等时，标记校验和无效，最后一个pgOff和pgLost数组记录了offset和lost变量，返回OSAL_NV_ITEM_NULL，这个函数有很多逻辑搞不清楚，希望有人帮忙讲解一下总体逻辑，这样看着毫无思绪可言那，看了跟没看差不多，返回到上一级函数中。

剩下一些新页和旧页的一些操作，搞的这么麻烦，看注释说首先旧页被擦除，然后新页投入使用，如果有个一个传输在进行中，那么新页将总是不投入使用，传输结束才可以。当有一个空闲的页面预留时，将新页投入使用，后面这些个都有些看不懂了，看了注释也不甚了解，日后再说吧。功力太低了。。。

新年？

哦，这个是我刚才查资料时，感觉不错，转载的，我标注了。