大家可以根据需要对MDK的某些文件单独的做高等级优化

eric2013

这个功能还是比较实用了，如果工程无法整体做等级优化，可以把一些重要的文件单独做优化。

又或者反过来，整体做高等级优化，不支持的文件设置为低等级即可。

eric2013

对一些函数做优化也是可以的。

1. #if defined   (__CC_ARM) /*!< ARM Compiler */
   
2. #pragma O0
   
3. #elif defined (__GNUC__) /*!< GNU Compiler */
   
4. #pragma GCC optimize ("O0")
   
5. #endif /* __CC_ARM */
   
6. HAL_StatusTypeDef USB_HC_StartXfer(USB_OTG_GlobalTypeDef *USBx, USB_OTG_HCTypeDef *hc, uint8_t dma)
   
7. {
   
8.   uint8_t  is_oddframe = 0;
   
9.   uint16_t len_words = 0;   
   
10.   uint16_t num_packets = 0;
    
11.   uint16_t max_hc_pkt_count = 256;
    
12.   uint32_t tmpreg = 0;
    
13.    
    
14.   if((USBx != USB2_OTG_FS) && (hc->speed == USB_OTG_SPEED_HIGH))
    
15.   {
    
16.     if((dma == 0) && (hc->do_ping == 1))
    
17.     {
    
18.       USB_DoPing(USBx, hc->ch_num);
    
19.       return HAL_OK;
    
20.     }
    
21.     else if(dma == 1)
    
22.     {
    
23.       USBx_HC(hc->ch_num)->HCINTMSK &= ~(USB_OTG_HCINTMSK_NYET | USB_OTG_HCINTMSK_ACKM);
    
24.       hc->do_ping = 0;
    
25.     }
    
26.   }
    
27.   
    
28.   /* Compute the expected number of packets associated to the transfer */
    
29.   if (hc->xfer_len > 0)
    
30.   {
    
31.     num_packets = (hc->xfer_len + hc->max_packet - 1) / hc->max_packet;
    
32.    
    
33.     if (num_packets > max_hc_pkt_count)
    
34.     {
    
35.       num_packets = max_hc_pkt_count;
    
36.       hc->xfer_len = num_packets * hc->max_packet;
    
37.     }
    
38.   }
    
39.   else
    
40.   {
    
41.     num_packets = 1;
    
42.   }
    
43.   if (hc->ep_is_in)
    
44.   {
    
45.     hc->xfer_len = num_packets * hc->max_packet;
    
46.   }
    
47.   
    
48.   /* Initialize the HCTSIZn register */
    
49.   USBx_HC(hc->ch_num)->HCTSIZ = (((hc->xfer_len) & USB_OTG_HCTSIZ_XFRSIZ)) |\
    
50.     ((num_packets << 19) & USB_OTG_HCTSIZ_PKTCNT) |\
    
51.       (((hc->data_pid) << 29) & USB_OTG_HCTSIZ_DPID);
    
52.   
    
53.   if (dma)
    
54.   {
    
55.     /* xfer_buff MUST be 32-bits aligned */
    
56.     USBx_HC(hc->ch_num)->HCDMA = (uint32_t)hc->xfer_buff;
    
57.   }
    
58.   
    
59.   is_oddframe = (USBx_HOST->HFNUM & 0x01) ? 0 : 1;
    
60.   USBx_HC(hc->ch_num)->HCCHAR &= ~USB_OTG_HCCHAR_ODDFRM;
    
61.   USBx_HC(hc->ch_num)->HCCHAR |= (is_oddframe << 29);
    
62.   
    
63.   /* Set host channel enable */
    
64.   tmpreg = USBx_HC(hc->ch_num)->HCCHAR;
    
65.   tmpreg &= ~USB_OTG_HCCHAR_CHDIS;
    
66.   tmpreg |= USB_OTG_HCCHAR_CHENA;
    
67.   USBx_HC(hc->ch_num)->HCCHAR = tmpreg;
    
68.   
    
69.   if (dma == 0) /* Slave mode */
    
70.   {  
    
71.     if((hc->ep_is_in == 0) && (hc->xfer_len > 0))
    
72.     {
    
73.       switch(hc->ep_type)
    
74.       {
    
75.         /* Non periodic transfer */
    
76.       case EP_TYPE_CTRL:
    
77.       case EP_TYPE_BULK:
    
78.         
    
79.         len_words = (hc->xfer_len + 3) / 4;
    
80.         
    
81.         /* check if there is enough space in FIFO space */
    
82.         if(len_words > (USBx->HNPTXSTS & 0xFFFF))
    
83.         {
    
84.           /* need to process data in nptxfempty interrupt */
    
85.           USBx->GINTMSK |= USB_OTG_GINTMSK_NPTXFEM;
    
86.         }
    
87.         break;
    
88.         /* Periodic transfer */
    
89.       case EP_TYPE_INTR:
    
90.       case EP_TYPE_ISOC:
    
91.         len_words = (hc->xfer_len + 3) / 4;
    
92.         /* check if there is enough space in FIFO space */
    
93.         if(len_words > (USBx_HOST->HPTXSTS & 0xFFFF)) /* split the transfer */
    
94.         {
    
95.           /* need to process data in ptxfempty interrupt */
    
96.           USBx->GINTMSK |= USB_OTG_GINTMSK_PTXFEM;         
    
97.         }
    
98.         break;
    
99.         
    
100.       default:
     
101.         break;
     
102.       }
     
103.       
     
104.       /* Write packet into the Tx FIFO. */
     
105.       USB_WritePacket(USBx, hc->xfer_buff, hc->ch_num, hc->xfer_len, 0);
     
106.     }
     
107.   }
     
108.   
     
109.   return HAL_OK;
     
110. }

复制代码

北海之风

学习了 啊哈哈

ccc228

正好遇到优化后异常的问题，顺藤摸瓜 摸到这