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小弟在把网上的uda1341驱动改成了adv212的驱动，adv212用的是DCS dma mode，但在2440的dma部分遇到了问题（2.6.29的内核）： 1、在分配dma buffer时如果小于我请求read的大小就会不停的请求中断； 2、dma完成一buffer传输后再次enqueue时出错，出错原因是等待load buffer timeout; 3、我看到网上总有人说dma的驱动有问题，还说物理通道和映射通道什么的，但在看源码后还是不能理解，求正解；如果有需要改正的bug望告知小弟。以上问题我都在debug的情况下走了遍源代码，会出现这样的问题完全符合设计者的思路，但关键是我不能理解…… 如果有用过adv202 or adv212+2440 的有更好的数据传输方法也望赐教。这是我第一次在这里发请教贴，希望能感受到byr的热情，谢谢～关于dma初始化部分的源代码： static int __init adv212_init_dma(audio_stream_t * s) { int ret ; int dmacount; enum s3c2410_dmasrc source; int hwcfg; unsigned long devaddr; int dcon = 0; unsigned int flags = 0; devaddr = ADV212_BASE_PHYS+ ADV212_DIRECT_REG_CODE; if(s->dmach == DMACH_XD0) { source =S3C2410_DMASRC_HW; hwcfg =1 ; dmacount = 0; dcon=S3C2410_DCON_HANDSHAKE|S3C2410_DCON_SYNC_HCLK|S3C2410_DCON_INTREQ|S3C2410_DCON_WHOLE_SERVICE|S3C2410_DCON_INTREQ|S3C2410_DCON_AUTORELOAD|S3C2410_DCON_HWTRIG|S3C2410_DCON_WORD|dmacount; flags = S3C2410_DMAF_AUTOSTART; ret = s3c2410_dma_request(s->dmach, &s3c2440adv212_dma_in, NULL); s3c2410_dma_devconfig(s->dmach, source, hwcfg, devaddr);//write source addr, srrc ctl,dist ctl s3c2410_dma_config(s->dmach, 4, dcon); //wsh wrire dcon, change xferunit from 2 to 4 s3c2410_dma_set_buffdone_fn(s->dmach, adv212_dmain_done_callback); s3c2410_dma_setflags(s->dmach, flags); return 0 ; } else return 1; } 关于read部分的源代码： static ssize_t smdk2440_adv212_read(struct file *file, char *buffer, size_t count, loff_t * ppos) { /*nyp*/ const char *buffer0 = buffer; audio_stream_t *s = &input_stream; int chunksize, ret = 0; unsigned short value16; int jp2_size,i,size_tmp； if (!s->buffers) { int i; if (adv212_setup_buf(s)) //alloc DMA buffers return -ENOMEM; for (i = 0; i < s->nbfrags; i++) { audio_buf_t *b = s->buf; printk("s->buf_idx = %u\n", s->buf_idx); down(&b->sem); printk("s->dmach = %d\n",s->dmach); s3c2410_dma_enqueue(s->dmach, (void *) b, b->dma_addr, s->fragsize); NEXT_BUF(s, buf); } } if(start_flag == 0) { printk("\nstart output\n"); reg16_adv212_eirqflg =0xFFFF;//start compress and make adv212 can output printk("\n***nyp3 : eirqflg=0x%x***\n",reg16_adv212_eirqflg); value16 = s3c2410_gpio_getpin(S3C2410_GPB10); while(value16 != 0) value16 = s3c2410_gpio_getpin(S3C2410_GPB10); start_flag = 1; printk("lalala\n"); } while (count > 0) { audio_buf_t *b = s->buf; // Wait for a buffer to become full if (file->f_flags & O_NONBLOCK) { ret = -EAGAIN; if (down_trylock(&b->sem)) break; } else { ret = -ERESTARTSYS; if (down_interruptible(&b->sem)) break; } chunksize = b->size; if (chunksize > count) // we required less than buffer size chunksize = count; if (copy_to_user(buffer, b->start + s->fragsize - b->size, chunksize)) { up(&b->sem); return -EFAULT; } b->size -= chunksize; buffer += chunksize; count -= chunksize; if (b->size > 0) { up(&b->sem); break; } //Make current buffer available for DMA again printk("in the while s->buf_idx = %u\n", s->buf_idx); s3c2410_dma_enqueue(s->dmach, (void *) b, b->dma_addr, s->fragsize); NEXT_BUF(s, buf); } if ((buffer - buffer0)) ret = buffer - buffer0; printk("adv212_read: return=%d bytes!\n", ret); return ret; }

2440DMA求教！