Hi, I am a fresher to linux kernel and now trying to add some features to mmc driver.
One of the features is that terminate a long time writing request(e.x. lasts 50ms or more), and make the following reading request run. I read the JEDEC STANDARD and found that a writing operation could be terminated with sending a STOP_TRANSMISSION(CMD12). But I am not quite sure how I can send the command. Here is the working flow I am working in: 1) In the function mmc_blk_issue_rq() @ drivers/mmc/card/block.c before mmc_wait_for_req() is called, check if the request to be issued is WRITE. If it is a WRITE request, add a timer of 50ms to check whether it is a long time writing operation. 2) In the timeout callback function, get the next request in the queue and check whether it is a READ request. If it is a READ request, send a STOP_TRANSMISSION command with mmc_wait_for_cmd() to terminate the request. But I got some fault messages when I sent the STOP_TRANSMISSION command. It seems that without completing the WRITE request sent by mmc_wait_for_req(), the STOP_TRANSMISSION command(sent with mmc_wait_for_cmd() ) could not be accepted, because in the function of mmc_wait_for_cmd(), mmc_wait_for_req() is called. And that is why I got the fault messages. So my question is, How to send a STOP_TRANSMISSION command to terminate the writing request in my case. Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
