mmc代码的疑惑,mmc_wait_for_cmd函数

dzhjsofo 2012-04-24 06:00:42
在mmc代码的mmc_blk_issue_rq函数中有如下一段代码:
do {
int err;

cmd.opcode = MMC_SEND_STATUS;
cmd.arg = card->rca << 16;
cmd.flags = MMC_RSP_R1 | MMC_CMD_AC;

err = mmc_wait_for_cmd(card->host, &cmd, 5);
if (err) {
printk(KERN_ERR "%s: error %d requesting status\n",
req->rq_disk->disk_name, err);
goto cmd_err;
}

} while (!(cmd.resp[0] & R1_READY_FOR_DATA) ||
(R1_CURRENT_STATE(cmd.resp[0]) == 7));
从代码中可以看出cmd.resp[0]是在调用mmc_wait_for_cmd函数时发生改变的。但我跟踪mmc_wait_for_cmd函数时,最终并未发现它改变过cmd.resp[0]。哪位大侠可以告诉我cmd.resp[0]到底是在哪里改变的?????
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dzhjsofo 2012-04-24
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SD 卡驱动分析...................................................................................................................................1 块请求处理(linux/driver/mmc/card).....................................................................................2 1.probe.................................................................................................................................................2 2.do_request......................................................................................................................................13 3.小结................................................................................................................................................24 core 层处理(linux/driver/mmc/core)...................................................................................25 1.core 层初始化................................................................................................................................25 2.mmc_claim_host............................................................................................................................28 3.mmc_release_host..........................................................................................................................31 4.mmc_wait_for_req.........................................................................................................................33 5.mmc_wait_for_cmd.......................................................................................................................35 SD 控制器之初始化(linux/driver/mmc/host).....................................................................37 core 层续集之 mmc_add_host..................................................................................................49 SD 控制器之真正的硬件操作.................................................................................................82 1.s3cmci_get_ro................................................................................................................................83 2.s3cmci_set_ios...............................................................................................................................84 3.s3cmci_request 之命令处理..........................................................................................................86 4.s3cmci_request 之数据传输..........................................................................................................97 小结.........................................................................................................................................113

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