emmc host是如果处理uboot 传递过来的flashlayout信息呢？
source/drivers/mmc/host/pxamci.c
static int pxamci_probe(struct platform_device *pdev)
637 {
653 
654         mmc = mmc_alloc_host(sizeof(struct pxamci_host), &pdev->dev);
655         if (!mmc) {
656                 ret = -ENOMEM;
657                 goto out;
658         }
probe 函数中会调用mmc_alloc_host来增加一个host
drivers/mmc/core/host.c
337 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
338 {
381         INIT_DELAYED_WORK(&host->detect, mmc_rescan);
396 }
这个函数总重要的是初始化一个workqueue，回调函数是mmc_rescan.
那这个workqueue是怎么启动的呢？
可以看到是mmc_start_host调用_mmc_detect_change
2649 void mmc_start_host(struct mmc_host *host)
2650 {
2663         _mmc_detect_change(host, 0, false);
2664 }
_mmc_detect_change 实现如下：
1872 static void _mmc_detect_change(struct mmc_host *host, unsigned long delay,
1873                                 bool cd_irq)
1874 {
1891         mmc_schedule_delayed_work(&host->detect, delay);
1892 }
可见是1891行启动这个workqueue的.
我们再来看看mmc_rescan是怎么处理flashlayout的.
mmc_rescan->mmc_attach_mmc->mmc_add_card->device_add->bus_probe_device->device_attach->bus_for_each_drv->device_probe_device->mmc_blk_probe->mmc_add_disk->add_disk->blkdev_get->__blkdev_get->rescan_partition->check_partition
142 check_partition(struct gendisk *hd, struct block_device *bdev)
143 {
163         i = res = err = 0;
164         while (!res && check_part[i]) {
165                 memset(state->parts, 0, state->limit * sizeof(state->parts[0]));
166                 res = check_part[i++](state);


check_partition会调用check_part数组
 41 static int (*check_part[])(struct parsed_partitions *) = {
 83 #endif
 84 #ifdef CONFIG_OSF_PARTITION
 85         osf_partition,


如果定义CONFIG_OSF_PARTITION，实际调用的就是osf_partition
 15 int osf_partition(struct parsed_partitions *state)
 16 {
 73         }
 74         for (i = 0 ; i < npartitions; i++, partition++) {
 75                 if (slot == state->limit)
 76                         break;
 77                 if (le32_to_cpu(partition->p_size))
 78                         put_partition(state, slot,
 79                                 le32_to_cpu(partition->p_offset),
 80                                 le32_to_cpu(partition->p_size));
 81                 slot++;
 82         }
 83         strlcat(state->pp_buf, " ", PAGE_SIZE);
 84         put_dev_sector(sect);
 85         return 1;
 86 }


在78行会调用put_partition来初始化partition
 40 static inline void
 41 put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)
 42 {
 43         if (n < p->limit) {
 44                 char tmp[1 + BDEVNAME_SIZE + 10 + 1];
 45 
 46                 p->parts[n].from = from;
 47                 p->parts[n].size = size;
 48                 snprintf(tmp, sizeof(tmp), " %s%d", p->name, n);
 49                 strlcat(p->pp_buf, tmp, PAGE_SIZE);
 50         }
 51 }
保存partition的起始地址和size,以及名字.