Dear Wolfgang
Thanks for the review.
On 6/12/2014 2:26 PM, Wolfgang Denk wrote:
Dear Josh Wu,
In message 1402552643-13297-1-git-send-email-josh.wu@atmel.com you wrote:
For SPL in FAT and envrionment load/save in FAT, to support no partition table device (whole device is FAT partition). We need specify the partition number as 0.
Sorry, I cannot parse this. What exactly do you mean here?
Sorry, Let me try to explain it a little bit: In U-Boot when we access a partition of a device, we use 'ifname dev:part' format. For instance: 'mmc 0:1' means the MMC card's #1 partition of the device #0.
But for a case if the mmc device has no partition table (MBR), it only has one FAT partition. To support that case, we need to access by using 'mmc 0:0'.
So the problem is: if we specify mmc 0:0 then I cannot access the mmc device if it has a partition table. And if we specify mmc 0:1 then I cannot access if it has no partition table.
For the fs layer this case is solved by use 'mmc 0', or 'mmc 0:auto' by commit: 10a37fd7a4 (disk: get_device_and_partition() "auto" partition and cleanup)
But for env fat and SPL fat, we don't use the function in above commit as we use a simpler function fat_register_device(). So this patch make this function works too.
But in FAT SPL and environment case, when we specify the partition number as 1, it is reasonable to support the device has no partition table and only a FAT partition.
Why would the expectations in SPL be different from other use cases?
For example, when I use SPL binary in mmc card, I want it to load the file: u-boot.img from the first partition. I expect it should work even if the mmc device has no partition table.
But when I define CONFIG_SYS_MMC_SD_FAT_BOOT_PARTITION as 1. it cannot work when the mmc has no partition table.
same thing happens for saving environment to a FAT file in MMC.
+int fat_register_device(block_dev_desc_t *dev_desc, int part_no,
bool allow_whole_dev);Please make this an "int" type, and use 0 and 1.
Is there any special concern for that? like cause machine compatiable issue?
Best Regards, Josh Wu
Thanks.
Best regards,
Wolfgang Denk