회신: Re: a question about SD card rtems_blkdev_generic functions

[김찬]

Hi, Andre,
I reallize the ioctl function does it all.
I,m home now so I'll check tomorrow.
Thanks!
Chan

-----원본 메시지-----
보낸사람: "André Marques"
보낸날짜: 2015-08-19 23:23:03
받는사람: "김찬"
참조: "users at rtems.org"
Hello Chan,



On 19-08-2015 13:46, Chan Kim wrote:

> Hello, rtems folks,

> I managed to write an SD card driver on our platform (it was a month ago but I was doing other things lately) and am

> tryng to test file read and write. File read is done anyway and I can print the file contents.

> Couple of days ago I saw block write starting initiated by file write operation, but somehow I don't know how to make block write start.

>

> somewhere in the driver, there are lines below.

>

> static const rtems_driver_address_table sd_card_disk_ops = {

> .initialization_entry = sd_card_disk_init,

> .open_entry = rtems_blkdev_generic_open,

> .close_entry = rtems_blkdev_generic_close,

> .read_entry = rtems_blkdev_generic_read,

> .write_entry = rtems_blkdev_generic_write,

> .control_entry = rtems_blkdev_generic_ioctl

> };

>

> sc = rtems_io_register_driver( 0, &sd_card_disk_ops, &major);

>

> but strangely, even when I read a file successfully(using fopen, fgets) and print it, only rtems_blkdev_generic_open and rtems_blkdev_generic_close function are called and rtems_blkdev_generic_read/write.functions are not called.

> Is this normal? Can someone direct me to a good document on how this works or explain it to me?

> Thanks!

> Chan



sd_card_disk_init should be creating the disk in the system through

rtems_disk_create_phys, which takes an IO control handler for the block

operations. This controller is the one that should be doing your reads

and writes.



From [1] :



These primitives (except initialize) can be implemented in a generic

fashion based upon the supplied block device driver IO control handler.

*Every block device driver should provide an initialize entry point,

which registers the appropriate IO control handler.*



[1] -

https://docs.rtems.org/doxygen/cpukit/html/group__rtems__blkdev__generic.html#gab2d9149dc532657053697e5010fffa82



--André Marques



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