[U-Boot] i.MX8MQ-EVK with ext4 read support

[Chris Spencer]

Hi,

I'm trying to get started with the new i.MX8MQ-EVK support and I've
got a bit of an issue enabling ext4 read support without also enabling
write support.

CONFIG_FS_EXT4=y

I get a build error here:

fs/fs.c:198:12: error: ‘ext4_write_file’ undeclared here (not in a
function); did you mean ‘ext4_read_file’?
   .write = ext4_write_file,
            ^~~~~~~~~~~~~~~

This line is wrapped with an ifdef check for CONFIG_CMD_EXT4_WRITE.
The write function is declared in include/ext4fs.h, where it is
wrapped with a check for CONFIG_EXT4_WRITE.

The problem is that include/configs/imx8mq_evk.h has this define:

#define CONFIG_CMD_EXT4_WRITE

This results in the 'write' code being enabled in fs.c but disabled in
ext4fs.h. The two ifdefs probably ought to be made consistent, but I
don't really understand why imx8mq_evk.h needs to define it in the
first place. Can anybody shed some light on this?

Thanks,

Chris