[PATCH] net: fec_mxc: add DM_FLAG_ACTIVE_DMA flag for FEC network driver

[Peng Fan]

> Subject: [PATCH] net: fec_mxc: add DM_FLAG_ACTIVE_DMA flag for
> FEC network driver
> 
> From: Meng Li <meng.li at windriver.com>
> 
> When FEC network card works as the prime one in u-boot, and is in
> active status, kernel might crash during booting up stage, especially
> working with grub. Because the DMA of FEC is still in active status, and
> copy data into momey if there is network data received. In this case, if
> kernel allocated a part of memory that has overlay with the memory
> used by DMA, kernel memory may be destroyed and cause kernel
> crashes.
> Because before kernel boots up really, u-boot
> dm_remove_devices_flags() can call the remove callback of FEC driver
> with DM_FLAG_ACTIVE_DMA flag. In fecmxc_remove(), phy power is
> disabled, so there is no data received. In this way, it makes sure that
> there is no DMA action, so that avoid kernel crashing occurs.
> 
> Signed-off-by: Meng Li <Meng.Li at windriver.com>

This looks good to me.

Reviewed-by: Peng Fan <peng.fan at nxp.com>