On 05/09/2017 09:58 AM, Timur Tabi wrote: > I'm trying to add a platform_driver.shutdown function to my Ethernet driver > (drivers/net/ethernet/qualcomm/emac/*), but I can't find any definitive > information as to what a network driver shutdown callback is supposed to do. > I also don't know what testcase I should use to verify that my function is > working.
A good test case for exercising a .shutdown() function is kexec'ing a new kernel for instance. > > I see only four instances of a platform_driver.shutdown function in > drivers/net/ethernet: > > $ git grep -A 20 -w platform_driver | grep '\.shutdown' > apm/xgene-v2/main.c- .shutdown = xge_shutdown, > apm/xgene/xgene_enet_main.c- .shutdown = xgene_enet_shutdown, > marvell/mv643xx_eth.c- .shutdown = mv643xx_eth_shutdown, > marvell/pxa168_eth.c- .shutdown = pxa168_eth_shutdown, > > (Other shutdown functions are for pci_driver.shutdown). > > For the xgene drivers, the shutdown function just calls the 'remove' > function. Isn't that overkill? Why bother with a shutdown function if it's > just the same thing as removing the driver outright? Yes, that appears unnecessary. > > mv643xx_eth_shutdown() seems more reasonable. All it does is halt the TX > and RX queues. > > pxa168_eth_shutdown() is a little more heavyweight: halts the queues, and > stops the DMA and calls phy_stop(). > > Can anyone help me figure out what my driver really should do? You should put your HW in a state where it won't be doing DMA, or have any adverse side effects to the system, putting it in a low power state is also a good approach. -- Florian
