WoL is enabled in the suspend callback by setting MagicPacket detection and disabling all interrupts expect MagicPacket. In the resume path the driver needs to reset the hardware to rearm the WoL logic, this prevents the driver from simply restoring the registers and to take advantage of that ravb was not suspended to reduce resume time. To reset the hardware the driver closes the device, sets it in reset mode and reopens the device just like it would do in a normal suspend/resume scenario without WoL enabled, but it both closes and opens the device in the resume callback since the device needs to be reset for WoL to work. One quirk needed for WoL is that the module clock needs to be prevented from being switched off by Runtime PM. To keep the clock alive the suspend callback need to call clk_enable() directly to increase the usage count of the clock. Then when Runtime PM decreases the clock usage count it won't reach 0 and be switched off. Changes since v2 - Only do the clock dance to workaround PSCI sleep when resuming if WoL is enabled. This was a bug in v2 which resulted in a WARN if resuming from PSCI sleep with WoL disabled, thanks Sergei for pointing this out! - Break out clock dance workaround in separate patch to make it easier to revert once a fix is upstream for the clock driver as suggested by Sergei. Changes since v1 - Fix issue where device would fail to resume from PSCI suspend if WoL was enabled, reported by Geert. The fault was that the clock driver thinks the clock is on, but PSCI have disabled it, added workaround for this in ravb driver which can be removed once the clock driver is aware of the PSCI behavior. - Only try to restore from wol wake up if netif is running, since this is a condition to enable wol in the first place this was a bug in v1. Niklas Söderlund (2): ravb: add wake-on-lan support via magic packet ravb: add workaround for clock when resuming with WoL enabled drivers/net/ethernet/renesas/ravb.h | 2 + drivers/net/ethernet/renesas/ravb_main.c | 131 ++++++++++++++++++++++++++++++- 2 files changed, 129 insertions(+), 4 deletions(-) -- 2.13.3
