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Implement Wake-on-Lan for RTL8211F correctly. The existing implementation has multiple issues: 1. It assumes that Wake-on-Lan can always be used, whether or not the interrupt is wired, and whether or not the interrupt is capable of waking the system. This breaks the ability for MAC drivers to detect whether the PHY WoL is functional. 2. switching the interrupt pin in the .set_wol() method to PMEB mode immediately silences link-state interrupts, which breaks phylib when interrupts are being used rather than polling mode. 3. the code claiming to "reset WOL status" was doing nothing of the sort. Bit 15 in page 0xd8a register 17 controls WoL reset, and needs to be pulsed low to reset the WoL state. This bit was always written as '1', resulting in no reset. 4. not resetting WoL state results in the PMEB pin remaining asserted, which in turn leads to an interrupt storm. Only resetting the WoL state in .set_wol() is not sufficient. 5. PMEB mode does not allow software detection of the wake-up event as there is no status bit to indicate we received the WoL packet. 6. across reboots of at least the Jetson Xavier NX system, the WoL configuration is preserved. Fix all of these issues by essentially rewriting the support. We: 1. clear the WoL event enable register at probe time. 2. detect whether we can support wake-up by having a valid interrupt, and the "wakeup-source" property in DT. If we can, then we mark the MDIO device as wakeup capable, and associate the interrupt with the wakeup source. 3. arrange for the get_wol() and set_wol() implementations to handle the case where the MDIO device has not been marked as wakeup capable (thereby returning no WoL support, and refusing to enable WoL support.) 4. avoid switching to PMEB mode, instead using INTB mode with the interrupt enable, reconfiguring the interrupt enables at suspend time, and restoring their original state at resume time (we track the state of the interrupt enable register in .config_intr() register.) 5. move WoL reset from .set_wol() to the suspend function to ensure that WoL state is cleared prior to suspend. This is necessary after the PME interrupt has been enabled as a second WoL packet will not re-raise a previously cleared PME interrupt. 6. when a PME interrupt (for wakeup) is asserted, pass this to the PM wakeup so it knows which device woke the system. This fixes WoL support in the Realtek RTL8211F driver when used on the nVidia Jetson Xavier NX platform, and needs to be applied before stmmac patches which allow these platforms to forward the ethtool WoL commands to the Realtek PHY. Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Link: https://patch.msgid.link/E1um8Ld-008jxD-Mc@rmk-PC.armlinux.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.