b7fc72c633
SoCs supporting ULP0 or ULP1 modes and variants of Cadence Ethernet IP (controlled by macb driver) may behave buggy when Wake-on-Lan (WoL) is configured and WoL packet is received while in ULP0/ULP1. On some SoCs Ethernet interface is not working after resume. On other SoCs the CPU goes to abort on resume path when switching execution from internal SRAM to DRAM. For ULP1 + WoL the issue is related a particular restart sequence of the internal clocks when resuming. These clocks are automatically managed by PMC and may happen that GMAC peripheral clock is restarted few clock cycles before internal clocks causing blocking of Ethernet's DMA. As a consequence Ethernet TX transactions are stopped and RX transactions are partially stopped (packets are received by MAC, RX counters incremented but the data is not transferred to DRAM). The workaround for this is to disable Ethernet's peripheral clock when going to ULP1. Same behavior has been reproduced on ULP0 for some platforms (SAMA5D2, SAMA5D3) and the same workaround solves the issue. The problem has been solved on pm.c as quirk to avoid polluting the MACB driver with AT91 specific issues as this driver is generic to multiple vendors. At probe pointers to struct device_node are retrieved and on the at91_pm_enter() the quirk specifics are applied: for all Ethernet interfaces that were parsed the peripheral clocks are disabled. A special handling is done for modes in dns_modes mask as these are considered modes that blocks the system if WoL packet are received but for which applying quirk will lead to not waking up on WoL packets: in situation where Ethernet interface(s) has suspend mode in dns_modes mask and Ethernet interface(s) is the only available wakeup source the suspend is canceled. Signed-off-by: Claudiu Beznea <claudiu.beznea@microchip.com> Signed-off-by: Nicolas Ferre <nicolas.ferre@microchip.com>
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 Restructured Text 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.