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cd348ae871
Delaying link training need the irq to help set dly2_done which couldn't
come true in resume due to the noirq phase. If the training is still going
but the EP issues a hot reset request, the LTSSM will be stuck and the
link never be back even if we reset the EP. The only way is to reset the
whole controller, which is unacceptable.
The issue is very difficult to be reproduced but finally we spot the key
point from fifo status of ltssm. From the designe point of view, the only
way to make ltssm from 0x0(DETECT_QUIET) to 0x5(PRE_DETECT_QUIET) is
core_rst_n be active and dly logic taking over client settings.
[816669.085768][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xf0009
[816669.085775][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xe000a
[816669.085783][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xd000b
[816669.085790][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xc000c
[816669.085797][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xb0011
[816669.085804][ T2707] rk-pcie fe180000.pcie: fifo_status = 0xa000d
[816669.085811][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x9000f
[816669.085818][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x8000e
[816669.085826][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x107000d
[816669.085833][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x106000e
[816669.085840][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x5000d
[816669.085847][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x40005
[816669.085854][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x30000
[816669.085861][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x20005
[816669.085868][ T2707] rk-pcie fe180000.pcie: fifo_status = 0x10000
Given dly2_done is slef-clear bit, so we can't set it in advance but have
to disable dly2_en when linking in resume and enable it later.
Fixes: 679557456b ("PCIe: dw: rockchip: Delaying the link training after hot reset")
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
Change-Id: I85c24c7d7ea4c5f6718bcbdfbd7bf328d9a7f170
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.