[PATCH RFC 0/2] clk: meson: g12a: handle clock hw changes while in suspend

Neil Armstrong narmstrong at baylibre.com
Thu Sep 19 03:25:16 PDT 2019

This serie aime to support when the suspend/resume firmware alters the
clock tree, leading to an incorrect representation of the clock tree
after a resume from suspend-to-mem.

For the Amlogic G12A/G12B/SM1 case, the SCPI firmware handling suspend
alters the CPU clock tree in various ways.

Since we know which part of the tree is possibly altered, we introduce here
the clk_invalidate_rate() function that will rebuild the tree from the
hardware registers in case parents and dividers have changed.

Finally we call clk_invalidate_rate() from a new resume callback to refresh
the CPU clock tree after a resume.

With the clock tree refreshed, CCF can now handle the new clock tree
configuration and avoid crashing the system on further DVFS set_rates.

Neil Armstrong (2):
  clk: introduce clk_invalidate_rate()
  clk: meson: g12a: add suspend-resume hooks

 drivers/clk/clk.c        | 70 +++++++++++++++++++++++++++++++++++++++
 drivers/clk/meson/g12a.c | 71 +++++++++++++++++++++++++++++++++++-----
 include/linux/clk.h      | 13 ++++++++
 3 files changed, 146 insertions(+), 8 deletions(-)


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