Hi Krzysztof,

On 05/12/14 12:00, Krzysztof Kozlowski wrote:

Audio subsystem clocks are located in separate block. If clock for this
block (from main clock domain) 'mau_epll' is gated then any read or
write to audss registers will block.

This was observed on Exynos 5420 platforms (Arndale Octa and Peach
Pi/Pit) after introducing runtime PM to pl330 DMA driver. After that
commit the 'mau_epll' was gated, because the "amba" clock was disabled
and there were no more users of mau_epll. The system hang on disabling
unused clocks from audss block.

Unfortunately the 'mau_epll' clock is not parent of some of audss clocks.

Whenever system wants to operate on audss clocks it has to enable epll
clock. The solution reuses common clk-gate/divider/mux code and duplicates
clk_register_*() functions.

Additionally this patch fixes memory leak of clock gate/divider/mux
structures. The leak exists in generic clk_register_*() functions. Patch
replaces them with custom code with managed allocation.

Signed-off-by: Krzysztof Kozlowski <redacted>
Reported-by: Javier Martinez Canillas <redacted>
Reported-by: Kevin Hilman <khilman@kernel.org>
Tested-by: Javier Martinez Canillas <redacted>

Instead of this big patch perhaps for v3.19 we could just add
a clk_enable() call in exynos5420 clock controller driver, to make
sure the required clock is always enabled, as it was before you have
added runtime PM support to the PL330 DMA controller driver ?

It sounds like a workaround but wouldn't be as intrusive as this
patch.

--
Regards,
Sylwester