Re: [PATCH v2 0/5] clk: imx6: work around LDB hang caused by ERR009219

[Andrey Smirnov <andrew.smirnov@gmail.com>]

On Tue, May 21, 2019 at 8:56 AM Ahmad Fatoum <a.fatoum@pengutronix.de> wrote:
>
> Short version:
>
> barebox always reparents the ldb_di[01] clocks to pll5_video_div.
> Due to a hardware erratum, this can trigger a glitch that causes
> LDB lock up.
>
> Thus:
>
> 1) remove the automatic reparenting, like the kernel now does and
>    mark the affected clocks read only, so assigned-clock-parents
>    can't affect them
> 2) parse assigned-clock-parents in the clk-imx6 code as well, but
>    there use a convoluted non-glitchy work around to apply them
>
> Long version available alongside v1 here:
> https://www.spinics.net/lists/u-boot-v2/msg37658.html;
> and in the commit messages of the patches.
>
> Changes since v2:
>  - reordered/squashed commits after discussion with Sascha and Phillip
>  - removed superfluous comment
>  - add MUX_READ_ONLY at the correct place in the MUX_READ_ONLY arguments
>
> Except for the last two, the total diff, is exactly the same
> as v1's.
>
>
> Ahmad Fatoum (2):
>   clk: imx6: remove quirky clk_set_parent(LDB_diN_sel, pll5_video_div)
>   clk: imx6: define an enum for ldb mux inputs
>
> Fabio Estevam (1):
>   clk: imx6: Fix procedure to switch the parent of LDB_DI_CLK
>
> Philipp Zabel (2):
>   clk: imx6: Make the LDB_DI0 and LDB_DI1 clocks read-only
>   clk: imx6: Mask mmdc_ch1 handshake for periph2_sel and
>     mmdc_ch1_axi_podf
>
>  drivers/clk/imx/clk-imx6.c | 320 +++++++++++++++++++++++++++++++++++--
>  drivers/clk/imx/clk.h      |   8 +
>  2 files changed, 312 insertions(+), 16 deletions(-)
>

Tested this on non 6Q+ RDU2, seems to work as expected when the whole
series is applied.

Tested-by: Andrey Smirnov <andrew.smirnov@gmail.com>

Thanks,
Andrey Smirnov

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