Re: [PATCH v5 0/8] imx8mp: Add support to Run/Stall DSP via reset API

[Mathieu Poirier]

Thanks for the re-spin.  I will wait for Shawn and Sascha to review their
respective bits before picking up this set.

Mathieu

On Tue, Mar 11, 2025 at 10:58:03AM +0200, Daniel Baluta wrote:
> This patch series adds support to control the Run/Stall DSP bits found on
> i.MX8MP via the reset controller API instead of using the syscon API.
> 
> DSP found on i.MX8MP doesn't have a direct reset line so according to hardware
> design team in order to handle assert/deassert/reset functionality we
> need to use a combination of control bits from two modules.
> 
> Audio block control module:
> 	- for Run/Stall control bits of the DSP
> 
> Debug Access Port (DAP)
> 	- for Software Reset via IMX8M_DAP_PWRCTL register
> 
> The current implementation for IMX DSP Remotproc driver and for Sound Open
> Firmware driver (already upstream) uses the following approach:
> 	- maps the Audio Block Control address via syscon API through
>           the fsl,dsp-ctrl property of the dsp node.
> 	- maps the DAP address space using directly a call to ioremap
>           with IMX8M_DAP_DEBUG macro depicting the DAP base address.
> 
> The both approaches are problematic when comes to describing the address
> spaces via the DT:
> 	- for Audio Block Control, because it uses the syscon interface
> 	- for DAP because it hardcodes de base address instead of using a dt node.
> 
> This patch series aims to fix the Audio Block control usage of the
> syscon interface and replace it with Reset Controller interface.
> 
> Main advantages of using the Reset Controller API is that we stop
> abusing the syscon interface, offer a better probe ordering, PM runtime
> support. Main critique of using the Reset Controller API is that
> Run/Stall bits are not reset bits (but according the hardware design
> team they are part of the reset proccess since there is no real reset
> line).
> 
> Initial discussion is here:
> https://patchwork.kernel.org/project/imx/patch/20250212085222.107102-6-daniel.baluta@xxxxxxx/
> 
> Note that we can safely remove the fsl,dsp-ctrl property usage from IMX DSP
> remoteproc driver because there is no Device Tree users.
> 
> Changes since v4:
> https://lore.kernel.org/lkml/20250305100037.373782-3-daniel.baluta@xxxxxxx/T/
> 	- picked-up R-b tags from Frank Li and Peng Fan
> 	- reworded commit message of patch 8/8 as per Mathieu Poirier suggestion
> 
> Changes since v3:
> https://lore.kernel.org/linux-arm-kernel/20250225102005.408773-5-daniel.baluta@xxxxxxx/T/
> 	- renamed resets ids as per Philipp comments
> 	- add boths resets (named them runstall and softreset) as per Philipp comments
> 
> Changes since v2:
> (https://lore.kernel.org/lkml/Z7ZNngd3wtJ5MZgl@lizhi-Precision-Tower-5810/T/)
>         - picked R-b and A-b tags
>         - use run_stall instead of reset to refer to reset controller
>           instance
>         - remove 'resets' description as it is a common property
>         - add correct include in the yaml dts snippet example
> Changes since v1:
> (https://lore.kernel.org/imx/20250219030809.GD6537@nxa18884-linux/T/)
>         - addresed comments received on v1
>         - picked up R-b and A-b tags
> 
> Daniel Baluta (8):
>   dt-bindings: reset: audiomix: Add reset ids for EARC and DSP
>   dt-bindings: dsp: fsl,dsp: Add resets property
>   arm64: dts: imx8mp: Use resets property
>   reset: imx8mp-audiomix: Add prefix for internal macro
>   reset: imx8mp-audiomix: Prepare the code for more reset bits
>   reset: imx8mp-audiomix: Introduce active_low configuration option
>   reset: imx8mp-audiomix: Add support for DSP run/stall
>   imx_dsp_rproc: Use reset controller API to control the DSP
> 
>  .../devicetree/bindings/dsp/fsl,dsp.yaml      | 24 +++++-
>  arch/arm64/boot/dts/freescale/imx8mp.dtsi     |  3 +
>  drivers/remoteproc/imx_dsp_rproc.c            | 25 ++++--
>  drivers/remoteproc/imx_rproc.h                |  2 +
>  drivers/reset/reset-imx8mp-audiomix.c         | 78 +++++++++++++------
>  .../dt-bindings/reset/imx8mp-reset-audiomix.h | 13 ++++
>  6 files changed, 114 insertions(+), 31 deletions(-)
>  create mode 100644 include/dt-bindings/reset/imx8mp-reset-audiomix.h
> 
> -- 
> 2.43.0
>