[V5,0/2] Re-initialize DLL when MCLK is gated dynamically

Message

Veerabhadrarao Badiganti Nov. 12, 2018, 6:52 a.m. UTC

On few SDHCI-MSM controllers, the host controller's clock tuning
circuit may go out of sync if controller clocks are gated which
eventually, result in data CRC and command CRC/timeout errors.
To fix this issue, the DLL needs to be re-initialized and restored with
its old settings once clocks are ungated. SDHC cotroller on SDM845 SOC
has this limitation.

Changes since V4:
	- Exactly same as V3, posted multiple mails for V4.
	So to avoid confusion updating it as V5.

Changes since V3:
	- Introduced SoC specific dt compatible string for sdhci-msm
	controller
	- Moved the condition which checks whether tuning is needed or
	not, to a common function.

Changes since V2:
	- Removed an unused variable.
	- Renamed the newly introduced flags to be more meaningful.
	- Added new dt compatible string for SDM845 SOC.

Changes since V1:
	- Replaced dt flag with a dt compatible string to
	indicate SHDCI-MSM controller varients which need this fix.
	- Moved the DLL settings restoration logic from request 
	context to platform driver runtime pm context.

Tested on: sdm845
Veerabhadrarao Badiganti (2):
  dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings
  mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically

 .../devicetree/bindings/mmc/sdhci-msm.txt          | 21 ++++--
 drivers/mmc/host/sdhci-msm.c                       | 78 +++++++++++++++++++---
 2 files changed, 84 insertions(+), 15 deletions(-)

Comments

Ulf Hansson Nov. 20, 2018, 9:29 a.m. UTC | #1

On 12 November 2018 at 07:52, Veerabhadrarao Badiganti
<[e-mail]> wrote:
> On few SDHCI-MSM controllers, the host controller's clock tuning
> circuit may go out of sync if controller clocks are gated which
> eventually, result in data CRC and command CRC/timeout errors.
> To fix this issue, the DLL needs to be re-initialized and restored with
> its old settings once clocks are ungated. SDHC cotroller on SDM845 SOC
> has this limitation.
>
> Changes since V4:
>         - Exactly same as V3, posted multiple mails for V4.
>         So to avoid confusion updating it as V5.
>
> Changes since V3:
>         - Introduced SoC specific dt compatible string for sdhci-msm
>         controller
>         - Moved the condition which checks whether tuning is needed or
>         not, to a common function.
>
> Changes since V2:
>         - Removed an unused variable.
>         - Renamed the newly introduced flags to be more meaningful.
>         - Added new dt compatible string for SDM845 SOC.
>
> Changes since V1:
>         - Replaced dt flag with a dt compatible string to
>         indicate SHDCI-MSM controller varients which need this fix.
>         - Moved the DLL settings restoration logic from request
>         context to platform driver runtime pm context.
>
> Tested on: sdm845
> Veerabhadrarao Badiganti (2):
>   dt-bindings: mmc: sdhci-msm: Add SoC-specific compatible strings
>   mmc: sdhci-msm: Re-initialize DLL if MCLK is gated dynamically
>
>  .../devicetree/bindings/mmc/sdhci-msm.txt          | 21 ++++--
>  drivers/mmc/host/sdhci-msm.c                       | 78 +++++++++++++++++++---
>  2 files changed, 84 insertions(+), 15 deletions(-)

Applied for next, thanks!

Kind regards
Uffe