Re: [PATCH v6 02/12] dmaengine: add DMA_PREP_LOCK and DMA_PREP_UNLOCK flag

[Vinod Koul <vkoul@kernel.org>]

On 15-01-25, 15:59, Md Sadre Alam wrote:
> Add lock and unlock flag support on command descriptor.
> Once lock set in requester pipe, then the bam controller
> will lock all others pipe and process the request only
> from requester pipe. Unlocking only can be performed from
> the same pipe.
> 
> If DMA_PREP_LOCK flag passed in command descriptor then requester
> of this transaction wanted to lock the BAM controller for this
> transaction so BAM driver should set LOCK bit for the HW descriptor.
> 
> If DMA_PREP_UNLOCK flag passed in command descriptor then requester
> of this transaction wanted to unlock the BAM controller.so BAM driver
> should set UNLOCK bit for the HW descriptor.
> 
> BAM IP version 1.4.0 and above only supports this LOCK/UNLOCK
> feature.

Have you aligned internally b/w team at Qualcomm to have this as single
approach for LOCK implementation. I would like to see ack from
Mukesh/Bjorn before proceeding ahead with this

> 
> Signed-off-by: Md Sadre Alam <quic_mdalam@quicinc.com>
> ---
> 
> Change in [v6]
> 
> * Change "BAM" to "DAM"
> 
> Change in [v5]
> 
> * Added DMA_PREP_LOCK and DMA_PREP_UNLOCK flag support
> 
> Change in [v4]
> 
> * This patch was not included in v4
> 
> Change in [v3]
> 
> * This patch was not included in v3
> 
> Change in [v2]
> 
> * This patch was not included in v2
>  
> Change in [v1]
> 
> * This patch was not included in v1
> 
>  Documentation/driver-api/dmaengine/provider.rst | 15 +++++++++++++++
>  include/linux/dmaengine.h                       |  6 ++++++
>  2 files changed, 21 insertions(+)
> 
> diff --git a/Documentation/driver-api/dmaengine/provider.rst b/Documentation/driver-api/dmaengine/provider.rst
> index 3085f8b460fa..a032e55d0a4f 100644
> --- a/Documentation/driver-api/dmaengine/provider.rst
> +++ b/Documentation/driver-api/dmaengine/provider.rst
> @@ -628,6 +628,21 @@ DMA_CTRL_REUSE
>    - This flag is only supported if the channel reports the DMA_LOAD_EOT
>      capability.
>  
> +- DMA_PREP_LOCK
> +
> +  - If set, the DMA will lock all other pipes not related to the current
> +    pipe group, and keep handling the current pipe only.
> +
> +  - All pipes not within this group will be locked by this pipe upon lock
> +    event.
> +
> +  - only pipes which are in the same group and relate to the same Environment
> +    Execution(EE) will not be locked by a certain pipe.
> +
> +- DMA_PREP_UNLOCK
> +
> +  - If set, DMA will release all locked pipes
> +
>  General Design Notes
>  ====================
>  
> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
> index 346251bf1026..8ebd43a998a7 100644
> --- a/include/linux/dmaengine.h
> +++ b/include/linux/dmaengine.h
> @@ -200,6 +200,10 @@ struct dma_vec {
>   *  transaction is marked with DMA_PREP_REPEAT will cause the new transaction
>   *  to never be processed and stay in the issued queue forever. The flag is
>   *  ignored if the previous transaction is not a repeated transaction.
> + *  @DMA_PREP_LOCK: tell the driver that there is a lock bit set on command
> + *  descriptor.
> + *  @DMA_PREP_UNLOCK: tell the driver that there is a un-lock bit set on command
> + *  descriptor.
>   */
>  enum dma_ctrl_flags {
>  	DMA_PREP_INTERRUPT = (1 << 0),
> @@ -212,6 +216,8 @@ enum dma_ctrl_flags {
>  	DMA_PREP_CMD = (1 << 7),
>  	DMA_PREP_REPEAT = (1 << 8),
>  	DMA_PREP_LOAD_EOT = (1 << 9),
> +	DMA_PREP_LOCK = (1 << 10),
> +	DMA_PREP_UNLOCK = (1 << 11),
>  };
>  
>  /**
> -- 
> 2.34.1

-- 
~Vinod