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Subject: Re: [PATCH v4 02/37] firmware: arm_scmi: introduce protocol handle
 definitions
To:     Cristian Marussi <cristian.marussi@arm.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Cc:     sudeep.holla@arm.com, lukasz.luba@arm.com,
        james.quinlan@broadcom.com, Jonathan.Cameron@Huawei.com,
        f.fainelli@gmail.com, etienne.carriere@linaro.org,
        vincent.guittot@linaro.org, souvik.chakravarty@arm.com
References: <20210106201610.26538-1-cristian.marussi@arm.com>
 <20210106201610.26538-3-cristian.marussi@arm.com>
From:   Thara Gopinath <thara.gopinath@linaro.org>
Message-ID: <19054e89-c117-ef85-444e-8e126a8a9efb@linaro.org>
Date:   Thu, 7 Jan 2021 09:29:17 -0500
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On 1/6/21 3:15 PM, Cristian Marussi wrote:
> Add basic protocol handles definitions and private data helpers support.
> 
> A protocol handle identifies a protocol instance initialized against a
> specific handle; it embeds all the references to the core SCMI xfer methods
> that will be needed by a protocol implementation to build and send its own
> protocol specific messages using common core methods.
> 
> As such, in the interface, a protocol handle will be passed down from the
> core to the protocol specific initialization callback at init time.
> 
> Anyway at this point only definitions are introduced, all protocols
> initialization code and SCMI drivers probing is still based on the old
> interface, so no functional change.
> 
> Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
> ---
>   drivers/firmware/arm_scmi/common.h | 59 ++++++++++++++++++++++++++++++
>   drivers/firmware/arm_scmi/driver.c | 45 +++++++++++++++++++++++
>   2 files changed, 104 insertions(+)
> 
> diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
> index e052507dc918..977e31224efe 100644
> --- a/drivers/firmware/arm_scmi/common.h
> +++ b/drivers/firmware/arm_scmi/common.h
> @@ -149,6 +149,65 @@ int scmi_xfer_get_init(const struct scmi_handle *h, u8 msg_id, u8 prot_id,
>   		       size_t tx_size, size_t rx_size, struct scmi_xfer **p);
>   void scmi_reset_rx_to_maxsz(const struct scmi_handle *handle,
>   			    struct scmi_xfer *xfer);
> +
> +struct scmi_xfer_ops;
> +
> +/**
> + * struct scmi_protocol_handle  - Reference to an initialized protocol instance
> + *
> + * @dev: A reference to the associated SCMI instance device (handle->dev).
> + * @xops: A reference to a struct holding refs to the core xfer operations that
> + *	  can be used by the protocol implementation to generate SCMI messages.
> + * @set_priv: A method to set protocol private data for this instance.
> + * @get_priv: A method to get protocol private data previously set.
> + *
> + * This structure represents a protocol initialized against specific SCMI
> + * instance and it will be used as follows:
> + * - as a parameter fed from the core to the protocol initialization code so
> + *   that it can access the core xfer operations to build and generate SCMI
> + *   messages exclusively for the specific underlying protocol instance.
> + * - as an opaque handle fed by an SCMI driver user when it tries to access
> + *   this protocol through its own protocol operations.
> + *   In this case this handle will be returned as an opaque object together
> + *   with the related protocol operations when the SCMI driver tries to access
> + *   the protocol.
> + */
> +struct scmi_protocol_handle {
> +	struct device *dev;
> +	const struct scmi_xfer_ops *xops;
> +	int (*set_priv)(const struct scmi_protocol_handle *ph, void *priv);
> +	void *(*get_priv)(const struct scmi_protocol_handle *ph);
> +};
> +
> +/**
> + * struct scmi_xfer_ops  - References to the core SCMI xfer operations.
> + * @version_get: Get this version protocol.
> + * @xfer_get_init: Initialize one struct xfer if any xfer slot is free.
> + * @reset_rx_to_maxsz: Reset rx size to max transport size.
> + * @do_xfer: Do the SCMI transfer.
> + * @do_xfer_with_response: Do the SCMI transfer waiting for a response.
> + * @xfer_put: Free the xfer slot.
> + *
> + * Note that all this operations expect a protocol handle as first parameter;
> + * they then internally use it to infer the underlying protocol number: this
> + * way is not possible for a protocol implementation to forge messages for
> + * another protocol.
> + */
> +struct scmi_xfer_ops {

Maybe move the definition above struct scmi_protocol_handle to avoid a 
declaration ?


-- 
Warm Regards
Thara