linux-kernel - Re: [PATCH] soc: qcom: smp2p: Access APCS as mailbox client

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Date:   Thu, 16 Nov 2017 17:47:32 +0530
From:   Arun Kumar Neelakantam <aneela@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <andy.gross@...aro.org>,
        David Brown <david.brown@...aro.org>
Cc:     linux-arm-msm@...r.kernel.org, linux-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: qcom: smp2p: Access APCS as mailbox client



On 11/16/2017 12:48 PM, Bjorn Andersson wrote:
> Attempt to acquire the APCS IPC through the mailbox framework and fall
> back to the old syscon based approach, to allow us to move away from
> using the syscon.
>
> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
> ---
>   drivers/soc/qcom/Kconfig |  1 +
>   drivers/soc/qcom/smp2p.c | 38 ++++++++++++++++++++++++++++++++------
>   2 files changed, 33 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
> index b00bccddcd3b..e67d9534fca0 100644
> --- a/drivers/soc/qcom/Kconfig
> +++ b/drivers/soc/qcom/Kconfig
> @@ -64,6 +64,7 @@ config QCOM_SMEM_STATE
>   
>   config QCOM_SMP2P
>   	tristate "Qualcomm Shared Memory Point to Point support"
> +	depends on MAILBOX
>   	depends on QCOM_SMEM
>   	select QCOM_SMEM_STATE
>   	help
> diff --git a/drivers/soc/qcom/smp2p.c b/drivers/soc/qcom/smp2p.c
> index f51fb2ea7200..7fdbb64142a0 100644
> --- a/drivers/soc/qcom/smp2p.c
> +++ b/drivers/soc/qcom/smp2p.c
> @@ -18,6 +18,7 @@
>   #include <linux/of.h>
>   #include <linux/irq.h>
>   #include <linux/irqdomain.h>
> +#include <linux/mailbox_client.h>
>   #include <linux/mfd/syscon.h>
>   #include <linux/module.h>
>   #include <linux/platform_device.h>
> @@ -126,6 +127,8 @@ struct smp2p_entry {
>    * @ipc_regmap:	regmap for the outbound ipc
>    * @ipc_offset:	offset within the regmap
>    * @ipc_bit:	bit in regmap@...set to kick to signal remote processor
> + * @mbox_client: mailbox client handle
> + * @mbox_chan:	apcs ipc mailbox channel handle
>    * @inbound:	list of inbound entries
>    * @outbound:	list of outbound entries
>    */
> @@ -146,6 +149,9 @@ struct qcom_smp2p {
>   	int ipc_offset;
>   	int ipc_bit;
>   
> +	struct mbox_client mbox_client;
> +	struct mbox_chan *mbox_chan;
> +
>   	struct list_head inbound;
>   	struct list_head outbound;
>   };
> @@ -154,7 +160,13 @@ static void qcom_smp2p_kick(struct qcom_smp2p *smp2p)
>   {
>   	/* Make sure any updated data is written before the kick */
>   	wmb();
> -	regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
> +
> +	if (smp2p->mbox_chan) {
> +		mbox_send_message(smp2p->mbox_chan, NULL);
> +		mbox_client_txdone(smp2p->mbox_chan, 0);
> +	} else {
> +		regmap_write(smp2p->ipc_regmap, smp2p->ipc_offset, BIT(smp2p->ipc_bit));
> +	}
>   }
>   
>   /**
> @@ -453,10 +465,6 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
>   
>   	platform_set_drvdata(pdev, smp2p);
>   
> -	ret = smp2p_parse_ipc(smp2p);
> -	if (ret)
> -		return ret;
> -
>   	key = "qcom,smem";
>   	ret = of_property_read_u32_array(pdev->dev.of_node, key,
>   					 smp2p->smem_items, 2);
> @@ -483,9 +491,22 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
>   		return irq;
>   	}
>   
> +	smp2p->mbox_client.dev = &pdev->dev;
> +	smp2p->mbox_chan = mbox_request_channel(&smp2p->mbox_client, 0);
any reason why we are not using "knows_txdone = true" for SMP2P but 
using for only SMD drivers
> +	if (IS_ERR(smp2p->mbox_chan)) {
> +		if (PTR_ERR(smp2p->mbox_chan) != -ENODEV)
> +			return PTR_ERR(smp2p->mbox_chan);
> +
> +		smp2p->mbox_chan = NULL;
> +
> +		ret = smp2p_parse_ipc(smp2p);
> +		if (ret)
> +			return ret;
> +	}
> +
>   	ret = qcom_smp2p_alloc_outbound_item(smp2p);
>   	if (ret < 0)
> -		return ret;
> +		goto release_mbox;
>   
>   	for_each_available_child_of_node(pdev->dev.of_node, node) {
>   		entry = devm_kzalloc(&pdev->dev, sizeof(*entry), GFP_KERNEL);
> @@ -540,6 +561,9 @@ static int qcom_smp2p_probe(struct platform_device *pdev)
>   
>   	smp2p->out->valid_entries = 0;
>   
> +release_mbox:
> +	mbox_free_channel(smp2p->mbox_chan);
> +
>   	return ret;
>   }
>   
> @@ -554,6 +578,8 @@ static int qcom_smp2p_remove(struct platform_device *pdev)
>   	list_for_each_entry(entry, &smp2p->outbound, node)
>   		qcom_smem_state_unregister(entry->state);
>   
> +	mbox_free_channel(smp2p->mbox_chan);
> +
>   	smp2p->out->valid_entries = 0;
>   
>   	return 0;