linux-kernel - Re: [PATCH 02/11] firmware: arm_scmi: Segregate tx channel handling and prepare to add rx

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Date:   Thu, 18 Jul 2019 17:23:10 -0400
From:   Jim Quinlan <james.quinlan@...adcom.com>
To:     Sudeep Holla <sudeep.holla@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Peng Fan <peng.fan@....com>,
        Bo Zhang <bozhang.zhang@...adcom.com>,
        Volodymyr Babchuk <volodymyr_babchuk@...m.com>
Subject: Re: [PATCH 02/11] firmware: arm_scmi: Segregate tx channel handling
 and prepare to add rx

On Mon, Jul 8, 2019 at 11:47 AM Sudeep Holla <sudeep.holla@....com> wrote:
>
> The transmit(Tx) channels are specified as the first entry and the
> receive(Rx) channels are the second entry as per the device tree
> bindings. Since we currently just support Tx, index 0 is hardcoded at
> all required callsites.
>
> In order to prepare for adding Rx support, let's remove those hardcoded
> index and add boolean parameter to identify Tx/Rx channels when setting
> them up.
>
> Signed-off-by: Sudeep Holla <sudeep.holla@....com>
> ---
>  drivers/firmware/arm_scmi/driver.c | 33 ++++++++++++++++--------------
>  1 file changed, 18 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
> index 0bd2af0a008f..f7fb6d5bfc64 100644
> --- a/drivers/firmware/arm_scmi/driver.c
> +++ b/drivers/firmware/arm_scmi/driver.c
> @@ -112,7 +112,7 @@ struct scmi_chan_info {
>   * @version: SCMI revision information containing protocol version,
>   *     implementation version and (sub-)vendor identification.
>   * @minfo: Message info
> - * @tx_idr: IDR object to map protocol id to channel info pointer
> + * @tx_idr: IDR object to map protocol id to Tx channel info pointer
>   * @protocols_imp: List of protocols implemented, currently maximum of
>   *     MAX_PROTOCOLS_IMP elements allocated by the base protocol
>   * @node: List head
> @@ -640,22 +640,26 @@ static int scmi_xfer_info_init(struct scmi_info *sinfo)
>         return 0;
>  }
>
> -static int scmi_mailbox_check(struct device_node *np)
> +static int scmi_mailbox_check(struct device_node *np, int idx)
>  {
> -       return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells", 0, NULL);
> +       return of_parse_phandle_with_args(np, "mboxes", "#mbox-cells",
> +                                         idx, NULL);
>  }
>
> -static inline int
> -scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
> +static int scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev,
> +                               int prot_id, bool tx)
>  {
> -       int ret;
> +       int ret, idx;
>         struct resource res;
>         resource_size_t size;
>         struct device_node *shmem, *np = dev->of_node;
>         struct scmi_chan_info *cinfo;
>         struct mbox_client *cl;
>
> -       if (scmi_mailbox_check(np)) {
> +       /* Transmit channel is first entry i.e. index 0 */
> +       idx = tx ? 0 : 1;
> +
> +       if (scmi_mailbox_check(np, idx)) {
>                 cinfo = idr_find(&info->tx_idr, SCMI_PROTOCOL_BASE);
>                 goto idr_alloc;
>         }
> @@ -669,11 +673,11 @@ scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
>         cl = &cinfo->cl;
>         cl->dev = dev;
>         cl->rx_callback = scmi_rx_callback;
> -       cl->tx_prepare = scmi_tx_prepare;
> +       cl->tx_prepare = tx ? scmi_tx_prepare : NULL;
>         cl->tx_block = false;
> -       cl->knows_txdone = true;
> +       cl->knows_txdone = tx;
>
> -       shmem = of_parse_phandle(np, "shmem", 0);
> +       shmem = of_parse_phandle(np, "shmem", idx);
Hi Sudeep,

You can't see it in the diff but you have two error messages that use
"Tx"; should this be changed to "Tx/Rx"?

Jim
>         ret = of_address_to_resource(shmem, 0, &res);
>         of_node_put(shmem);
>         if (ret) {
> @@ -688,8 +692,7 @@ scmi_mbox_chan_setup(struct scmi_info *info, struct device *dev, int prot_id)
>                 return -EADDRNOTAVAIL;
>         }
>
> -       /* Transmit channel is first entry i.e. index 0 */
> -       cinfo->chan = mbox_request_channel(cl, 0);
> +       cinfo->chan = mbox_request_channel(cl, idx);
>         if (IS_ERR(cinfo->chan)) {
>                 ret = PTR_ERR(cinfo->chan);
>                 if (ret != -EPROBE_DEFER)
> @@ -721,7 +724,7 @@ scmi_create_protocol_device(struct device_node *np, struct scmi_info *info,
>                 return;
>         }
>
> -       if (scmi_mbox_chan_setup(info, &sdev->dev, prot_id)) {
> +       if (scmi_mbox_chan_setup(info, &sdev->dev, prot_id, true)) {
>                 dev_err(&sdev->dev, "failed to setup transport\n");
>                 scmi_device_destroy(sdev);
>                 return;
> @@ -741,7 +744,7 @@ static int scmi_probe(struct platform_device *pdev)
>         struct device_node *child, *np = dev->of_node;
>
>         /* Only mailbox method supported, check for the presence of one */
> -       if (scmi_mailbox_check(np)) {
> +       if (scmi_mailbox_check(np, 0)) {
>                 dev_err(dev, "no mailbox found in %pOF\n", np);
>                 return -EINVAL;
>         }
> @@ -769,7 +772,7 @@ static int scmi_probe(struct platform_device *pdev)
>         handle->dev = info->dev;
>         handle->version = &info->version;
>
> -       ret = scmi_mbox_chan_setup(info, dev, SCMI_PROTOCOL_BASE);
> +       ret = scmi_mbox_chan_setup(info, dev, SCMI_PROTOCOL_BASE, true);
>         if (ret)
>                 return ret;
>
> --
> 2.17.1
>