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SubjectRe: [PATCH v4 12/27] bus: mhi: ep: Add support for creating and destroying MHI EP devices
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On 2/28/22 6:43 AM, Manivannan Sadhasivam wrote:
> This commit adds support for creating and destroying MHI endpoint devices.
> The MHI endpoint devices binds to the MHI endpoint channels and are used
> to transfer data between MHI host and endpoint device.
>
> There is a single MHI EP device for each channel pair. The devices will be
> created when the corresponding channels has been started by the host and
> will be destroyed during MHI EP power down and reset.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

Looks good.

Reviewed-by: Alex Elder <elder@linaro.org>

> ---
> drivers/bus/mhi/ep/main.c | 83 +++++++++++++++++++++++++++++++++++++++
> 1 file changed, 83 insertions(+)
>
> diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
> index 2bdcf1657479..3afae0bfd83c 100644
> --- a/drivers/bus/mhi/ep/main.c
> +++ b/drivers/bus/mhi/ep/main.c
> @@ -68,6 +68,89 @@ static struct mhi_ep_device *mhi_ep_alloc_device(struct mhi_ep_cntrl *mhi_cntrl,
> return mhi_dev;
> }
>
> +/*
> + * MHI channels are always defined in pairs with UL as the even numbered
> + * channel and DL as odd numbered one. This function gets UL channel (primary)
> + * as the ch_id and always looks after the next entry in channel list for
> + * the corresponding DL channel (secondary).
> + */
> +static int mhi_ep_create_device(struct mhi_ep_cntrl *mhi_cntrl, u32 ch_id)
> +{
> + struct mhi_ep_chan *mhi_chan = &mhi_cntrl->mhi_chan[ch_id];
> + struct device *dev = mhi_cntrl->cntrl_dev;
> + struct mhi_ep_device *mhi_dev;
> + int ret;
> +
> + /* Check if the channel name is same for both UL and DL */
> + if (strcmp(mhi_chan->name, mhi_chan[1].name)) {
> + dev_err(dev, "UL and DL channel names are not same: (%s) != (%s)\n",
> + mhi_chan->name, mhi_chan[1].name);
> + return -EINVAL;
> + }
> +
> + mhi_dev = mhi_ep_alloc_device(mhi_cntrl, MHI_DEVICE_XFER);
> + if (IS_ERR(mhi_dev))
> + return PTR_ERR(mhi_dev);
> +
> + /* Configure primary channel */
> + mhi_dev->ul_chan = mhi_chan;
> + get_device(&mhi_dev->dev);
> + mhi_chan->mhi_dev = mhi_dev;
> +
> + /* Configure secondary channel as well */
> + mhi_chan++;
> + mhi_dev->dl_chan = mhi_chan;
> + get_device(&mhi_dev->dev);
> + mhi_chan->mhi_dev = mhi_dev;
> +
> + /* Channel name is same for both UL and DL */
> + mhi_dev->name = mhi_chan->name;
> + dev_set_name(&mhi_dev->dev, "%s_%s",
> + dev_name(&mhi_cntrl->mhi_dev->dev),
> + mhi_dev->name);
> +
> + ret = device_add(&mhi_dev->dev);
> + if (ret)
> + put_device(&mhi_dev->dev);
> +
> + return ret;
> +}
> +
> +static int mhi_ep_destroy_device(struct device *dev, void *data)
> +{
> + struct mhi_ep_device *mhi_dev;
> + struct mhi_ep_cntrl *mhi_cntrl;
> + struct mhi_ep_chan *ul_chan, *dl_chan;
> +
> + if (dev->bus != &mhi_ep_bus_type)
> + return 0;
> +
> + mhi_dev = to_mhi_ep_device(dev);
> + mhi_cntrl = mhi_dev->mhi_cntrl;
> +
> + /* Only destroy devices created for channels */
> + if (mhi_dev->dev_type == MHI_DEVICE_CONTROLLER)
> + return 0;
> +
> + ul_chan = mhi_dev->ul_chan;
> + dl_chan = mhi_dev->dl_chan;
> +
> + if (ul_chan)
> + put_device(&ul_chan->mhi_dev->dev);
> +
> + if (dl_chan)
> + put_device(&dl_chan->mhi_dev->dev);
> +
> + dev_dbg(&mhi_cntrl->mhi_dev->dev, "Destroying device for chan:%s\n",
> + mhi_dev->name);
> +
> + /* Notify the client and remove the device from MHI bus */
> + device_del(dev);
> + put_device(dev);
> +
> + return 0;
> +}
> +
> static int mhi_ep_chan_init(struct mhi_ep_cntrl *mhi_cntrl,
> const struct mhi_ep_cntrl_config *config)
> {

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