On 10/9/21 2:25 AM, Bjorn Andersson wrote: > On Mon 12 Jul 06:23 PDT 2021, Arnaud Pouliquen wrote: > >> Allow the user space application to create and release an rpmsg device >> by adding RPMSG_CREATE_DEV_IOCTL and RPMSG_RELEASE_DEV_IOCTL ioctrls to >> the /dev/rpmsg_ctrl interface >> > > With > https://lore.kernel.org/linux-remoteproc/CAHk-=wgea9bo-j4+LAvZF7OKPAXKqrGgiBAhXTJ3Jv5JAZgA+A@xxxxxxxxxxxxxx/ > and > https://lore.kernel.org/linux-arm-msm/1609958656-15064-1-git-send-email-hemantk@xxxxxxxxxxxxxx/ > in mind, I would like some concrete examples of when and how this is > going to be used. > > > Also, as I said previously, this would have been better to put together > with the split out of rpmsg_ctrl, because afaict this is the only reason > for doing that. Or am I simply missing something? This as been done by steps to ease the review. Any way, these controls also require, to be usable for the rpmsg_char, the implementation of the rpmsg-raw channel in the rpmsg_char. Should i squash the 3 patchsets in one and add concrete examples in cover letter? > >> The RPMSG_CREATE_DEV_IOCTL Ioctl can be used to instantiate a local rpmsg >> device. >> Depending on the back-end implementation, the associated rpmsg driver is >> probed and a NS announcement can be sent to the remote processor. >> > > So, does this imply that in order to spawn a new rpmsg_char from the > host side, I would use RPMSG_CREATE_DEV_IOCTL and to open a channel > announced by the remote I would use RPMSG_CREATE_EPT_IOCTL? No, if announced by the remote side the rpmsg_char dev should be automatically probed by the virtio bus. The RPMSG_CREATE_EPT_IOCTL is the legacy control that is used by QCOM drivers to creates the cdev. It doesn't really make sense for the virtio backend, as virtio is based on a rpmsg channel that is associated to a rpmsg device. The only use case I have in mind would be to create endpoint without channel but using fixed addresses. No concrete use case identified in ST Microelectronics for hardcoded endpoint addresses. > >> The RPMSG_RELEASE_DEV_IOCTL allows the user application to release a >> rpmsg device created either by the remote processor or with the >> RPMSG_CREATE_DEV_IOCTL call. > > Is this a side effect, bug or a feature? Both a side effect but also a feature to remove a channel from the initiative of the user application. Regards, Arnaud > > Regards, > Bjorn > >> Depending on the back-end implementation, the associated rpmsg driver is >> removed and a NS destroy rpmsg can be sent to the remote processor. >> >> Suggested-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> >> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@xxxxxxxxxxx> >> Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> >> --- >> update from V2 >> - add Reviewed-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx> >> - rebased on kernel V.14-rc1 + >> series V5 Restructure the rpmsg char to decorrelate the control part [1] >> >> >> [1] https://patchwork.kernel.org/project/linux-remoteproc/list/?series=514017 >> >> --- >> drivers/rpmsg/rpmsg_ctrl.c | 37 +++++++++++++++++++++++++++++++++---- >> include/uapi/linux/rpmsg.h | 10 ++++++++++ >> 2 files changed, 43 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/rpmsg/rpmsg_ctrl.c b/drivers/rpmsg/rpmsg_ctrl.c >> index eeb1708548c1..cb19e32d05e1 100644 >> --- a/drivers/rpmsg/rpmsg_ctrl.c >> +++ b/drivers/rpmsg/rpmsg_ctrl.c >> @@ -23,6 +23,7 @@ >> #include <uapi/linux/rpmsg.h> >> >> #include "rpmsg_char.h" >> +#include "rpmsg_internal.h" >> >> static dev_t rpmsg_major; >> >> @@ -37,11 +38,13 @@ static DEFINE_IDA(rpmsg_minor_ida); >> * @rpdev: underlaying rpmsg device >> * @cdev: cdev for the ctrl device >> * @dev: device for the ctrl device >> + * @ctrl_lock: serialize the ioctrls. >> */ >> struct rpmsg_ctrldev { >> struct rpmsg_device *rpdev; >> struct cdev cdev; >> struct device dev; >> + struct mutex ctrl_lock; >> }; >> >> static int rpmsg_ctrldev_open(struct inode *inode, struct file *filp) >> @@ -70,9 +73,8 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, >> void __user *argp = (void __user *)arg; >> struct rpmsg_endpoint_info eptinfo; >> struct rpmsg_channel_info chinfo; >> - >> - if (cmd != RPMSG_CREATE_EPT_IOCTL) >> - return -EINVAL; >> + struct rpmsg_device *rpdev; >> + int ret = 0; >> >> if (copy_from_user(&eptinfo, argp, sizeof(eptinfo))) >> return -EFAULT; >> @@ -82,7 +84,33 @@ static long rpmsg_ctrldev_ioctl(struct file *fp, unsigned int cmd, >> chinfo.src = eptinfo.src; >> chinfo.dst = eptinfo.dst; >> >> - return rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); >> + mutex_lock(&ctrldev->ctrl_lock); >> + switch (cmd) { >> + case RPMSG_CREATE_EPT_IOCTL: >> + ret = rpmsg_chrdev_eptdev_create(ctrldev->rpdev, &ctrldev->dev, chinfo); >> + break; >> + >> + case RPMSG_CREATE_DEV_IOCTL: >> + rpdev = rpmsg_create_channel(ctrldev->rpdev, &chinfo); >> + if (!rpdev) { >> + dev_err(&ctrldev->dev, "failed to create %s channel\n", chinfo.name); >> + ret = -ENXIO; >> + } >> + break; >> + >> + case RPMSG_RELEASE_DEV_IOCTL: >> + ret = rpmsg_release_channel(ctrldev->rpdev, &chinfo); >> + if (ret) >> + dev_err(&ctrldev->dev, "failed to release %s channel (%d)\n", >> + chinfo.name, ret); >> + break; >> + >> + default: >> + ret = -EINVAL; >> + } >> + mutex_unlock(&ctrldev->ctrl_lock); >> + >> + return ret; >> }; >> >> static const struct file_operations rpmsg_ctrldev_fops = { >> @@ -119,6 +147,7 @@ static int rpmsg_ctrldev_probe(struct rpmsg_device *rpdev) >> device_initialize(dev); >> dev->parent = &rpdev->dev; >> >> + mutex_init(&ctrldev->ctrl_lock); >> cdev_init(&ctrldev->cdev, &rpmsg_ctrldev_fops); >> ctrldev->cdev.owner = THIS_MODULE; >> >> diff --git a/include/uapi/linux/rpmsg.h b/include/uapi/linux/rpmsg.h >> index f5ca8740f3fb..1637e68177d9 100644 >> --- a/include/uapi/linux/rpmsg.h >> +++ b/include/uapi/linux/rpmsg.h >> @@ -33,4 +33,14 @@ struct rpmsg_endpoint_info { >> */ >> #define RPMSG_DESTROY_EPT_IOCTL _IO(0xb5, 0x2) >> >> +/** >> + * Instantiate a new local rpmsg service device. >> + */ >> +#define RPMSG_CREATE_DEV_IOCTL _IOW(0xb5, 0x3, struct rpmsg_endpoint_info) >> + >> +/** >> + * Release a local rpmsg device. >> + */ >> +#define RPMSG_RELEASE_DEV_IOCTL _IOW(0xb5, 0x4, struct rpmsg_endpoint_info) >> + >> #endif >> -- >> 2.17.1 >>
