On Wed, May 31, 2023 at 07:58:03PM +0530, Manivannan Sadhasivam wrote: > + Jakub (who NACKed the previous submission of UCI driver) > Link to previous submission: https://lore.kernel.org/all/1606533966-22821-1-git-send-email-hemantk@xxxxxxxxxxxxxx/ > > On Mon, May 22, 2023 at 01:04:59PM -0600, Jeffrey Hugo wrote: > > From: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@xxxxxxxxxxx> > > > > I2C, USB, and PCIe are examples of buses which have a mechanism to give > > userspace direct access to a device on those buses. The MHI userspace > > character interface (uci) is the MHI bus analogue. > > > > The MHI bus devices are MHI channels which ferry blocks of data from one > > end to the other. With this simple purpose, we can define a simple > > interface to userspace - a character device that supports open/close/read/ > > write/poll operations. Since bus devices can only have a single consumer > > we encode a whitelist of MHI channels to be exported to userspace so as > > to avoid conflicts. > > > > We also make this mechanism open to any device that implements MHI. > > Today this includes WLAN (Wi-Fi), WWAN (4G/5G cellular), and ML/AI > > devices. More devices are expected in the future. > > > > In addition to implementing the framework for uci, we include an initial > > usecase - the QAIC Sahara device. > > > > Sahara is a file transfer protocol that is commonly used for two purposes > > when interacting with a device - transferring firmware to the device and > > transferring crashdumps from the device. The Sahara protocol puts the > > receiver of the data in control of the transfer. A firmware transfer > > operation would have the device requesting the specific firmware images > > that the device wants, and the host satisfying those requests. > > > > In most cases, including for AIC100, Sahara is used as part of a two stage > > loading process. The device will boot a very limited bootloader that does > > the base minimum initialization and jump to the next stage. A simple, one- > > shot protocol like BHI is used to send the next stage bootloader to the > > device. This second stage bootloader contains more functionality and > > implements the Sahara protocol. The second stage determines from various > > inputs what set of runtime firmware is required to boot the device into an > > operational status, and requests those pieces from the host. With those > > images transferred over, the device can funnly initialize. > > > > Each AIC100 instance (currently, up to 16) in a system will create a > > MHI device for QAIC_SAHARA. MHI_uci will consume each of these and create > > a unique chardev which will be found as > > /dev/<mhi instance>_QAIC_SAHARA > > For example - /dev/mhi0_QAIC_SAHARA > > > > An open userspace application that can consume these devices for firmware > > transfers is located at https://github.com/andersson/qdl > > > > Signed-off-by: Pranjal Ramajor Asha Kanojiya <quic_pkanojiy@xxxxxxxxxxx> > > [jhugo: Rename to uci, plumb to mhi, rewrite commit text] > > Signed-off-by: Jeffrey Hugo <quic_jhugo@xxxxxxxxxxx> > > The previous attempt on adding UCI driver was NACKed by Jakub. For merging this > patch, I need an ACK from Jakub. Given that this fails the kernel robot tests, why would anyone ack it as-is? confused, greg k-h
