On Thu, Aug 01, 2019 at 12:56:36PM +0300, Daniel Baluta wrote: > Some of i.MX8 processors (e.g i.MX8QM, i.MX8QXP) contain > the Tensilica HiFi4 DSP for advanced pre- and post-audio > processing. > > The communication between Host CPU and DSP firmware is > taking place using a shared memory area for message passing > and a dedicated Messaging Unit for notifications. > > DSP IPC protocol offers a doorbell interface using > imx-mailbox API. > > We use 4 MU channels (2 x TXDB, 2 x RXDB) to implement a > request-reply protocol. > > Connection 0 (txdb0, rxdb0): > - Host writes messasge to shared memory [SHMEM] > - Host sends a request [MU] > - DSP handles request [SHMEM] > - DSP sends reply [MU] > > Connection 1 (txdb1, rxdb1): > - DSP writes a message to shared memory [SHMEM] > - DSP sends a request [MU] > - Host handles request [SHMEM] > - Host sends reply [MU] > > The protocol interface will be used by a Host client to > communicate with the DSP. First client will be the i.MX8 > part from Sound Open Firmware infrastructure. > > The protocol offers the following interface: > > On Tx: > - imx_dsp_ring_doorbell, will be called to notify the DSP > that it needs to handle a request. > > On Rx: > - clients need to provide two callbacks: > .handle_reply > .handle_request > - the callbacks will be used by the protocol on > notification arrival from DSP. > > Signed-off-by: Daniel Baluta <[email protected]>
Applied, thanks.
