On Thu, 13 Jan 2022, Ricardo Martinez wrote: > From: Haijun Liu <haijun.liu@xxxxxxxxxxxx> > > Cross Layer DMA (CLDMA) Hardware interface (HIF) enables the control > path of Host-Modem data transfers. CLDMA HIF layer provides a common > interface to the Port Layer. > > CLDMA manages 8 independent RX/TX physical channels with data flow > control in HW queues. CLDMA uses ring buffers of General Packet > Descriptors (GPD) for TX/RX. GPDs can represent multiple or single > data buffers (DB). > > CLDMA HIF initializes GPD rings, registers ISR handlers for CLDMA > interrupts, and initializes CLDMA HW registers. > > CLDMA TX flow: > 1. Port Layer write > 2. Get DB address > 3. Configure GPD > 4. Triggering processing via HW register write > > CLDMA RX flow: > 1. CLDMA HW sends a RX "done" to host > 2. Driver starts thread to safely read GPD > 3. DB is sent to Port layer > 4. Create a new buffer for GPD ring > > Signed-off-by: Haijun Liu <haijun.liu@xxxxxxxxxxxx> > Signed-off-by: Chandrashekar Devegowda <chandrashekar.devegowda@xxxxxxxxx> > Co-developed-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx> > Signed-off-by: Ricardo Martinez <ricardo.martinez@xxxxxxxxxxxxxxx> > --- > + struct cldma_ring *tr_ring; > + struct cldma_request *tr_done; > + struct cldma_request *rx_refill; > + struct cldma_request *tx_xmit; > + int budget; /* Same as ring buffer size by default */ > + spinlock_t ring_lock; I couldn't figure out what ring_lock is supposed to protect exactly. Since there were tr_ring operations done w/o ring_lock (in t7xx_cldma_gpd_rx_from_q), I was left to wonder whether it's due to a locking bug or me not understanding what ring_lock is supposed to protect. -- i.
