Hi, Julien: On Wed, 2025-01-22 at 14:59 +0100, Julien Stephan wrote: > External email : Please do not click links or open attachments until you have verified the sender or the content. > > > From: Phi-bang Nguyen <pnguyen@xxxxxxxxxxxx> > > This driver provides a path to bypass the SoC ISP so that image data > coming from the SENINF can go directly into memory without any image > processing. This allows the use of an external ISP. > > Signed-off-by: Phi-bang Nguyen <pnguyen@xxxxxxxxxxxx> > Signed-off-by: Florian Sylvestre <fsylvestre@xxxxxxxxxxxx> > [Paul Elder fix irq locking] > Signed-off-by: Paul Elder <paul.elder@xxxxxxxxxxxxxxxx> > Co-developed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Co-developed-by: Julien Stephan <jstephan@xxxxxxxxxxxx> > Signed-off-by: Julien Stephan <jstephan@xxxxxxxxxxxx> > --- [snip] > + > +/* > + * Camsv module is able to handle underrruns using the FBC > + * > + * - FBC_FB_NUM: the number of userspace buffers available (fifo depth) > + * - RCNT_INC: user writes 1 when buffer is queued/unqueued > + * - FBC_CNT: decreased at SOF indicating that the number of buffers filled > + * by write-DMA decreases. Increased when write-dma done indicating that > + * the number of buffers filled by write-DMA increases > + * - RCNT: increased at the end of enqueue indicating that the software > + * moves to the next buffer for reading > + * - WCNT: increased to indicate that write-dma writes to the next buffer > + * Drop condition: FBC_CNT == FBC_NUM The description more confuse me. Below is what I guess: RCNT_INT: This is used to increase 1 of RCNT RCNT: Read pointer which point to the last software prepared buffer count WCNT: Write pointer which point to the hardware last write buffer count Drop condition: WCNT == RCNT My guess is totally different with your description. So let me ask question about your description. RCNT_INC: user writes 1 when buffer is queued/unqueued => Describe what it actually do, does it increase any counter? Which counter? FBC_CNT or RCNT?
