Le ven. 22 nov. 2024 à 11:01, CK Hu (胡俊光) <ck.hu@xxxxxxxxxxxx> a écrit :
>
> On Fri, 2024-11-22 at 10:50 +0100, Julien Stephan wrote:
> > External email : Please do not click links or open attachments until you have verified the sender or the content.
> >
> >
> > Le ven. 22 nov. 2024 à 10:49, CK Hu (胡俊光) <ck.hu@xxxxxxxxxxxx> a écrit :
> > >
> > > On Fri, 2024-11-22 at 10:25 +0100, Julien Stephan wrote:
> > > > External email : Please do not click links or open attachments until you have verified the sender or the content.
> > > >
> > > >
> > > > Le ven. 22 nov. 2024 à 09:41, CK Hu (胡俊光) <ck.hu@xxxxxxxxxxxx> a écrit :
> > > > >
> > > > > Hi, Julien:
> > > > >
> > > > > On Thu, 2024-11-21 at 09:53 +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]
> > > > >
> > > > > > +static irqreturn_t isp_irq_camsv30(int irq, void *data)
> > > > > > +{
> > > > > > + struct mtk_cam_dev *cam_dev = (struct mtk_cam_dev *)data;
> > > > > > + struct mtk_cam_dev_buffer *buf;
> > > > > > + unsigned int irq_status;
> > > > > > +
> > > > > > + spin_lock(&cam_dev->buf_list_lock);
> > > > > > +
> > > > > > + irq_status = mtk_camsv30_read(cam_dev, CAMSV_INT_STATUS);
> > > > > > +
> > > > > > + if (irq_status & INT_ST_MASK_CAMSV_ERR)
> > > > > > + dev_err(cam_dev->dev, "irq error 0x%lx\n",
> > > > > > + irq_status & INT_ST_MASK_CAMSV_ERR);
> > > > > > +
> > > > > > + /* De-queue frame */
> > > > > > + if (irq_status & CAMSV_IRQ_PASS1_DON) {
> > > > > > + cam_dev->sequence++;
> > > > > > +
> > > > > > + buf = list_first_entry_or_null(&cam_dev->buf_list,
> > > > > > + struct mtk_cam_dev_buffer,
> > > > > > + list);
> > > > > > + if (buf) {
> > > > > > + buf->v4l2_buf.sequence = cam_dev->sequence;
> > > > > > + buf->v4l2_buf.vb2_buf.timestamp =
> > > > > > + ktime_get_ns();
> > > > > > + vb2_buffer_done(&buf->v4l2_buf.vb2_buf,
> > > > > > + VB2_BUF_STATE_DONE);
> > > > > > + list_del(&buf->list);
> > > > > > + }
> > > > > > +
> > > > > > + buf = list_first_entry_or_null(&cam_dev->buf_list,
> > > > > > + struct mtk_cam_dev_buffer,
> > > > > > + list);
> > > > > > + if (buf)
> > > > > > + mtk_camsv30_update_buffers_add(cam_dev, buf);
> > > > >
> > > > > If buf == NULL, so hardware would automatically stop DMA?
> > > > > I don't know how this hardware work.
> > > > > Below is my imagine about this hardware.
> > > > >
> > > > > 1. Software use CAMSV_IMGO_FBC_RCNT_INC to increase software buffer index.
> > > > > 2. Hardware has a hardware buffer index. After hardware finish one frame, hardware buffer index increase.
> > > > > 3. After software buffer index increase, hardware start DMA.
> > > > > 4. When hardware buffer index is equal to software buffer index, hardware automatically stop DMA.
> > > > >
> > > > > Does the hardware work as my imagine?
> > > > > If hardware could automatically stop DMA, add comment to describe.
> > > > > If hardware could not automatically stop DMA, software should do something to stop DMA when buf == NULL.
> > > > >
> > > >
> > > > You are right except that dma is not stopped but frames are
> > > > automatically dropped by hardware until a new buffer is enqueued and
> > > > software uses CAMSV_IMGO_FBC_RCNT_INC to increase the software buffer
> > > > index.
> > > >
> > > > What about adding the following comment:
> > > >
> > > > /*
> > > > * If there is no user buffer available, hardware will drop automatically
> > > > * frames until buf_queue is called
> > > > */
> > >
> > > You say DMA is not stopped. Do you mean hardware still write data into latest buffer which would be dequeued to user space?
> > > I think hardware should not write data into the buffer which has been take away by user space.
> > > I think software should do something to stop DMA. Maybe use mtk_camsv30_cmos_vf_hw_disable() to stop DMA.
> > >
> >
> > No, I said frame is dropped.. It does not write any data.
>
> OK, for me, DMA mean memory access. Not writing any data is equal to stop DMA for me.
> The comment is OK for me now. But it may change after we discuss fbc_inc.
>
OK, sorry for confusion!
Did you notice my previous reply about fbc_inc?
Cheers
Julien
> Regards,
> CK
>
> >
> > > Regards,
> > > CK
> > >
> > > >
> > > > Let me know if that works for you
> > > >
> > > > Cheers
> > > > Julien
> > > >
> > > > > Regards,
> > > > > CK
> > > > >
> > > > > > + }
> > > > > > +
> > > > > > + spin_unlock(&cam_dev->buf_list_lock);
> > > > > > +
> > > > > > + return IRQ_HANDLED;
> > > > > > +}
> > > > > > +
> > > > >
> > > > > ************* MEDIATEK Confidentiality Notice ********************
> > > > > The information contained in this e-mail message (including any
> > > > > attachments) may be confidential, proprietary, privileged, or otherwise
> > > > > exempt from disclosure under applicable laws. It is intended to be
> > > > > conveyed only to the designated recipient(s). Any use, dissemination,
> > > > > distribution, printing, retaining or copying of this e-mail (including its
> > > > > attachments) by unintended recipient(s) is strictly prohibited and may
> > > > > be unlawful. If you are not an intended recipient of this e-mail, or believe
> > > > > that you have received this e-mail in error, please notify the sender
> > > > > immediately (by replying to this e-mail), delete any and all copies of
> > > > > this e-mail (including any attachments) from your system, and do not
> > > > > disclose the content of this e-mail to any other person. Thank you!
> > >
> > > ************* MEDIATEK Confidentiality Notice ********************
> > > The information contained in this e-mail message (including any
> > > attachments) may be confidential, proprietary, privileged, or otherwise
> > > exempt from disclosure under applicable laws. It is intended to be
> > > conveyed only to the designated recipient(s). Any use, dissemination,
> > > distribution, printing, retaining or copying of this e-mail (including its
> > > attachments) by unintended recipient(s) is strictly prohibited and may
> > > be unlawful. If you are not an intended recipient of this e-mail, or believe
> > > that you have received this e-mail in error, please notify the sender
> > > immediately (by replying to this e-mail), delete any and all copies of
> > > this e-mail (including any attachments) from your system, and do not
> > > disclose the content of this e-mail to any other person. Thank you!
> >
> >
>
> ************* MEDIATEK Confidentiality Notice ********************
> The information contained in this e-mail message (including any
> attachments) may be confidential, proprietary, privileged, or otherwise
> exempt from disclosure under applicable laws. It is intended to be
> conveyed only to the designated recipient(s). Any use, dissemination,
> distribution, printing, retaining or copying of this e-mail (including its
> attachments) by unintended recipient(s) is strictly prohibited and may
> be unlawful. If you are not an intended recipient of this e-mail, or believe
> that you have received this e-mail in error, please notify the sender
> immediately (by replying to this e-mail), delete any and all copies of
> this e-mail (including any attachments) from your system, and do not
> disclose the content of this e-mail to any other person. Thank you!
