Re: [PATCH v22 4/4] soc: mediatek: Add Mediatek CMDQ helper

[houlong wei]

On Thu, 2018-06-28 at 18:41 +0800, CK Hu wrote:
> Hi, Houlong:
> 
> Some inline comment.
> 
> On Wed, 2018-06-27 at 19:16 +0800, Houlong Wei wrote:
> > Add Mediatek CMDQ helper to create CMDQ packet and assemble GCE op code.
> > 
> > Signed-off-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
> > Signed-off-by: HS Liao <hs.liao@xxxxxxxxxxxx>
> > ---
> >  drivers/soc/mediatek/Kconfig           |   12 ++
> >  drivers/soc/mediatek/Makefile          |    1 +
> >  drivers/soc/mediatek/mtk-cmdq-helper.c |  258 ++++++++++++++++++++++++++++++++
> >  include/linux/soc/mediatek/mtk-cmdq.h  |  132 ++++++++++++++++
> >  4 files changed, 403 insertions(+)
> >  create mode 100644 drivers/soc/mediatek/mtk-cmdq-helper.c
> >  create mode 100644 include/linux/soc/mediatek/mtk-cmdq.h
> > 
> > diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> > index a7d0667..17bd759 100644
> > --- a/drivers/soc/mediatek/Kconfig
> > +++ b/drivers/soc/mediatek/Kconfig
> > @@ -4,6 +4,18 @@
> >  menu "MediaTek SoC drivers"
> >  	depends on ARCH_MEDIATEK || COMPILE_TEST
> >  
> 
> [...]
> 
> > +
> > +int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u32 event)
> > +{
> > +	u32 arg_b;
> > +
> > +	if (event >= CMDQ_MAX_EVENT || event < 0)
> 
> The type of event is 'u32', so checking 'event < 0' is redundant.

will fix.

> 
> > +		return -EINVAL;
> > +
> > +	/*
> > +	 * WFE arg_b
> > +	 * bit 0-11: wait value
> > +	 * bit 15: 1 - wait, 0 - no wait
> > +	 * bit 16-27: update value
> > +	 * bit 31: 1 - update, 0 - no update
> > +	 */
> > +	arg_b = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
> > +
> > +	return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE, event, arg_b);
> > +}
> > +EXPORT_SYMBOL(cmdq_pkt_wfe);
> > +
> > +int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, u32 event)
> > +{
> > +	if (event >= CMDQ_MAX_EVENT || event < 0)
> 
> The type of event is 'u32', so checking 'event < 0' is redundant.

Will fix.

> 
> > +		return -EINVAL;
> > +
> > +	return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE, event,
> > +				       CMDQ_WFE_UPDATE);
> > +}
> > +EXPORT_SYMBOL(cmdq_pkt_clear_event);
> > +
> > +static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> > +{
> > +	int err;
> > +
> > +	if (cmdq_pkt_is_finalized(pkt))
> > +		return 0;
> > +
> > +	/* insert EOC and generate IRQ for each command iteration */
> > +	err = cmdq_pkt_append_command(pkt, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	/* JUMP to end */
> > +	err = cmdq_pkt_append_command(pkt, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	return 0;
> > +}
> > +
> > +int cmdq_pkt_flush_async(struct cmdq_client *client, struct cmdq_pkt *pkt,
> > +			 cmdq_async_flush_cb cb, void *data)
> > +{
> > +	int err;
> > +	struct device *dev;
> > +	dma_addr_t dma_addr;
> > +
> > +	err = cmdq_pkt_finalize(pkt);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	dev = client->chan->mbox->dev;
> > +	dma_addr = dma_map_single(dev, pkt->va_base, pkt->cmd_buf_size,
> > +		DMA_TO_DEVICE);
> 
> You map here, but I could not find unmap, so the unmap should be done in
> client driver. I would prefer a symmetric map/unmap which means that
> both map and unmap are done in client driver. I think you put map here
> because you should map after finalize. 

The unmap is done before callback to client, in function
cmdq_task_exec_done, mtk-cmdq-mailbox.c.

> Therefore, export
> cmdq_pkt_finalize() to client driver and let client do finalize, so
> there is no finalize in flush function. This method have a benefit that
> if client reuse command buffer, it need not to map/unmap frequently.

If client reuse command buffer or cmdq_pkt(command queue packet), client
will add new commands to the cmdq_pkt, so map/unmap are necessary for
each cmdq_pkt flush.

> 
> Regards,
> CK
> 
> > +	if (dma_mapping_error(dev, dma_addr)) {
> > +		dev_err(client->chan->mbox->dev, "dma map failed\n");
> > +		return -ENOMEM;
> > +	}
> > +
> > +	pkt->pa_base = dma_addr;
> > +	pkt->cb.cb = cb;
> > +	pkt->cb.data = data;
> > +
> > +	mbox_send_message(client->chan, pkt);
> > +	/* We can send next packet immediately, so just call txdone. */
> > +	mbox_client_txdone(client->chan, 0);
> > +
> > +	return 0;
> > +}
> > +EXPORT_SYMBOL(cmdq_pkt_flush_async);
> > +
> > +struct cmdq_flush_completion {
> > +	struct completion cmplt;
> > +	bool err;
> > +};
> > +
> > +static void cmdq_pkt_flush_cb(struct cmdq_cb_data data)
> > +{
> > +	struct cmdq_flush_completion *cmplt = data.data;
> > +
> > +	cmplt->err = data.err;
> > +	complete(&cmplt->cmplt);
> > +}
> > +
> > +int cmdq_pkt_flush(struct cmdq_client *client, struct cmdq_pkt *pkt)
> > +{
> > +	struct cmdq_flush_completion cmplt;
> > +	int err;
> > +
> > +	init_completion(&cmplt.cmplt);
> > +	err = cmdq_pkt_flush_async(client, pkt, cmdq_pkt_flush_cb, &cmplt);
> > +	if (err < 0)
> > +		return err;
> > +	wait_for_completion(&cmplt.cmplt);
> > +
> > +	return cmplt.err ? -EFAULT : 0;
> > +}
> > +EXPORT_SYMBOL(cmdq_pkt_flush);
> 
> [...]
> 
>