Re: [PATCH v1 10/12] soc: mediatek: cmdq: add loop function - Dennis-YC Hsieh

From: Dennis-YC Hsieh <dennis-yc.hsieh@mediatek.com>
To: CK Hu <ck.hu@mediatek.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Jassi Brar <jassisinghbrar@gmail.com>,
	<linux-kernel@vger.kernel.org>,
	<linux-mediatek@lists.infradead.org>,
	<devicetree@vger.kernel.org>, <wsd_upstream@mediatek.com>,
	Bibby Hsieh <bibby.hsieh@mediatek.com>,
	Houlong Wei <houlong.wei@mediatek.com>,
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v1 10/12] soc: mediatek: cmdq: add loop function
Date: Mon, 25 Nov 2019 15:36:56 +0800	[thread overview]
Message-ID: <1574667416.9851.1.camel@mtkswgap22> (raw)
In-Reply-To: <1574645703.4712.7.camel@mtksdaap41>

Hi CK,

On Mon, 2019-11-25 at 09:35 +0800, CK Hu wrote:
> Hi, Dennis:
> 
> On Fri, 2019-11-22 at 18:29 +0800, Dennis-YC Hsieh wrote:
> > Hi CK,
> > 
> > On Fri, 2019-11-22 at 17:46 +0800, CK Hu wrote:
> > > Hi, Dennis:
> > > 
> > > On Thu, 2019-11-21 at 17:12 +0800, Dennis YC Hsieh wrote:
> > > > Add finalize loop function in cmdq helper functions which loop whole pkt
> > > > in gce hardware thread without cpu operation.
> > > > 
> > > > Signed-off-by: Dennis YC Hsieh <dennis-yc.hsieh@mediatek.com>
> > > > ---
> > > >  drivers/soc/mediatek/mtk-cmdq-helper.c |   41 ++++++++++++++++++++++++++++++++
> > > >  include/linux/soc/mediatek/mtk-cmdq.h  |    8 +++++++
> > > >  2 files changed, 49 insertions(+)
> > > > 
> > > > diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > > > index 4235cf8..3b10241 100644
> > > > --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> > > > +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > > > @@ -385,12 +385,27 @@ int cmdq_pkt_assign(struct cmdq_pkt *pkt, u16 reg_idx, u32 value)
> > > >  }
> > > >  EXPORT_SYMBOL(cmdq_pkt_assign);
> > > >  
> > > > +static bool cmdq_pkt_finalized(struct cmdq_pkt *pkt)
> > > > +{
> > > > +	struct cmdq_instruction *inst;
> > > > +
> > > > +	if (pkt->cmd_buf_size < 2 * CMDQ_INST_SIZE)
> > > > +		return false;
> > > > +
> > > > +	inst = pkt->va_base + pkt->cmd_buf_size - 2 * CMDQ_INST_SIZE;
> > > > +	return inst->op == CMDQ_CODE_EOC;
> > > > +}
> > > > +
> > > >  static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> > > >  {
> > > >  	struct cmdq_client *cl = pkt->cl;
> > > >  	struct cmdq_instruction inst = { {0} };
> > > >  	int err;
> > > >  
> > > > +	/* do not finalize twice */
> > > > +	if (cmdq_pkt_finalized(pkt))
> > > > +		return 0;
> > > > +
> > > >  	/* insert EOC and generate IRQ for each command iteration */
> > > >  	inst.op = CMDQ_CODE_EOC;
> > > >  	inst.value = CMDQ_EOC_IRQ_EN;
> > > > @@ -406,6 +421,32 @@ static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> > > >  	return err;
> > > >  }
> > > >  
> > > > +int cmdq_pkt_finalize_loop(struct cmdq_pkt *pkt)
> > > > +{
> > > > +	struct cmdq_client *cl = pkt->cl;
> > > > +	struct cmdq_instruction inst = { {0} };
> > > > +	int err;
> > > > +
> > > > +	/* do not finalize twice */
> > > > +	if (cmdq_pkt_finalized(pkt))
> > > > +		return 0;
> > > 
> > > Why not just export cmdq_pkt_finalize() for user and do not call
> > > cmdq_pkt_finalize() in cmdq_pkt_flush_async(), so you don't need to
> > > check this.
> > > 
> > > I would be more like to export API such as cmdq_pkt_eoc(),
> > > cmdq_pkt_jump(), this would provide more flexibility for user to
> > > assemble the command it want.
> > > 
> > > Regards,
> > > CK
> > 
> > Thanks for your comment.
> > 
> > Should we backward compatible with existing clients? Remove finalize in
> > flush will cause existing client flush without IRQ.
> 
> The latest kernel (v5.4-rc8) still has no clients which use cmdq landed
> on upstream, and we don't need to consider backward compatible. [1] is
> the example that iommu would replace the proprietary interface with
> standard interface, so it would modify all clients which use the
> proprietary interface. So what you should do is to modify client as
> well.
> 
> [1]
> https://patchwork.kernel.org/project/linux-mediatek/list/?series=168801
> 
> Regards,
> CK

Ok, I'll remove all check code.
Thanks for your comment.

Regards,
Dennis

> > 
> > 
> > Regards,
> > Dennis
> > 
> > > 
> > > > +
> > > > +	/* insert EOC and generate IRQ for each command iteration */
> > > > +	inst.op = CMDQ_CODE_EOC;
> > > > +	err = cmdq_pkt_append_command(pkt, inst);
> > > > +	if (err < 0)
> > > > +		return err;
> > > > +
> > > > +	/* JUMP abaolute to begin */
> > > > +	inst.op = CMDQ_CODE_JUMP;
> > > > +	inst.offset = 1;
> > > > +	inst.value = pkt->pa_base >> cmdq_mbox_shift(cl->chan);
> > > > +	err = cmdq_pkt_append_command(pkt, inst);
> > > > +
> > > > +	return err;
> > > > +}
> > > > +EXPORT_SYMBOL(cmdq_pkt_finalize_loop);
> > > > +
> > > >  static void cmdq_pkt_flush_async_cb(struct cmdq_cb_data data)
> > > >  {
> > > >  	struct cmdq_pkt *pkt = (struct cmdq_pkt *)data.data;
> > > > diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
> > > > index b3474f2..77e8944 100644
> > > > --- a/include/linux/soc/mediatek/mtk-cmdq.h
> > > > +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> > > > @@ -203,6 +203,14 @@ int cmdq_pkt_poll_mask(struct cmdq_pkt *pkt, u8 subsys,
> > > >  int cmdq_pkt_assign(struct cmdq_pkt *pkt, u16 reg_idx, u32 value);
> > > >  
> > > >  /**
> > > > + * cmdq_pkt_finalize_loop() - Append EOC and jump command to loop pkt.
> > > > + * @pkt:	the CMDQ packet
> > > > + *
> > > > + * Return: 0 for success; else the error code is returned
> > > > + */
> > > > +int cmdq_pkt_finalize_loop(struct cmdq_pkt *pkt);
> > > > +
> > > > +/**
> > > >   * cmdq_pkt_flush_async() - trigger CMDQ to asynchronously execute the CMDQ
> > > >   *                          packet and call back at the end of done packet
> > > >   * @pkt:	the CMDQ packet
> > > 
> > > 
> > 
> > 
> 
> 