Re: [RESEND, PATCH 3/5] soc: mediatek: mtk-cmdq: Add cmdq_pkt_poll_addr() function

["Jason-JH Lin (林睿祥)" <Jason-JH.Lin@mediatek.com>]

Hi CK,

Thanks for the reviews.

On Mon, 2024-03-04 at 03:11 +0000, CK Hu (胡俊光) wrote:
> Hi, Jason:
> 
> On Fri, 2024-03-01 at 22:44 +0800, Jason-JH.Lin wrote:
> > Add cmdq_pkt_poll_addr function to support CMDQ user making
> > an instruction for polling a specific address of hardware rigster
> > to check the value with or without mask.
> > 
> > POLL is an old operation in GCE, so it does not support SPR and
> > CMDQ_CODE_LOGIC. CMDQ users need to use GPR and CMDQ_CODE_MASK
> > to move polling register address to GPR to make an instruction.
> > This will be done in cmdq_pkt_poll_addr().
> > 
> > Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> > ---
> >  drivers/soc/mediatek/mtk-cmdq-helper.c | 38
> > ++++++++++++++++++++++++++
> >  include/linux/soc/mediatek/mtk-cmdq.h  | 16 +++++++++++
> >  2 files changed, 54 insertions(+)
> > 
> > diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c
> > b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > index 3a1e47ad8a41..2e9fc9bb1183 100644
> > --- a/drivers/soc/mediatek/mtk-cmdq-helper.c
> > +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> > @@ -12,6 +12,7 @@
> >  
> >  #define CMDQ_WRITE_ENABLE_MASK	BIT(0)
> >  #define CMDQ_POLL_ENABLE_MASK	BIT(0)
> > +#define CMDQ_POLL_HIGH_ADDR_GPR	(14)
> 
> I think there are multiple GPR and you use #14 to store high addr. I
> would like you to list all GPR and do not limit the usage of each
> GPR.
> The question is, why limit #14 to be high addr? If the GPR is shared
> by
> all threads, there should be a mechanism to manage GPR usage for
> client
> driver to allocate/free GPR.

Yes, there are 16 GPR, from GPR_R0 ~ GPR_R15 and they are shared by all
threads, but GPR_R0 and GPR_R1 is used by GCE HW itself.

I think user may not know which GPR is available, so I think CMDQ
driver should manage the usage of GPR instead of configure by the user.

Currently, we only use 1 dedicated GPR in poll, so I defined it in CMDQ
driver to make it simpler.

> 
> >  #define CMDQ_EOC_IRQ_EN		BIT(0)
> >  #define CMDQ_REG_TYPE		1
> >  #define CMDQ_JUMP_RELATIVE	1
> > @@ -406,6 +407,43 @@ int cmdq_pkt_poll_mask(struct cmdq_pkt *pkt,
> > u8
> > subsys,
> >  }
> >  EXPORT_SYMBOL(cmdq_pkt_poll_mask);
> >  
> > +int cmdq_pkt_poll_addr(struct cmdq_pkt *pkt, dma_addr_t addr, u32
> > value, u32 mask)
> > +{
> > +	struct cmdq_instruction inst = { {0} };
> > +	int err;
> > +	u8 use_mask = 0;
> > +
> > +	if (mask != U32_MAX) {
> > +		inst.op = CMDQ_CODE_MASK;
> > +		inst.mask = ~mask;
> > +		err = cmdq_pkt_append_command(pkt, inst);
> > +		if (err != 0)
> > +			return err;
> > +		use_mask = CMDQ_POLL_ENABLE_MASK;
> > +	}
> > +
> > +	/*
> > +	 * POLL is an old operation in GCE and it does not support SPR
> > and CMDQ_CODE_LOGIC,
> > +	 * so it can not use cmdq_pkt_assign to keep polling register
> > address to SPR.
> > +	 * It needs to use GPR and CMDQ_CODE_MASK to move polling
> > register address to GPR.
> > +	 */
> > +	inst.op = CMDQ_CODE_MASK;
> > +	inst.dst_t = CMDQ_REG_TYPE;
> > +	inst.sop = CMDQ_POLL_HIGH_ADDR_GPR;
> > +	inst.mask = addr;
> 
> This is full address, not high address. Why name the GPR to
> CMDQ_POLL_HIGH_ADDR_GPR?
> 
My mistake, I'll remove that 'HIGH' word.

> The addr is not mask, so I would like inst.value = addr.

OK, I'll change it.

Regards,
Jason-JH.Lin

> 
> Regards,
> CK
>