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Date: Fri, 2 Feb 2024 17:56:48 +0530
From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: Mrinmay Sarkar <quic_msarkar@quicinc.com>, vkoul@kernel.org,
	jingoohan1@gmail.com, conor+dt@kernel.org, konrad.dybcio@linaro.org,
	robh+dt@kernel.org, quic_shazhuss@quicinc.com,
	quic_nitegupt@quicinc.com, quic_ramkri@quicinc.com,
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	mhi@lists.linux.dev
Subject: Re: [PATCH v1 4/6] dmaengine: dw-edma: Move HDMA_V0_MAX_NR_CH
 definition to edma.h
Message-ID: <20240202122648.GD8020@thinkpad>
References: <1705669223-5655-1-git-send-email-quic_msarkar@quicinc.com>
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In-Reply-To: <qfdsnz7louqdrs6mhz72o6mzjo66kw63vtlhgpz6hgqfyyzyhq@tge3r7mvwtw3>

On Fri, Feb 02, 2024 at 01:47:37PM +0300, Serge Semin wrote:
> Hi Mrinmay
> 
> On Fri, Jan 19, 2024 at 06:30:20PM +0530, Mrinmay Sarkar wrote:
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > 
> > To maintain uniformity with eDMA, let's move the HDMA max channel
> > definition to edma.h. While at it, let's also rename it to HDMA_MAX_NR_CH.
> 
> First of all include/linux/dma/edma.h already contains the common DW
> EDMA and _HDMA_ settings/entities including the number of channels.
> Both of these IP-cores have the same constraints on the max amount of
> channels. Moreover the EDMA_MAX_WR_CH/EDMA_MAX_RD_CH macros are
> already utilized in the common dw_edma_probe() method. So to speak you
> can freely use these macros for HDMA too. Thus this change is
> redundant. So is the patches 1/6 and 2/6.
> 
> Note currently all the common DW EDMA driver code uses the EDMA_/edma_
> prefixes. HDMA_/hdma_ prefixes are utilized in the Native
> HDMA-specific module only. So if you wished to provide some IP-core
> specific settings utilized in the common part of the driver, then the
> best approach would be to provide a change for the entire driver
> interface (for instance first convert it to having a neutral prefixes,
> like xdma_/etc, and then use the IP-core specific ones). So please
> just use the EDMA_MAX_WR_CH and EDMA_MAX_RD_CH macros and drop the
> patches 1, 2, and 4.
> 

Hmm. With my limited access to the HDMA IP insights, I was not aware that the
constraints are similar with EDMA. If so, then it makes sense to reuse the same
macros. But I would also add a comment on top of the macros to avoid confusion.

- Mani

> -Serge(y)
> 
> > 
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Signed-off-by: Mrinmay Sarkar <quic_msarkar@quicinc.com>
> > ---
> >  drivers/dma/dw-edma/dw-hdma-v0-core.c | 4 ++--
> >  drivers/dma/dw-edma/dw-hdma-v0-regs.h | 3 +--
> >  include/linux/dma/edma.h              | 1 +
> >  3 files changed, 4 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-core.c b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > index 1f4cb7d..819ef1f 100644
> > --- a/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > +++ b/drivers/dma/dw-edma/dw-hdma-v0-core.c
> > @@ -54,7 +54,7 @@ static void dw_hdma_v0_core_off(struct dw_edma *dw)
> >  {
> >  	int id;
> >  
> > -	for (id = 0; id < HDMA_V0_MAX_NR_CH; id++) {
> > +	for (id = 0; id < HDMA_MAX_NR_CH; id++) {
> >  		SET_BOTH_CH_32(dw, id, int_setup,
> >  			       HDMA_V0_STOP_INT_MASK | HDMA_V0_ABORT_INT_MASK);
> >  		SET_BOTH_CH_32(dw, id, int_clear,
> > @@ -70,7 +70,7 @@ static u16 dw_hdma_v0_core_ch_count(struct dw_edma *dw, enum dw_edma_dir dir)
> >  	 * available, we set it to maximum channels and let the platform
> >  	 * set the right number of channels.
> >  	 */
> > -	return HDMA_V0_MAX_NR_CH;
> > +	return HDMA_MAX_NR_CH;
> >  }
> >  
> >  static enum dma_status dw_hdma_v0_core_ch_status(struct dw_edma_chan *chan)
> > diff --git a/drivers/dma/dw-edma/dw-hdma-v0-regs.h b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > index a974abd..cd7eab2 100644
> > --- a/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > +++ b/drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > @@ -11,7 +11,6 @@
> >  
> >  #include <linux/dmaengine.h>
> >  
> > -#define HDMA_V0_MAX_NR_CH			8
> >  #define HDMA_V0_LOCAL_ABORT_INT_EN		BIT(6)
> >  #define HDMA_V0_REMOTE_ABORT_INT_EN		BIT(5)
> >  #define HDMA_V0_LOCAL_STOP_INT_EN		BIT(4)
> > @@ -92,7 +91,7 @@ struct dw_hdma_v0_ch {
> >  } __packed;
> >  
> >  struct dw_hdma_v0_regs {
> > -	struct dw_hdma_v0_ch ch[HDMA_V0_MAX_NR_CH];	/* 0x0000..0x0fa8 */
> > +	struct dw_hdma_v0_ch ch[HDMA_MAX_NR_CH];	/* 0x0000..0x0fa8 */
> >  } __packed;
> >  
> >  struct dw_hdma_v0_lli {
> > diff --git a/include/linux/dma/edma.h b/include/linux/dma/edma.h
> > index 550f6a4..2cdf249a 100644
> > --- a/include/linux/dma/edma.h
> > +++ b/include/linux/dma/edma.h
> > @@ -14,6 +14,7 @@
> >  
> >  #define EDMA_MAX_WR_CH                                  8
> >  #define EDMA_MAX_RD_CH                                  8
> > +#define HDMA_MAX_NR_CH					8
> >  
> >  struct dw_edma;
> >  struct dw_edma_chip;
> > -- 
> > 2.7.4
> > 

-- 
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