RE: [PATCH v4 11/15] dmaengine: dw-axi-dmac: Add Intel KeemBay DMA register fields

[Sia, Jee Heng]

> -----Original Message-----
> From: Eugeniy Paltsev <Eugeniy.Paltsev@xxxxxxxxxxxx>
> Sent: 19 November 2020 7:58 AM
> To: Sia, Jee Heng <jee.heng.sia@xxxxxxxxx>
> Cc: andriy.shevchenko@xxxxxxxxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; vkoul@xxxxxxxxxx;
> robh+dt@xxxxxxxxxx
> Subject: Re: [PATCH v4 11/15] dmaengine: dw-axi-dmac: Add Intel KeemBay DMA
> register fields
> 
> Hi Sia,
> 
> > Subject: [PATCH v4 11/15] dmaengine: dw-axi-dmac: Add Intel KeemBay
> > DMA register fields
> >
> > Add support for Intel KeemBay DMA registers. These registers are
> > required to run data transfer between device to memory and memory to
> > device on Intel KeemBay SoC.
> >
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> > Signed-off-by: Sia Jee Heng <jee.heng.sia@xxxxxxxxx>
> > ---
> >  drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c |  4 ++++
> >  drivers/dma/dw-axi-dmac/dw-axi-dmac.h          | 14 ++++++++++++++
> >  2 files changed, 18 insertions(+)
> >
> > diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > index 7c97b58206bf..9f7f908b89d8 100644
> > --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> > @@ -1192,6 +1192,10 @@ static int dw_probe(struct platform_device *pdev)
> >         if (IS_ERR(chip->regs))
> >                 return PTR_ERR(chip->regs);
> >
> > +       chip->apb_regs = devm_platform_ioremap_resource(pdev, 1);
> > +       if (IS_ERR(chip->apb_regs))
> > +               dev_warn(&pdev->dev, "apb_regs not supported\n");
> 
> There shouldn't be warning in case of compatible = "snps,axi-dma-1.01a" and
> apb_regs missing. Could you please try to do ioremap for this region only in case of
> intel,kmb-axi-dma?
[>>] The intention is to fallback to snps solution in case of apb_reg missing. Yes, I can include the intel,kmb-axi-dma condition check if this is the prefer solution.
> 
> > +
> >         chip->core_clk = devm_clk_get(chip->dev, "core-clk");
> >         if (IS_ERR(chip->core_clk))
> >                 return PTR_ERR(chip->core_clk); diff --git
> > a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > index bdb66d775125..f64e8d33b127 100644
> > --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> > @@ -63,6 +63,7 @@ struct axi_dma_chip {
> >         struct device           *dev;
> >         int                     irq;
> >         void __iomem            *regs;
> > +       void __iomem            *apb_regs;
> >         struct clk              *core_clk;
> >         struct clk              *cfgr_clk;
> >         struct dw_axi_dma       *dw;
> > @@ -169,6 +170,19 @@ static inline struct axi_dma_chan
> *dchan_to_axi_dma_chan(struct dma_chan *dchan)
> >  #define CH_INTSIGNAL_ENA       0x090 /* R/W Chan Interrupt Signal Enable */
> >  #define CH_INTCLEAR            0x098 /* W Chan Interrupt Clear */
> >
> > +/* Apb slave registers */
> Could you please add the comment that all this registers exist only in case of
> intel,kmb-axi-dma extension?
[>>] OK, will include the comment in v5
> 
> > +#define DMAC_APB_CFG           0x000 /* DMAC Apb Configuration Register */
> > +#define DMAC_APB_STAT          0x004 /* DMAC Apb Status Register */
> > +#define DMAC_APB_DEBUG_STAT_0  0x008 /* DMAC Apb Debug Status
> > +Register 0 */ #define DMAC_APB_DEBUG_STAT_1  0x00C /* DMAC Apb Debug
> Status Register 1 */
> > +#define DMAC_APB_HW_HS_SEL_0   0x010 /* DMAC Apb HW HS register 0 */
> > +#define DMAC_APB_HW_HS_SEL_1   0x014 /* DMAC Apb HW HS register 1 */
> > +#define DMAC_APB_LPI           0x018 /* DMAC Apb Low Power Interface Reg */
> > +#define DMAC_APB_BYTE_WR_CH_EN 0x01C /* DMAC Apb Byte Write Enable */
> > +#define DMAC_APB_HALFWORD_WR_CH_EN     0x020 /* DMAC Halfword write
> enables */
> > +
> > +#define UNUSED_CHANNEL         0x3F /* Set unused DMA channel to 0x3F */
> > +#define MAX_BLOCK_SIZE         0x1000 /* 1024 blocks * 4 bytes data width */
> >
> >  /* DMAC_CFG */
> >  #define DMAC_EN_POS                    0
> > --
> > 2.18.0
> >