RE: [PATCH v6 5/7] PCI: rcar-gen4: Add .ltssm_enable() for other SoC support

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Hello Manivannan,

> From: Manivannan Sadhasivam, Sent: Thursday, April 11, 2024 2:24 AM
> 
> On Wed, Apr 10, 2024 at 09:48:30AM +0900, Yoshihiro Shimoda wrote:
> > This driver can reuse other R-Car Gen4 SoCs support like r8a779g0 and
> > r8a779h0. However, r8a779g0 and r8a779h0 require other initializing
> > settings that differ than r8a779f0. So, add a new function pointer
> > .ltssm_enable() for it. No behavior changes.
> >
> > After applied this patch, probing SoCs by rcar_gen4_pcie_of_match[]
> > will be changed like below:
> >
> > - r8a779f0 as "renesas,r8a779f0-pcie" and "renesas,r8a779f0-pcie-ep"
> >
> 
> If r8a779f0 SoC can work with the existing 'renesas,rcar-gen4-pcie' and
> 'renesas,rcar-gen4-pcie-ep' compatibles, then you should just leave it as it is
> and add a new compatible with dedicated callbacks for only r8a779g0 and
> r8a779h0.

My implementation will have 4 entries. And, it can support r8a779[fgh]0:
---
static const struct of_device_id rcar_gen4_pcie_of_match[] = {
        {
                .compatible = "renesas,r8a779f0-pcie",
                .data = &platdata_r8a779f0_pcie,
        },
        {
                .compatible = "renesas,r8a779f0-pcie-ep",
                .data = &platdata_r8a779f0_pcie_ep,
        },
        {
                .compatible = "renesas,rcar-gen4-pcie",	/* for r8a779[gh]0 */
                .data = &platdata_rcar_gen4_pcie,
        },
        {
                .compatible = "renesas,rcar-gen4-pcie-ep",	/* for r8a779[gh]0 */
                .data = &platdata_rcar_gen4_pcie_ep,
        },
---
Also it will not break existing all r8a779f0 SoC environment because
the compatible is
                         compatible = "renesas,r8a779f0-pcie",
                                     "renesas,rcar-gen4-pcie";

However, if I changed the implementation like your suggestion,
it will be 6 entries like below:
---
static const struct of_device_id rcar_gen4_pcie_of_match[] = {
        {
                .compatible = "renesas,r8a779g0-pcie",
                .data = &platdata_r8a779g0_pcie,
        },
        {
                .compatible = "renesas,r8a779g0-pcie-ep",
                .data = &platdata_r8a779g0_pcie_ep,
        },
        {
                .compatible = "renesas,r8a779h0-pcie",
                .data = &platdata_r8a779g0_pcie,		/* We can reuse r8a779g0's one */
        },
        {
                .compatible = "renesas,r8a779h0-pcie-ep",
                .data = &platdata_r8a779g0_pcie_ep, 	/* We can reuse r8a779g0's one */
        },        {
                .compatible = "renesas,rcar-gen4-pcie",
                .data = &platdata_rcar_gen4_pcie,		/* for r8a779f0 */
        },
        {
                .compatible = "renesas,rcar-gen4-pcie-ep",
                .data = &platdata_rcar_gen4_pcie_ep, 	/* for r8a779f0 */
        },
-----

So, I prefer my implementation because code readability is good to me. But, what do you think?

Best regards,
Yoshihiro Shimoda

> - Mani
> 
> > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> > ---
> >  drivers/pci/controller/dwc/pcie-rcar-gen4.c | 41 ++++++++++++++++++---
> >  1 file changed, 36 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-rcar-gen4.c b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > index da2821d6efce..47ec394885f5 100644
> > --- a/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > +++ b/drivers/pci/controller/dwc/pcie-rcar-gen4.c
> > @@ -48,7 +48,9 @@
> >  #define RCAR_GEN4_PCIE_EP_FUNC_DBI_OFFSET	0x1000
> >  #define RCAR_GEN4_PCIE_EP_FUNC_DBI2_OFFSET	0x800
> >
> > +struct rcar_gen4_pcie;
> >  struct rcar_gen4_pcie_platdata {
> > +	int (*ltssm_enable)(struct rcar_gen4_pcie *rcar);
> >  	enum dw_pcie_device_mode mode;
> >  };
> >
> > @@ -61,8 +63,8 @@ struct rcar_gen4_pcie {
> >  #define to_rcar_gen4_pcie(_dw)	container_of(_dw, struct rcar_gen4_pcie, dw)
> >
> >  /* Common */
> > -static void rcar_gen4_pcie_ltssm_enable(struct rcar_gen4_pcie *rcar,
> > -					bool enable)
> > +static void rcar_gen4_pcie_ltssm_control(struct rcar_gen4_pcie *rcar,
> > +					 bool enable)
> >  {
> >  	u32 val;
> >
> > @@ -127,9 +129,13 @@ static int rcar_gen4_pcie_speed_change(struct dw_pcie *dw)
> >  static int rcar_gen4_pcie_start_link(struct dw_pcie *dw)
> >  {
> >  	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> > -	int i, changes;
> > +	int i, changes, ret;
> >
> > -	rcar_gen4_pcie_ltssm_enable(rcar, true);
> > +	if (rcar->platdata->ltssm_enable) {
> > +		ret = rcar->platdata->ltssm_enable(rcar);
> > +		if (ret)
> > +			return ret;
> > +	}
> >
> >  	/*
> >  	 * Require direct speed change with retrying here if the link_gen is
> > @@ -157,7 +163,7 @@ static void rcar_gen4_pcie_stop_link(struct dw_pcie *dw)
> >  {
> >  	struct rcar_gen4_pcie *rcar = to_rcar_gen4_pcie(dw);
> >
> > -	rcar_gen4_pcie_ltssm_enable(rcar, false);
> > +	rcar_gen4_pcie_ltssm_control(rcar, false);
> >  }
> >
> >  static int rcar_gen4_pcie_common_init(struct rcar_gen4_pcie *rcar)
> > @@ -504,6 +510,23 @@ static void rcar_gen4_pcie_remove(struct platform_device *pdev)
> >  	rcar_gen4_pcie_unprepare(rcar);
> >  }
> >
> > +static int r8a779f0_pcie_ltssm_enable(struct rcar_gen4_pcie *rcar)
> > +{
> > +	rcar_gen4_pcie_ltssm_control(rcar, true);
> > +
> > +	return 0;
> > +}
> > +
> > +static struct rcar_gen4_pcie_platdata platdata_r8a779f0_pcie = {
> > +	.ltssm_enable = r8a779f0_pcie_ltssm_enable,
> > +	.mode = DW_PCIE_RC_TYPE,
> > +};
> > +
> > +static struct rcar_gen4_pcie_platdata platdata_r8a779f0_pcie_ep = {
> > +	.ltssm_enable = r8a779f0_pcie_ltssm_enable,
> > +	.mode = DW_PCIE_EP_TYPE,
> > +};
> > +
> >  static struct rcar_gen4_pcie_platdata platdata_rcar_gen4_pcie = {
> >  	.mode = DW_PCIE_RC_TYPE,
> >  };
> > @@ -513,6 +536,14 @@ static struct rcar_gen4_pcie_platdata platdata_rcar_gen4_pcie_ep = {
> >  };
> >
> >  static const struct of_device_id rcar_gen4_pcie_of_match[] = {
> > +	{
> > +		.compatible = "renesas,r8a779f0-pcie",
> > +		.data = &platdata_r8a779f0_pcie,
> > +	},
> > +	{
> > +		.compatible = "renesas,r8a779f0-pcie-ep",
> > +		.data = &platdata_r8a779f0_pcie_ep,
> > +	},
> >  	{
> >  		.compatible = "renesas,rcar-gen4-pcie",
> >  		.data = &platdata_rcar_gen4_pcie,
> > --
> > 2.25.1
> >
> >
> 
> --
> மணிவண்ணன் சதாசிவம்




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