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Date: Fri, 2 Feb 2024 08:25:58 -0500
From: Frank Li <Frank.li@nxp.com>
To: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: manivannan.sadhasivam@linaro.org, bhelgaas@google.com,
	conor+dt@kernel.org, devicetree@vger.kernel.org, festevam@gmail.com,
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	shawnguo@kernel.org
Subject: Re: [PATCH v9 05/16] PCI: imx6: Using "linux,pci-domain" as slot ID
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References: <20240119171122.3057511-1-Frank.Li@nxp.com>
 <20240119171122.3057511-6-Frank.Li@nxp.com>
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On Fri, Feb 02, 2024 at 01:12:41PM +0100, Lorenzo Pieralisi wrote:
> "PCI: imx6: Use "linux,pci-domain" as slot ID"
> 
> On Fri, Jan 19, 2024 at 12:11:11PM -0500, Frank Li wrote:
> > Avoid use get slot id by compared with register physical address. If there
> > are more than 2 slots, compared logic will become complex.
> > 
> > "linux,pci-domain" already exist at dts since commit:
> > 	commit (c0b70f05c87f3b arm64: dts: imx8mq: use_dt_domains for pci node).
> > 
> > So it is safe to remove compare basic address code:
> > 	...
> > 	if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> > 		imx6_pcie->controller_id = 1;
> 
> No it is not unless you magically update all firmware out
> there in the field.

commit c0b70f05c87f3b09b391027c6f056d0facf331ef
Author:     Peng Fan <peng.fan@nxp.com>
AuthorDate: Fri Jan 15 11:26:57 2021 +0800
Commit:     Shawn Guo <shawnguo@kernel.org>
CommitDate: Fri Jan 29 14:46:28 2021 +0800

I am not sure if it is neccesary to compatible with 2 years ago's dts.
I think it may not boot at all with using 2 year agao dtb file directly.

Do you have other comments? I can remove it from this big patch series,

Frank
> 
> > 	...
> > 
> > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> > 
> > Notes:
> >     Change from v7 to v8
> >     - fixed comments
> >     - Added Manivannan Sadhasivam's review tag
> >     Change from v5 to v7
> >     - none
> >     Change from v3 to v4
> >     - remove compare basic address logic
> >     Change from v2 to v3
> >     - none
> >     Change from v1 to v2
> >     - fix of_get_pci_domain_nr return value check logic
> > 
> >  drivers/pci/controller/dwc/pci-imx6.c | 20 ++++++++++++--------
> >  1 file changed, 12 insertions(+), 8 deletions(-)
> > 
> > diff --git a/drivers/pci/controller/dwc/pci-imx6.c b/drivers/pci/controller/dwc/pci-imx6.c
> > index eda6bc6ef80ee..773411d20329f 100644
> > --- a/drivers/pci/controller/dwc/pci-imx6.c
> > +++ b/drivers/pci/controller/dwc/pci-imx6.c
> > @@ -33,6 +33,7 @@
> >  #include <linux/pm_domain.h>
> >  #include <linux/pm_runtime.h>
> >  
> > +#include "../../pci.h"
> >  #include "pcie-designware.h"
> >  
> >  #define IMX8MQ_GPR_PCIE_REF_USE_PAD		BIT(9)
> > @@ -40,7 +41,6 @@
> >  #define IMX8MQ_GPR_PCIE_CLK_REQ_OVERRIDE	BIT(11)
> >  #define IMX8MQ_GPR_PCIE_VREG_BYPASS		BIT(12)
> >  #define IMX8MQ_GPR12_PCIE2_CTRL_DEVICE_TYPE	GENMASK(11, 8)
> > -#define IMX8MQ_PCIE2_BASE_ADDR			0x33c00000
> >  
> >  #define to_imx6_pcie(x)	dev_get_drvdata((x)->dev)
> >  
> > @@ -1279,13 +1279,17 @@ static int imx6_pcie_probe(struct platform_device *pdev)
> >  					     "Failed to get PCIEPHY reset control\n");
> >  	}
> >  
> > -	switch (imx6_pcie->drvdata->variant) {
> > -	case IMX7D:
> > -		if (dbi_base->start == IMX8MQ_PCIE2_BASE_ADDR)
> > -			imx6_pcie->controller_id = 1;
> > -	default:
> > -		break;
> > -	}
> > +	/* Using linux,pci-domain as PCI slot id */
> > +	imx6_pcie->controller_id = of_get_pci_domain_nr(node);
> > +	/*
> > +	 * If there are no "linux,pci-domain" property specified in DT, then assume only one
> > +	 * controller is available.
> > +	 */
> > +	if (imx6_pcie->controller_id == -EINVAL)
> > +		imx6_pcie->controller_id = 0;
> 
> See above, this breaks compatibility with old DTs (and -EINVAL is not
> the only error code you should handle).
> 
> Lorenzo
> 
> > +	else if (imx6_pcie->controller_id < 0)
> > +		return dev_err_probe(dev, imx6_pcie->controller_id,
> > +				     "linux,pci-domain have wrong value\n");
> >  
> >  	/* Grab turnoff reset */
> >  	imx6_pcie->turnoff_reset = devm_reset_control_get_optional_exclusive(dev, "turnoff");
> > -- 
> > 2.34.1
> >