linux-kernel - Re: [PATCH v16 08/22] PCI: microchip: Change the argument of plda_pcie_setup

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Date: Thu, 23 May 2024 01:09:58 +0000
From: Minda Chen <minda.chen@...rfivetech.com>
To: Bjorn Helgaas <helgaas@...nel.org>
CC: Lorenzo Pieralisi <lpieralisi@...nel.org>, Conor Dooley
	<conor@...nel.org>, Krzysztof Wilczyński <kw@...ux.com>,
	Rob Herring <robh+dt@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>, Thomas
 Gleixner <tglx@...utronix.de>, Daire McNamara <daire.mcnamara@...rochip.com>,
	Emil Renner Berthing <emil.renner.berthing@...onical.com>, Krzysztof
 Kozlowski <krzysztof.kozlowski+dt@...aro.org>, "devicetree@...r.kernel.org"
	<devicetree@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "linux-riscv@...ts.infradead.org"
	<linux-riscv@...ts.infradead.org>, "linux-pci@...r.kernel.org"
	<linux-pci@...r.kernel.org>, Paul Walmsley <paul.walmsley@...ive.com>, Palmer
 Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, Philipp
 Zabel <p.zabel@...gutronix.de>, Mason Huo <mason.huo@...rfivetech.com>,
	Leyfoon Tan <leyfoon.tan@...rfivetech.com>, Kevin Xie
	<kevin.xie@...rfivetech.com>
Subject: Re: [PATCH v16 08/22] PCI: microchip: Change the argument of
 plda_pcie_setup_iomems()



> 
> On Wed, May 22, 2024 at 01:50:57AM +0000, Minda Chen wrote:
> > > The patch is OK, but the subject line is not very informative.  It
> > > should be useful all by itself even without the commit log.
> > > "Change the argument of X" doesn't say anything about why we would
> > > want to do that.
> > >
> > > On Thu, Mar 28, 2024 at 05:18:21PM +0800, Minda Chen wrote:
> > > > If other vendor do not select PCI_HOST_COMMON, the driver data is
> > > > not struct pci_host_bridge.
> > >
> > > Also, I don't think this is the real problem.  Your
> > > PCIE_MICROCHIP_HOST Kconfig selects PCI_HOST_COMMON, and the
> driver
> > > calls pci_host_common_probe(), so the driver wouldn't even build
> > > without PCI_HOST_COMMON.
> > >
> > > This patch is already applied and ready to go, but if you can tell
> > > us what's really going on here, I'd like to update the commit log.
> > >
> > It is modified for Starfive code. Starfive JH7110 PCIe do not select
> > PCI_HOST_COMMON
> > plda_pcie_setup_iomems() will be changed to common plda code.
> >
> > I think I can modify the title and commit log like this.
> >
> > Title:
> > PCI: microchip: Get struct pci_host_bridge pointer from platform code
> >
> > Since plda_pcie_setup_iomems() will be a common PLDA core driver
> > function, but the argument0 is a struct platform_device pointer.
> > plda_pcie_setup_iomems() actually using struct pci_host_bridge pointer
> > other than platform_device pointer. Further more if a new PLDA core
> > PCIe driver do not select PCI_HOST_COMMON, the platform driver data is
> > not struct pci_host_bridge pointer. So get struct pci_host_bridge
> > pointer from platform code function
> > mc_platform_init() and make it to be an argument of
> > plda_pcie_setup_iomems().
> 
> OK, I see what you're doing.  This actually has nothing to do with whether
> PCI_HOST_COMMON is *enabled*.  It has to do with whether drivers use
> pci_host_common_probe().  Here's what I propose:
> 
>   PCI: plda: Pass pci_host_bridge to plda_pcie_setup_iomems()
> 
>   plda_pcie_setup_iomems() needs the bridge->windows list from struct
>   pci_host_bridge and is currently used only by pcie-microchip-host.c.  This
>   driver uses pci_host_common_probe(), which sets a pci_host_bridge as the
>   drvdata, so plda_pcie_setup_iomems() used platform_get_drvdata() to find
>   the pci_host_bridge.
> 
>   But we also want to use plda_pcie_setup_iomems() in the new pcie-starfive.c
>   driver, which does not use pci_host_common_probe() and will have struct
>   starfive_jh7110_pcie as its drvdata, so pass the pci_host_bridge directly
>   to plda_pcie_setup_iomems() so it doesn't need platform_get_drvdata() to
>   find it.
> 
OK, Thanks. 

I see PCIe 6.10 changed have been merged to main line. 
Should I resend this patch set base on 6.10-rc1? 

> > > > Move calling platform_get_drvdata() to mc_platform_init().
> > > >
> > > > Signed-off-by: Minda Chen <minda.chen@...rfivetech.com>
> > > > Reviewed-by: Conor Dooley <conor.dooley@...rochip.com>
> > > > ---
> > > >  drivers/pci/controller/plda/pcie-microchip-host.c | 6 +++---
> > > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/pci/controller/plda/pcie-microchip-host.c
> > > > b/drivers/pci/controller/plda/pcie-microchip-host.c
> > > > index 9b367927cd32..805870aed61d 100644
> > > > --- a/drivers/pci/controller/plda/pcie-microchip-host.c
> > > > +++ b/drivers/pci/controller/plda/pcie-microchip-host.c
> > > > @@ -876,11 +876,10 @@ static void plda_pcie_setup_window(void
> > > > __iomem
> > > *bridge_base_addr, u32 index,
> > > >  	writel(0, bridge_base_addr + ATR0_PCIE_WIN0_SRC_ADDR);  }
> > > >
> > > > -static int plda_pcie_setup_iomems(struct platform_device *pdev,
> > > > +static int plda_pcie_setup_iomems(struct pci_host_bridge *bridge,
> > > >  				  struct plda_pcie_rp *port)
> > > >  {
> > > >  	void __iomem *bridge_base_addr = port->bridge_addr;
> > > > -	struct pci_host_bridge *bridge = platform_get_drvdata(pdev);
> > > >  	struct resource_entry *entry;
> > > >  	u64 pci_addr;
> > > >  	u32 index = 1;
> > > > @@ -1018,6 +1017,7 @@ static int mc_platform_init(struct
> > > > pci_config_window *cfg)  {
> > > >  	struct device *dev = cfg->parent;
> > > >  	struct platform_device *pdev = to_platform_device(dev);
> > > > +	struct pci_host_bridge *bridge = platform_get_drvdata(pdev);
> > > >  	void __iomem *bridge_base_addr =
> > > >  		port->axi_base_addr + MC_PCIE_BRIDGE_ADDR;
> > > >  	int ret;
> > > > @@ -1031,7 +1031,7 @@ static int mc_platform_init(struct
> > > pci_config_window *cfg)
> > > >  	mc_pcie_enable_msi(port, cfg->win);
> > > >
> > > >  	/* Configure non-config space outbound ranges */
> > > > -	ret = plda_pcie_setup_iomems(pdev, &port->plda);
> > > > +	ret = plda_pcie_setup_iomems(bridge, &port->plda);
> > > >  	if (ret)
> > > >  		return ret;
> > > >
> > > > --
> > > > 2.17.1
> > > >