Re: [PATCH v2] PCI: aardvark: Add support for PCI Bridge Subsystem Vendor ID on emulated bridge

From: "Pali Rohár" <pali@kernel.org>
To: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: "Thomas Petazzoni" <thomas.petazzoni@bootlin.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Wilczyński" <kw@linux.com>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] PCI: aardvark: Add support for PCI Bridge Subsystem Vendor ID on emulated bridge
Date: Mon, 29 Aug 2022 11:34:28 +0200	[thread overview]
Message-ID: <20220829093428.4danatwennps55dr@pali> (raw)
In-Reply-To: <YwyHdMv1JsQNuVGS@lpieralisi>

On Monday 29 August 2022 11:31:32 Lorenzo Pieralisi wrote:
> On Tue, Jul 12, 2022 at 12:59:15AM +0200, Pali Rohár wrote:
> > Register with Subsystem Device/Vendor ID is at offset 0x2c. Export is via
> > emulated bridge.
> 
> "Export it..." I suppose.

Yes, it is a typo :-(

> So in short, this patch enables support for the Subsystem Device/Vendor
> ID - by reading it in the PCI controller config space and storing it
> in the emulated bridge control structures, so that it is exposed in
> the respective PCI capability.

Yes, it reads it from internal aardvark registers and stores it into the
emulated bridge config space.

> Correct ?
> 
> Thanks,
> Lorenzo
> 
> > After this change Subsystem ID is visible in lspci output at line:
> > 
> >   Capabilities: [40] Subsystem
> > 
> > Signed-off-by: Pali Rohár <pali@kernel.org>
> > 
> > ---
> > Changes in v2:
> > * Fix wrong rebase, do not add PCIE_CORE_EXP_ROM_BAR_REG
> > ---
> >  drivers/pci/controller/pci-aardvark.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> > index 74511f015168..060936ef01fe 100644
> > --- a/drivers/pci/controller/pci-aardvark.c
> > +++ b/drivers/pci/controller/pci-aardvark.c
> > @@ -32,6 +32,7 @@
> >  #define PCIE_CORE_DEV_ID_REG					0x0
> >  #define PCIE_CORE_CMD_STATUS_REG				0x4
> >  #define PCIE_CORE_DEV_REV_REG					0x8
> > +#define PCIE_CORE_SSDEV_ID_REG					0x2c
> >  #define PCIE_CORE_PCIEXP_CAP					0xc0
> >  #define PCIE_CORE_ERR_CAPCTL_REG				0x118
> >  #define     PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX			BIT(5)
> > @@ -982,6 +983,8 @@ static int advk_sw_pci_bridge_init(struct advk_pcie *pcie)
> >  	/* Indicates supports for Completion Retry Status */
> >  	bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_CRSVIS);
> >  
> > +	bridge->subsystem_vendor_id = advk_readl(pcie, PCIE_CORE_SSDEV_ID_REG) & 0xffff;
> > +	bridge->subsystem_id = advk_readl(pcie, PCIE_CORE_SSDEV_ID_REG) >> 16;
> >  	bridge->has_pcie = true;
> >  	bridge->data = pcie;
> >  	bridge->ops = &advk_pci_bridge_emul_ops;
> > -- 
> > 2.20.1
> > 

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