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From: Bjorn Helgaas <helgaas@kernel.org>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: "lpieralisi@kernel.org" <lpieralisi@kernel.org>,
	"robh+dt@kernel.org" <robh+dt@kernel.org>,
	"kw@linux.com" <kw@linux.com>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"krzk+dt@kernel.org" <krzk+dt@kernel.org>,
	"geert+renesas@glider.be" <geert+renesas@glider.be>,
	"magnus.damm@gmail.com" <magnus.damm@gmail.com>,
	"marek.vasut+renesas@gmail.com" <marek.vasut+renesas@gmail.com>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH v5 03/12] PCI: Add PCI_EXP_LNKCAP_MLW macros
Date: Tue, 20 Sep 2022 21:22:04 -0500	[thread overview]
Message-ID: <20220921022204.GA1154967@bhelgaas> (raw)
In-Reply-To: <TYBPR01MB5341A75BFA6AFFCF59FA4502D84F9@TYBPR01MB5341.jpnprd01.prod.outlook.com>

On Wed, Sep 21, 2022 at 12:05:26AM +0000, Yoshihiro Shimoda wrote:
> Hi Bjorn,
> 
> Thank you for your review!
> 
> > From: Bjorn Helgaas, Sent: Wednesday, September 21, 2022 5:08 AM
> > 
> > On Mon, Sep 05, 2022 at 04:12:48PM +0900, Yoshihiro Shimoda wrote:
> > > Add macros defining Maximum Link Width bits in Link Capabilities
> > > Register.
> > >
> > > Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> > > ---
> > >  include/uapi/linux/pci_regs.h | 7 +++++++
> > >  1 file changed, 7 insertions(+)
> > >
> > > diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
> > > index 57b8e2ffb1dd..c9f4c452e210 100644
> > > --- a/include/uapi/linux/pci_regs.h
> > > +++ b/include/uapi/linux/pci_regs.h
> > > @@ -538,6 +538,13 @@
> > >  #define  PCI_EXP_LNKCAP_SLS_16_0GB 0x00000004 /* LNKCAP2 SLS Vector bit 3 */
> > >  #define  PCI_EXP_LNKCAP_SLS_32_0GB 0x00000005 /* LNKCAP2 SLS Vector bit 4 */
> > >  #define  PCI_EXP_LNKCAP_SLS_64_0GB 0x00000006 /* LNKCAP2 SLS Vector bit 5 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X1	0x00000010 /* Maximum Link Width x1 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X2	0x00000020 /* Maximum Link Width x2 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X4	0x00000040 /* Maximum Link Width x4 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X8	0x00000080 /* Maximum Link Width x8 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X12	0x000000c0 /* Maximum Link Width x12 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X16	0x00000100 /* Maximum Link Width x16 */
> > > +#define  PCI_EXP_LNKCAP_MLW_X32	0x00000200 /* Maximum Link Width x32 */
> > 
> > In PCIe r6.0, x32 is mentioned a few times, but not actually defined
> > for Link Capabilities.  Has it been defined in an ECN or something?
> 
> I should have looked PCIe r6.0, but I looked PCIe r4.0 v1.0 and it mentioned x32.
> So, I wrote the x32 macro.

Sure enough.  It's there in r4.0 and r5.0, but dropped from r6.0.
Wish there were a git tree where we could see whether this was a
mistake or there was some reason for it.  Maybe nobody had actually
built x32 hardware and they wanted to reserve the flexibility for
something else.

> I'll drop PCI_EXP_LNKCAP_MLW_X32 on v6 patch.

When you do, add my:

Acked-by: Bjorn Helgaas <bhelgaas@google.com>


  reply	other threads:[~2022-09-21  2:22 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-05  7:12 [PATCH v5 00/12] treewide: PCI: renesas: Add R-Car Gen4 PCIe support Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 01/12] dt-bindings: PCI: renesas: Add R-Car Gen4 PCIe Host Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 02/12] dt-bindings: PCI: renesas: Add R-Car Gen4 PCIe Endpoint Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 03/12] PCI: Add PCI_EXP_LNKCAP_MLW macros Yoshihiro Shimoda
2022-09-20 20:08   ` Bjorn Helgaas
2022-09-21  0:05     ` Yoshihiro Shimoda
2022-09-21  2:22       ` Bjorn Helgaas [this message]
2022-09-21  8:50         ` Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 04/12] PCI: controller: dwc: Expose dw_pcie_ep_exit() to module Yoshihiro Shimoda
2022-09-20 20:00   ` Bjorn Helgaas
2022-09-05  7:12 ` [PATCH v5 05/12] PCI: dwc: Add ep_pre_init() callback to dw_pcie_ep_ops Yoshihiro Shimoda
2022-09-20 20:03   ` Bjorn Helgaas
2022-09-05  7:12 ` [PATCH v5 06/12] PCI: dwc: Add reset_all_bars flag Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 07/12] PCI: dwc: Avoid reading a register to detect whether eDMA exists Yoshihiro Shimoda
2022-09-05  8:39   ` Sergei Shtylyov
2022-09-05 13:13     ` Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 08/12] PCI: renesas: Add R-Car Gen4 PCIe Host support Yoshihiro Shimoda
2022-09-20 19:59   ` Bjorn Helgaas
2022-09-05  7:12 ` [PATCH v5 09/12] PCI: renesas: Add R-Car Gen4 PCIe Endpoint support Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 10/12] MAINTAINERS: Update PCI DRIVER FOR RENESAS R-CAR for R-Car Gen4 Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 11/12] arm64: dts: renesas: r8a779f0: Add PCIe Host and Endpoint nodes Yoshihiro Shimoda
2022-09-05  7:12 ` [PATCH v5 12/12] arm64: dts: renesas: r8a779f0: spider: Enable PCIe Host ch0 Yoshihiro Shimoda

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