From: Naveen Naidu <naveennaidu479@gmail.com> To: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "Bjorn Helgaas" <bhelgaas@google.com>, linux-kernel-mentees@lists.linuxfoundation.org, linux-pci <linux-pci@vger.kernel.org>, "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, "Marek Vasut" <marek.vasut+renesas@gmail.com>, "Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Rob Herring" <robh@kernel.org>, "Krzysztof Wilczyński" <kw@linux.com>, "open list:PCI DRIVER FOR RENESAS R-CAR" <linux-renesas-soc@vger.kernel.org> Subject: Re: [PATCH v2 14/24] PCI: rcar: Remove redundant error fabrication when device read fails Date: Mon, 18 Oct 2021 17:21:48 +0530 [thread overview] Message-ID: <20211018115148.iwhiknpd6o4okudq@theprophet> (raw) In-Reply-To: <CAMuHMdVh79gvAZn+nBeWWtkJqvUb3woi1rRY=BkY+bc4YXFj1Q@mail.gmail.com> On 18/10, Geert Uytterhoeven wrote: > Hi Naveen, > > On Sat, Oct 16, 2021 at 5:33 PM Naveen Naidu <naveennaidu479@gmail.com> wrote: > > An MMIO read from a PCI device that doesn't exist or doesn't respond > > causes a PCI error. There's no real data to return to satisfy the > > CPU read, so most hardware fabricates ~0 data. > > > > The host controller drivers sets the error response values (~0) and > > returns an error when faulty hardware read occurs. But the error > > response value (~0) is already being set in PCI_OP_READ and > > PCI_USER_READ_CONFIG whenever a read by host controller driver fails. > > > > Thus, it's no longer necessary for the host controller drivers to > > fabricate any error response. > > > > This helps unify PCI error response checking and make error check > > consistent and easier to find. > > > > Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com> > > Thanks for your patch! > > > --- a/drivers/pci/controller/pcie-rcar-host.c > > +++ b/drivers/pci/controller/pcie-rcar-host.c > > @@ -161,10 +161,8 @@ static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn, > > > > ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ, > > bus, devfn, where, val); > > - if (ret != PCIBIOS_SUCCESSFUL) { > > - *val = 0xffffffff; > > I don't see the behavior you describe in PCI_OP_READ(), so dropping > this will lead to returning an uninitialized value? > Hello Geert, Thank you for looking into the patch. The described behaviour for PCI_OP_READ is part of the 01/24 [1] patch of the series. [1]: https://lore.kernel.org/linux-pci/b913b4966938b7cad8c049dc34093e6c4b2fae68.1634306198.git.naveennaidu479@gmail.com/T/#u It looks like, I did not add proper receipients for that patch and hence is leading to confusion. I really apologize for that. I do not know what the right approach here should be, should I resend the entire patch series, adding proper receipients OR should I reply to each of the patches for the drivers and add the link to the patch. I did not want to spam people with a lot of mails so I was confused as to what the right option is. Thanks, Naveen > > + if (ret != PCIBIOS_SUCCESSFUL) > > return ret; > > - } > > > > if (size == 1) > > *val = (*val >> (BITS_PER_BYTE * (where & 3))) & 0xff; > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds
WARNING: multiple messages have this Message-ID (diff)
From: Naveen Naidu <naveennaidu479@gmail.com> To: Geert Uytterhoeven <geert@linux-m68k.org> Cc: "Rob Herring" <robh@kernel.org>, "Lorenzo Pieralisi" <lorenzo.pieralisi@arm.com>, "Krzysztof Wilczyński" <kw@linux.com>, linux-pci <linux-pci@vger.kernel.org>, "Yoshihiro Shimoda" <yoshihiro.shimoda.uh@renesas.com>, "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>, "open list:PCI DRIVER FOR RENESAS R-CAR" <linux-renesas-soc@vger.kernel.org>, "Bjorn Helgaas" <bhelgaas@google.com>, linux-kernel-mentees@lists.linuxfoundation.org, "Marek Vasut" <marek.vasut+renesas@gmail.com> Subject: Re: [PATCH v2 14/24] PCI: rcar: Remove redundant error fabrication when device read fails Date: Mon, 18 Oct 2021 17:21:48 +0530 [thread overview] Message-ID: <20211018115148.iwhiknpd6o4okudq@theprophet> (raw) In-Reply-To: <CAMuHMdVh79gvAZn+nBeWWtkJqvUb3woi1rRY=BkY+bc4YXFj1Q@mail.gmail.com> On 18/10, Geert Uytterhoeven wrote: > Hi Naveen, > > On Sat, Oct 16, 2021 at 5:33 PM Naveen Naidu <naveennaidu479@gmail.com> wrote: > > An MMIO read from a PCI device that doesn't exist or doesn't respond > > causes a PCI error. There's no real data to return to satisfy the > > CPU read, so most hardware fabricates ~0 data. > > > > The host controller drivers sets the error response values (~0) and > > returns an error when faulty hardware read occurs. But the error > > response value (~0) is already being set in PCI_OP_READ and > > PCI_USER_READ_CONFIG whenever a read by host controller driver fails. > > > > Thus, it's no longer necessary for the host controller drivers to > > fabricate any error response. > > > > This helps unify PCI error response checking and make error check > > consistent and easier to find. > > > > Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com> > > Thanks for your patch! > > > --- a/drivers/pci/controller/pcie-rcar-host.c > > +++ b/drivers/pci/controller/pcie-rcar-host.c > > @@ -161,10 +161,8 @@ static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn, > > > > ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ, > > bus, devfn, where, val); > > - if (ret != PCIBIOS_SUCCESSFUL) { > > - *val = 0xffffffff; > > I don't see the behavior you describe in PCI_OP_READ(), so dropping > this will lead to returning an uninitialized value? > Hello Geert, Thank you for looking into the patch. The described behaviour for PCI_OP_READ is part of the 01/24 [1] patch of the series. [1]: https://lore.kernel.org/linux-pci/b913b4966938b7cad8c049dc34093e6c4b2fae68.1634306198.git.naveennaidu479@gmail.com/T/#u It looks like, I did not add proper receipients for that patch and hence is leading to confusion. I really apologize for that. I do not know what the right approach here should be, should I resend the entire patch series, adding proper receipients OR should I reply to each of the patches for the drivers and add the link to the patch. I did not want to spam people with a lot of mails so I was confused as to what the right option is. Thanks, Naveen > > + if (ret != PCIBIOS_SUCCESSFUL) > > return ret; > > - } > > > > if (size == 1) > > *val = (*val >> (BITS_PER_BYTE * (where & 3))) & 0xff; > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees
next prev parent reply other threads:[~2021-10-18 11:52 UTC|newest] Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-10-15 14:35 [PATCH v2 00/24] Unify PCI error response checking Naveen Naidu 2021-10-15 14:35 ` Naveen Naidu 2021-10-15 14:35 ` Naveen Naidu 2021-10-15 14:35 ` Naveen Naidu 2021-10-15 14:35 ` Naveen Naidu 2021-10-15 14:35 ` Naveen Naidu 2021-10-15 14:28 ` [PATCH v2 01/24] PCI: Add PCI_ERROR_RESPONSE and it's related definitions Naveen Naidu 2021-10-15 14:28 ` Naveen Naidu 2021-10-20 13:24 ` Rob Herring 2021-10-20 13:24 ` Rob Herring 2021-10-15 14:28 ` [PATCH v2 02/24] PCI: Set error response in config access defines when ops->read() fails Naveen Naidu 2021-10-15 14:28 ` Naveen Naidu 2021-10-20 13:41 ` Rob Herring 2021-10-20 13:41 ` Rob Herring 2021-10-20 13:52 ` Pali Rohár 2021-10-20 13:52 ` Pali Rohár 2021-10-20 15:13 ` Naveen Naidu 2021-10-20 15:13 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 03/24] PCI: Unify PCI error response checking Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-20 13:13 ` Rob Herring 2021-10-20 13:13 ` Rob Herring 2021-10-20 15:15 ` Naveen Naidu 2021-10-20 15:15 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 04/24] PCI: Remove redundant error fabrication when device read fails Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-20 13:42 ` Rob Herring 2021-10-20 13:42 ` Rob Herring 2021-10-15 14:38 ` [PATCH v2 05/24] PCI: thunder: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 06/24] PCI: iproc: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 16:49 ` Ray Jui 2021-10-15 16:49 ` Ray Jui 2021-10-15 16:49 ` Ray Jui via Linux-kernel-mentees 2021-10-15 17:05 ` Naveen Naidu 2021-10-15 17:05 ` Naveen Naidu 2021-10-15 17:05 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 07/24] PCI: mediatek: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 08/24] PCI: exynos: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 09/24] PCI: histb: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 10/24] PCI: kirin: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 11/24] PCI: aardvark: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 12/24] PCI: mvebu: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 13/24] PCI: altera: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 14/24] PCI: rcar: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-18 11:32 ` Geert Uytterhoeven 2021-10-18 11:32 ` Geert Uytterhoeven 2021-10-18 11:51 ` Naveen Naidu [this message] 2021-10-18 11:51 ` Naveen Naidu 2021-10-18 12:00 ` Geert Uytterhoeven 2021-10-18 12:00 ` Geert Uytterhoeven 2021-10-15 14:38 ` [PATCH v2 15/24] PCI: rockchip: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 16/24] PCI/ERR: Use RESPONSE_IS_PCI_ERROR() to check read from hardware Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 17/24] PCI: vmd: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 14:52 ` Naveen Naidu 2021-10-15 14:52 ` Naveen Naidu 2021-10-15 14:38 ` [PATCH v2 18/24] PCI: pciehp: " Naveen Naidu 2021-10-15 14:38 ` Naveen Naidu 2021-10-15 15:15 ` Naveen Naidu 2021-10-15 15:15 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 19/24] PCI/DPC: " Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 20/24] PCI/PME: " Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 21/24] PCI: cpqphp: " Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 22/24] PCI: keystone: Use PCI_ERROR_RESPONSE to specify hardware error Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 23/24] PCI: hv: Use PCI_ERROR_RESPONSE to specify hardware read error Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` [PATCH v2 24/24] PCI: xgene: Use PCI_ERROR_RESPONSE to specify hardware error Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu 2021-10-15 14:39 ` Naveen Naidu
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