From: Rob Herring <robh@kernel.org>
To: Naveen Naidu <naveennaidu479@gmail.com>
Cc: bhelgaas@google.com,
linux-kernel-mentees@lists.linuxfoundation.org,
linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 01/24] PCI: Add PCI_ERROR_RESPONSE and it's related definitions
Date: Wed, 20 Oct 2021 08:24:30 -0500 [thread overview]
Message-ID: <YXAYjkLyS53Bod3j@robh.at.kernel.org> (raw)
In-Reply-To: <4516b02d3c0fe3593a1a9f59bab47e99cdb65f02.1634306198.git.naveennaidu479@gmail.com>
On Fri, Oct 15, 2021 at 07:58:16PM +0530, Naveen Naidu 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.
>
> Add a PCI_ERROR_RESPONSE definition for that and use it where
> appropriate to make these checks consistent and easier to find.
>
> Also add helper definitions SET_PCI_ERROR_RESPONSE and
> RESPONSE_IS_PCI_ERROR to make the code more readable.
>
> Suggested-by: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Naveen Naidu <naveennaidu479@gmail.com>
> ---
> include/linux/pci.h | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index cd8aa6fce204..928c589bb5c4 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -154,6 +154,15 @@ enum pci_interrupt_pin {
> /* The number of legacy PCI INTx interrupts */
> #define PCI_NUM_INTX 4
>
> +/*
> + * Reading from a device that doesn't respond typically returns ~0. A
> + * successful read from a device may also return ~0, so you need additional
> + * information to reliably identify errors.
> + */
> +#define PCI_ERROR_RESPONSE (~0ULL)
> +#define SET_PCI_ERROR_RESPONSE(val) (*val = ((typeof(*val)) PCI_ERROR_RESPONSE))
> +#define RESPONSE_IS_PCI_ERROR(val) (*val == ((typeof(*val)) PCI_ERROR_RESPONSE))
No reason for val to be a pointer.
Also, macro parameters need () around them. val could be an expression
like 'ptr + 1' which would blow up for example.
> +
> /*
> * pci_power_t values must match the bits in the Capabilities PME_Support
> * and Control/Status PowerState fields in the Power Management capability.
> --
> 2.25.1
>
>
next prev parent reply other threads:[~2021-10-20 13:24 UTC|newest]
Thread overview: 39+ 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 14:28 ` [PATCH v2 01/24] PCI: Add PCI_ERROR_RESPONSE and it's related definitions Naveen Naidu
2021-10-20 13:24 ` Rob Herring [this message]
2021-10-15 14:28 ` [PATCH v2 02/24] PCI: Set error response in config access defines when ops->read() fails Naveen Naidu
2021-10-20 13:41 ` Rob Herring
2021-10-20 13:52 ` Pali Rohár
2021-10-20 15:13 ` Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 03/24] PCI: Unify PCI error response checking Naveen Naidu
2021-10-20 13:13 ` Rob Herring
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
2021-10-20 13:42 ` Rob Herring
2021-10-15 14:38 ` [PATCH v2 05/24] PCI: thunder: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 06/24] PCI: iproc: " Naveen Naidu
2021-10-15 16:49 ` Ray Jui
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 ` [PATCH v2 08/24] PCI: exynos: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 09/24] PCI: histb: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 10/24] PCI: kirin: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 11/24] PCI: aardvark: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 12/24] PCI: mvebu: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 13/24] PCI: altera: " Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 14/24] PCI: rcar: " Naveen Naidu
2021-10-18 11:32 ` Geert Uytterhoeven
2021-10-18 11:51 ` Naveen Naidu
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 ` [PATCH v2 16/24] PCI/ERR: Use RESPONSE_IS_PCI_ERROR() to check read from hardware Naveen Naidu
2021-10-15 14:38 ` [PATCH v2 17/24] PCI: vmd: " 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 15:15 ` Naveen Naidu
2021-10-15 14:39 ` [PATCH v2 19/24] PCI/DPC: " Naveen Naidu
2021-10-15 14:39 ` [PATCH v2 20/24] PCI/PME: " Naveen Naidu
2021-10-15 14:39 ` [PATCH v2 21/24] PCI: cpqphp: " 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 ` [PATCH v2 23/24] PCI: hv: Use PCI_ERROR_RESPONSE to specify hardware read error Naveen Naidu
2021-10-15 14:39 ` [PATCH v2 24/24] PCI: xgene: Use PCI_ERROR_RESPONSE to specify hardware error Naveen Naidu
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