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From: Bjorn Helgaas <helgaas@kernel.org>
To: "Marek Behún" <kabel@kernel.org>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	pali@kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH v4 01/11] PCI: pci-bridge-emul: Add description for class_revision field
Date: Fri, 3 Dec 2021 10:36:49 -0600	[thread overview]
Message-ID: <20211203163649.GA3004204@bhelgaas> (raw)
In-Reply-To: <20211130172913.9727-2-kabel@kernel.org>

On Tue, Nov 30, 2021 at 06:29:03PM +0100, Marek Behún wrote:
> From: Pali Rohár <pali@kernel.org>
> 
> The current assignment to the class_revision member
> 
>   class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16);
> 
> can make the reader think that class is at high 16 bits of the member and
> revision at low 16 bits.
> 
> In reality, class is at high 24 bits, but the class for PCI Bridge Normal
> Decode is PCI_CLASS_BRIDGE_PCI << 8.
> 
> Change the assignment and add a comment to make this clearer.
> 
> Signed-off-by: Pali Rohár <pali@kernel.org>
> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>  drivers/pci/pci-bridge-emul.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
> index db97cddfc85e..a4af1a533d71 100644
> --- a/drivers/pci/pci-bridge-emul.c
> +++ b/drivers/pci/pci-bridge-emul.c
> @@ -265,7 +265,11 @@ int pci_bridge_emul_init(struct pci_bridge_emul *bridge,
>  {
>  	BUILD_BUG_ON(sizeof(bridge->conf) != PCI_BRIDGE_CONF_END);
>  
> -	bridge->conf.class_revision |= cpu_to_le32(PCI_CLASS_BRIDGE_PCI << 16);
> +	/*
> +	 * class_revision: Class is high 24 bits and revision is low 8 bit of this member,
> +	 * while class for PCI Bridge Normal Decode has the 24-bit value: PCI_CLASS_BRIDGE_PCI << 8
> +	 */

Can you please re-wrap this comment so it fits in 80 columns like the
rest of the file?

I'd do something with the assignment, too.  It's hard to read when it
wraps, especially since at 80 columns it splits the "<<" in half.

I assume from the commit log that this is purely a readability change,
not a fix, right?

> +	bridge->conf.class_revision |= cpu_to_le32((PCI_CLASS_BRIDGE_PCI << 8) << 8);
>  	bridge->conf.header_type = PCI_HEADER_TYPE_BRIDGE;
>  	bridge->conf.cache_line_size = 0x10;
>  	bridge->conf.status = cpu_to_le16(PCI_STATUS_CAP_LIST);
> -- 
> 2.32.0
> 

  reply	other threads:[~2021-12-03 16:36 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-30 17:29 [PATCH v4 00/11] PCI: aardvark controller fixes BATCH 3 Marek Behún
2021-11-30 17:29 ` [PATCH v4 01/11] PCI: pci-bridge-emul: Add description for class_revision field Marek Behún
2021-12-03 16:36   ` Bjorn Helgaas [this message]
2021-12-03 18:52     ` Marek Behún
2021-11-30 17:29 ` [PATCH v4 02/11] PCI: pci-bridge-emul: Add definitions for missing capabilities registers Marek Behún
2021-12-03 16:45   ` Bjorn Helgaas
2021-11-30 17:29 ` [PATCH v4 03/11] PCI: aardvark: Add support for DEVCAP2, DEVCTL2, LNKCAP2 and LNKCTL2 registers on emulated bridge Marek Behún
2021-11-30 17:29 ` [PATCH v4 04/11] PCI: aardvark: Clear all MSIs at setup Marek Behún
2021-11-30 17:29 ` [PATCH v4 05/11] PCI: aardvark: Comment actions in driver remove method Marek Behún
2021-11-30 17:29 ` [PATCH v4 06/11] PCI: aardvark: Disable bus mastering when unbinding driver Marek Behún
2021-11-30 17:29 ` [PATCH v4 07/11] PCI: aardvark: Mask all interrupts " Marek Behún
2021-11-30 17:29 ` [PATCH v4 08/11] PCI: aardvark: Fix memory leak in driver unbind Marek Behún
2021-11-30 17:29 ` [PATCH v4 09/11] PCI: aardvark: Assert PERST# when unbinding driver Marek Behún
2021-11-30 17:29 ` [PATCH v4 10/11] PCI: aardvark: Disable link training " Marek Behún
2021-11-30 17:29 ` [PATCH v4 11/11] PCI: aardvark: Disable common PHY " Marek Behún
2021-12-02 10:01 ` [PATCH v4 00/11] PCI: aardvark controller fixes BATCH 3 Lorenzo Pieralisi

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