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From: Simon Horman <horms@kernel.org>
To: Wei Huang <wei.huang2@amd.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-doc@vger.kernel.org, netdev@vger.kernel.org,
	bhelgaas@google.com, corbet@lwn.net, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
	alex.williamson@redhat.com, gospo@broadcom.com,
	michael.chan@broadcom.com, ajit.khaparde@broadcom.com,
	manoj.panicker2@amd.com, Eric.VanTassell@amd.com
Subject: Re: [PATCH V1 5/9] PCI/TPH: Introduce API functions to get/set steering tags
Date: Sat, 11 May 2024 21:15:54 +0100	[thread overview]
Message-ID: <20240511201554.GV2347895@kernel.org> (raw)
In-Reply-To: <20240509162741.1937586-6-wei.huang2@amd.com>

On Thu, May 09, 2024 at 11:27:37AM -0500, Wei Huang wrote:
> This patch introduces two API functions, pcie_tph_get_st() and
> pcie_tph_set_st(), for a driver to retrieve or configure device's
> steering tags. There are two possible locations for steering tag
> table and the code automatically figure out the right location to
> set the tags if pcie_tph_set_st() is called. Note the tag value is
> always zero currently and will be extended in the follow-up patches.
> 
> Co-developed-by: Eric Van Tassell <Eric.VanTassell@amd.com>
> Signed-off-by: Eric Van Tassell <Eric.VanTassell@amd.com>
> Signed-off-by: Wei Huang <wei.huang2@amd.com>

Hi Eric and Wei,

I noticed a few minor problems flagged by Sparse
which I'd like to bring to your attention.

> ---
>  drivers/pci/pcie/tph.c  | 383 ++++++++++++++++++++++++++++++++++++++++
>  include/linux/pci-tph.h |  19 ++
>  2 files changed, 402 insertions(+)
> 
> diff --git a/drivers/pci/pcie/tph.c b/drivers/pci/pcie/tph.c

...

> +/*
> + * For a given device, return a pointer to the MSI table entry at msi_index.
> + */
> +static void __iomem *tph_msix_table_entry(struct pci_dev *dev,
> +					  __le16 msi_index)
> +{
> +	void *entry;
> +	u16 tbl_sz;
> +	int ret;
> +
> +	ret = tph_get_table_size(dev, &tbl_sz);
> +	if (ret || msi_index > tbl_sz)

While tbl_sz is a host-byte order integer value, msi_index is little endian.
So maths operations involving the latter doesn't seem right.

Flagged by Sparse.

> +		return NULL;
> +
> +	entry = dev->msix_base + msi_index * PCI_MSIX_ENTRY_SIZE;

Likewise, there seem to be endian problems here here.

Also, entry is used on the line above and below in a way
where an __iomem annotation is expected, but entry doesn't have one.

Also flagged by Sparse.

> +
> +	return entry;
> +}

...

> +/* Write the steering tag to MSI-X vector control register */
> +static void tph_write_tag_to_msix(struct pci_dev *dev, int msix_nr, u16 tag)
> +{
> +	u32 val;
> +	void __iomem *vec_ctrl;
> +	struct msi_desc *msi_desc;
> +
> +	msi_desc = tph_msix_index_to_desc(dev, msix_nr);
> +	if (!msi_desc) {
> +		pr_err("MSI-X descriptor for #%d not found\n", msix_nr);
> +		return;
> +	}
> +
> +	vec_ctrl = tph_msix_vector_control(dev, msi_desc->msi_index);

According to Sparse, the type of msi_desc->msi_index is unsigned short.
But tph_msix_vector_control expects it's second argument to be __le16.

> +
> +	val = readl(vec_ctrl);
> +	val &= 0xffff;
> +	val |= (tag << 16);
> +	writel(val, vec_ctrl);
> +
> +	/* read back to flush the update */
> +	val = readl(vec_ctrl);
> +	msi_unlock_descs(&dev->dev);
> +}

...

  parent reply	other threads:[~2024-05-11 20:16 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-09 16:27 [PATCH V1 0/9] PCIe TPH and cache direct injection support Wei Huang
2024-05-09 16:27 ` [PATCH V1 1/9] PCI: Introduce PCIe TPH support framework Wei Huang
2024-05-09 16:27 ` [PATCH V1 2/9] PCI: Add TPH related register definition Wei Huang
2024-05-09 16:27 ` [PATCH V1 3/9] PCI/TPH: Implement a command line option to disable TPH Wei Huang
2024-05-09 16:27 ` [PATCH V1 4/9] PCI/TPH: Implement a command line option to force No ST Mode Wei Huang
2024-05-09 16:27 ` [PATCH V1 5/9] PCI/TPH: Introduce API functions to get/set steering tags Wei Huang
2024-05-10  3:07   ` kernel test robot
2024-05-11 20:15   ` Simon Horman [this message]
2024-05-13 13:29     ` Wei Huang
2024-05-09 16:27 ` [PATCH V1 6/9] PCI/TPH: Retrieve steering tag from ACPI _DSM Wei Huang
2024-05-10  4:20   ` kernel test robot
2024-05-10  5:24   ` kernel test robot
2024-05-09 16:27 ` [PATCH V1 7/9] PCI/TPH: Add TPH documentation Wei Huang
2024-05-15 12:11   ` Bagas Sanjaya
2024-05-09 16:27 ` [PATCH V1 8/9] bnxt_en: Add TPH support in BNXT driver Wei Huang
2024-05-09 21:50   ` Vadim Fedorenko
2024-05-10  3:55     ` Ajit Khaparde
2024-05-10 10:35       ` Vadim Fedorenko
2024-05-10 15:23         ` Andy Gospodarek
2024-05-10 20:03           ` David Wei
2024-05-10 20:33             ` Andy Gospodarek
2024-05-10 20:33           ` Vadim Fedorenko
2024-05-10 20:37             ` Andy Gospodarek
2024-05-10  3:10   ` Somnath Kotur
2024-05-09 16:27 ` [PATCH V1 9/9] bnxt_en: Pass NQ ID to the FW when allocating RX/RX AGG rings Wei Huang

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