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@xxxxxxx>
> Signed-off-by: Eric Van Tassell <Eric.VanTassell@xxxxxxx>
> Signed-off-by: Wei Huang <wei.huang2@xxxxxxx>
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);
> +}
...
