On 5/11/24 15:15, Simon Horman wrote:
> 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.
Thanks, will take care of it in the next revision.
>
> 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.
Will fix
>
>> +
>> + 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.
Will fix
>
>> +
>> + 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);
>> +}
>
> ...
