Dave Jiang wrote:
> On 4/9/24 12:35 AM, Kobayashi,Daisuke wrote:
> > Add rcd_regs initialization at __rcrb_to_component() to cache the
> > cxl1.1 device link status information. Reduce access to the memory map
> > area where the RCRB is located by caching the cxl1.1 device link status
> information.
> >
> > Signed-off-by: "Kobayashi,Daisuke" <kobayashi.da-06@xxxxxxxxxxx>
> > ---
> > drivers/cxl/core/regs.c | 18 ++++++++++++++++++
> > 1 file changed, 18 insertions(+)
> >
> > diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c index
> > 372786f80955..308eb951613e 100644
> > --- a/drivers/cxl/core/regs.c
> > +++ b/drivers/cxl/core/regs.c
> > @@ -514,6 +514,8 @@ resource_size_t __rcrb_to_component(struct device
> *dev, struct cxl_rcrb_info *ri
> > u32 bar0, bar1;
> > u16 cmd;
> > u32 id;
> > + u16 offset;
> > + u32 cap_hdr;
> >
> > if (which == CXL_RCRB_UPSTREAM)
> > rcrb += SZ_4K;
> > @@ -537,6 +539,22 @@ resource_size_t __rcrb_to_component(struct device
> *dev, struct cxl_rcrb_info *ri
> > cmd = readw(addr + PCI_COMMAND);
> > bar0 = readl(addr + PCI_BASE_ADDRESS_0);
> > bar1 = readl(addr + PCI_BASE_ADDRESS_1);
> > +
> > + offset = readw(addr + PCI_CAPABILITY_LIST);
> > + offset &= 0x00ff;
>
> GENMASK(7,0) is preferred to 0x00ff. Although a properly defined mask would
> be nice.
> Also please consider using FIELD_GET().
>
Thank you for your feedback.
I will update the patch to use those macros.
> > + cap_hdr = readl(addr + offset);
> > + while ((cap_hdr & 0x000000ff) != PCI_CAP_ID_EXP) {
>
> Same comment as above
>
>
> > + offset = (cap_hdr >> 8) & 0x000000ff;
>
> Also here
>
> > + if (offset == 0) // End of capability list
>
> Please use /* */ instead of // for Linux kernel code
>
Also I will fix it.
> > + break;
> > + cap_hdr = readl(addr + offset);
> > + }
> > + if (offset) {
> > + ri->rcd_lnkcap = readl(addr + offset + PCI_EXP_LNKCAP);
> > + ri->rcd_lnkctrl = readl(addr + offset + PCI_EXP_LNKCTL);
> > + ri->rcd_lnkstatus = readl(addr + offset + PCI_EXP_LNKSTA);
> > + }
> > +
> > iounmap(addr);
> > release_mem_region(rcrb, SZ_4K);
> >
