On 4/12/24 12:07 AM, Kobayashi,Daisuke wrote:
> Add rcd_regs and its 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 | 16 ++++++++++++++++
> drivers/cxl/cxl.h | 3 +++
> 2 files changed, 19 insertions(+)
>
> diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c
> index 372786f80955..e0e96be0ca7d 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 +539,20 @@ 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 = FIELD_GET(GENMASK(7, 0), readw(addr + PCI_CAPABILITY_LIST));
Maybe
#define PCI_RCRB_CAPABILITY_LIST_ID_MASK GENMASK(7, 0)
> + cap_hdr = readl(addr + offset);
> + while ((cap_hdr & GENMASK(7, 0)) != PCI_CAP_ID_EXP) {
while ((FIELD_GET(PCI_RCRB_CAP_HDR_ID_MASK, cap_hdr) != PCI_CAP_ID_EXP) {
Also I think you need to add a check and see if the loop went beyond SZ_4K that was mapped.
> + offset = (cap_hdr >> 8) & GENMASK(7, 0);
#define PCI_RCRB_CAP_HDR_NEXT_MASK GENMASK(15, 8);
offset = FIELD_GET(PCI_RCRB_CAP_HDR_NEXT_MASK, cap_hdr);
> + if (offset == 0)
> + 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);
>
> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
> index 003feebab79b..2dc827c301a1 100644
> --- a/drivers/cxl/cxl.h
> +++ b/drivers/cxl/cxl.h
> @@ -647,6 +647,9 @@ cxl_find_dport_by_dev(struct cxl_port *port, const struct device *dport_dev)
> struct cxl_rcrb_info {
> resource_size_t base;
> u16 aer_cap;
> + u16 rcd_lnkctrl;
> + u16 rcd_lnkstatus;
> + u32 rcd_lnkcap;
> };
>
> /**
