On 01.12.22 13:34:05, Dan Williams wrote:
> From: Robert Richter <[email protected]>
>
> A downstream port must be connected to a component register block.
> For restricted hosts the base address is determined from the RCRB. The
> RCRB is provided by the host's CEDT CHBS entry. Rework CEDT parser to
> get the RCRB and add code to extract the component register block from
> it.
>
> RCRB's BAR[0..1] point to the component block containing CXL subsystem
> component registers. MEMBAR extraction follows the PCI base spec here,
> esp. 64 bit extraction and memory range alignment (6.0, 7.5.1.2.1). The
> RCRB base address is cached in the cxl_dport per-host bridge so that the
> upstream port component registers can be retrieved later by an RCD
> (RCIEP) associated with the host bridge.
>
> Note: Right now the component register block is used for HDM decoder
> capability only which is optional for RCDs. If unsupported by the RCD,
> the HDM init will fail. It is future work to bypass it in this case.
>
> Co-developed-by: Terry Bowman <[email protected]>
> Signed-off-by: Terry Bowman <[email protected]>
> Signed-off-by: Robert Richter <[email protected]>
> Link: https://lore.kernel.org/r/[email protected]
> [djbw: introduce devm_cxl_add_rch_dport()]
> Signed-off-by: Dan Williams <[email protected]>
Found an issue below. Patch looks good to me otherwise.
> ---
> drivers/cxl/acpi.c | 51 ++++++++++++++++++++++++++++-----
> drivers/cxl/core/port.c | 53 ++++++++++++++++++++++++++++++----
> drivers/cxl/core/regs.c | 64
> +++++++++++++++++++++++++++++++++++++++++
> drivers/cxl/cxl.h | 16 ++++++++++
> tools/testing/cxl/Kbuild | 1 +
> tools/testing/cxl/test/cxl.c | 10 ++++++
> tools/testing/cxl/test/mock.c | 19 ++++++++++++
> tools/testing/cxl/test/mock.h | 3 ++
> 8 files changed, 203 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
> @@ -274,21 +301,29 @@ static int add_host_bridge_dport(struct device *match,
> void *arg)
> dev_dbg(match, "UID found: %lld\n", uid);
>
> ctx = (struct cxl_chbs_context) {
> - .dev = host,
> + .dev = match,
> .uid = uid,
> };
> acpi_table_parse_cedt(ACPI_CEDT_TYPE_CHBS, cxl_get_chbcr, &ctx);
>
> - if (ctx.chbcr == 0) {
> + if (ctx.rcrb != CXL_RESOURCE_NONE)
> + dev_dbg(match, "RCRB found for UID %lld: %pa\n", uid,
> &ctx.rcrb);
> +
> + if (ctx.chbcr == CXL_RESOURCE_NONE) {
> dev_warn(match, "No CHBS found for Host Bridge (UID %lld)\n",
> uid);
> return 0;
> }
The logic must be changed to handle the case where the chbs entry is
missing:
if (!ctx.chbcr) {
dev_warn(match, "No CHBS found for Host Bridge (UID %lld)\n",
uid);
return 0;
}
if (ctx.rcrb != CXL_RESOURCE_NONE)
dev_dbg(match, "RCRB found for UID %lld: %pa\n", uid,
&ctx.rcrb);
if (ctx.chbcr == CXL_RESOURCE_NONE) {
dev_warn(match, "CHBCR missing for Host Bridge (UID %lld)\n",
uid);
return 0;
}
>
> - dev_dbg(match, "CHBCR found: 0x%08llx\n", (u64)ctx.chbcr);
> + dev_dbg(match, "CHBCR found: %pa\n", &ctx.chbcr);
