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Message-Id: <20220621201259.1547474-1-dave@stgolabs.net>
Date: Tue, 21 Jun 2022 13:12:59 -0700
From: Davidlohr Bueso <dave@...olabs.net>
To: linux-cxl@...r.kernel.org
Cc: dan.j.williams@...el.com, alison.schofield@...el.com,
bwidawsk@...nel.org, ira.weiny@...el.com, vishal.l.verma@...el.com,
a.manzanares@...sung.com, dave@...olabs.net,
linux-kernel@...r.kernel.org
Subject: [PATCH] cxl/acpi: Verify CHBS consistency
Similarly to verifying the cfwms, have a cxl_acpi_chbs_verify(),
as described by the CXL T3 Memory Device Software Guide
for CXL 2.0 platforms.
Also while at it, tuck the rc check for nvdimm bridge into
the pmem branch.
Signed-off-by: Davidlohr Bueso <dave@...olabs.net>
---
drivers/cxl/acpi.c | 64 +++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 61 insertions(+), 3 deletions(-)
diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 40286f5df812..33b5f362c9f1 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -187,14 +187,65 @@ static int add_host_bridge_uport(struct device *match, void *arg)
struct cxl_chbs_context {
struct device *dev;
unsigned long long uid;
+ struct cxl_port *root_port;
resource_size_t chbcr;
};
+static inline bool range_overlaps(struct range *r1, struct range *r2)
+{
+ return r1->start <= r2->end && r2->start <= r1->end;
+}
+
+static int cxl_acpi_chbs_verify(struct cxl_chbs_context *cxt,
+ struct acpi_cedt_chbs *chbs)
+{
+ struct device *dev = cxt->dev;
+ struct cxl_dport *dport;
+ struct cxl_port *root_port = cxt->root_port;
+ struct range chbs_range = {
+ .start = chbs->base,
+ .end = chbs->base + chbs->length - 1,
+ };
+
+ if (chbs->cxl_version > 1) {
+ dev_err(dev, "CHBS Unsupported CXL Version\n");
+ return -EINVAL;
+ }
+
+ if (chbs->cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11)
+ return 0;
+
+ if (chbs->cxl_version == ACPI_CEDT_CHBS_VERSION_CXL20 &&
+ (chbs->length != ACPI_CEDT_CHBS_LENGTH_CXL20)) {
+ dev_err(dev, "Platform does not support CXL 2.0\n");
+ return -EINVAL;
+ }
+
+ device_lock(&root_port->dev);
+ list_for_each_entry(dport, &root_port->dports, list) {
+ struct range dport_range = {
+ .start = dport->component_reg_phys,
+ .end = dport->component_reg_phys +
+ CXL_COMPONENT_REG_BLOCK_SIZE - 1,
+ };
+
+ if (range_overlaps(&chbs_range, &dport_range)) {
+ device_unlock(&root_port->dev);
+ dev_err(dev, "CHBS overlapping Base and Length pair\n");
+ return -EINVAL;
+ }
+ }
+ device_unlock(&root_port->dev);
+
+ return 0;
+}
+
static int cxl_get_chbcr(union acpi_subtable_headers *header, void *arg,
const unsigned long end)
{
struct cxl_chbs_context *ctx = arg;
struct acpi_cedt_chbs *chbs;
+ int ret;
if (ctx->chbcr)
return 0;
@@ -203,6 +254,11 @@ static int cxl_get_chbcr(union acpi_subtable_headers *header, void *arg,
if (ctx->uid != chbs->uid)
return 0;
+
+ ret = cxl_acpi_chbs_verify(ctx, chbs);
+ if (ret)
+ return ret;
+
ctx->chbcr = chbs->base;
return 0;
@@ -232,6 +288,7 @@ static int add_host_bridge_dport(struct device *match, void *arg)
ctx = (struct cxl_chbs_context) {
.dev = host,
.uid = uid,
+ .root_port = root_port,
};
acpi_table_parse_cedt(ACPI_CEDT_TYPE_CHBS, cxl_get_chbcr, &ctx);
@@ -321,11 +378,12 @@ static int cxl_acpi_probe(struct platform_device *pdev)
if (rc < 0)
return rc;
- if (IS_ENABLED(CONFIG_CXL_PMEM))
+ if (IS_ENABLED(CONFIG_CXL_PMEM)) {
rc = device_for_each_child(&root_port->dev, root_port,
add_root_nvdimm_bridge);
- if (rc < 0)
- return rc;
+ if (rc < 0)
+ return rc;
+ }
/* In case PCI is scanned before ACPI re-trigger memdev attach */
return cxl_bus_rescan();
--
2.36.1
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