@@ -125,8 +125,73 @@ static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)
return true;
}
+static int match_root_decoder(struct device *dev, void *dport_dev)
+{
+ struct cxl_switch_decoder *cxlsd;
+
+ if (!is_switch_decoder(dev))
+ return 0;
+
+ cxlsd = to_cxl_switch_decoder(dev);
+
+ guard(rwsem_read)(&cxl_region_rwsem);
+
+ for (int i = 0; i < cxlsd->nr_targets; i++) {
+ if (dport_dev == cxlsd->target[i]->dport_dev)
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct cxl_decoder *find_root_decoder(struct cxl_port *port,
+ struct device *dport_dev)
+{
+ struct device *dev;
+
+ dev = device_find_child(&port->dev, dport_dev, match_root_decoder);
+
+ return dev ? to_cxl_decoder(dev) : NULL;
+}
+
+static void setup_base_hpa_cfmws(struct cxl_hdm *cxlhdm,
+ struct cxl_root *cxl_root)
+{
+ struct cxl_port *port = cxlhdm->port;
+ struct cxl_decoder *cxld;
+ u64 base;
+
+ if (!port->host_bridge) {
+ dev_dbg(&port->dev, "No host bridge found for port.\n");
+ return;
+ }
+
+ cxld = find_root_decoder(&cxl_root->port, port->host_bridge);
+ if (!cxld) {
+ dev_dbg(&port->dev,
+ "CFMWS missing for host bridge %s, HPA range not found.\n",
+ dev_name(port->host_bridge));
+ return;
+ }
+
+ base = cxld->hpa_range.start;
+ dev_dbg(&port->dev,
+ "HPA translation for decoders enabled, base 0x%08llx\n",
+ base);
+ put_device(&cxld->dev);
+
+ cxlhdm->base_hpa = base;
+}
+
static void setup_base_hpa(struct cxl_hdm *cxlhdm)
{
+ struct cxl_port *port = cxlhdm->port;
+
+ struct cxl_root *cxl_root __free(put_cxl_root) = find_cxl_root(port);
+
+ if (!cxl_root)
+ return;
+
/*
* Address translation is not needed on platforms with HPA ==
* SPA. HDM decoder addresses all base on system addresses,
@@ -134,6 +199,10 @@ static void setup_base_hpa(struct cxl_hdm *cxlhdm)
* == 0). Nothing to do here as it is already pre-initialized
* zero.
*/
+ if (!cxl_root->hpa_xlat_enable)
+ return;
+
+ setup_base_hpa_cfmws(cxlhdm, cxl_root);
}
/**
There are platforms where an address translation between decoder's (HPA) and the system's physical addresses (SPA) is needed. The HPA window in the CFMWS can be used to determine the address offset for the translation. Each CXL endpoint or switch is uniquely attached to a CXL host bridge. The host bridge is assigned a unique HPA window in an CFMWS entry of the CEDT (host bridge is in target list). The hardware base addresses of a CFMWS is an SPA. With that, the offset can be determined using the HDM decoder's base address from the registers and the HPA window in the CFMWS entry of the corresponding CXL host bridge. The CFMWS entries are parsed during host bridge enablement and set up in the CXL root decoder during CXL decoder enumeration before a CXL endpoint is enabled. That is, the endpoint's host bridge's root decoder can be determined. The HPA range of it marks the beginning of the HDM decoder's base address and the offset between both can be used for later address translation. Setup HPA base address (@base_hpa) of a struct cxl_hdm by determining the offset as described. Use the port's host bridge and CXL root port to find the corresponding CXL root decoder containing the HPA window in the bridge's CFMWS entry. Only enable this for platforms with the @hpa_xlat_enable flag set. Signed-off-by: Robert Richter <rrichter@amd.com> --- drivers/cxl/core/hdm.c | 69 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+)