cxl/acpi: Extract component registers of restricted hosts from RCRB

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 <terry.bowman@amd.com>
Signed-off-by: Terry Bowman <terry.bowman@amd.com>
Signed-off-by: Robert Richter <rrichter@amd.com>
Link: https://lore.kernel.org/r/Y4dsGZ24aJlxSfI1@rric.localdomain
[djbw: introduce devm_cxl_add_rch_dport()]
Link: https://lore.kernel.org/r/166993044524.1882361.2539922887413208807.stgit@dwillia2-xfh.jf.intel.com
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

4 files changed, 33 insertions, 0 deletions

diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
index 500be85729cc..9e4d94e81723 100644
--- a/tools/testing/cxl/Kbuild
+++ b/tools/testing/cxl/Kbuild
@@ -10,6 +10,7 @@ ldflags-y += --wrap=devm_cxl_add_passthrough_decoder
 ldflags-y += --wrap=devm_cxl_enumerate_decoders
 ldflags-y += --wrap=cxl_await_media_ready
 ldflags-y += --wrap=cxl_hdm_decode_init
+ldflags-y += --wrap=cxl_rcrb_to_component
 
 DRIVERS := ../../../drivers
 CXL_SRC := $(DRIVERS)/cxl
diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index 4f9dc2b3f655..7d87be53ac8e 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -696,6 +696,15 @@ static int mock_cxl_port_enumerate_dports(struct cxl_port *port)
 	return 0;
 }
 
+resource_size_t mock_cxl_rcrb_to_component(struct device *dev,
+					   resource_size_t rcrb,
+					   enum cxl_rcrb which)
+{
+	dev_dbg(dev, "rcrb: %pa which: %d\n", &rcrb, which);
+
+	return (resource_size_t) which + 1;
+}
+
 static struct cxl_mock_ops cxl_mock_ops = {
 	.is_mock_adev = is_mock_adev,
 	.is_mock_bridge = is_mock_bridge,
@@ -704,6 +713,7 @@ static struct cxl_mock_ops cxl_mock_ops = {
 	.is_mock_dev = is_mock_dev,
 	.acpi_table_parse_cedt = mock_acpi_table_parse_cedt,
 	.acpi_evaluate_integer = mock_acpi_evaluate_integer,
+	.cxl_rcrb_to_component = mock_cxl_rcrb_to_component,
 	.acpi_pci_find_root = mock_acpi_pci_find_root,
 	.devm_cxl_port_enumerate_dports = mock_cxl_port_enumerate_dports,
 	.devm_cxl_setup_hdm = mock_cxl_setup_hdm,
diff --git a/tools/testing/cxl/test/mock.c b/tools/testing/cxl/test/mock.c
index bce6a21df0d5..5dface08e0de 100644
--- a/tools/testing/cxl/test/mock.c
+++ b/tools/testing/cxl/test/mock.c
@@ -224,6 +224,25 @@ int __wrap_cxl_hdm_decode_init(struct cxl_dev_state *cxlds,
 }
 EXPORT_SYMBOL_NS_GPL(__wrap_cxl_hdm_decode_init, CXL);
 
+resource_size_t __wrap_cxl_rcrb_to_component(struct device *dev,
+					     resource_size_t rcrb,
+					     enum cxl_rcrb which)
+{
+	int index;
+	resource_size_t component_reg_phys;
+	struct cxl_mock_ops *ops = get_cxl_mock_ops(&index);
+
+	if (ops && ops->is_mock_port(dev))
+		component_reg_phys =
+			ops->cxl_rcrb_to_component(dev, rcrb, which);
+	else
+		component_reg_phys = cxl_rcrb_to_component(dev, rcrb, which);
+	put_cxl_mock_ops(index);
+
+	return component_reg_phys;
+}
+EXPORT_SYMBOL_NS_GPL(__wrap_cxl_rcrb_to_component, CXL);
+
 MODULE_LICENSE("GPL v2");
 MODULE_IMPORT_NS(ACPI);
 MODULE_IMPORT_NS(CXL);
diff --git a/tools/testing/cxl/test/mock.h b/tools/testing/cxl/test/mock.h
index 738f24e3988a..ef33f159375e 100644
--- a/tools/testing/cxl/test/mock.h
+++ b/tools/testing/cxl/test/mock.h
@@ -15,6 +15,9 @@ struct cxl_mock_ops {
 					     acpi_string pathname,
 					     struct acpi_object_list *arguments,
 					     unsigned long long *data);
+	resource_size_t (*cxl_rcrb_to_component)(struct device *dev,
+						 resource_size_t rcrb,
+						 enum cxl_rcrb which);
 	struct acpi_pci_root *(*acpi_pci_find_root)(acpi_handle handle);
 	bool (*is_mock_bus)(struct pci_bus *bus);
 	bool (*is_mock_port)(struct device *dev);