cxl/core/hdm: Add CXL standard decoder enumeration to the core

Unlike the decoder enumeration for "root decoders" described by platform
firmware, standard decoders can be enumerated from the component
registers space once the base address has been identified (via PCI,
ACPI, or another mechanism).

Add common infrastructure for HDM (Host-managed-Device-Memory) Decoder
enumeration and share it between host-bridge, upstream switch port, and
cxl_test defined decoders.

The locking model for switch level decoders is to hold the port lock
over the enumeration. This facilitates moving the dport and decoder
enumeration to a 'port' driver. For now, the only enumerator of decoder
resources is the cxl_acpi root driver.

Co-developed-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164374688404.395335.9239248252443123526.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/tools/testing/cxl/test/cxl.c b/tools/testing/cxl/test/cxl.c
index ef002e909d38..81c09380c537 100644
--- a/tools/testing/cxl/test/cxl.c
+++ b/tools/testing/cxl/test/cxl.c
@@ -8,6 +8,7 @@
 #include <linux/acpi.h>
 #include <linux/pci.h>
 #include <linux/mm.h>
+#include <cxlmem.h>
 #include "mock.h"
 
 #define NR_CXL_HOST_BRIDGES 4
@@ -398,6 +399,31 @@ static struct acpi_pci_root *mock_acpi_pci_find_root(acpi_handle handle)
 	return &mock_pci_root[host_bridge_index(adev)];
 }
 
+static struct cxl_hdm *mock_cxl_setup_hdm(struct device *host,
+					  struct cxl_port *port)
+{
+	struct cxl_hdm *cxlhdm = devm_kzalloc(&port->dev, sizeof(*cxlhdm), GFP_KERNEL);
+
+	if (!cxlhdm)
+		return ERR_PTR(-ENOMEM);
+
+	cxlhdm->port = port;
+	return cxlhdm;
+}
+
+static int mock_cxl_add_passthrough_decoder(struct device *host,
+					    struct cxl_port *port)
+{
+	dev_err(&port->dev, "unexpected passthrough decoder for cxl_test\n");
+	return -EOPNOTSUPP;
+}
+
+static int mock_cxl_enumerate_decoders(struct device *host,
+				       struct cxl_hdm *cxlhdm)
+{
+	return 0;
+}
+
 static int mock_cxl_port_enumerate_dports(struct device *host,
 					  struct cxl_port *port)
 {
@@ -439,6 +465,9 @@ static struct cxl_mock_ops cxl_mock_ops = {
 	.acpi_evaluate_integer = mock_acpi_evaluate_integer,
 	.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,
+	.devm_cxl_add_passthrough_decoder = mock_cxl_add_passthrough_decoder,
+	.devm_cxl_enumerate_decoders = mock_cxl_enumerate_decoders,
 	.list = LIST_HEAD_INIT(cxl_mock_ops.list),
 };