[PATCH v4 0/2] CXL ACPI tables for object creation

[PATCH v4 0/2] CXL ACPI tables for object creation

[Alison Schofield]

Changes since v3 [1]:
- Align func params to open parens (Checkpatch, Ben)
- Added Ben & Jonathan Reviewed-by tags

[1] https://lore.kernel.org/linux-cxl/cover.1623890468.git.alison.schofield@intel.com/

--
Parse the ACPI CXL Early Discovery Table (CEDT) and use the CHBS & CFMWS
when creating port and decoder objects.

CHBS: CXL Host Bridge Structure - Patch 1
CFMWS: CXL Fixed Memory Window Structure - Patch 2


Alison Schofield (2):
  cxl/acpi: Add the Host Bridge base address to CXL port objects
  cxl/acpi: Use the ACPI CFMWS to create static decoder objects

 drivers/cxl/acpi.c | 219 +++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 214 insertions(+), 5 deletions(-)


base-commit: 21083f51521fb0f60dbac591f175c3ed48435af4
-- 
2.26.2

[PATCH v4 1/2] cxl/acpi: Add the Host Bridge base address to CXL port objects

[Alison Schofield]

The base address for the Host Bridge port component registers is located
in the CXL Host Bridge Structure (CHBS) of the ACPI CXL Early Discovery
Table (CEDT). Retrieve the CHBS for each Host Bridge (ACPI0016 device)
and include that base address in the port object.

Co-developed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
---
 drivers/cxl/acpi.c | 98 +++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 93 insertions(+), 5 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 8a723f7f3f73..852b5c270464 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -8,6 +8,58 @@
 #include <linux/pci.h>
 #include "cxl.h"
 
+static struct acpi_table_header *acpi_cedt;
+
+static struct acpi_cedt_chbs *cxl_acpi_match_chbs(struct device *dev, u32 uid)
+{
+	struct acpi_cedt_chbs *chbs, *chbs_match = NULL;
+	acpi_size len, cur = 0;
+	void *cedt_subtable;
+
+	len = acpi_cedt->length - sizeof(*acpi_cedt);
+	cedt_subtable = acpi_cedt + 1;
+
+	while (cur < len) {
+		struct acpi_cedt_header *c = cedt_subtable + cur;
+
+		if (c->type != ACPI_CEDT_TYPE_CHBS) {
+			cur += c->length;
+			continue;
+		}
+
+		chbs = cedt_subtable + cur;
+
+		if (dev_WARN_ONCE(dev, chbs->header.length < sizeof(*chbs),
+				  "CHBS entry skipped: invalid length:%u\n",
+				  chbs->header.length)) {
+			cur += c->length;
+			continue;
+		}
+
+		if (chbs->uid != uid) {
+			cur += c->length;
+			continue;
+		}
+
+		if (dev_WARN_ONCE(dev, chbs_match,
+				  "CHBS entry skipped: duplicate UID:%u\n",
+				  uid)) {
+			cur += c->length;
+			continue;
+		}
+
+		chbs_match = chbs;
+		cur += c->length;
+	}
+
+	return chbs_match ? chbs_match : ERR_PTR(-ENODEV);
+}
+
+static resource_size_t get_chbcr(struct acpi_cedt_chbs *chbs)
+{
+	return IS_ERR(chbs) ? CXL_RESOURCE_NONE : chbs->base;
+}
+
 struct cxl_walk_context {
 	struct device *dev;
 	struct pci_bus *root;
@@ -50,6 +102,21 @@ static int match_add_root_ports(struct pci_dev *pdev, void *data)
 	return 0;
 }
 
+static struct cxl_dport *find_dport_by_dev(struct cxl_port *port, struct device *dev)
+{
+	struct cxl_dport *dport;
+
+	device_lock(&port->dev);
+	list_for_each_entry(dport, &port->dports, list)
+		if (dport->dport == dev) {
+			device_unlock(&port->dev);
+			return dport;
+		}
+
+	device_unlock(&port->dev);
+	return NULL;
+}
+
 static struct acpi_device *to_cxl_host_bridge(struct device *dev)
 {
 	struct acpi_device *adev = to_acpi_device(dev);
@@ -71,6 +138,7 @@ static int add_host_bridge_uport(struct device *match, void *arg)
 	struct acpi_pci_root *pci_root;
 	struct cxl_walk_context ctx;
 	struct cxl_decoder *cxld;
+	struct cxl_dport *dport;
 	struct cxl_port *port;
 
 	if (!bridge)
@@ -80,8 +148,14 @@ static int add_host_bridge_uport(struct device *match, void *arg)
 	if (!pci_root)
 		return -ENXIO;
 
-	/* TODO: fold in CEDT.CHBS retrieval */
-	port = devm_cxl_add_port(host, match, CXL_RESOURCE_NONE, root_port);
+	dport = find_dport_by_dev(root_port, match);
+	if (!dport) {
+		dev_dbg(host, "host bridge expected and not found\n");
+		return -ENODEV;
+	}
+
+	port = devm_cxl_add_port(host, match, dport->component_reg_phys,
+				 root_port);
 	if (IS_ERR(port))
 		return PTR_ERR(port);
 	dev_dbg(host, "%s: add: %s\n", dev_name(match), dev_name(&port->dev));
@@ -120,6 +194,7 @@ static int add_host_bridge_dport(struct device *match, void *arg)
 	int rc;
 	acpi_status status;
 	unsigned long long uid;
+	struct acpi_cedt_chbs *chbs;
 	struct cxl_port *root_port = arg;
 	struct device *host = root_port->dev.parent;
 	struct acpi_device *bridge = to_cxl_host_bridge(match);
@@ -135,7 +210,12 @@ static int add_host_bridge_dport(struct device *match, void *arg)
 		return -ENODEV;
 	}
 
-	rc = cxl_add_dport(root_port, match, uid, CXL_RESOURCE_NONE);
+	chbs = cxl_acpi_match_chbs(host, uid);
+	if (IS_ERR(chbs))
+		dev_dbg(host, "No CHBS found for Host Bridge: %s\n",
+			dev_name(match));
+
+	rc = cxl_add_dport(root_port, match, uid, get_chbcr(chbs));
 	if (rc) {
 		dev_err(host, "failed to add downstream port: %s\n",
 			dev_name(match));
@@ -172,6 +252,7 @@ static int add_root_nvdimm_bridge(struct device *match, void *data)
 static int cxl_acpi_probe(struct platform_device *pdev)
 {
 	int rc;
+	acpi_status status;
 	struct cxl_port *root_port;
 	struct device *host = &pdev->dev;
 	struct acpi_device *adev = ACPI_COMPANION(host);
@@ -181,10 +262,14 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 		return PTR_ERR(root_port);
 	dev_dbg(host, "add: %s\n", dev_name(&root_port->dev));
 
+	status = acpi_get_table(ACPI_SIG_CEDT, 0, &acpi_cedt);
+	if (ACPI_FAILURE(status))
+		return -ENXIO;
+
 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 			      add_host_bridge_dport);
 	if (rc)
-		return rc;
+		goto out;
 
 	/*
 	 * Root level scanned with host-bridge as dports, now scan host-bridges
@@ -193,11 +278,14 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
 			      add_host_bridge_uport);
 	if (rc)
-		return rc;
+		goto out;
 
 	if (IS_ENABLED(CONFIG_CXL_PMEM))
 		rc = device_for_each_child(&root_port->dev, root_port,
 					   add_root_nvdimm_bridge);
+
+out:
+	acpi_put_table(acpi_cedt);
 	if (rc < 0)
 		return rc;
 	return 0;
-- 
2.26.2

[PATCH v4 2/2] cxl/acpi: Use the ACPI CFMWS to create static decoder objects

[Alison Schofield]

The ACPI CXL Early Discovery Table (CEDT) includes a list of CXL memory
resources in CXL Fixed Memory Window Structures (CFMWS). Retrieve each
CFMWS in the CEDT and add a cxl_decoder object to the root port (root0)
for each memory resource.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Ben Widawsky <ben.widawsky@intel.com>
---
 drivers/cxl/acpi.c | 121 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index 852b5c270464..7e83c68cb12f 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -10,6 +10,125 @@
 
 static struct acpi_table_header *acpi_cedt;
 
+/* Encode defined in CXL 2.0 8.2.5.12.7 HDM Decoder Control Register */
+#define CFMWS_INTERLEAVE_WAYS(x)	(1 << (x)->interleave_ways)
+#define CFMWS_INTERLEAVE_GRANULARITY(x)	((x)->granularity + 8)
+
+static unsigned long cfmws_to_decoder_flags(int restrictions)
+{
+	unsigned long flags = 0;
+
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE2)
+		flags |= CXL_DECODER_F_TYPE2;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE3)
+		flags |= CXL_DECODER_F_TYPE3;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
+		flags |= CXL_DECODER_F_RAM;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_PMEM)
+		flags |= CXL_DECODER_F_PMEM;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_FIXED)
+		flags |= CXL_DECODER_F_LOCK;
+
+	return flags;
+}
+
+static int cxl_acpi_cfmws_verify(struct device *dev,
+				 struct acpi_cedt_cfmws *cfmws)
+{
+	int expected_len;
+
+	if (cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_MODULO) {
+		dev_err(dev, "CFMWS Unsupported Interleave Arithmetic\n");
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(cfmws->base_hpa, SZ_256M)) {
+		dev_err(dev, "CFMWS Base HPA not 256MB aligned\n");
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(cfmws->window_size, SZ_256M)) {
+		dev_err(dev, "CFMWS Window Size not 256MB aligned\n");
+		return -EINVAL;
+	}
+
+	expected_len = struct_size((cfmws), interleave_targets,
+				   CFMWS_INTERLEAVE_WAYS(cfmws));
+
+	if (cfmws->header.length < expected_len) {
+		dev_err(dev, "CFMWS length %d less than expected %d\n",
+			cfmws->header.length, expected_len);
+		return -EINVAL;
+	}
+
+	if (cfmws->header.length > expected_len)
+		dev_dbg(dev, "CFMWS length %d greater than expected %d\n",
+			cfmws->header.length, expected_len);
+
+	return 0;
+}
+
+static void cxl_add_cfmws_decoders(struct device *dev,
+				   struct cxl_port *root_port)
+{
+	struct acpi_cedt_cfmws *cfmws;
+	struct cxl_decoder *cxld;
+	acpi_size len, cur = 0;
+	void *cedt_subtable;
+	unsigned long flags;
+	int rc;
+
+	len = acpi_cedt->length - sizeof(*acpi_cedt);
+	cedt_subtable = acpi_cedt + 1;
+
+	while (cur < len) {
+		struct acpi_cedt_header *c = cedt_subtable + cur;
+
+		if (c->type != ACPI_CEDT_TYPE_CFMWS) {
+			cur += c->length;
+			continue;
+		}
+
+		cfmws = cedt_subtable + cur;
+
+		if (dev_WARN_ONCE(dev, cfmws->header.length < sizeof(*cfmws),
+				  "CFMWS entry skipped: invalid length:%u\n",
+				  cfmws->header.length)) {
+			cur += c->length;
+			continue;
+		}
+
+		rc = cxl_acpi_cfmws_verify(dev, cfmws);
+		if (rc) {
+			dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",
+				cfmws->base_hpa, cfmws->base_hpa +
+				cfmws->window_size - 1);
+			cur += c->length;
+			continue;
+		}
+
+		flags = cfmws_to_decoder_flags(cfmws->restrictions);
+		cxld = devm_cxl_add_decoder(dev, root_port,
+					    CFMWS_INTERLEAVE_WAYS(cfmws),
+					    cfmws->base_hpa, cfmws->window_size,
+					    CFMWS_INTERLEAVE_WAYS(cfmws),
+					    CFMWS_INTERLEAVE_GRANULARITY(cfmws),
+					    CXL_DECODER_EXPANDER,
+					    flags);
+
+		if (IS_ERR(cxld)) {
+			dev_err(dev, "Failed to add decoder for %#llx-%#llx\n",
+				cfmws->base_hpa, cfmws->base_hpa +
+				cfmws->window_size - 1);
+		} else {
+			dev_dbg(dev, "add: %s range %#llx-%#llx\n",
+				dev_name(&cxld->dev), cfmws->base_hpa,
+				 cfmws->base_hpa + cfmws->window_size - 1);
+		}
+		cur += c->length;
+	}
+}
+
 static struct acpi_cedt_chbs *cxl_acpi_match_chbs(struct device *dev, u32 uid)
 {
 	struct acpi_cedt_chbs *chbs, *chbs_match = NULL;
@@ -271,6 +390,8 @@ static int cxl_acpi_probe(struct platform_device *pdev)
 	if (rc)
 		goto out;
 
+	cxl_add_cfmws_decoders(host, root_port);
+
 	/*
 	 * Root level scanned with host-bridge as dports, now scan host-bridges
 	 * for their role as CXL uports to their CXL-capable PCIe Root Ports.
-- 
2.26.2