1 files changed, 224 insertions, 91 deletions

diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
index 5b46bc46aaa9..5b023a0178a4 100644
--- a/drivers/cxl/core/pci.c
+++ b/drivers/cxl/core/pci.c
@@ -24,84 +24,52 @@ static unsigned short media_ready_timeout = 60;
 module_param(media_ready_timeout, ushort, 0644);
 MODULE_PARM_DESC(media_ready_timeout, "seconds to wait for media ready");
 
-struct cxl_walk_context {
-	struct pci_bus *bus;
-	struct cxl_port *port;
+static int pci_get_port_num(struct pci_dev *pdev)
+{
+	u32 lnkcap;
 	int type;
-	int error;
-	int count;
-};
 
-static int match_add_dports(struct pci_dev *pdev, void *data)
-{
-	struct cxl_walk_context *ctx = data;
-	struct cxl_port *port = ctx->port;
-	int type = pci_pcie_type(pdev);
-	struct cxl_register_map map;
-	struct cxl_dport *dport;
-	u32 lnkcap, port_num;
-	int rc;
+	type = pci_pcie_type(pdev);
+	if (type != PCI_EXP_TYPE_DOWNSTREAM && type != PCI_EXP_TYPE_ROOT_PORT)
+		return -EINVAL;
 
-	if (pdev->bus != ctx->bus)
-		return 0;
-	if (!pci_is_pcie(pdev))
-		return 0;
-	if (type != ctx->type)
-		return 0;
 	if (pci_read_config_dword(pdev, pci_pcie_cap(pdev) + PCI_EXP_LNKCAP,
 				  &lnkcap))
-		return 0;
-
-	rc = cxl_find_regblock(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
-	if (rc)
-		dev_dbg(&port->dev, "failed to find component registers\n");
-
-	port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap);
-	dport = devm_cxl_add_dport(port, &pdev->dev, port_num, map.resource);
-	if (IS_ERR(dport)) {
-		ctx->error = PTR_ERR(dport);
-		return PTR_ERR(dport);
-	}
-	ctx->count++;
+		return -ENXIO;
 
-	return 0;
+	return FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap);
 }
 
 /**
- * devm_cxl_port_enumerate_dports - enumerate downstream ports of the upstream port
- * @port: cxl_port whose ->uport_dev is the upstream of dports to be enumerated
+ * __devm_cxl_add_dport_by_dev - allocate a dport by dport device
+ * @port: cxl_port that hosts the dport
+ * @dport_dev: 'struct device' of the dport
  *
- * Returns a positive number of dports enumerated or a negative error
- * code.
+ * Returns the allocated dport on success or ERR_PTR() of -errno on error
  */
-int devm_cxl_port_enumerate_dports(struct cxl_port *port)
+struct cxl_dport *__devm_cxl_add_dport_by_dev(struct cxl_port *port,
+					      struct device *dport_dev)
 {
-	struct pci_bus *bus = cxl_port_to_pci_bus(port);
-	struct cxl_walk_context ctx;
-	int type;
+	struct cxl_register_map map;
+	struct pci_dev *pdev;
+	int port_num, rc;
 
-	if (!bus)
-		return -ENXIO;
+	if (!dev_is_pci(dport_dev))
+		return ERR_PTR(-EINVAL);
 
-	if (pci_is_root_bus(bus))
-		type = PCI_EXP_TYPE_ROOT_PORT;
-	else
-		type = PCI_EXP_TYPE_DOWNSTREAM;
+	pdev = to_pci_dev(dport_dev);
+	port_num = pci_get_port_num(pdev);
+	if (port_num < 0)
+		return ERR_PTR(port_num);
 
-	ctx = (struct cxl_walk_context) {
-		.port = port,
-		.bus = bus,
-		.type = type,
-	};
-	pci_walk_bus(bus, match_add_dports, &ctx);
+	rc = cxl_find_regblock(pdev, CXL_REGLOC_RBI_COMPONENT, &map);
+	if (rc)
+		return ERR_PTR(rc);
 
-	if (ctx.count == 0)
-		return -ENODEV;
-	if (ctx.error)
-		return ctx.error;
-	return ctx.count;
+	device_lock_assert(&port->dev);
+	return devm_cxl_add_dport(port, dport_dev, port_num, map.resource);
 }
-EXPORT_SYMBOL_NS_GPL(devm_cxl_port_enumerate_dports, CXL);
+EXPORT_SYMBOL_NS_GPL(__devm_cxl_add_dport_by_dev, "CXL");
 
 static int cxl_dvsec_mem_range_valid(struct cxl_dev_state *cxlds, int id)
 {
@@ -209,7 +177,7 @@ int cxl_await_media_ready(struct cxl_dev_state *cxlds)
 
 	return 0;
 }
-EXPORT_SYMBOL_NS_GPL(cxl_await_media_ready, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_await_media_ready, "CXL");
 
 static int cxl_set_mem_enable(struct cxl_dev_state *cxlds, u16 val)
 {
@@ -252,9 +220,9 @@ static int devm_cxl_enable_mem(struct device *host, struct cxl_dev_state *cxlds)
 }
 
 /* require dvsec ranges to be covered by a locked platform window */
-static int dvsec_range_allowed(struct device *dev, void *arg)
+static int dvsec_range_allowed(struct device *dev, const void *arg)
 {
-	struct range *dev_range = arg;
+	const struct range *dev_range = arg;
 	struct cxl_decoder *cxld;
 
 	if (!is_root_decoder(dev))
@@ -291,11 +259,11 @@ static int devm_cxl_enable_hdm(struct device *host, struct cxl_hdm *cxlhdm)
 	return devm_add_action_or_reset(host, disable_hdm, cxlhdm);
 }
 
-int cxl_dvsec_rr_decode(struct device *dev, struct cxl_port *port,
+int cxl_dvsec_rr_decode(struct cxl_dev_state *cxlds,
 			struct cxl_endpoint_dvsec_info *info)
 {
-	struct pci_dev *pdev = to_pci_dev(dev);
-	struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);
+	struct pci_dev *pdev = to_pci_dev(cxlds->dev);
+	struct device *dev = cxlds->dev;
 	int hdm_count, rc, i, ranges = 0;
 	int d = cxlds->cxl_dvsec;
 	u16 cap, ctrl;
@@ -386,7 +354,7 @@ int cxl_dvsec_rr_decode(struct device *dev, struct cxl_port *port,
 
 	return 0;
 }
-EXPORT_SYMBOL_NS_GPL(cxl_dvsec_rr_decode, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_dvsec_rr_decode, "CXL");
 
 /**
  * cxl_hdm_decode_init() - Setup HDM decoding for the endpoint
@@ -415,17 +383,20 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 	 */
 	if (global_ctrl & CXL_HDM_DECODER_ENABLE || (!hdm && info->mem_enabled))
 		return devm_cxl_enable_mem(&port->dev, cxlds);
-	else if (!hdm)
-		return -ENODEV;
 
-	root = to_cxl_port(port->dev.parent);
-	while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))
-		root = to_cxl_port(root->dev.parent);
-	if (!is_cxl_root(root)) {
-		dev_err(dev, "Failed to acquire root port for HDM enable\n");
+	/*
+	 * If the HDM Decoder Capability does not exist and DVSEC was
+	 * not setup, the DVSEC based emulation cannot be used.
+	 */
+	if (!hdm)
 		return -ENODEV;
-	}
 
+	/* The HDM Decoder Capability exists but is globally disabled. */
+
+	/*
+	 * If the DVSEC CXL Range registers are not enabled, just
+	 * enable and use the HDM Decoder Capability registers.
+	 */
 	if (!info->mem_enabled) {
 		rc = devm_cxl_enable_hdm(&port->dev, cxlhdm);
 		if (rc)
@@ -434,6 +405,26 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 		return devm_cxl_enable_mem(&port->dev, cxlds);
 	}
 
+	/*
+	 * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base
+	 * [High,Low] when HDM operation is enabled the range register values
+	 * are ignored by the device, but the spec also recommends matching the
+	 * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges
+	 * are expected even though Linux does not require or maintain that
+	 * match. Check if at least one DVSEC range is enabled and allowed by
+	 * the platform. That is, the DVSEC range must be covered by a locked
+	 * platform window (CFMWS). Fail otherwise as the endpoint's decoders
+	 * cannot be used.
+	 */
+
+	root = to_cxl_port(port->dev.parent);
+	while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))
+		root = to_cxl_port(root->dev.parent);
+	if (!is_cxl_root(root)) {
+		dev_err(dev, "Failed to acquire root port for HDM enable\n");
+		return -ENODEV;
+	}
+
 	for (i = 0, allowed = 0; i < info->ranges; i++) {
 		struct device *cxld_dev;
 
@@ -453,18 +444,9 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm,
 		return -ENXIO;
 	}
 
-	/*
-	 * Per CXL 2.0 Section 8.1.3.8.3 and 8.1.3.8.4 DVSEC CXL Range 1 Base
-	 * [High,Low] when HDM operation is enabled the range register values
-	 * are ignored by the device, but the spec also recommends matching the
-	 * DVSEC Range 1,2 to HDM Decoder Range 0,1. So, non-zero info->ranges
-	 * are expected even though Linux does not require or maintain that
-	 * match. If at least one DVSEC range is enabled and allowed, skip HDM
-	 * Decoder Capability Enable.
-	 */
 	return 0;
 }
-EXPORT_SYMBOL_NS_GPL(cxl_hdm_decode_init, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_hdm_decode_init, "CXL");
 
 #define CXL_DOE_TABLE_ACCESS_REQ_CODE		0x000000ff
 #define   CXL_DOE_TABLE_ACCESS_REQ_CODE_READ	0
@@ -648,7 +630,7 @@ err:
 	devm_kfree(dev, buf);
 	dev_err(dev, "Failed to read/validate CDAT.\n");
 }
-EXPORT_SYMBOL_NS_GPL(read_cdat_data, CXL);
+EXPORT_SYMBOL_NS_GPL(read_cdat_data, "CXL");
 
 static void __cxl_handle_cor_ras(struct cxl_dev_state *cxlds,
 				 void __iomem *ras_base)
@@ -805,7 +787,7 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
 		cxl_disable_rch_root_ints(dport);
 	}
 }
-EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
 
 static void cxl_handle_rdport_cor_ras(struct cxl_dev_state *cxlds,
 					  struct cxl_dport *dport)
@@ -916,7 +898,7 @@ void cxl_cor_error_detected(struct pci_dev *pdev)
 		cxl_handle_endpoint_cor_ras(cxlds);
 	}
 }
-EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_cor_error_detected, "CXL");
 
 pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 				    pci_channel_state_t state)
@@ -966,7 +948,7 @@ pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
 	}
 	return PCI_ERS_RESULT_NEED_RESET;
 }
-EXPORT_SYMBOL_NS_GPL(cxl_error_detected, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_error_detected, "CXL");
 
 static int cxl_flit_size(struct pci_dev *pdev)
 {
@@ -1030,7 +1012,7 @@ bool cxl_endpoint_decoder_reset_detected(struct cxl_port *port)
 	return device_for_each_child(&port->dev, port,
 				     __cxl_endpoint_decoder_reset_detected);
 }
-EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_reset_detected, CXL);
+EXPORT_SYMBOL_NS_GPL(cxl_endpoint_decoder_reset_detected, "CXL");
 
 int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c)
 {
@@ -1054,3 +1036,154 @@ int cxl_pci_get_bandwidth(struct pci_dev *pdev, struct access_coordinate *c)
 
 	return 0;
 }
+
+/*
+ * Set max timeout such that platforms will optimize GPF flow to avoid
+ * the implied worst-case scenario delays. On a sane platform, all
+ * devices should always complete GPF within the energy budget of
+ * the GPF flow. The kernel does not have enough information to pick
+ * anything better than "maximize timeouts and hope it works".
+ *
+ * A misbehaving device could block forward progress of GPF for all
+ * the other devices, exhausting the energy budget of the platform.
+ * However, the spec seems to assume that moving on from slow to respond
+ * devices is a virtue. It is not possible to know that, in actuality,
+ * the slow to respond device is *the* most critical device in the
+ * system to wait.
+ */
+#define GPF_TIMEOUT_BASE_MAX 2
+#define GPF_TIMEOUT_SCALE_MAX 7 /* 10 seconds */
+
+u16 cxl_gpf_get_dvsec(struct device *dev)
+{
+	struct pci_dev *pdev;
+	bool is_port = true;
+	u16 dvsec;
+
+	if (!dev_is_pci(dev))
+		return 0;
+
+	pdev = to_pci_dev(dev);
+	if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT)
+		is_port = false;
+
+	dvsec = pci_find_dvsec_capability(pdev, PCI_VENDOR_ID_CXL,
+			is_port ? CXL_DVSEC_PORT_GPF : CXL_DVSEC_DEVICE_GPF);
+	if (!dvsec)
+		dev_warn(dev, "%s GPF DVSEC not present\n",
+			 is_port ? "Port" : "Device");
+	return dvsec;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_gpf_get_dvsec, "CXL");
+
+static int update_gpf_port_dvsec(struct pci_dev *pdev, int dvsec, int phase)
+{
+	u64 base, scale;
+	int rc, offset;
+	u16 ctrl;
+
+	switch (phase) {
+	case 1:
+		offset = CXL_DVSEC_PORT_GPF_PHASE_1_CONTROL_OFFSET;
+		base = CXL_DVSEC_PORT_GPF_PHASE_1_TMO_BASE_MASK;
+		scale = CXL_DVSEC_PORT_GPF_PHASE_1_TMO_SCALE_MASK;
+		break;
+	case 2:
+		offset = CXL_DVSEC_PORT_GPF_PHASE_2_CONTROL_OFFSET;
+		base = CXL_DVSEC_PORT_GPF_PHASE_2_TMO_BASE_MASK;
+		scale = CXL_DVSEC_PORT_GPF_PHASE_2_TMO_SCALE_MASK;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	rc = pci_read_config_word(pdev, dvsec + offset, &ctrl);
+	if (rc)
+		return rc;
+
+	if (FIELD_GET(base, ctrl) == GPF_TIMEOUT_BASE_MAX &&
+	    FIELD_GET(scale, ctrl) == GPF_TIMEOUT_SCALE_MAX)
+		return 0;
+
+	ctrl = FIELD_PREP(base, GPF_TIMEOUT_BASE_MAX);
+	ctrl |= FIELD_PREP(scale, GPF_TIMEOUT_SCALE_MAX);
+
+	rc = pci_write_config_word(pdev, dvsec + offset, ctrl);
+	if (!rc)
+		pci_dbg(pdev, "Port GPF phase %d timeout: %d0 secs\n",
+			phase, GPF_TIMEOUT_BASE_MAX);
+
+	return rc;
+}
+
+int cxl_gpf_port_setup(struct cxl_dport *dport)
+{
+	if (!dport)
+		return -EINVAL;
+
+	if (!dport->gpf_dvsec) {
+		struct pci_dev *pdev;
+		int dvsec;
+
+		dvsec = cxl_gpf_get_dvsec(dport->dport_dev);
+		if (!dvsec)
+			return -EINVAL;
+
+		dport->gpf_dvsec = dvsec;
+		pdev = to_pci_dev(dport->dport_dev);
+		update_gpf_port_dvsec(pdev, dport->gpf_dvsec, 1);
+		update_gpf_port_dvsec(pdev, dport->gpf_dvsec, 2);
+	}
+
+	return 0;
+}
+
+struct cxl_walk_context {
+	struct pci_bus *bus;
+	struct cxl_port *port;
+	int type;
+	int error;
+	int count;
+};
+
+static int count_dports(struct pci_dev *pdev, void *data)
+{
+	struct cxl_walk_context *ctx = data;
+	int type = pci_pcie_type(pdev);
+
+	if (pdev->bus != ctx->bus)
+		return 0;
+	if (!pci_is_pcie(pdev))
+		return 0;
+	if (type != ctx->type)
+		return 0;
+
+	ctx->count++;
+	return 0;
+}
+
+int cxl_port_get_possible_dports(struct cxl_port *port)
+{
+	struct pci_bus *bus = cxl_port_to_pci_bus(port);
+	struct cxl_walk_context ctx;
+	int type;
+
+	if (!bus) {
+		dev_err(&port->dev, "No PCI bus found for port %s\n",
+			dev_name(&port->dev));
+		return -ENXIO;
+	}
+
+	if (pci_is_root_bus(bus))
+		type = PCI_EXP_TYPE_ROOT_PORT;
+	else
+		type = PCI_EXP_TYPE_DOWNSTREAM;
+
+	ctx = (struct cxl_walk_context) {
+		.bus = bus,
+		.type = type,
+	};
+	pci_walk_bus(bus, count_dports, &ctx);
+
+	return ctx.count;
+}