cxl: read PHB indications from the device tree

Configure the P9 XSL_DSNCTL register with PHB indications found
in the device tree, or else use legacy hard-coded values.
Signed-off-by: Philippe Bergheaud <felix@linux.vnet.ibm.com>
Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Reviewed-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

drivers/misc/cxl/cxl.h

@@ -1069,7 +1069,7 @@ int cxl_psl_purge(struct cxl_afu *afu);
 int cxl_calc_capp_routing(struct pci_dev *dev, u64 *chipid,
 			  u32 *phb_index, u64 *capp_unit_id);
 int cxl_slot_is_switched(struct pci_dev *dev);
-int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg);
+int cxl_get_xsl9_dsnctl(struct pci_dev *dev, u64 capp_unit_id, u64 *reg);
 u64 cxl_calculate_sr(bool master, bool kernel, bool real_mode, bool p9);
 
 void cxl_native_irq_dump_regs_psl9(struct cxl_context *ctx);

drivers/misc/cxl/cxllib.c

@@ -99,7 +99,7 @@ int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
 	if (rc)
 		return rc;
 
-	rc = cxl_get_xsl9_dsnctl(capp_unit_id, &cfg->dsnctl);
+	rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl);
 	if (rc)
 		return rc;
 	if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {

drivers/misc/cxl/pci.c

@@ -407,21 +407,59 @@ int cxl_calc_capp_routing(struct pci_dev *dev, u64 *chipid,
 	return 0;
 }
 
-int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg)
+static DEFINE_MUTEX(indications_mutex);
+
+static int get_phb_indications(struct pci_dev *dev, u64 *capiind, u64 *asnind,
+			       u64 *nbwind)
+{
+	static u64 nbw, asn, capi = 0;
+	struct device_node *np;
+	const __be32 *prop;
+
+	mutex_lock(&indications_mutex);
+	if (!capi) {
+		if (!(np = pnv_pci_get_phb_node(dev))) {
+			mutex_unlock(&indications_mutex);
+			return -ENODEV;
+		}
+
+		prop = of_get_property(np, "ibm,phb-indications", NULL);
+		if (!prop) {
+			nbw = 0x0300UL; /* legacy values */
+			asn = 0x0400UL;
+			capi = 0x0200UL;
+		} else {
+			nbw = (u64)be32_to_cpu(prop[2]);
+			asn = (u64)be32_to_cpu(prop[1]);
+			capi = (u64)be32_to_cpu(prop[0]);
+		}
+		of_node_put(np);
+	}
+	*capiind = capi;
+	*asnind = asn;
+	*nbwind = nbw;
+	mutex_unlock(&indications_mutex);
+	return 0;
+}
+
+int cxl_get_xsl9_dsnctl(struct pci_dev *dev, u64 capp_unit_id, u64 *reg)
 {
 	u64 xsl_dsnctl;
+	u64 capiind, asnind, nbwind;
 
 	/*
 	 * CAPI Identifier bits [0:7]
 	 * bit 61:60 MSI bits --> 0
 	 * bit 59 TVT selector --> 0
 	 */
+	if (get_phb_indications(dev, &capiind, &asnind, &nbwind))
+		return -ENODEV;
 
 	/*
 	 * Tell XSL where to route data to.
 	 * The field chipid should match the PHB CAPI_CMPM register
 	 */
-	xsl_dsnctl = ((u64)0x2 << (63-7)); /* Bit 57 */
+	xsl_dsnctl = (capiind << (63-15)); /* Bit 57 */
 	xsl_dsnctl |= (capp_unit_id << (63-15));
 
 	/* nMMU_ID Defaults to: b’000001001’*/
@@ -435,14 +473,14 @@ int cxl_get_xsl9_dsnctl(u64 capp_unit_id, u64 *reg)
 		 * nbwind=0x03, bits [57:58], must include capi indicator.
 		 * Not supported on P9 DD1.
 		 */
-		xsl_dsnctl |= ((u64)0x03 << (63-47));
+		xsl_dsnctl |= (nbwind << (63-55));
 
 		/*
 		 * Upper 16b address bits of ASB_Notify messages sent to the
 		 * system. Need to match the PHB’s ASN Compare/Mask Register.
 		 * Not supported on P9 DD1.
 		 */
-		xsl_dsnctl |= ((u64)0x04 << (63-55));
+		xsl_dsnctl |= asnind;
 	}
 
 	*reg = xsl_dsnctl;
@@ -463,7 +501,7 @@ static int init_implementation_adapter_regs_psl9(struct cxl *adapter,
 	if (rc)
 		return rc;
 
-	rc = cxl_get_xsl9_dsnctl(capp_unit_id, &xsl_dsnctl);
+	rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &xsl_dsnctl);
 	if (rc)
 		return rc;