powerpc/vas: Alloc and setup IRQ and trigger port address

Allocate a xive irq on each chip with a vas instance. The NX coprocessor
raises a host CPU interrupt via vas if it encounters page fault on user
space request buffer. Subsequent patches register the trigger port with
the NX coprocessor, and create a vas fault handler for this interrupt
mapping.
Signed-off-by: Haren Myneni <haren@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1587016806.2275.1050.camel@hbabu-laptop

arch/powerpc/platforms/powernv/vas.c

@@ -15,6 +15,7 @@
 #include <linux/of_address.h>
 #include <linux/of.h>
 #include <asm/prom.h>
+#include <asm/xive.h>
 
 #include "vas.h"
 
@@ -25,10 +26,12 @@ static DEFINE_PER_CPU(int, cpu_vas_id);
 
 static int init_vas_instance(struct platform_device *pdev)
 {
-	int rc, cpu, vasid;
-	struct resource *res;
-	struct vas_instance *vinst;
 	struct device_node *dn = pdev->dev.of_node;
+	struct vas_instance *vinst;
+	struct xive_irq_data *xd;
+	uint32_t chipid, hwirq;
+	struct resource *res;
+	int rc, cpu, vasid;
 
 	rc = of_property_read_u32(dn, "ibm,vas-id", &vasid);
 	if (rc) {
@@ -36,6 +39,12 @@ static int init_vas_instance(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
+	rc = of_property_read_u32(dn, "ibm,chip-id", &chipid);
+	if (rc) {
+		pr_err("No ibm,chip-id property for %s?\n", pdev->name);
+		return -ENODEV;
+	}
+
 	if (pdev->num_resources != 4) {
 		pr_err("Unexpected DT configuration for [%s, %d]\n",
 				pdev->name, vasid);
@@ -69,9 +78,32 @@ static int init_vas_instance(struct platform_device *pdev)
 
 	vinst->paste_win_id_shift = 63 - res->end;
 
-	pr_devel("Initialized instance [%s, %d], paste_base 0x%llx, "
-			"paste_win_id_shift 0x%llx\n", pdev->name, vasid,
-			vinst->paste_base_addr, vinst->paste_win_id_shift);
+	hwirq = xive_native_alloc_irq_on_chip(chipid);
+	if (!hwirq) {
+		pr_err("Inst%d: Unable to allocate global irq for chip %d\n",
+				vinst->vas_id, chipid);
+		return -ENOENT;
+	}
+
+	vinst->virq = irq_create_mapping(NULL, hwirq);
+	if (!vinst->virq) {
+		pr_err("Inst%d: Unable to map global irq %d\n",
+				vinst->vas_id, hwirq);
+		return -EINVAL;
+	}
+
+	xd = irq_get_handler_data(vinst->virq);
+	if (!xd) {
+		pr_err("Inst%d: Invalid virq %d\n",
+				vinst->vas_id, vinst->virq);
+		return -EINVAL;
+	}
+
+	vinst->irq_port = xd->trig_page;
+	pr_devel("Initialized instance [%s, %d] paste_base 0x%llx paste_win_id_shift 0x%llx IRQ %d Port 0x%llx\n",
+			pdev->name, vasid, vinst->paste_base_addr,
+			vinst->paste_win_id_shift, vinst->virq,
+			vinst->irq_port);
 
 	for_each_possible_cpu(cpu) {
 		if (cpu_to_chip_id(cpu) == of_get_ibm_chip_id(dn))

arch/powerpc/platforms/powernv/vas.h

@@ -313,6 +313,8 @@ struct vas_instance {
 	u64 paste_base_addr;
 	u64 paste_win_id_shift;
 
+	u64 irq_port;
+	int virq;
 	struct mutex mutex;
 	struct vas_window *rxwin[VAS_COP_TYPE_MAX];
 	struct vas_window *windows[VAS_WINDOWS_PER_CHIP];