scsi: cxlflash: Access interrupt trigger page from xive directly

xive is already mapping the trigger page in kernel space and it can be
accessed through standard APIs, so let's reuse it and simplify the code.
Signed-off-by: Frederic Barrat <fbarrat@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Matthew R. Ochs <mrochs@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200403153838.29224-2-fbarrat@linux.ibm.com

drivers/scsi/cxlflash/ocxl_hw.c

@@ -15,7 +15,8 @@
 #include <linux/pseudo_fs.h>
 #include <linux/poll.h>
 #include <linux/sched/signal.h>
-
+#include <linux/interrupt.h>
+#include <asm/xive.h>
 #include <misc/ocxl.h>
 
 #include <uapi/misc/cxl.h>
@@ -180,7 +181,7 @@ static int afu_map_irq(u64 flags, struct ocxlflash_context *ctx, int num,
 	struct ocxl_hw_afu *afu = ctx->hw_afu;
 	struct device *dev = afu->dev;
 	struct ocxlflash_irqs *irq;
-	void __iomem *vtrig;
+	struct xive_irq_data *xd;
 	u32 virq;
 	int rc = 0;
 
@@ -204,15 +205,15 @@ static int afu_map_irq(u64 flags, struct ocxlflash_context *ctx, int num,
 		goto err1;
 	}
 
-	vtrig = ioremap(irq->ptrig, PAGE_SIZE);
-	if (unlikely(!vtrig)) {
-		dev_err(dev, "%s: Trigger page mapping failed\n", __func__);
-		rc = -ENOMEM;
+	xd = irq_get_handler_data(virq);
+	if (unlikely(!xd)) {
+		dev_err(dev, "%s: Can't get interrupt data\n", __func__);
+		rc = -ENXIO;
 		goto err2;
 	}
 
 	irq->virq = virq;
-	irq->vtrig = vtrig;
+	irq->vtrig = xd->trig_mmio;
 out:
 	return rc;
 err2:
@@ -259,8 +260,6 @@ static void afu_unmap_irq(u64 flags, struct ocxlflash_context *ctx, int num,
 	}
 
 	irq = &ctx->irqs[num];
-	if (irq->vtrig)
-		iounmap(irq->vtrig);
 
 	if (irq_find_mapping(NULL, irq->hwirq)) {
 		free_irq(irq->virq, cookie);
@@ -648,7 +647,6 @@ static int alloc_afu_irqs(struct ocxlflash_context *ctx, int num)
 		}
 
 		irqs[i].hwirq = hwirq;
-		irqs[i].ptrig = addr;
 	}
 
 	ctx->irqs = irqs;

drivers/scsi/cxlflash/ocxl_hw.h

@@ -13,7 +13,6 @@
 struct ocxlflash_irqs {
 	int hwirq;
 	u32 virq;
-	u64 ptrig;
 	void __iomem *vtrig;
 };