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From:   "Alastair D'Silva" <alastair@au1.ibm.com>
To:     alastair@d-silva.org
Cc:     "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
        "Oliver O'Halloran" <oohall@gmail.com>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
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        Andrew Donnellan <ajd@linux.ibm.com>,
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        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
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        Krzysztof Kozlowski <krzk@kernel.org>,
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        =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= <clg@kaod.org>,
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        Hari Bathini <hbathini@linux.ibm.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Greg Kurz <groug@kaod.org>,
        Nicholas Piggin <npiggin@gmail.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-nvdimm@lists.01.org, linux-mm@kvack.org
Subject: [PATCH v3 20/27] powerpc/powernv/pmem: Forward events to userspace
Date:   Fri, 21 Feb 2020 14:27:13 +1100
In-Reply-To: <20200221032720.33893-1-alastair@au1.ibm.com>
References: <20200221032720.33893-1-alastair@au1.ibm.com>
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From: Alastair D'Silva <alastair@d-silva.org>

Some of the interrupts that the card generates are better handled
by the userspace daemon, in particular:
Controller Hardware/Firmware Fatal
Controller Dump Available
Error Log available

This patch allows a userspace application to register an eventfd with
the driver via SCM_IOCTL_EVENTFD to receive notifications of these
interrupts.

Userspace can then identify what events have occurred by calling
SCM_IOCTL_EVENT_CHECK and checking against the SCM_IOCTL_EVENT_FOO
masks.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 arch/powerpc/platforms/powernv/pmem/ocxl.c    | 216 ++++++++++++++++++
 .../platforms/powernv/pmem/ocxl_internal.h    |   5 +
 include/uapi/nvdimm/ocxl-pmem.h               |  16 ++
 3 files changed, 237 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 009d4fd29e7d..e46696d3cc36 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
@@ -10,6 +10,7 @@
 #include <misc/ocxl.h>
 #include <linux/delay.h>
 #include <linux/ndctl.h>
+#include <linux/eventfd.h>
 #include <linux/fs.h>
 #include <linux/mm_types.h>
 #include <linux/memory_hotplug.h>
@@ -335,11 +336,22 @@ static void free_ocxlpmem(struct ocxlpmem *ocxlpmem)
 {
 	int rc;
 
+	// Disable doorbells
+	(void)ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIEC,
+				     OCXL_LITTLE_ENDIAN,
+				     GLOBAL_MMIO_CHI_ALL);
+
 	if (ocxlpmem->nvdimm_bus)
 		nvdimm_bus_unregister(ocxlpmem->nvdimm_bus);
 
 	free_minor(ocxlpmem);
 
+	if (ocxlpmem->irq_addr[1])
+		iounmap(ocxlpmem->irq_addr[1]);
+
+	if (ocxlpmem->irq_addr[0])
+		iounmap(ocxlpmem->irq_addr[0]);
+
 	if (ocxlpmem->cdev.owner)
 		cdev_del(&ocxlpmem->cdev);
 
@@ -443,6 +455,11 @@ static int file_release(struct inode *inode, struct file *file)
 {
 	struct ocxlpmem *ocxlpmem = file->private_data;
 
+	if (ocxlpmem->ev_ctx) {
+		eventfd_ctx_put(ocxlpmem->ev_ctx);
+		ocxlpmem->ev_ctx = NULL;
+	}
+
 	ocxlpmem_put(ocxlpmem);
 	return 0;
 }
@@ -938,6 +955,51 @@ static int ioctl_controller_stats(struct ocxlpmem *ocxlpmem,
 	return rc;
 }
 
+static int ioctl_eventfd(struct ocxlpmem *ocxlpmem,
+		 struct ioctl_ocxl_pmem_eventfd __user *uarg)
+{
+	struct ioctl_ocxl_pmem_eventfd args;
+
+	if (copy_from_user(&args, uarg, sizeof(args)))
+		return -EFAULT;
+
+	if (ocxlpmem->ev_ctx)
+		return -EINVAL;
+
+	ocxlpmem->ev_ctx = eventfd_ctx_fdget(args.eventfd);
+	if (!ocxlpmem->ev_ctx)
+		return -EFAULT;
+
+	return 0;
+}
+
+static int ioctl_event_check(struct ocxlpmem *ocxlpmem, u64 __user *uarg)
+{
+	u64 val = 0;
+	int rc;
+	u64 chi = 0;
+
+	rc = ocxlpmem_chi(ocxlpmem, &chi);
+	if (rc < 0)
+		return rc;
+
+	if (chi & GLOBAL_MMIO_CHI_ELA)
+		val |= IOCTL_OCXL_PMEM_EVENT_ERROR_LOG_AVAILABLE;
+
+	if (chi & GLOBAL_MMIO_CHI_CDA)
+		val |= IOCTL_OCXL_PMEM_EVENT_CONTROLLER_DUMP_AVAILABLE;
+
+	if (chi & GLOBAL_MMIO_CHI_CFFS)
+		val |= IOCTL_OCXL_PMEM_EVENT_FIRMWARE_FATAL;
+
+	if (chi & GLOBAL_MMIO_CHI_CHFS)
+		val |= IOCTL_OCXL_PMEM_EVENT_HARDWARE_FATAL;
+
+	rc = copy_to_user((u64 __user *) uarg, &val, sizeof(val));
+
+	return rc;
+}
+
 static long file_ioctl(struct file *file, unsigned int cmd, unsigned long args)
 {
 	struct ocxlpmem *ocxlpmem = file->private_data;
@@ -966,6 +1028,15 @@ static long file_ioctl(struct file *file, unsigned int cmd, unsigned long args)
 		rc = ioctl_controller_stats(ocxlpmem,
 					    (struct ioctl_ocxl_pmem_controller_stats __user *)args);
 		break;
+
+	case IOCTL_OCXL_PMEM_EVENTFD:
+		rc = ioctl_eventfd(ocxlpmem,
+				   (struct ioctl_ocxl_pmem_eventfd __user *)args);
+		break;
+
+	case IOCTL_OCXL_PMEM_EVENT_CHECK:
+		rc = ioctl_event_check(ocxlpmem, (u64 __user *)args);
+		break;
 	}
 
 	return rc;
@@ -1107,6 +1178,146 @@ static void dump_error_log(struct ocxlpmem *ocxlpmem)
 	kfree(buf);
 }
 
+static irqreturn_t imn0_handler(void *private)
+{
+	struct ocxlpmem *ocxlpmem = private;
+	u64 chi = 0;
+
+	(void)ocxlpmem_chi(ocxlpmem, &chi);
+
+	if (chi & GLOBAL_MMIO_CHI_ELA) {
+		dev_warn(&ocxlpmem->dev, "Error log is available\n");
+
+		if (ocxlpmem->ev_ctx)
+			eventfd_signal(ocxlpmem->ev_ctx, 1);
+	}
+
+	if (chi & GLOBAL_MMIO_CHI_CDA) {
+		dev_warn(&ocxlpmem->dev, "Controller dump is available\n");
+
+		if (ocxlpmem->ev_ctx)
+			eventfd_signal(ocxlpmem->ev_ctx, 1);
+	}
+
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t imn1_handler(void *private)
+{
+	struct ocxlpmem *ocxlpmem = private;
+	u64 chi = 0;
+
+	(void)ocxlpmem_chi(ocxlpmem, &chi);
+
+	if (chi & (GLOBAL_MMIO_CHI_CFFS | GLOBAL_MMIO_CHI_CHFS)) {
+		dev_err(&ocxlpmem->dev,
+			"Controller status is fatal, chi=0x%llx, going offline\n", chi);
+
+		if (ocxlpmem->nvdimm_bus) {
+			nvdimm_bus_unregister(ocxlpmem->nvdimm_bus);
+			ocxlpmem->nvdimm_bus = NULL;
+		}
+
+		if (ocxlpmem->ev_ctx)
+			eventfd_signal(ocxlpmem->ev_ctx, 1);
+	}
+
+	return IRQ_HANDLED;
+}
+
+
+/**
+ * ocxlpmem_setup_irq() - Set up the IRQs for the OpenCAPI Persistent Memory device
+ * @ocxlpmem: the device metadata
+ * Return: 0 on success, negative on failure
+ */
+static int ocxlpmem_setup_irq(struct ocxlpmem *ocxlpmem)
+{
+	int rc;
+	u64 irq_addr;
+
+	rc = ocxl_afu_irq_alloc(ocxlpmem->ocxl_context, &ocxlpmem->irq_id[0]);
+	if (rc)
+		return rc;
+
+	rc = ocxl_irq_set_handler(ocxlpmem->ocxl_context, ocxlpmem->irq_id[0],
+				  imn0_handler, NULL, ocxlpmem);
+
+	irq_addr = ocxl_afu_irq_get_addr(ocxlpmem->ocxl_context, ocxlpmem->irq_id[0]);
+	if (!irq_addr)
+		return -EINVAL;
+
+	ocxlpmem->irq_addr[0] = ioremap(irq_addr, PAGE_SIZE);
+	if (!ocxlpmem->irq_addr[0])
+		return -EINVAL;
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_IMA0_OHP,
+				      OCXL_LITTLE_ENDIAN,
+				      (u64)ocxlpmem->irq_addr[0]);
+	if (rc)
+		goto out_irq0;
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_IMA0_CFP,
+				      OCXL_LITTLE_ENDIAN, 0);
+	if (rc)
+		goto out_irq0;
+
+	rc = ocxl_afu_irq_alloc(ocxlpmem->ocxl_context, &ocxlpmem->irq_id[1]);
+	if (rc)
+		goto out_irq0;
+
+
+	rc = ocxl_irq_set_handler(ocxlpmem->ocxl_context, ocxlpmem->irq_id[1],
+				  imn1_handler, NULL, ocxlpmem);
+	if (rc)
+		goto out_irq0;
+
+	irq_addr = ocxl_afu_irq_get_addr(ocxlpmem->ocxl_context, ocxlpmem->irq_id[1]);
+	if (!irq_addr) {
+		rc = -EFAULT;
+		goto out_irq0;
+	}
+
+	ocxlpmem->irq_addr[1] = ioremap(irq_addr, PAGE_SIZE);
+	if (!ocxlpmem->irq_addr[1]) {
+		rc = -EINVAL;
+		goto out_irq0;
+	}
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_IMA1_OHP,
+				      OCXL_LITTLE_ENDIAN,
+				      (u64)ocxlpmem->irq_addr[1]);
+	if (rc)
+		goto out_irq1;
+
+	rc = ocxl_global_mmio_write64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_IMA1_CFP,
+				      OCXL_LITTLE_ENDIAN, 0);
+	if (rc)
+		goto out_irq1;
+
+	// Enable doorbells
+	rc = ocxl_global_mmio_set64(ocxlpmem->ocxl_afu, GLOBAL_MMIO_CHIE,
+				    OCXL_LITTLE_ENDIAN,
+				    GLOBAL_MMIO_CHI_ELA | GLOBAL_MMIO_CHI_CDA |
+				    GLOBAL_MMIO_CHI_CFFS | GLOBAL_MMIO_CHI_CHFS |
+				    GLOBAL_MMIO_CHI_NSCRA);
+	if (rc)
+		goto out_irq1;
+
+	return 0;
+
+out_irq1:
+	iounmap(ocxlpmem->irq_addr[1]);
+	ocxlpmem->irq_addr[1] = NULL;
+
+out_irq0:
+	iounmap(ocxlpmem->irq_addr[0]);
+	ocxlpmem->irq_addr[0] = NULL;
+
+	return rc;
+}
+
 /**
  * probe_function0() - Set up function 0 for an OpenCAPI persistent memory device
  * This is important as it enables templates higher than 0 across all other functions,
@@ -1216,6 +1427,11 @@ static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (ocxlpmem_setup_irq(ocxlpmem)) {
+		dev_err(&pdev->dev, "Could not set up OCXL IRQs\n");
+		goto err;
+	}
+
 	if (setup_command_metadata(ocxlpmem)) {
 		dev_err(&pdev->dev, "Could not read OCXL command matada\n");
 		goto err;
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
index b953ee522ed4..927690f4888f 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
@@ -103,6 +103,10 @@ struct ocxlpmem {
 	struct pci_dev *pdev;
 	struct cdev cdev;
 	struct ocxl_fn *ocxl_fn;
+#define SCM_IRQ_COUNT 2
+	int irq_id[SCM_IRQ_COUNT];
+	struct dev_pagemap irq_pgmap[SCM_IRQ_COUNT];
+	void *irq_addr[SCM_IRQ_COUNT];
 	struct nd_interleave_set nd_set;
 	struct nvdimm_bus_descriptor bus_desc;
 	struct nvdimm_bus *nvdimm_bus;
@@ -113,6 +117,7 @@ struct ocxlpmem {
 	struct command_metadata ns_command;
 	struct resource pmem_res;
 	struct nd_region *nd_region;
+	struct eventfd_ctx *ev_ctx;
 	char fw_version[8+1];
 	u32 timeouts[ADMIN_COMMAND_MAX+1];
 
diff --git a/include/uapi/nvdimm/ocxl-pmem.h b/include/uapi/nvdimm/ocxl-pmem.h
index add223aa2fdb..988eb0bc413d 100644
--- a/include/uapi/nvdimm/ocxl-pmem.h
+++ b/include/uapi/nvdimm/ocxl-pmem.h
@@ -66,6 +66,20 @@ struct ioctl_ocxl_pmem_controller_stats {
 	__u64 cache_write_latency; /* nanoseconds */
 };
 
+struct ioctl_ocxl_pmem_eventfd {
+	__s32 eventfd;
+	__u32 reserved;
+};
+
+#ifndef BIT_ULL
+#define BIT_ULL(nr)	(1ULL << (nr))
+#endif
+
+#define IOCTL_OCXL_PMEM_EVENT_CONTROLLER_DUMP_AVAILABLE	BIT_ULL(0)
+#define IOCTL_OCXL_PMEM_EVENT_ERROR_LOG_AVAILABLE	BIT_ULL(1)
+#define IOCTL_OCXL_PMEM_EVENT_HARDWARE_FATAL		BIT_ULL(2)
+#define IOCTL_OCXL_PMEM_EVENT_FIRMWARE_FATAL		BIT_ULL(3)
+
 /* ioctl numbers */
 #define OCXL_PMEM_MAGIC 0x5C
 /* SCM devices */
@@ -74,5 +88,7 @@ struct ioctl_ocxl_pmem_controller_stats {
 #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_DATA		_IOWR(OCXL_PMEM_MAGIC, 0x03, struct ioctl_ocxl_pmem_controller_dump_data)
 #define IOCTL_OCXL_PMEM_CONTROLLER_DUMP_COMPLETE	_IO(OCXL_PMEM_MAGIC, 0x04)
 #define IOCTL_OCXL_PMEM_CONTROLLER_STATS		_IO(OCXL_PMEM_MAGIC, 0x05)
+#define IOCTL_OCXL_PMEM_EVENTFD				_IOW(OCXL_PMEM_MAGIC, 0x06, struct ioctl_ocxl_pmem_eventfd)
+#define IOCTL_OCXL_PMEM_EVENT_CHECK			_IOR(OCXL_PMEM_MAGIC, 0x07, __u64)
 
 #endif /* _UAPI_OCXL_SCM_H */
-- 
2.24.1