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 <alast...@d-silva.org>
---
 drivers/nvdimm/ocxl/main.c     | 220 +++++++++++++++++++++++++++++++++
 drivers/nvdimm/ocxl/ocxlpmem.h |   4 +
 include/uapi/nvdimm/ocxlpmem.h |  12 ++
 3 files changed, 236 insertions(+)

diff --git a/drivers/nvdimm/ocxl/main.c b/drivers/nvdimm/ocxl/main.c
index 0040fc09cceb..cb6cdc9eb899 100644
--- a/drivers/nvdimm/ocxl/main.c
+++ b/drivers/nvdimm/ocxl/main.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>
@@ -301,8 +302,19 @@ 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);
+
        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->ocxl_context) {
                rc = ocxl_context_detach(ocxlpmem->ocxl_context);
                if (rc == -EBUSY)
@@ -398,6 +410,11 @@ 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;
 }
@@ -928,6 +945,52 @@ static int ioctl_controller_stats(struct ocxlpmem 
*ocxlpmem,
        return rc;
 }
 
+static int ioctl_eventfd(struct ocxlpmem *ocxlpmem,
+                        struct ioctl_ocxlpmem_eventfd __user *uarg)
+{
+       struct ioctl_ocxlpmem_eventfd args;
+
+       if (copy_from_user(&args, uarg, sizeof(args)))
+               return -EFAULT;
+
+       if (ocxlpmem->ev_ctx)
+               return -EBUSY;
+
+       ocxlpmem->ev_ctx = eventfd_ctx_fdget(args.eventfd);
+       if (IS_ERR(ocxlpmem->ev_ctx))
+               return PTR_ERR(ocxlpmem->ev_ctx);
+
+       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_OCXLPMEM_EVENT_ERROR_LOG_AVAILABLE;
+
+       if (chi & GLOBAL_MMIO_CHI_CDA)
+               val |= IOCTL_OCXLPMEM_EVENT_CONTROLLER_DUMP_AVAILABLE;
+
+       if (chi & GLOBAL_MMIO_CHI_CFFS)
+               val |= IOCTL_OCXLPMEM_EVENT_FIRMWARE_FATAL;
+
+       if (chi & GLOBAL_MMIO_CHI_CHFS)
+               val |= IOCTL_OCXLPMEM_EVENT_HARDWARE_FATAL;
+
+       if (copy_to_user((u64 __user *)uarg, &val, sizeof(val)))
+               return -EFAULT;
+
+       return rc;
+}
+
 static long file_ioctl(struct file *file, unsigned int cmd, unsigned long args)
 {
        struct ocxlpmem *ocxlpmem = file->private_data;
@@ -956,6 +1019,15 @@ static long file_ioctl(struct file *file, unsigned int 
cmd, unsigned long args)
                rc = ioctl_controller_stats(ocxlpmem,
                                            (struct 
ioctl_ocxlpmem_controller_stats __user *)args);
                break;
+
+       case IOCTL_OCXLPMEM_EVENTFD:
+               rc = ioctl_eventfd(ocxlpmem,
+                                  (struct ioctl_ocxlpmem_eventfd __user 
*)args);
+               break;
+
+       case IOCTL_OCXLPMEM_EVENT_CHECK:
+               rc = ioctl_event_check(ocxlpmem, (u64 __user *)args);
+               break;
        }
 
        return rc;
@@ -1109,6 +1181,148 @@ 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 setup_irqs(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 -EFAULT;
+
+       ocxlpmem->irq_addr[0] = ioremap(irq_addr, PAGE_SIZE);
+       if (!ocxlpmem->irq_addr[0])
+               return -ENODEV;
+
+       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 = -ENODEV;
+               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);
+       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
@@ -1212,6 +1426,12 @@ static int probe(struct pci_dev *pdev, const struct 
pci_device_id *ent)
                goto err;
        }
 
+       rc = setup_irqs(ocxlpmem);
+       if (rc) {
+               dev_err(&pdev->dev, "Could not set up OCXL IRQs\n");
+               goto err;
+       }
+
        rc = setup_command_metadata(ocxlpmem);
        if (rc) {
                dev_err(&pdev->dev, "Could not read command metadata\n");
diff --git a/drivers/nvdimm/ocxl/ocxlpmem.h b/drivers/nvdimm/ocxl/ocxlpmem.h
index ee3bd651f254..01721596f982 100644
--- a/drivers/nvdimm/ocxl/ocxlpmem.h
+++ b/drivers/nvdimm/ocxl/ocxlpmem.h
@@ -106,6 +106,9 @@ 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];
+       void __iomem *irq_addr[SCM_IRQ_COUNT];
        struct nd_interleave_set nd_set;
        struct nvdimm_bus_descriptor bus_desc;
        struct nvdimm_bus *nvdimm_bus;
@@ -117,6 +120,7 @@ struct ocxlpmem {
        struct nd_region *nd_region;
        char fw_version[8 + 1];
        u32 timeouts[ADMIN_COMMAND_MAX + 1];
+       struct eventfd_ctx *ev_ctx;
        u32 max_controller_dump_size;
        u16 scm_revision; // major/minor
        u8 readiness_timeout;  /* The worst case time (in seconds) that the host
diff --git a/include/uapi/nvdimm/ocxlpmem.h b/include/uapi/nvdimm/ocxlpmem.h
index ca3a7098fa9d..d573bd307e35 100644
--- a/include/uapi/nvdimm/ocxlpmem.h
+++ b/include/uapi/nvdimm/ocxlpmem.h
@@ -71,6 +71,16 @@ struct ioctl_ocxlpmem_controller_stats {
        __u64 fast_write_count;
 };
 
+struct ioctl_ocxlpmem_eventfd {
+       __s32 eventfd;
+       __u32 reserved;
+};
+
+#define IOCTL_OCXLPMEM_EVENT_CONTROLLER_DUMP_AVAILABLE (1ULL << (0))
+#define IOCTL_OCXLPMEM_EVENT_ERROR_LOG_AVAILABLE       (1ULL << (1))
+#define IOCTL_OCXLPMEM_EVENT_HARDWARE_FATAL            (1ULL << (2))
+#define IOCTL_OCXLPMEM_EVENT_FIRMWARE_FATAL            (1ULL << (3))
+
 /* ioctl numbers */
 #define OCXLPMEM_MAGIC 0xCA
 /* OpenCAPI Persistent memory devices */
@@ -79,5 +89,7 @@ struct ioctl_ocxlpmem_controller_stats {
 #define IOCTL_OCXLPMEM_CONTROLLER_DUMP_DATA            _IOWR(OCXLPMEM_MAGIC, 
0x32, struct ioctl_ocxlpmem_controller_dump_data)
 #define IOCTL_OCXLPMEM_CONTROLLER_DUMP_COMPLETE                
_IO(OCXLPMEM_MAGIC, 0x33)
 #define IOCTL_OCXLPMEM_CONTROLLER_STATS                        
_IO(OCXLPMEM_MAGIC, 0x34)
+#define IOCTL_OCXLPMEM_EVENTFD                         _IOW(OCXLPMEM_MAGIC, 
0x35, struct ioctl_ocxlpmem_eventfd)
+#define IOCTL_OCXLPMEM_EVENT_CHECK                     _IOR(OCXLPMEM_MAGIC, 
0x36, __u64)
 
 #endif /* _UAPI_OCXL_SCM_H */
-- 
2.24.1

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