From: Alastair D'Silva <alast...@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 <alast...@d-silva.org>
---
 drivers/nvdimm/ocxl/scm.c          | 216 +++++++++++++++++++++++++++++
 drivers/nvdimm/ocxl/scm_internal.h |   5 +
 include/uapi/nvdimm/ocxl-scm.h     |  16 +++
 3 files changed, 237 insertions(+)

diff --git a/drivers/nvdimm/ocxl/scm.c b/drivers/nvdimm/ocxl/scm.c
index 54a2bac1cab7..854787950334 100644
--- a/drivers/nvdimm/ocxl/scm.c
+++ b/drivers/nvdimm/ocxl/scm.c
@@ -9,6 +9,7 @@
 #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>
@@ -382,11 +383,22 @@ static void free_scm(struct scm_data *scm_data)
 {
        int rc;
 
+       // Disable doorbells
+       (void)ocxl_global_mmio_set64(scm_data->ocxl_afu, GLOBAL_MMIO_CHIEC,
+                                    OCXL_LITTLE_ENDIAN,
+                                    GLOBAL_MMIO_CHI_ALL);
+
        if (scm_data->nvdimm_bus)
                nvdimm_bus_unregister(scm_data->nvdimm_bus);
 
        free_scm_minor(scm_data);
 
+       if (scm_data->irq_addr[1])
+               iounmap(scm_data->irq_addr[1]);
+
+       if (scm_data->irq_addr[0])
+               iounmap(scm_data->irq_addr[0]);
+
        if (scm_data->cdev.owner)
                cdev_del(&scm_data->cdev);
 
@@ -491,6 +503,11 @@ static int scm_file_release(struct inode *inode, struct 
file *file)
 {
        struct scm_data *scm_data = file->private_data;
 
+       if (scm_data->ev_ctx) {
+               eventfd_ctx_put(scm_data->ev_ctx);
+               scm_data->ev_ctx = NULL;
+       }
+
        scm_put(scm_data);
        return 0;
 }
@@ -986,6 +1003,51 @@ static int scm_ioctl_controller_stats(struct scm_data 
*scm_data,
        return rc;
 }
 
+static int scm_ioctl_eventfd(struct scm_data *scm_data,
+                            struct scm_ioctl_eventfd __user *uarg)
+{
+       struct scm_ioctl_eventfd args;
+
+       if (copy_from_user(&args, uarg, sizeof(args)))
+               return -EFAULT;
+
+       if (scm_data->ev_ctx)
+               return -EINVAL;
+
+       scm_data->ev_ctx = eventfd_ctx_fdget(args.eventfd);
+       if (!scm_data->ev_ctx)
+               return -EFAULT;
+
+       return 0;
+}
+
+static int scm_ioctl_event_check(struct scm_data *scm_data, u64 __user *uarg)
+{
+       u64 val = 0;
+       int rc;
+       u64 chi = 0;
+
+       rc = scm_chi(scm_data, &chi);
+       if (rc < 0)
+               return rc;
+
+       if (chi & GLOBAL_MMIO_CHI_ELA)
+               val |= SCM_IOCTL_EVENT_ERROR_LOG_AVAILABLE;
+
+       if (chi & GLOBAL_MMIO_CHI_CDA)
+               val |= SCM_IOCTL_EVENT_CONTROLLER_DUMP_AVAILABLE;
+
+       if (chi & GLOBAL_MMIO_CHI_CFFS)
+               val |= SCM_IOCTL_EVENT_FIRMWARE_FATAL;
+
+       if (chi & GLOBAL_MMIO_CHI_CHFS)
+               val |= SCM_IOCTL_EVENT_HARDWARE_FATAL;
+
+       rc = copy_to_user((u64 __user *) uarg, &val, sizeof(val));
+
+       return rc;
+}
+
 static long scm_file_ioctl(struct file *file, unsigned int cmd,
                           unsigned long args)
 {
@@ -1015,6 +1077,15 @@ static long scm_file_ioctl(struct file *file, unsigned 
int cmd,
                rc = scm_ioctl_controller_stats(scm_data,
                                                (struct 
scm_ioctl_controller_stats __user *)args);
                break;
+
+       case SCM_IOCTL_EVENTFD:
+               rc = scm_ioctl_eventfd(scm_data,
+                                      (struct scm_ioctl_eventfd __user *)args);
+               break;
+
+       case SCM_IOCTL_EVENT_CHECK:
+               rc = scm_ioctl_event_check(scm_data, (u64 __user *)args);
+               break;
        }
 
        return rc;
@@ -1156,6 +1227,146 @@ static void scm_dump_error_log(struct scm_data 
*scm_data)
        kfree(buf);
 }
 
+static irqreturn_t scm_imn0_handler(void *private)
+{
+       struct scm_data *scm_data = private;
+       u64 chi = 0;
+
+       (void)scm_chi(scm_data, &chi);
+
+       if (chi & GLOBAL_MMIO_CHI_ELA) {
+               dev_warn(&scm_data->dev, "Error log is available\n");
+
+               if (scm_data->ev_ctx)
+                       eventfd_signal(scm_data->ev_ctx, 1);
+       }
+
+       if (chi & GLOBAL_MMIO_CHI_CDA) {
+               dev_warn(&scm_data->dev, "Controller dump is available\n");
+
+               if (scm_data->ev_ctx)
+                       eventfd_signal(scm_data->ev_ctx, 1);
+       }
+
+
+       return IRQ_HANDLED;
+}
+
+static irqreturn_t scm_imn1_handler(void *private)
+{
+       struct scm_data *scm_data = private;
+       u64 chi = 0;
+
+       (void)scm_chi(scm_data, &chi);
+
+       if (chi & (GLOBAL_MMIO_CHI_CFFS | GLOBAL_MMIO_CHI_CHFS)) {
+               dev_err(&scm_data->dev,
+                       "Controller status is fatal, chi=0x%llx, going 
offline\n", chi);
+
+               if (scm_data->nvdimm_bus) {
+                       nvdimm_bus_unregister(scm_data->nvdimm_bus);
+                       scm_data->nvdimm_bus = NULL;
+               }
+
+               if (scm_data->ev_ctx)
+                       eventfd_signal(scm_data->ev_ctx, 1);
+       }
+
+       return IRQ_HANDLED;
+}
+
+
+/**
+ * scm_setup_irq() - Set up the IRQs for the SCM device
+ * @scm_data: the SCM metadata
+ * Return: 0 on success, negative on failure
+ */
+static int scm_setup_irq(struct scm_data *scm_data)
+{
+       int rc;
+       u64 irq_addr;
+
+       rc = ocxl_afu_irq_alloc(scm_data->ocxl_context, &scm_data->irq_id[0]);
+       if (rc)
+               return rc;
+
+       rc = ocxl_irq_set_handler(scm_data->ocxl_context, scm_data->irq_id[0],
+                                 scm_imn0_handler, NULL, scm_data);
+
+       irq_addr = ocxl_afu_irq_get_addr(scm_data->ocxl_context, 
scm_data->irq_id[0]);
+       if (!irq_addr)
+               return -EINVAL;
+
+       scm_data->irq_addr[0] = ioremap(irq_addr, PAGE_SIZE);
+       if (!scm_data->irq_addr[0])
+               return -EINVAL;
+
+       rc = ocxl_global_mmio_write64(scm_data->ocxl_afu, GLOBAL_MMIO_IMA0_OHP,
+                                     OCXL_LITTLE_ENDIAN,
+                                     (u64)scm_data->irq_addr[0]);
+       if (rc)
+               goto out_irq0;
+
+       rc = ocxl_global_mmio_write64(scm_data->ocxl_afu, GLOBAL_MMIO_IMA0_CFP,
+                                     OCXL_LITTLE_ENDIAN, 0);
+       if (rc)
+               goto out_irq0;
+
+       rc = ocxl_afu_irq_alloc(scm_data->ocxl_context, &scm_data->irq_id[1]);
+       if (rc)
+               goto out_irq0;
+
+
+       rc = ocxl_irq_set_handler(scm_data->ocxl_context, scm_data->irq_id[1],
+                                 scm_imn1_handler, NULL, scm_data);
+       if (rc)
+               goto out_irq0;
+
+       irq_addr = ocxl_afu_irq_get_addr(scm_data->ocxl_context, 
scm_data->irq_id[1]);
+       if (!irq_addr) {
+               rc = -EFAULT;
+               goto out_irq0;
+       }
+
+       scm_data->irq_addr[1] = ioremap(irq_addr, PAGE_SIZE);
+       if (!scm_data->irq_addr[1]) {
+               rc = -EINVAL;
+               goto out_irq0;
+       }
+
+       rc = ocxl_global_mmio_write64(scm_data->ocxl_afu, GLOBAL_MMIO_IMA1_OHP,
+                                     OCXL_LITTLE_ENDIAN,
+                                     (u64)scm_data->irq_addr[1]);
+       if (rc)
+               goto out_irq1;
+
+       rc = ocxl_global_mmio_write64(scm_data->ocxl_afu, GLOBAL_MMIO_IMA1_CFP,
+                                     OCXL_LITTLE_ENDIAN, 0);
+       if (rc)
+               goto out_irq1;
+
+       // Enable doorbells
+       rc = ocxl_global_mmio_set64(scm_data->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(scm_data->irq_addr[1]);
+       scm_data->irq_addr[1] = NULL;
+
+out_irq0:
+       iounmap(scm_data->irq_addr[0]);
+       scm_data->irq_addr[0] = NULL;
+
+       return rc;
+}
+
 /**
  * scm_probe_function_0 - Set up function 0 for an OpenCAPI Storage Class 
Memory device
  * This is important as it enables templates higher than 0 across all other 
functions,
@@ -1261,6 +1472,11 @@ static int scm_probe(struct pci_dev *pdev, const struct 
pci_device_id *ent)
                goto err;
        }
 
+       if (scm_setup_irq(scm_data)) {
+               dev_err(&pdev->dev, "Could not set up OCXL IRQs for SCM\n");
+               goto err;
+       }
+
        if (scm_setup_command_metadata(scm_data)) {
                dev_err(&pdev->dev, "Could not read OCXL command matada\n");
                goto err;
diff --git a/drivers/nvdimm/ocxl/scm_internal.h 
b/drivers/nvdimm/ocxl/scm_internal.h
index 9bf8fcf30ea6..693fd59f8bde 100644
--- a/drivers/nvdimm/ocxl/scm_internal.h
+++ b/drivers/nvdimm/ocxl/scm_internal.h
@@ -104,6 +104,10 @@ struct scm_data {
        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;
@@ -114,6 +118,7 @@ struct scm_data {
        struct command_metadata ns_command;
        struct resource scm_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-scm.h b/include/uapi/nvdimm/ocxl-scm.h
index 0a5de46c5acd..e86ffb02d31f 100644
--- a/include/uapi/nvdimm/ocxl-scm.h
+++ b/include/uapi/nvdimm/ocxl-scm.h
@@ -66,6 +66,20 @@ struct scm_ioctl_controller_stats {
        __u64 cache_write_latency; // nanoseconds
 };
 
+struct scm_ioctl_eventfd {
+       __s32 eventfd;
+       __u32 reserved;
+};
+
+#ifndef BIT_ULL
+#define BIT_ULL(nr)    (1ULL << (nr))
+#endif
+
+#define SCM_IOCTL_EVENT_CONTROLLER_DUMP_AVAILABLE      BIT_ULL(0)
+#define SCM_IOCTL_EVENT_ERROR_LOG_AVAILABLE            BIT_ULL(1)
+#define SCM_IOCTL_EVENT_HARDWARE_FATAL                 BIT_ULL(2)
+#define SCM_IOCTL_EVENT_FIRMWARE_FATAL                 BIT_ULL(3)
+
 /* ioctl numbers */
 #define SCM_MAGIC 0x5C
 /* SCM devices */
@@ -74,5 +88,7 @@ struct scm_ioctl_controller_stats {
 #define SCM_IOCTL_CONTROLLER_DUMP_DATA _IOWR(SCM_MAGIC, 0x03, struct 
scm_ioctl_controller_dump_data)
 #define SCM_IOCTL_CONTROLLER_DUMP_COMPLETE _IO(SCM_MAGIC, 0x04)
 #define SCM_IOCTL_CONTROLLER_STATS _IO(SCM_MAGIC, 0x05)
+#define SCM_IOCTL_EVENTFD      _IOW(SCM_MAGIC, 0x06, struct scm_ioctl_eventfd)
+#define SCM_IOCTL_EVENT_CHECK  _IOR(SCM_MAGIC, 0x07, __u64)
 
 #endif /* _UAPI_OCXL_SCM_H */
-- 
2.23.0

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