ocxl: Create a clear delineation between ocxl backend & frontend

The OCXL driver contains both frontend code for interacting with userspace,
as well as backend code for interacting with the hardware.

This patch separates the backend code from the frontend so that it can be
used by other device drivers that communicate via OpenCAPI.

Relocate dev, cdev & sysfs files to the frontend code to allow external
drivers to maintain their own devices.

Reference counting on the device in the backend is replaced with kref
counting.

Move file & sysfs layer initialisation from core.c (backend) to
pci.c (frontend).

Create an ocxl_function oriented interface for initing devices &
enumerating AFUs.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
Acked-by: Frederic Barrat <fbarrat@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 32 insertions, 22 deletions

diff --git a/drivers/misc/ocxl/sysfs.c b/drivers/misc/ocxl/sysfs.c
index 0ab1fd1b2682..58f1ba264206 100644
--- a/drivers/misc/ocxl/sysfs.c
+++ b/drivers/misc/ocxl/sysfs.c
@@ -3,11 +3,18 @@
 #include <linux/sysfs.h>
 #include "ocxl_internal.h"
 
+static inline struct ocxl_afu *to_afu(struct device *device)
+{
+	struct ocxl_file_info *info = container_of(device, struct ocxl_file_info, dev);
+
+	return info->afu;
+}
+
 static ssize_t global_mmio_size_show(struct device *device,
 				struct device_attribute *attr,
 				char *buf)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(device);
+	struct ocxl_afu *afu = to_afu(device);
 
 	return scnprintf(buf, PAGE_SIZE, "%d\n",
 			afu->config.global_mmio_size);
@@ -17,7 +24,7 @@ static ssize_t pp_mmio_size_show(struct device *device,
 				struct device_attribute *attr,
 				char *buf)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(device);
+	struct ocxl_afu *afu = to_afu(device);
 
 	return scnprintf(buf, PAGE_SIZE, "%d\n",
 			afu->config.pp_mmio_stride);
@@ -27,7 +34,7 @@ static ssize_t afu_version_show(struct device *device,
 				struct device_attribute *attr,
 				char *buf)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(device);
+	struct ocxl_afu *afu = to_afu(device);
 
 	return scnprintf(buf, PAGE_SIZE, "%hhu:%hhu\n",
 			afu->config.version_major,
@@ -38,7 +45,7 @@ static ssize_t contexts_show(struct device *device,
 		struct device_attribute *attr,
 		char *buf)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(device);
+	struct ocxl_afu *afu = to_afu(device);
 
 	return scnprintf(buf, PAGE_SIZE, "%d/%d\n",
 			afu->pasid_count, afu->pasid_max);
@@ -55,7 +62,7 @@ static ssize_t global_mmio_read(struct file *filp, struct kobject *kobj,
 				struct bin_attribute *bin_attr, char *buf,
 				loff_t off, size_t count)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(kobj_to_dev(kobj));
+	struct ocxl_afu *afu = to_afu(kobj_to_dev(kobj));
 
 	if (count == 0 || off < 0 ||
 		off >= afu->config.global_mmio_size)
@@ -86,7 +93,7 @@ static int global_mmio_mmap(struct file *filp, struct kobject *kobj,
 			struct bin_attribute *bin_attr,
 			struct vm_area_struct *vma)
 {
-	struct ocxl_afu *afu = to_ocxl_afu(kobj_to_dev(kobj));
+	struct ocxl_afu *afu = to_afu(kobj_to_dev(kobj));
 
 	if ((vma_pages(vma) + vma->vm_pgoff) >
 		(afu->config.global_mmio_size >> PAGE_SHIFT))
@@ -99,27 +106,25 @@ static int global_mmio_mmap(struct file *filp, struct kobject *kobj,
 	return 0;
 }
 
-int ocxl_sysfs_add_afu(struct ocxl_afu *afu)
+int ocxl_sysfs_register_afu(struct ocxl_file_info *info)
 {
 	int i, rc;
 
 	for (i = 0; i < ARRAY_SIZE(afu_attrs); i++) {
-		rc = device_create_file(&afu->dev, &afu_attrs[i]);
+		rc = device_create_file(&info->dev, &afu_attrs[i]);
 		if (rc)
 			goto err;
 	}
 
-	sysfs_attr_init(&afu->attr_global_mmio.attr);
-	afu->attr_global_mmio.attr.name = "global_mmio_area";
-	afu->attr_global_mmio.attr.mode = 0600;
-	afu->attr_global_mmio.size = afu->config.global_mmio_size;
-	afu->attr_global_mmio.read = global_mmio_read;
-	afu->attr_global_mmio.mmap = global_mmio_mmap;
-	rc = device_create_bin_file(&afu->dev, &afu->attr_global_mmio);
+	sysfs_attr_init(&info->attr_global_mmio.attr);
+	info->attr_global_mmio.attr.name = "global_mmio_area";
+	info->attr_global_mmio.attr.mode = 0600;
+	info->attr_global_mmio.size = info->afu->config.global_mmio_size;
+	info->attr_global_mmio.read = global_mmio_read;
+	info->attr_global_mmio.mmap = global_mmio_mmap;
+	rc = device_create_bin_file(&info->dev, &info->attr_global_mmio);
 	if (rc) {
-		dev_err(&afu->dev,
-			"Unable to create global mmio attr for afu: %d\n",
-			rc);
+		dev_err(&info->dev, "Unable to create global mmio attr for afu: %d\n", rc);
 		goto err;
 	}
 
@@ -127,15 +132,20 @@ int ocxl_sysfs_add_afu(struct ocxl_afu *afu)
 
 err:
 	for (i--; i >= 0; i--)
-		device_remove_file(&afu->dev, &afu_attrs[i]);
+		device_remove_file(&info->dev, &afu_attrs[i]);
+
 	return rc;
 }
 
-void ocxl_sysfs_remove_afu(struct ocxl_afu *afu)
+void ocxl_sysfs_unregister_afu(struct ocxl_file_info *info)
 {
 	int i;
 
+	/*
+	 * device_remove_bin_file is safe to call if the file is not added as
+	 * the files are removed by name, and early exit if not found
+	 */
 	for (i = 0; i < ARRAY_SIZE(afu_attrs); i++)
-		device_remove_file(&afu->dev, &afu_attrs[i]);
-	device_remove_bin_file(&afu->dev, &afu->attr_global_mmio);
+		device_remove_file(&info->dev, &afu_attrs[i]);
+	device_remove_bin_file(&info->dev, &info->attr_global_mmio);
 }