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From:   Kai Ye <yekai13@huawei.com>
To:     <gregkh@linuxfoundation.org>,
        <linux-accelerators@lists.ozlabs.org>,
        <linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>,
        <zhangfei.gao@linaro.org>, <wangzhou1@hisilicon.com>,
        <yekai13@huawei.com>
Subject: [PATCH 1/2] uacce: supports device isolation feature
Date:   Sat, 11 Jun 2022 15:08:07 +0800
Message-ID: <20220611070808.49219-2-yekai13@huawei.com>
In-Reply-To: <20220611070808.49219-1-yekai13@huawei.com>
References: <20220611070808.49219-1-yekai13@huawei.com>
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UACCE add the hardware error isolation API. Users can configure
the error frequency threshold by this vfs node. This API interface
certainly supports the configuration of user protocol strategy. Then
parse it inside the device driver. UACCE only reports the device
isolate state. When the error frequency is exceeded, the device
will be isolated. The isolation strategy should be defined in each
driver module.

Signed-off-by: Kai Ye <yekai13@huawei.com>
Reviewed-by: Zhou Wang <wangzhou1@hisilicon.com>
---
 drivers/misc/uacce/uacce.c | 76 ++++++++++++++++++++++++++++++++++++++
 include/linux/uacce.h      | 21 ++++++++++-
 2 files changed, 96 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/uacce/uacce.c b/drivers/misc/uacce/uacce.c
index b6219c6bfb48..26c07f6f2f7c 100644
--- a/drivers/misc/uacce/uacce.c
+++ b/drivers/misc/uacce/uacce.c
@@ -12,6 +12,38 @@ static dev_t uacce_devt;
 static DEFINE_MUTEX(uacce_mutex);
 static DEFINE_XARRAY_ALLOC(uacce_xa);
 
+static int cdev_get(struct device *dev, void *data)
+{
+	struct uacce_device *uacce;
+	struct device **t_dev = data;
+
+	uacce = container_of(dev, struct uacce_device, dev);
+	if (uacce->parent == *t_dev) {
+		*t_dev = dev;
+		return 1;
+	}
+
+	return 0;
+}
+
+/**
+ * dev_to_uacce - Get structure uacce device from its parent device
+ * @dev: the device
+ */
+struct uacce_device *dev_to_uacce(struct device *dev)
+{
+	struct device **tdev = &dev;
+	int ret;
+
+	ret = class_for_each_device(uacce_class, NULL, tdev, cdev_get);
+	if (ret) {
+		dev = *tdev;
+		return container_of(dev, struct uacce_device, dev);
+	}
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(dev_to_uacce);
+
 static int uacce_start_queue(struct uacce_queue *q)
 {
 	int ret = 0;
@@ -54,6 +86,7 @@ static int uacce_put_queue(struct uacce_queue *q)
 		uacce->ops->put_queue(q);
 
 	q->state = UACCE_Q_ZOMBIE;
+	atomic_dec(&uacce->ref);
 out:
 	mutex_unlock(&uacce_mutex);
 
@@ -155,6 +188,7 @@ static int uacce_fops_open(struct inode *inode, struct file *filep)
 			goto out_with_bond;
 	}
 
+	atomic_inc(&uacce->ref);
 	init_waitqueue_head(&q->wait);
 	filep->private_data = q;
 	uacce->inode = inode;
@@ -346,12 +380,52 @@ static ssize_t region_dus_size_show(struct device *dev,
 		       uacce->qf_pg_num[UACCE_QFRT_DUS] << PAGE_SHIFT);
 }
 
+static ssize_t isolate_show(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%d\n", uacce->ops->get_isolate_state(uacce));
+}
+
+static ssize_t isolate_strategy_show(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+
+	return sysfs_emit(buf, "%s\n", uacce->isolate_strategy);
+}
+
+static ssize_t isolate_strategy_store(struct device *dev,
+				      struct device_attribute *attr,
+				      const char *buf, size_t count)
+{
+	struct uacce_device *uacce = to_uacce_device(dev);
+	int ret;
+
+	if (atomic_read(&uacce->ref))
+		return -EBUSY;
+
+	if (!buf || sizeof(buf) > UACCE_MAX_ISOLATE_STRATEGY_LEN)
+		return -EINVAL;
+
+	memcpy(uacce->isolate_strategy, buf, strlen(buf));
+
+	ret = uacce->ops->isolate_strategy_write(uacce, buf);
+	if (ret)
+		return -EINVAL;
+
+	return count;
+}
+
 static DEVICE_ATTR_RO(api);
 static DEVICE_ATTR_RO(flags);
 static DEVICE_ATTR_RO(available_instances);
 static DEVICE_ATTR_RO(algorithms);
 static DEVICE_ATTR_RO(region_mmio_size);
 static DEVICE_ATTR_RO(region_dus_size);
+static DEVICE_ATTR_RO(isolate);
+static DEVICE_ATTR_RW(isolate_strategy);
 
 static struct attribute *uacce_dev_attrs[] = {
 	&dev_attr_api.attr,
@@ -360,6 +434,8 @@ static struct attribute *uacce_dev_attrs[] = {
 	&dev_attr_algorithms.attr,
 	&dev_attr_region_mmio_size.attr,
 	&dev_attr_region_dus_size.attr,
+	&dev_attr_isolate.attr,
+	&dev_attr_isolate_strategy.attr,
 	NULL,
 };
 
diff --git a/include/linux/uacce.h b/include/linux/uacce.h
index 48e319f40275..30b1595b3f85 100644
--- a/include/linux/uacce.h
+++ b/include/linux/uacce.h
@@ -8,6 +8,7 @@
 #define UACCE_NAME		"uacce"
 #define UACCE_MAX_REGION	2
 #define UACCE_MAX_NAME_SIZE	64
+#define UACCE_MAX_ISOLATE_STRATEGY_LEN	256
 
 struct uacce_queue;
 struct uacce_device;
@@ -30,6 +31,8 @@ struct uacce_qfile_region {
  * @is_q_updated: check whether the task is finished
  * @mmap: mmap addresses of queue to user space
  * @ioctl: ioctl for user space users of the queue
+ * @get_isolate_state: get the device state after set the isolate strategy
+ * @isolate_strategy_store: stored the isolate strategy to the device
  */
 struct uacce_ops {
 	int (*get_available_instances)(struct uacce_device *uacce);
@@ -43,6 +46,8 @@ struct uacce_ops {
 		    struct uacce_qfile_region *qfr);
 	long (*ioctl)(struct uacce_queue *q, unsigned int cmd,
 		      unsigned long arg);
+	enum uacce_dev_state (*get_isolate_state)(struct uacce_device *uacce);
+	int (*isolate_strategy_write)(struct uacce_device *uacce, const char *buf);
 };
 
 /**
@@ -57,6 +62,12 @@ struct uacce_interface {
 	const struct uacce_ops *ops;
 };
 
+enum uacce_dev_state {
+	UACCE_DEV_ERR = -1,
+	UACCE_DEV_NORMAL,
+	UACCE_DEV_ISOLATE,
+};
+
 enum uacce_q_state {
 	UACCE_Q_ZOMBIE = 0,
 	UACCE_Q_INIT,
@@ -99,6 +110,7 @@ struct uacce_queue {
  * @dev: dev of the uacce
  * @priv: private pointer of the uacce
  * @queues: list of queues
+ * @ref: reference of the uacce
  * @queues_lock: lock for queues list
  * @inode: core vfs
  */
@@ -114,9 +126,11 @@ struct uacce_device {
 	struct cdev *cdev;
 	struct device dev;
 	void *priv;
+	atomic_t ref;
 	struct list_head queues;
 	struct mutex queues_lock;
 	struct inode *inode;
+	char isolate_strategy[UACCE_MAX_ISOLATE_STRATEGY_LEN];
 };
 
 #if IS_ENABLED(CONFIG_UACCE)
@@ -125,7 +139,7 @@ struct uacce_device *uacce_alloc(struct device *parent,
 				 struct uacce_interface *interface);
 int uacce_register(struct uacce_device *uacce);
 void uacce_remove(struct uacce_device *uacce);
-
+struct uacce_device *dev_to_uacce(struct device *dev);
 #else /* CONFIG_UACCE */
 
 static inline
@@ -142,6 +156,11 @@ static inline int uacce_register(struct uacce_device *uacce)
 
 static inline void uacce_remove(struct uacce_device *uacce) {}
 
+static inline struct uacce_device *dev_to_uacce(struct device *dev)
+{
+	return NULL;
+}
+
 #endif /* CONFIG_UACCE */
 
 #endif /* _LINUX_UACCE_H */
-- 
2.33.0