1 files changed, 127 insertions, 0 deletions
diff --git a/drivers/misc/bcm-vk/bcm_vk_msg.c b/drivers/misc/bcm-vk/bcm_vk_msg.c
new file mode 100644
index 000000000000..2d9a6b4e5f61
--- /dev/null
+++ b/drivers/misc/bcm-vk/bcm_vk_msg.c
@@ -0,0 +1,127 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2018-2020 Broadcom.
+ */
+
+#include "bcm_vk.h"
+#include "bcm_vk_msg.h"
+
+/*
+ * allocate a ctx per file struct
+ */
+static struct bcm_vk_ctx *bcm_vk_get_ctx(struct bcm_vk *vk, const pid_t pid)
+{
+	u32 i;
+	struct bcm_vk_ctx *ctx = NULL;
+	u32 hash_idx = hash_32(pid, VK_PID_HT_SHIFT_BIT);
+
+	spin_lock(&vk->ctx_lock);
+
+	for (i = 0; i < ARRAY_SIZE(vk->ctx); i++) {
+		if (!vk->ctx[i].in_use) {
+			vk->ctx[i].in_use = true;
+			ctx = &vk->ctx[i];
+			break;
+		}
+	}
+
+	if (!ctx) {
+		dev_err(&vk->pdev->dev, "All context in use\n");
+
+		goto all_in_use_exit;
+	}
+
+	/* set the pid and insert it to hash table */
+	ctx->pid = pid;
+	ctx->hash_idx = hash_idx;
+	list_add_tail(&ctx->node, &vk->pid_ht[hash_idx].head);
+
+	/* increase kref */
+	kref_get(&vk->kref);
+
+all_in_use_exit:
+	spin_unlock(&vk->ctx_lock);
+
+	return ctx;
+}
+
+static int bcm_vk_free_ctx(struct bcm_vk *vk, struct bcm_vk_ctx *ctx)
+{
+	u32 idx;
+	u32 hash_idx;
+	pid_t pid;
+	struct bcm_vk_ctx *entry;
+	int count = 0;
+
+	if (!ctx) {
+		dev_err(&vk->pdev->dev, "NULL context detected\n");
+		return -EINVAL;
+	}
+	idx = ctx->idx;
+	pid = ctx->pid;
+
+	spin_lock(&vk->ctx_lock);
+
+	if (!vk->ctx[idx].in_use) {
+		dev_err(&vk->pdev->dev, "context[%d] not in use!\n", idx);
+	} else {
+		vk->ctx[idx].in_use = false;
+		vk->ctx[idx].miscdev = NULL;
+
+		/* Remove it from hash list and see if it is the last one. */
+		list_del(&ctx->node);
+		hash_idx = ctx->hash_idx;
+		list_for_each_entry(entry, &vk->pid_ht[hash_idx].head, node) {
+			if (entry->pid == pid)
+				count++;
+		}
+	}
+
+	spin_unlock(&vk->ctx_lock);
+
+	return count;
+}
+
+int bcm_vk_open(struct inode *inode, struct file *p_file)
+{
+	struct bcm_vk_ctx *ctx;
+	struct miscdevice *miscdev = (struct miscdevice *)p_file->private_data;
+	struct bcm_vk *vk = container_of(miscdev, struct bcm_vk, miscdev);
+	struct device *dev = &vk->pdev->dev;
+	int rc = 0;
+
+	/* get a context and set it up for file */
+	ctx = bcm_vk_get_ctx(vk, task_tgid_nr(current));
+	if (!ctx) {
+		dev_err(dev, "Error allocating context\n");
+		rc = -ENOMEM;
+	} else {
+		/*
+		 * set up context and replace private data with context for
+		 * other methods to use.  Reason for the context is because
+		 * it is allowed for multiple sessions to open the sysfs, and
+		 * for each file open, when upper layer query the response,
+		 * only those that are tied to a specific open should be
+		 * returned.  The context->idx will be used for such binding
+		 */
+		ctx->miscdev = miscdev;
+		p_file->private_data = ctx;
+		dev_dbg(dev, "ctx_returned with idx %d, pid %d\n",
+			ctx->idx, ctx->pid);
+	}
+	return rc;
+}
+
+int bcm_vk_release(struct inode *inode, struct file *p_file)
+{
+	int ret;
+	struct bcm_vk_ctx *ctx = p_file->private_data;
+	struct bcm_vk *vk = container_of(ctx->miscdev, struct bcm_vk, miscdev);
+
+	ret = bcm_vk_free_ctx(vk, ctx);
+
+	kref_put(&vk->kref, bcm_vk_release_data);
+
+	return ret;
+}
+