drm/imagination: Implement context creation/destruction ioctls

Implement ioctls for the creation and destruction of contexts. Contexts are
used for job submission and each is associated with a particular job type.

Changes since v8:
- Fixed one error path in pvr_stream_process_1()
- Corrected license identifiers

Changes since v5:
- Fix context release in final error path in pvr_context_create()

Changes since v3:
- Use drm_dev_{enter,exit}

Co-developed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Sarah Walker <sarah.walker@imgtec.com>
Signed-off-by: Donald Robson <donald.robson@imgtec.com>
Link: https://lore.kernel.org/r/ac474a1f7dda2582d290798e4837140a2989aa2a.1700668843.git.donald.robson@imgtec.com
Signed-off-by: Maxime Ripard <mripard@kernel.org>

1 files changed, 161 insertions, 0 deletions

diff --git a/drivers/gpu/drm/imagination/pvr_context.h b/drivers/gpu/drm/imagination/pvr_context.h
new file mode 100644
index 000000000000..502dfad113e4
--- /dev/null
+++ b/drivers/gpu/drm/imagination/pvr_context.h
@@ -0,0 +1,161 @@
+/* SPDX-License-Identifier: GPL-2.0-only OR MIT */
+/* Copyright (c) 2023 Imagination Technologies Ltd. */
+
+#ifndef PVR_CONTEXT_H
+#define PVR_CONTEXT_H
+
+#include <drm/gpu_scheduler.h>
+
+#include <linux/compiler_attributes.h>
+#include <linux/dma-fence.h>
+#include <linux/kref.h>
+#include <linux/types.h>
+#include <linux/xarray.h>
+#include <uapi/drm/pvr_drm.h>
+
+#include "pvr_cccb.h"
+#include "pvr_device.h"
+
+/* Forward declaration from pvr_gem.h. */
+struct pvr_fw_object;
+
+enum pvr_context_priority {
+	PVR_CTX_PRIORITY_LOW = 0,
+	PVR_CTX_PRIORITY_MEDIUM,
+	PVR_CTX_PRIORITY_HIGH,
+};
+
+/**
+ * struct pvr_context - Context data
+ */
+struct pvr_context {
+	/** @ref_count: Refcount for context. */
+	struct kref ref_count;
+
+	/** @pvr_dev: Pointer to owning device. */
+	struct pvr_device *pvr_dev;
+
+	/** @vm_ctx: Pointer to associated VM context. */
+	struct pvr_vm_context *vm_ctx;
+
+	/** @type: Type of context. */
+	enum drm_pvr_ctx_type type;
+
+	/** @flags: Context flags. */
+	u32 flags;
+
+	/** @priority: Context priority*/
+	enum pvr_context_priority priority;
+
+	/** @fw_obj: FW object representing FW-side context data. */
+	struct pvr_fw_object *fw_obj;
+
+	/** @data: Pointer to local copy of FW context data. */
+	void *data;
+
+	/** @data_size: Size of FW context data, in bytes. */
+	u32 data_size;
+
+	/** @ctx_id: FW context ID. */
+	u32 ctx_id;
+};
+
+/**
+ * pvr_context_get() - Take additional reference on context.
+ * @ctx: Context pointer.
+ *
+ * Call pvr_context_put() to release.
+ *
+ * Returns:
+ *  * The requested context on success, or
+ *  * %NULL if no context pointer passed.
+ */
+static __always_inline struct pvr_context *
+pvr_context_get(struct pvr_context *ctx)
+{
+	if (ctx)
+		kref_get(&ctx->ref_count);
+
+	return ctx;
+}
+
+/**
+ * pvr_context_lookup() - Lookup context pointer from handle and file.
+ * @pvr_file: Pointer to pvr_file structure.
+ * @handle: Context handle.
+ *
+ * Takes reference on context. Call pvr_context_put() to release.
+ *
+ * Return:
+ *  * The requested context on success, or
+ *  * %NULL on failure (context does not exist, or does not belong to @pvr_file).
+ */
+static __always_inline struct pvr_context *
+pvr_context_lookup(struct pvr_file *pvr_file, u32 handle)
+{
+	struct pvr_context *ctx;
+
+	/* Take the array lock to protect against context removal.  */
+	xa_lock(&pvr_file->ctx_handles);
+	ctx = pvr_context_get(xa_load(&pvr_file->ctx_handles, handle));
+	xa_unlock(&pvr_file->ctx_handles);
+
+	return ctx;
+}
+
+/**
+ * pvr_context_lookup_id() - Lookup context pointer from ID.
+ * @pvr_dev: Device pointer.
+ * @id: FW context ID.
+ *
+ * Takes reference on context. Call pvr_context_put() to release.
+ *
+ * Return:
+ *  * The requested context on success, or
+ *  * %NULL on failure (context does not exist).
+ */
+static __always_inline struct pvr_context *
+pvr_context_lookup_id(struct pvr_device *pvr_dev, u32 id)
+{
+	struct pvr_context *ctx;
+
+	/* Take the array lock to protect against context removal.  */
+	xa_lock(&pvr_dev->ctx_ids);
+
+	/* Contexts are removed from the ctx_ids set in the context release path,
+	 * meaning the ref_count reached zero before they get removed. We need
+	 * to make sure we're not trying to acquire a context that's being
+	 * destroyed.
+	 */
+	ctx = xa_load(&pvr_dev->ctx_ids, id);
+	if (!kref_get_unless_zero(&ctx->ref_count))
+		ctx = NULL;
+
+	xa_unlock(&pvr_dev->ctx_ids);
+
+	return ctx;
+}
+
+static __always_inline u32
+pvr_context_get_fw_addr(struct pvr_context *ctx)
+{
+	u32 ctx_fw_addr = 0;
+
+	pvr_fw_object_get_fw_addr(ctx->fw_obj, &ctx_fw_addr);
+
+	return ctx_fw_addr;
+}
+
+void pvr_context_put(struct pvr_context *ctx);
+
+int pvr_context_create(struct pvr_file *pvr_file, struct drm_pvr_ioctl_create_context_args *args);
+
+int pvr_context_destroy(struct pvr_file *pvr_file, u32 handle);
+
+void pvr_destroy_contexts_for_file(struct pvr_file *pvr_file);
+
+void pvr_context_device_init(struct pvr_device *pvr_dev);
+
+void pvr_context_device_fini(struct pvr_device *pvr_dev);
+
+#endif /* PVR_CONTEXT_H */