gpu: ipu-v3: add driver for Prefetch Resolve Engine

This adds support for the i.MX6 QuadPlus PRE units. Currently only
linear prefetch into SRAM is supported, other modes of operation
like the tiled-to-linear conversion will be added later.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

drivers/gpu/ipu-v3/ipu-prv.h

@@ -173,6 +173,7 @@ struct ipu_ic_priv;
 struct ipu_vdi;
 struct ipu_image_convert_priv;
 struct ipu_smfc_priv;
+struct ipu_pre;
 
 struct ipu_devtype;
 
@@ -264,4 +265,17 @@ void ipu_cpmem_exit(struct ipu_soc *ipu);
 int ipu_smfc_init(struct ipu_soc *ipu, struct device *dev, unsigned long base);
 void ipu_smfc_exit(struct ipu_soc *ipu);
 
+struct ipu_pre *ipu_pre_lookup_by_phandle(struct device *dev, const char *name,
+					  int index);
+int ipu_pre_get_available_count(void);
+int ipu_pre_get(struct ipu_pre *pre);
+void ipu_pre_put(struct ipu_pre *pre);
+u32 ipu_pre_get_baddr(struct ipu_pre *pre);
+void ipu_pre_configure(struct ipu_pre *pre, unsigned int width,
+		       unsigned int height,
+		       unsigned int stride, u32 format, unsigned int bufaddr);
+void ipu_pre_update(struct ipu_pre *pre, unsigned int bufaddr);
+
+extern struct platform_driver ipu_pre_drv;
+
 #endif				/* __IPU_PRV_H__ */