media: hantro: vp9: use double buffering if needed

Some G2 variants need double buffering to be enabled in order to work
correctly, like that found in Allwinner H6 SoC.

Add platform quirk for that.
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/hantro/hantro.h

@@ -73,6 +73,7 @@ struct hantro_irq {
  * @num_clocks:			number of clocks in the array
  * @reg_names:			array of register range names
  * @num_regs:			number of register range names in the array
+ * @double_buffer:		core needs double buffering
  */
 struct hantro_variant {
 	unsigned int enc_offset;
@@ -94,6 +95,7 @@ struct hantro_variant {
 	int num_clocks;
 	const char * const *reg_names;
 	int num_regs;
+	unsigned int double_buffer : 1;
 };
 
 /**

drivers/staging/media/hantro/hantro_g2_regs.h

@@ -270,6 +270,7 @@
 #define g2_apf_threshold	G2_DEC_REG(55, 0, 0xffff)
 
 #define g2_clk_gate_e		G2_DEC_REG(58, 16, 0x1)
+#define g2_double_buffer_e	G2_DEC_REG(58, 15, 0x1)
 #define g2_buswidth		G2_DEC_REG(58, 8,  0x7)
 #define g2_max_burst		G2_DEC_REG(58, 0,  0xff)
 

drivers/staging/media/hantro/hantro_g2_vp9_dec.c

@@ -847,6 +847,8 @@ config_registers(struct hantro_ctx *ctx, const struct v4l2_ctrl_vp9_frame *dec_p
 	hantro_reg_write(ctx->dev, &g2_clk_gate_e, 1);
 	hantro_reg_write(ctx->dev, &g2_max_cb_size, 6);
 	hantro_reg_write(ctx->dev, &g2_min_cb_size, 3);
+	if (ctx->dev->variant->double_buffer)
+		hantro_reg_write(ctx->dev, &g2_double_buffer_e, 1);
 
 	config_output(ctx, dst, dec_params);