drm/ingenic: ipu: Only restart manually on older SoCs

On older SoCs, it is necessary to restart manually the IPU when a frame
is done processing. Doing so on newer SoCs (JZ4760/70) kinds of work
too, until the input or output resolutions or the framerate are too
high.

Make it work properly on newer SoCs by letting the LCD controller
trigger the IPU frame restart signal.
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200730144830.10479-2-paul@crapouillou.net

drivers/gpu/drm/ingenic/ingenic-ipu.c

@@ -35,6 +35,7 @@ struct soc_info {
 	const u32 *formats;
 	size_t num_formats;
 	bool has_bicubic;
+	bool manual_restart;
 
 	void (*set_coefs)(struct ingenic_ipu *ipu, unsigned int reg,
 			  unsigned int sharpness, bool downscale,
@@ -645,7 +646,8 @@ static irqreturn_t ingenic_ipu_irq_handler(int irq, void *arg)
 	unsigned int dummy;
 
 	/* dummy read allows CPU to reconfigure IPU */
-	regmap_read(ipu->map, JZ_REG_IPU_STATUS, &dummy);
+	if (ipu->soc_info->manual_restart)
+		regmap_read(ipu->map, JZ_REG_IPU_STATUS, &dummy);
 
 	/* ACK interrupt */
 	regmap_write(ipu->map, JZ_REG_IPU_STATUS, 0);
@@ -656,7 +658,8 @@ static irqreturn_t ingenic_ipu_irq_handler(int irq, void *arg)
 	regmap_write(ipu->map, JZ_REG_IPU_V_ADDR, ipu->addr_v);
 
 	/* Run IPU for the new frame */
-	regmap_set_bits(ipu->map, JZ_REG_IPU_CTRL, JZ_IPU_CTRL_RUN);
+	if (ipu->soc_info->manual_restart)
+		regmap_set_bits(ipu->map, JZ_REG_IPU_CTRL, JZ_IPU_CTRL_RUN);
 
 	drm_crtc_handle_vblank(crtc);
 
@@ -806,6 +809,7 @@ static const struct soc_info jz4725b_soc_info = {
 	.formats	= jz4725b_ipu_formats,
 	.num_formats	= ARRAY_SIZE(jz4725b_ipu_formats),
 	.has_bicubic	= false,
+	.manual_restart	= true,
 	.set_coefs	= jz4725b_set_coefs,
 };
 
@@ -831,6 +835,7 @@ static const struct soc_info jz4760_soc_info = {
 	.formats	= jz4760_ipu_formats,
 	.num_formats	= ARRAY_SIZE(jz4760_ipu_formats),
 	.has_bicubic	= true,
+	.manual_restart	= false,
 	.set_coefs	= jz4760_set_coefs,
 };