In this case, we can use the pigeon registers from this IP block in
order to do horizontal crop on the frame buffer processed by the eLCDIF
block.

Signed-off-by: Robert Chiras <robert.chiras@nxp.com>
Tested-by: Guido Günther <agx@sigxcpu.org>
---
 drivers/gpu/drm/mxsfb/mxsfb_crtc.c | 79 ++++++++++++++++++++++++++++++++++++--
 drivers/gpu/drm/mxsfb/mxsfb_drv.c  |  1 +
 drivers/gpu/drm/mxsfb/mxsfb_regs.h | 16 ++++++++
 3 files changed, 92 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c

b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
index a12f53d..317575e 100644

--- a/drivers/gpu/drm/mxsfb/mxsfb_crtc.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_crtc.c

@@ -15,6 +15,7 @@
 
 #include <video/videomode.h>
 
+#include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_fb_cma_helper.h>

@@ -435,13 +436,66 @@ void mxsfb_crtc_disable(struct mxsfb_drm_private *mxsfb)
 	clk_disable_unprepare(mxsfb->clk_axi);
 }
 
+void mxsfb_set_fb_hcrop(struct mxsfb_drm_private *mxsfb, u32 src_w, u32 fb_w)
+{
+	u32 mask_cnt, htotal, hcount;
+	u32 vdctrl2, vdctrl3, vdctrl4, transfer_count;
+	u32 pigeon_12_0, pigeon_12_1, pigeon_12_2;
+
+	if (src_w == fb_w) {
+		writel(0x0, mxsfb->base + HW_EPDC_PIGEON_12_0);
+		writel(0x0, mxsfb->base + HW_EPDC_PIGEON_12_1);
+
+		return;
+	}
+
+	transfer_count = readl(mxsfb->base + LCDC_V4_TRANSFER_COUNT);
+	hcount = TRANSFER_COUNT_GET_HCOUNT(transfer_count);
+
+	transfer_count &= ~TRANSFER_COUNT_SET_HCOUNT(0xffff);
+	transfer_count |= TRANSFER_COUNT_SET_HCOUNT(fb_w);
+	writel(transfer_count, mxsfb->base + LCDC_V4_TRANSFER_COUNT);
+
+	vdctrl2 = readl(mxsfb->base + LCDC_VDCTRL2);
+	htotal  = VDCTRL2_GET_HSYNC_PERIOD(vdctrl2);
+	htotal  += fb_w - hcount;
+	vdctrl2 &= ~VDCTRL2_SET_HSYNC_PERIOD(0x3ffff);
+	vdctrl2 |= VDCTRL2_SET_HSYNC_PERIOD(htotal);
+	writel(vdctrl2, mxsfb->base + LCDC_VDCTRL2);
+
+	vdctrl4 = readl(mxsfb->base + LCDC_VDCTRL4);
+	vdctrl4 &= ~SET_DOTCLK_H_VALID_DATA_CNT(0x3ffff);
+	vdctrl4 |= SET_DOTCLK_H_VALID_DATA_CNT(fb_w);
+	writel(vdctrl4, mxsfb->base + LCDC_VDCTRL4);
+
+	/* configure related pigeon registers */
+	vdctrl3  = readl(mxsfb->base + LCDC_VDCTRL3);
+	mask_cnt = GET_HOR_WAIT_CNT(vdctrl3) - 5;
+
+	pigeon_12_0 = PIGEON_12_0_SET_STATE_MASK(0x24)		|
+		      PIGEON_12_0_SET_MASK_CNT(mask_cnt)	|
+		      PIGEON_12_0_SET_MASK_CNT_SEL(0x6)		|
+		      PIGEON_12_0_POL_ACTIVE_LOW		|
+		      PIGEON_12_0_EN;
+	writel(pigeon_12_0, mxsfb->base + HW_EPDC_PIGEON_12_0);
+
+	pigeon_12_1 = PIGEON_12_1_SET_CLR_CNT(src_w) |
+		      PIGEON_12_1_SET_SET_CNT(0x0);
+	writel(pigeon_12_1, mxsfb->base + HW_EPDC_PIGEON_12_1);
+
+	pigeon_12_2 = 0x0;
+	writel(pigeon_12_2, mxsfb->base + HW_EPDC_PIGEON_12_2);
+}
+
 void mxsfb_plane_atomic_update(struct mxsfb_drm_private *mxsfb,
 			       struct drm_plane_state *state)
 {
 	struct drm_simple_display_pipe *pipe = &mxsfb->pipe;
 	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_plane_state *new_state = pipe->plane.state;
+	struct drm_framebuffer *fb = pipe->plane.state->fb;
 	struct drm_pending_vblank_event *event;
-	dma_addr_t paddr;
+	u32 fb_addr, src_off, src_w, stride, cpp = 0;

 
 	spin_lock_irq(&crtc->dev->event_lock);
 	event = crtc->state->event;

@@ -456,10 +510,27 @@ void mxsfb_plane_atomic_update(struct

mxsfb_drm_private *mxsfb,
 	}
 	spin_unlock_irq(&crtc->dev->event_lock);
 
-	paddr = mxsfb_get_fb_paddr(mxsfb);
-	if (paddr) {
+	if (!fb)
+		return;
+
+	fb_addr = mxsfb_get_fb_paddr(mxsfb);
+	if (mxsfb->devdata->ipversion >= 4) {
+		cpp = fb->format->cpp[0];
+		src_off = (new_state->src_y >> 16) * fb->pitches[0] +
+			  (new_state->src_x >> 16) * cpp;
+		fb_addr += fb->offsets[0] + src_off;
+	}
+
+	if (fb_addr) {
 		clk_prepare_enable(mxsfb->clk_axi);
-		writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
+		writel(fb_addr, mxsfb->base + mxsfb->devdata->next_buf);
 		clk_disable_unprepare(mxsfb->clk_axi);
 	}
+
+	if (mxsfb->devdata->ipversion >= 4 &&
+	    unlikely(drm_atomic_crtc_needs_modeset(new_state->crtc->state))) {
+		stride = DIV_ROUND_UP(fb->pitches[0], cpp);
+		src_w = new_state->src_w >> 16;
+		mxsfb_set_fb_hcrop(mxsfb, src_w, stride);
+	}
 }

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c

b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
index 888b520..06d3bf0 100644

--- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c

@@ -133,6 +133,7 @@ static int mxsfb_atomic_helper_check(struct drm_device *dev,
 		if (old_bpp != new_bpp)
 			new_state->mode_changed = true;
 	}
+

 	return ret;
 }
 

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_regs.h

b/drivers/gpu/drm/mxsfb/mxsfb_regs.h
index 0f63ba1..df3279b 100644

--- a/drivers/gpu/drm/mxsfb/mxsfb_regs.h
+++ b/drivers/gpu/drm/mxsfb/mxsfb_regs.h

@@ -145,6 +145,22 @@
 #define DEBUG0_HSYNC			BIT(26)
 #define DEBUG0_VSYNC			BIT(25)
 
+/* pigeon registers for crop */
+#define HW_EPDC_PIGEON_12_0		0xb00
+#define HW_EPDC_PIGEON_12_1		0xb10
+#define HW_EPDC_PIGEON_12_2		0xb20
+
+#define PIGEON_12_0_SET_STATE_MASK(x)	REG_PUT((x), 31, 24)
+#define PIGEON_12_0_SET_MASK_CNT(x)	REG_PUT((x), 23, 12)
+#define PIGEON_12_0_SET_MASK_CNT_SEL(x)	REG_PUT((x), 11,  8)
+#define PIGEON_12_0_SET_OFFSET(x)	REG_PUT((x),  7,  4)
+#define PIGEON_12_0_SET_INC_SEL(x)	REG_PUT((x),  3,  2)
+#define PIGEON_12_0_POL_ACTIVE_LOW	BIT(1)
+#define PIGEON_12_0_EN			BIT(0)
+
+#define PIGEON_12_1_SET_CLR_CNT(x)	REG_PUT((x), 31, 16)
+#define PIGEON_12_1_SET_SET_CNT(x)	REG_PUT((x), 15,  0)
+
 #define MXSFB_MIN_XRES			120
 #define MXSFB_MIN_YRES			120
 #define MXSFB_MAX_XRES			0xffff