drm/pl111: Initial drm/kms driver for pl111

This is a modesetting driver for the pl111 CLCD display controller
found on various ARM platforms such as the Versatile Express. The
driver has only been tested on the bcm911360_entphn platform so far,
with PRIME-based buffer sharing between vc4 and clcd.

It reuses the existing devicetree binding, while not using quite as
many of its properties as the fbdev driver does (those are left for
future work).

v2: Nearly complete rewrite by anholt, cutting 2/3 of the code thanks
    to DRM core's excellent new helpers.
v3: Don't match pl110 any more, don't attach if we don't have a DRM
    panel, use DRM_GEM_CMA_FOPS, update MAINTAINERS, use the simple
    display helper, use drm_gem_cma_dumb_create (same as our wrapper).
v4: Change the driver's .name to not clash with fbdev in sysfs, drop
    platform alias, drop redundant "drm" in DRM driver name, hook up
    .prepare_fb to the CMA helper so that DMA fences should work.
v5: Move register definitions inside the driver directory, fix build
    in COMPILE_TEST and !AMBA mode.
v6: Drop TIM2_CLKSEL for now to be consistent with existing DT
    bindings, switch back to external register definitions.

Signed-off-by: Tom Cooksey <tom.cooksey@arm.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org> (v5)
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20170413031746.12921-2-eric@anholt.net

1 files changed, 344 insertions, 0 deletions

diff --git a/drivers/gpu/drm/pl111/pl111_display.c b/drivers/gpu/drm/pl111/pl111_display.c
new file mode 100644
index 000000000000..39a5c33bce7d
--- /dev/null
+++ b/drivers/gpu/drm/pl111/pl111_display.c
@@ -0,0 +1,344 @@
+/*
+ * (C) COPYRIGHT 2012-2013 ARM Limited. All rights reserved.
+ *
+ * Parts of this file were based on sources as follows:
+ *
+ * Copyright (c) 2006-2008 Intel Corporation
+ * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
+ * Copyright (C) 2011 Texas Instruments
+ *
+ * This program is free software and is provided to you under the terms of the
+ * GNU General Public License version 2 as published by the Free Software
+ * Foundation, and any use by you of this program is subject to the terms of
+ * such GNU licence.
+ *
+ */
+
+#include <linux/amba/clcd-regs.h>
+#include <linux/clk.h>
+#include <linux/version.h>
+#include <linux/dma-buf.h>
+#include <linux/of_graph.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_panel.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+
+#include "pl111_drm.h"
+
+irqreturn_t pl111_irq(int irq, void *data)
+{
+	struct pl111_drm_dev_private *priv = data;
+	u32 irq_stat;
+	irqreturn_t status = IRQ_NONE;
+
+	irq_stat = readl(priv->regs + CLCD_PL111_MIS);
+
+	if (!irq_stat)
+		return IRQ_NONE;
+
+	if (irq_stat & CLCD_IRQ_NEXTBASE_UPDATE) {
+		drm_crtc_handle_vblank(&priv->pipe.crtc);
+
+		status = IRQ_HANDLED;
+	}
+
+	/* Clear the interrupt once done */
+	writel(irq_stat, priv->regs + CLCD_PL111_ICR);
+
+	return status;
+}
+
+static u32 pl111_get_fb_offset(struct drm_plane_state *pstate)
+{
+	struct drm_framebuffer *fb = pstate->fb;
+	struct drm_gem_cma_object *obj = drm_fb_cma_get_gem_obj(fb, 0);
+
+	return (obj->paddr +
+		fb->offsets[0] +
+		fb->format->cpp[0] * pstate->src_x +
+		fb->pitches[0] * pstate->src_y);
+}
+
+static int pl111_display_check(struct drm_simple_display_pipe *pipe,
+			       struct drm_plane_state *pstate,
+			       struct drm_crtc_state *cstate)
+{
+	const struct drm_display_mode *mode = &cstate->mode;
+	struct drm_framebuffer *old_fb = pipe->plane.state->fb;
+	struct drm_framebuffer *fb = pstate->fb;
+
+	if (mode->hdisplay % 16)
+		return -EINVAL;
+
+	if (fb) {
+		u32 offset = pl111_get_fb_offset(pstate);
+
+		/* FB base address must be dword aligned. */
+		if (offset & 3)
+			return -EINVAL;
+
+		/* There's no pitch register -- the mode's hdisplay
+		 * controls it.
+		 */
+		if (fb->pitches[0] != mode->hdisplay * fb->format->cpp[0])
+			return -EINVAL;
+
+		/* We can't change the FB format in a flicker-free
+		 * manner (and only update it during CRTC enable).
+		 */
+		if (old_fb && old_fb->format != fb->format)
+			cstate->mode_changed = true;
+	}
+
+	return 0;
+}
+
+static void pl111_display_enable(struct drm_simple_display_pipe *pipe,
+				 struct drm_crtc_state *cstate)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_plane *plane = &pipe->plane;
+	struct drm_device *drm = crtc->dev;
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+	const struct drm_display_mode *mode = &cstate->mode;
+	struct drm_framebuffer *fb = plane->state->fb;
+	struct drm_connector *connector = &priv->connector.connector;
+	u32 cntl;
+	u32 ppl, hsw, hfp, hbp;
+	u32 lpp, vsw, vfp, vbp;
+	u32 cpl;
+	int ret;
+
+	ret = clk_set_rate(priv->clk, mode->clock * 1000);
+	if (ret) {
+		dev_err(drm->dev,
+			"Failed to set pixel clock rate to %d: %d\n",
+			mode->clock * 1000, ret);
+	}
+
+	clk_prepare_enable(priv->clk);
+
+	ppl = (mode->hdisplay / 16) - 1;
+	hsw = mode->hsync_end - mode->hsync_start - 1;
+	hfp = mode->hsync_start - mode->hdisplay - 1;
+	hbp = mode->htotal - mode->hsync_end - 1;
+
+	lpp = mode->vdisplay - 1;
+	vsw = mode->vsync_end - mode->vsync_start - 1;
+	vfp = mode->vsync_start - mode->vdisplay;
+	vbp = mode->vtotal - mode->vsync_end;
+
+	cpl = mode->hdisplay - 1;
+
+	writel((ppl << 2) |
+	       (hsw << 8) |
+	       (hfp << 16) |
+	       (hbp << 24),
+	       priv->regs + CLCD_TIM0);
+	writel(lpp |
+	       (vsw << 10) |
+	       (vfp << 16) |
+	       (vbp << 24),
+	       priv->regs + CLCD_TIM1);
+	/* XXX: We currently always use CLCDCLK with no divisor.  We
+	 * could probably reduce power consumption by using HCLK
+	 * (apb_pclk) with a divisor when it gets us near our target
+	 * pixel clock.
+	 */
+	writel(((mode->flags & DRM_MODE_FLAG_NHSYNC) ? TIM2_IHS : 0) |
+	       ((mode->flags & DRM_MODE_FLAG_NVSYNC) ? TIM2_IVS : 0) |
+	       ((connector->display_info.bus_flags &
+		 DRM_BUS_FLAG_DE_LOW) ? TIM2_IOE : 0) |
+	       ((connector->display_info.bus_flags &
+		 DRM_BUS_FLAG_PIXDATA_NEGEDGE) ? TIM2_IPC : 0) |
+	       TIM2_BCD |
+	       (cpl << 16),
+	       priv->regs + CLCD_TIM2);
+	writel(0, priv->regs + CLCD_TIM3);
+
+	drm_panel_prepare(priv->connector.panel);
+
+	/* Enable and Power Up */
+	cntl = CNTL_LCDEN | CNTL_LCDTFT | CNTL_LCDPWR | CNTL_LCDVCOMP(1);
+
+	/* Note that the the hardware's format reader takes 'r' from
+	 * the low bit, while DRM formats list channels from high bit
+	 * to low bit as you read left to right.
+	 */
+	switch (fb->format->format) {
+	case DRM_FORMAT_ABGR8888:
+	case DRM_FORMAT_XBGR8888:
+		cntl |= CNTL_LCDBPP24;
+		break;
+	case DRM_FORMAT_ARGB8888:
+	case DRM_FORMAT_XRGB8888:
+		cntl |= CNTL_LCDBPP24 | CNTL_BGR;
+		break;
+	case DRM_FORMAT_BGR565:
+		cntl |= CNTL_LCDBPP16_565;
+		break;
+	case DRM_FORMAT_RGB565:
+		cntl |= CNTL_LCDBPP16_565 | CNTL_BGR;
+		break;
+	case DRM_FORMAT_ABGR1555:
+	case DRM_FORMAT_XBGR1555:
+		cntl |= CNTL_LCDBPP16;
+		break;
+	case DRM_FORMAT_ARGB1555:
+	case DRM_FORMAT_XRGB1555:
+		cntl |= CNTL_LCDBPP16 | CNTL_BGR;
+		break;
+	case DRM_FORMAT_ABGR4444:
+	case DRM_FORMAT_XBGR4444:
+		cntl |= CNTL_LCDBPP16_444;
+		break;
+	case DRM_FORMAT_ARGB4444:
+	case DRM_FORMAT_XRGB4444:
+		cntl |= CNTL_LCDBPP16_444 | CNTL_BGR;
+		break;
+	default:
+		WARN_ONCE(true, "Unknown FB format 0x%08x\n",
+			  fb->format->format);
+		break;
+	}
+
+	writel(cntl, priv->regs + CLCD_PL111_CNTL);
+
+	drm_panel_enable(priv->connector.panel);
+
+	drm_crtc_vblank_on(crtc);
+}
+
+void pl111_display_disable(struct drm_simple_display_pipe *pipe)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_device *drm = crtc->dev;
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+
+	drm_crtc_vblank_off(crtc);
+
+	drm_panel_disable(priv->connector.panel);
+
+	/* Disable and Power Down */
+	writel(0, priv->regs + CLCD_PL111_CNTL);
+
+	drm_panel_unprepare(priv->connector.panel);
+
+	clk_disable_unprepare(priv->clk);
+}
+
+static void pl111_display_update(struct drm_simple_display_pipe *pipe,
+				 struct drm_plane_state *old_pstate)
+{
+	struct drm_crtc *crtc = &pipe->crtc;
+	struct drm_device *drm = crtc->dev;
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+	struct drm_pending_vblank_event *event = crtc->state->event;
+	struct drm_plane *plane = &pipe->plane;
+	struct drm_plane_state *pstate = plane->state;
+	struct drm_framebuffer *fb = pstate->fb;
+
+	if (fb) {
+		u32 addr = pl111_get_fb_offset(pstate);
+
+		writel(addr, priv->regs + CLCD_UBAS);
+	}
+
+	if (event) {
+		crtc->state->event = NULL;
+
+		spin_lock_irq(&crtc->dev->event_lock);
+		if (crtc->state->active && drm_crtc_vblank_get(crtc) == 0)
+			drm_crtc_arm_vblank_event(crtc, event);
+		else
+			drm_crtc_send_vblank_event(crtc, event);
+		spin_unlock_irq(&crtc->dev->event_lock);
+	}
+}
+
+int pl111_enable_vblank(struct drm_device *drm, unsigned int crtc)
+{
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+
+	writel(CLCD_IRQ_NEXTBASE_UPDATE, priv->regs + CLCD_PL111_IENB);
+
+	return 0;
+}
+
+void pl111_disable_vblank(struct drm_device *drm, unsigned int crtc)
+{
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+
+	writel(0, priv->regs + CLCD_PL111_IENB);
+}
+
+static int pl111_display_prepare_fb(struct drm_simple_display_pipe *pipe,
+				    struct drm_plane_state *plane_state)
+{
+	return drm_fb_cma_prepare_fb(&pipe->plane, plane_state);
+}
+
+const struct drm_simple_display_pipe_funcs pl111_display_funcs = {
+	.check = pl111_display_check,
+	.enable = pl111_display_enable,
+	.disable = pl111_display_disable,
+	.update = pl111_display_update,
+	.prepare_fb = pl111_display_prepare_fb,
+};
+
+int pl111_display_init(struct drm_device *drm)
+{
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+	struct device *dev = drm->dev;
+	struct device_node *endpoint;
+	u32 tft_r0b0g0[3];
+	int ret;
+	static const u32 formats[] = {
+		DRM_FORMAT_ABGR8888,
+		DRM_FORMAT_XBGR8888,
+		DRM_FORMAT_ARGB8888,
+		DRM_FORMAT_XRGB8888,
+		DRM_FORMAT_BGR565,
+		DRM_FORMAT_RGB565,
+		DRM_FORMAT_ABGR1555,
+		DRM_FORMAT_XBGR1555,
+		DRM_FORMAT_ARGB1555,
+		DRM_FORMAT_XRGB1555,
+		DRM_FORMAT_ABGR4444,
+		DRM_FORMAT_XBGR4444,
+		DRM_FORMAT_ARGB4444,
+		DRM_FORMAT_XRGB4444,
+	};
+
+	endpoint = of_graph_get_next_endpoint(dev->of_node, NULL);
+	if (!endpoint)
+		return -ENODEV;
+
+	if (of_property_read_u32_array(endpoint,
+				       "arm,pl11x,tft-r0g0b0-pads",
+				       tft_r0b0g0,
+				       ARRAY_SIZE(tft_r0b0g0)) != 0) {
+		dev_err(dev, "arm,pl11x,tft-r0g0b0-pads should be 3 ints\n");
+		of_node_put(endpoint);
+		return -ENOENT;
+	}
+	of_node_put(endpoint);
+
+	if (tft_r0b0g0[0] != 0 ||
+	    tft_r0b0g0[1] != 8 ||
+	    tft_r0b0g0[2] != 16) {
+		dev_err(dev, "arm,pl11x,tft-r0g0b0-pads != [0,8,16] not yet supported\n");
+		return -EINVAL;
+	}
+
+	ret = drm_simple_display_pipe_init(drm, &priv->pipe,
+					   &pl111_display_funcs,
+					   formats, ARRAY_SIZE(formats),
+					   &priv->connector.connector);
+	if (ret)
+		return ret;
+
+	return 0;
+}