drm: Add Allwinner A10 Display Engine support

The Allwinner A10 and subsequent SoCs share the same display pipeline, with
variations in the number of controllers (1 or 2), or the presence or not of
some output (HDMI, TV, VGA) or not.

Add a driver with a limited set of features for now, and we will hopefully
support all of them eventually

Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 364 insertions, 0 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
new file mode 100644
index 0000000..f7a15c1
--- /dev/null
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) 2015 Free Electrons
+ * Copyright (C) 2015 NextThing Co
+ *
+ * Maxime Ripard <maxime.ripard@free-electrons.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ */
+
+#include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_plane_helper.h>
+
+#include <linux/component.h>
+#include <linux/reset.h>
+
+#include "sun4i_backend.h"
+#include "sun4i_drv.h"
+
+static u32 sunxi_rgb2yuv_coef[12] = {
+	0x00000107, 0x00000204, 0x00000064, 0x00000108,
+	0x00003f69, 0x00003ed6, 0x000001c1, 0x00000808,
+	0x000001c1, 0x00003e88, 0x00003fb8, 0x00000808
+};
+
+void sun4i_backend_apply_color_correction(struct sun4i_backend *backend)
+{
+	int i;
+
+	DRM_DEBUG_DRIVER("Applying RGB to YUV color correction\n");
+
+	/* Set color correction */
+	regmap_write(backend->regs, SUN4I_BACKEND_OCCTL_REG,
+		     SUN4I_BACKEND_OCCTL_ENABLE);
+
+	for (i = 0; i < 12; i++)
+		regmap_write(backend->regs, SUN4I_BACKEND_OCRCOEF_REG(i),
+			     sunxi_rgb2yuv_coef[i]);
+}
+EXPORT_SYMBOL(sun4i_backend_apply_color_correction);
+
+void sun4i_backend_disable_color_correction(struct sun4i_backend *backend)
+{
+	DRM_DEBUG_DRIVER("Disabling color correction\n");
+
+	/* Disable color correction */
+	regmap_update_bits(backend->regs, SUN4I_BACKEND_OCCTL_REG,
+			   SUN4I_BACKEND_OCCTL_ENABLE, 0);
+}
+EXPORT_SYMBOL(sun4i_backend_disable_color_correction);
+
+void sun4i_backend_commit(struct sun4i_backend *backend)
+{
+	DRM_DEBUG_DRIVER("Committing changes\n");
+
+	regmap_write(backend->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
+		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS |
+		     SUN4I_BACKEND_REGBUFFCTL_LOADCTL);
+}
+EXPORT_SYMBOL(sun4i_backend_commit);
+
+void sun4i_backend_layer_enable(struct sun4i_backend *backend,
+				int layer, bool enable)
+{
+	u32 val;
+
+	DRM_DEBUG_DRIVER("Enabling layer %d\n", layer);
+
+	if (enable)
+		val = SUN4I_BACKEND_MODCTL_LAY_EN(layer);
+	else
+		val = 0;
+
+	regmap_update_bits(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+			   SUN4I_BACKEND_MODCTL_LAY_EN(layer), val);
+}
+EXPORT_SYMBOL(sun4i_backend_layer_enable);
+
+static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
+{
+	switch (format) {
+	case DRM_FORMAT_ARGB8888:
+		*mode = SUN4I_BACKEND_LAY_FBFMT_ARGB8888;
+		break;
+
+	case DRM_FORMAT_XRGB8888:
+		*mode = SUN4I_BACKEND_LAY_FBFMT_XRGB8888;
+		break;
+
+	case DRM_FORMAT_RGB888:
+		*mode = SUN4I_BACKEND_LAY_FBFMT_RGB888;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
+				     int layer, struct drm_plane *plane)
+{
+	struct drm_plane_state *state = plane->state;
+	struct drm_framebuffer *fb = state->fb;
+
+	DRM_DEBUG_DRIVER("Updating layer %d\n", layer);
+
+	if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
+		DRM_DEBUG_DRIVER("Primary layer, updating global size W: %u H: %u\n",
+				 state->crtc_w, state->crtc_h);
+		regmap_write(backend->regs, SUN4I_BACKEND_DISSIZE_REG,
+			     SUN4I_BACKEND_DISSIZE(state->crtc_w,
+						   state->crtc_h));
+	}
+
+	/* Set the line width */
+	DRM_DEBUG_DRIVER("Layer line width: %d bits\n", fb->pitches[0] * 8);
+	regmap_write(backend->regs, SUN4I_BACKEND_LAYLINEWIDTH_REG(layer),
+		     fb->pitches[0] * 8);
+
+	/* Set height and width */
+	DRM_DEBUG_DRIVER("Layer size W: %u H: %u\n",
+			 state->crtc_w, state->crtc_h);
+	regmap_write(backend->regs, SUN4I_BACKEND_LAYSIZE_REG(layer),
+		     SUN4I_BACKEND_LAYSIZE(state->crtc_w,
+					   state->crtc_h));
+
+	/* Set base coordinates */
+	DRM_DEBUG_DRIVER("Layer coordinates X: %d Y: %d\n",
+			 state->crtc_x, state->crtc_y);
+	regmap_write(backend->regs, SUN4I_BACKEND_LAYCOOR_REG(layer),
+		     SUN4I_BACKEND_LAYCOOR(state->crtc_x,
+					   state->crtc_y));
+
+	return 0;
+}
+EXPORT_SYMBOL(sun4i_backend_update_layer_coord);
+
+int sun4i_backend_update_layer_formats(struct sun4i_backend *backend,
+				       int layer, struct drm_plane *plane)
+{
+	struct drm_plane_state *state = plane->state;
+	struct drm_framebuffer *fb = state->fb;
+	bool interlaced = false;
+	u32 val;
+	int ret;
+
+	if (plane->state->crtc)
+		interlaced = plane->state->crtc->state->adjusted_mode.flags
+			& DRM_MODE_FLAG_INTERLACE;
+
+	regmap_update_bits(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+			   SUN4I_BACKEND_MODCTL_ITLMOD_EN,
+			   interlaced ? SUN4I_BACKEND_MODCTL_ITLMOD_EN : 0);
+
+	DRM_DEBUG_DRIVER("Switching display backend interlaced mode %s\n",
+			 interlaced ? "on" : "off");
+
+	ret = sun4i_backend_drm_format_to_layer(fb->pixel_format, &val);
+	if (ret) {
+		DRM_DEBUG_DRIVER("Invalid format\n");
+		return val;
+	}
+
+	regmap_update_bits(backend->regs, SUN4I_BACKEND_ATTCTL_REG1(layer),
+			   SUN4I_BACKEND_ATTCTL_REG1_LAY_FBFMT, val);
+
+	return 0;
+}
+EXPORT_SYMBOL(sun4i_backend_update_layer_formats);
+
+int sun4i_backend_update_layer_buffer(struct sun4i_backend *backend,
+				      int layer, struct drm_plane *plane)
+{
+	struct drm_plane_state *state = plane->state;
+	struct drm_framebuffer *fb = state->fb;
+	struct drm_gem_cma_object *gem;
+	u32 lo_paddr, hi_paddr;
+	dma_addr_t paddr;
+	int bpp;
+
+	/* Get the physical address of the buffer in memory */
+	gem = drm_fb_cma_get_gem_obj(fb, 0);
+
+	DRM_DEBUG_DRIVER("Using GEM @ 0x%x\n", gem->paddr);
+
+	/* Compute the start of the displayed memory */
+	bpp = drm_format_plane_cpp(fb->pixel_format, 0);
+	paddr = gem->paddr + fb->offsets[0];
+	paddr += (state->src_x >> 16) * bpp;
+	paddr += (state->src_y >> 16) * fb->pitches[0];
+
+	DRM_DEBUG_DRIVER("Setting buffer address to 0x%x\n", paddr);
+
+	/* Write the 32 lower bits of the address (in bits) */
+	lo_paddr = paddr << 3;
+	DRM_DEBUG_DRIVER("Setting address lower bits to 0x%x\n", lo_paddr);
+	regmap_write(backend->regs, SUN4I_BACKEND_LAYFB_L32ADD_REG(layer),
+		     lo_paddr);
+
+	/* And the upper bits */
+	hi_paddr = paddr >> 29;
+	DRM_DEBUG_DRIVER("Setting address high bits to 0x%x\n", hi_paddr);
+	regmap_update_bits(backend->regs, SUN4I_BACKEND_LAYFB_H4ADD_REG,
+			   SUN4I_BACKEND_LAYFB_H4ADD_MSK(layer),
+			   SUN4I_BACKEND_LAYFB_H4ADD(layer, hi_paddr));
+
+	return 0;
+}
+EXPORT_SYMBOL(sun4i_backend_update_layer_buffer);
+
+static struct regmap_config sun4i_backend_regmap_config = {
+	.reg_bits	= 32,
+	.val_bits	= 32,
+	.reg_stride	= 4,
+	.max_register	= 0x5800,
+};
+
+static int sun4i_backend_bind(struct device *dev, struct device *master,
+			      void *data)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct drm_device *drm = data;
+	struct sun4i_drv *drv = drm->dev_private;
+	struct sun4i_backend *backend;
+	struct resource *res;
+	void __iomem *regs;
+	int i, ret;
+
+	backend = devm_kzalloc(dev, sizeof(*backend), GFP_KERNEL);
+	if (!backend)
+		return -ENOMEM;
+	dev_set_drvdata(dev, backend);
+	drv->backend = backend;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	regs = devm_ioremap_resource(dev, res);
+	if (IS_ERR(regs)) {
+		dev_err(dev, "Couldn't map the backend registers\n");
+		return PTR_ERR(regs);
+	}
+
+	backend->regs = devm_regmap_init_mmio(dev, regs,
+					      &sun4i_backend_regmap_config);
+	if (IS_ERR(backend->regs)) {
+		dev_err(dev, "Couldn't create the backend0 regmap\n");
+		return PTR_ERR(backend->regs);
+	}
+
+	backend->reset = devm_reset_control_get(dev, NULL);
+	if (IS_ERR(backend->reset)) {
+		dev_err(dev, "Couldn't get our reset line\n");
+		return PTR_ERR(backend->reset);
+	}
+
+	ret = reset_control_deassert(backend->reset);
+	if (ret) {
+		dev_err(dev, "Couldn't deassert our reset line\n");
+		return ret;
+	}
+
+	backend->bus_clk = devm_clk_get(dev, "ahb");
+	if (IS_ERR(backend->bus_clk)) {
+		dev_err(dev, "Couldn't get the backend bus clock\n");
+		ret = PTR_ERR(backend->bus_clk);
+		goto err_assert_reset;
+	}
+	clk_prepare_enable(backend->bus_clk);
+
+	backend->mod_clk = devm_clk_get(dev, "mod");
+	if (IS_ERR(backend->mod_clk)) {
+		dev_err(dev, "Couldn't get the backend module clock\n");
+		ret = PTR_ERR(backend->mod_clk);
+		goto err_disable_bus_clk;
+	}
+	clk_prepare_enable(backend->mod_clk);
+
+	backend->ram_clk = devm_clk_get(dev, "ram");
+	if (IS_ERR(backend->ram_clk)) {
+		dev_err(dev, "Couldn't get the backend RAM clock\n");
+		ret = PTR_ERR(backend->ram_clk);
+		goto err_disable_mod_clk;
+	}
+	clk_prepare_enable(backend->ram_clk);
+
+	/* Reset the registers */
+	for (i = 0x800; i < 0x1000; i += 4)
+		regmap_write(backend->regs, i, 0);
+
+	/* Disable registers autoloading */
+	regmap_write(backend->regs, SUN4I_BACKEND_REGBUFFCTL_REG,
+		     SUN4I_BACKEND_REGBUFFCTL_AUTOLOAD_DIS);
+
+	/* Enable the backend */
+	regmap_write(backend->regs, SUN4I_BACKEND_MODCTL_REG,
+		     SUN4I_BACKEND_MODCTL_DEBE_EN |
+		     SUN4I_BACKEND_MODCTL_START_CTL);
+
+	return 0;
+
+err_disable_mod_clk:
+	clk_disable_unprepare(backend->mod_clk);
+err_disable_bus_clk:
+	clk_disable_unprepare(backend->bus_clk);
+err_assert_reset:
+	reset_control_assert(backend->reset);
+	return ret;
+}
+
+static void sun4i_backend_unbind(struct device *dev, struct device *master,
+				 void *data)
+{
+	struct sun4i_backend *backend = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(backend->ram_clk);
+	clk_disable_unprepare(backend->mod_clk);
+	clk_disable_unprepare(backend->bus_clk);
+	reset_control_assert(backend->reset);
+}
+
+static struct component_ops sun4i_backend_ops = {
+	.bind	= sun4i_backend_bind,
+	.unbind	= sun4i_backend_unbind,
+};
+
+static int sun4i_backend_probe(struct platform_device *pdev)
+{
+	return component_add(&pdev->dev, &sun4i_backend_ops);
+}
+
+static int sun4i_backend_remove(struct platform_device *pdev)
+{
+	component_del(&pdev->dev, &sun4i_backend_ops);
+
+	return 0;
+}
+
+static const struct of_device_id sun4i_backend_of_table[] = {
+	{ .compatible = "allwinner,sun5i-a13-display-backend" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, sun4i_backend_of_table);
+
+static struct platform_driver sun4i_backend_platform_driver = {
+	.probe		= sun4i_backend_probe,
+	.remove		= sun4i_backend_remove,
+	.driver		= {
+		.name		= "sun4i-backend",
+		.of_match_table	= sun4i_backend_of_table,
+	},
+};
+module_platform_driver(sun4i_backend_platform_driver);
+
+MODULE_AUTHOR("Maxime Ripard <maxime.ripard@free-electrons.com>");
+MODULE_DESCRIPTION("Allwinner A10 Display Backend Driver");
+MODULE_LICENSE("GPL");