DRM: Armada: Add Armada DRM driver

This patch adds support for the pair of LCD controllers on the Marvell
Armada 510 SoCs.  This driver supports:
- multiple contiguous scanout buffers for video and graphics
- shm backed cacheable buffer objects for X pixmaps for Vivante GPU
  acceleration
- dual lcd0 and lcd1 crt operation
- video overlay on each LCD crt via DRM planes
- page flipping of the main scanout buffers
- DRM prime for buffer export/import

This driver is trivial to extend to other Armada SoCs.

Included in this commit is the core driver with no output support; output
support is platform and encoder driver dependent.

Tested-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/drivers/gpu/drm/armada/armada_drv.c b/drivers/gpu/drm/armada/armada_drv.c
new file mode 100644
index 0000000..7bfab9a
--- /dev/null
+++ b/drivers/gpu/drm/armada/armada_drv.c
@@ -0,0 +1,380 @@
+/*
+ * Copyright (C) 2012 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <drm/drmP.h>
+#include <drm/drm_crtc_helper.h>
+#include "armada_crtc.h"
+#include "armada_drm.h"
+#include "armada_gem.h"
+#include "armada_hw.h"
+#include <drm/armada_drm.h>
+#include "armada_ioctlP.h"
+
+static void armada_drm_unref_work(struct work_struct *work)
+{
+	struct armada_private *priv =
+		container_of(work, struct armada_private, fb_unref_work);
+	struct drm_framebuffer *fb;
+
+	while (kfifo_get(&priv->fb_unref, &fb))
+		drm_framebuffer_unreference(fb);
+}
+
+/* Must be called with dev->event_lock held */
+void __armada_drm_queue_unref_work(struct drm_device *dev,
+	struct drm_framebuffer *fb)
+{
+	struct armada_private *priv = dev->dev_private;
+
+	/*
+	 * Yes, we really must jump through these hoops just to store a
+	 * _pointer_ to something into the kfifo.  This is utterly insane
+	 * and idiotic, because it kfifo requires the _data_ pointed to by
+	 * the pointer const, not the pointer itself.  Not only that, but
+	 * you have to pass a pointer _to_ the pointer you want stored.
+	 */
+	const struct drm_framebuffer *silly_api_alert = fb;
+	WARN_ON(!kfifo_put(&priv->fb_unref, &silly_api_alert));
+	schedule_work(&priv->fb_unref_work);
+}
+
+void armada_drm_queue_unref_work(struct drm_device *dev,
+	struct drm_framebuffer *fb)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dev->event_lock, flags);
+	__armada_drm_queue_unref_work(dev, fb);
+	spin_unlock_irqrestore(&dev->event_lock, flags);
+}
+
+static int armada_drm_load(struct drm_device *dev, unsigned long flags)
+{
+	const struct platform_device_id *id;
+	struct armada_private *priv;
+	struct resource *res[ARRAY_SIZE(priv->dcrtc)];
+	struct resource *mem = NULL;
+	int ret, n, i;
+
+	memset(res, 0, sizeof(res));
+
+	for (n = i = 0; ; n++) {
+		struct resource *r = platform_get_resource(dev->platformdev,
+							   IORESOURCE_MEM, n);
+		if (!r)
+			break;
+
+		/* Resources above 64K are graphics memory */
+		if (resource_size(r) > SZ_64K)
+			mem = r;
+		else if (i < ARRAY_SIZE(priv->dcrtc))
+			res[i++] = r;
+		else
+			return -EINVAL;
+	}
+
+	if (!res[0] || !mem)
+		return -ENXIO;
+
+	if (!devm_request_mem_region(dev->dev, mem->start,
+			resource_size(mem), "armada-drm"))
+		return -EBUSY;
+
+	priv = devm_kzalloc(dev->dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		DRM_ERROR("failed to allocate private\n");
+		return -ENOMEM;
+	}
+
+	dev->dev_private = priv;
+
+	/* Get the implementation specific driver data. */
+	id = platform_get_device_id(dev->platformdev);
+	if (!id)
+		return -ENXIO;
+
+	priv->variant = (struct armada_variant *)id->driver_data;
+
+	ret = priv->variant->init(priv, dev->dev);
+	if (ret)
+		return ret;
+
+	INIT_WORK(&priv->fb_unref_work, armada_drm_unref_work);
+	INIT_KFIFO(priv->fb_unref);
+
+	/* Mode setting support */
+	drm_mode_config_init(dev);
+	dev->mode_config.min_width = 320;
+	dev->mode_config.min_height = 200;
+
+	/*
+	 * With vscale enabled, the maximum width is 1920 due to the
+	 * 1920 by 3 lines RAM
+	 */
+	dev->mode_config.max_width = 1920;
+	dev->mode_config.max_height = 2048;
+
+	dev->mode_config.preferred_depth = 24;
+	dev->mode_config.funcs = &armada_drm_mode_config_funcs;
+	drm_mm_init(&priv->linear, mem->start, resource_size(mem));
+
+	/* Create all LCD controllers */
+	for (n = 0; n < ARRAY_SIZE(priv->dcrtc); n++) {
+		if (!res[n])
+			break;
+
+		ret = armada_drm_crtc_create(dev, n, res[n]);
+		if (ret)
+			goto err_kms;
+	}
+
+	ret = drm_vblank_init(dev, n);
+	if (ret)
+		goto err_kms;
+
+	ret = drm_irq_install(dev);
+	if (ret)
+		goto err_kms;
+
+	dev->vblank_disable_allowed = 1;
+
+	ret = armada_fbdev_init(dev);
+	if (ret)
+		goto err_irq;
+
+	drm_kms_helper_poll_init(dev);
+
+	return 0;
+
+ err_irq:
+	drm_irq_uninstall(dev);
+ err_kms:
+	drm_mode_config_cleanup(dev);
+	drm_mm_takedown(&priv->linear);
+	flush_work(&priv->fb_unref_work);
+
+	return ret;
+}
+
+static int armada_drm_unload(struct drm_device *dev)
+{
+	struct armada_private *priv = dev->dev_private;
+
+	drm_kms_helper_poll_fini(dev);
+	armada_fbdev_fini(dev);
+	drm_irq_uninstall(dev);
+	drm_mode_config_cleanup(dev);
+	drm_mm_takedown(&priv->linear);
+	flush_work(&priv->fb_unref_work);
+	dev->dev_private = NULL;
+
+	return 0;
+}
+
+void armada_drm_vbl_event_add(struct armada_crtc *dcrtc,
+	struct armada_vbl_event *evt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dcrtc->irq_lock, flags);
+	if (list_empty(&evt->node)) {
+		list_add_tail(&evt->node, &dcrtc->vbl_list);
+
+		drm_vblank_get(dcrtc->crtc.dev, dcrtc->num);
+	}
+	spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
+}
+
+void armada_drm_vbl_event_remove(struct armada_crtc *dcrtc,
+	struct armada_vbl_event *evt)
+{
+	if (!list_empty(&evt->node)) {
+		list_del_init(&evt->node);
+		drm_vblank_put(dcrtc->crtc.dev, dcrtc->num);
+	}
+}
+
+void armada_drm_vbl_event_remove_unlocked(struct armada_crtc *dcrtc,
+	struct armada_vbl_event *evt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&dcrtc->irq_lock, flags);
+	armada_drm_vbl_event_remove(dcrtc, evt);
+	spin_unlock_irqrestore(&dcrtc->irq_lock, flags);
+}
+
+/* These are called under the vbl_lock. */
+static int armada_drm_enable_vblank(struct drm_device *dev, int crtc)
+{
+	struct armada_private *priv = dev->dev_private;
+	armada_drm_crtc_enable_irq(priv->dcrtc[crtc], VSYNC_IRQ_ENA);
+	return 0;
+}
+
+static void armada_drm_disable_vblank(struct drm_device *dev, int crtc)
+{
+	struct armada_private *priv = dev->dev_private;
+	armada_drm_crtc_disable_irq(priv->dcrtc[crtc], VSYNC_IRQ_ENA);
+}
+
+static irqreturn_t armada_drm_irq_handler(int irq, void *arg)
+{
+	struct drm_device *dev = arg;
+	struct armada_private *priv = dev->dev_private;
+	struct armada_crtc *dcrtc = priv->dcrtc[0];
+	uint32_t v, stat = readl_relaxed(dcrtc->base + LCD_SPU_IRQ_ISR);
+	irqreturn_t handled = IRQ_NONE;
+
+	/*
+	 * This is rediculous - rather than writing bits to clear, we
+	 * have to set the actual status register value.  This is racy.
+	 */
+	writel_relaxed(0, dcrtc->base + LCD_SPU_IRQ_ISR);
+
+	/* Mask out those interrupts we haven't enabled */
+	v = stat & dcrtc->irq_ena;
+
+	if (v & (VSYNC_IRQ|GRA_FRAME_IRQ|DUMB_FRAMEDONE)) {
+		armada_drm_crtc_irq(dcrtc, stat);
+		handled = IRQ_HANDLED;
+	}
+
+	return handled;
+}
+
+static int armada_drm_irq_postinstall(struct drm_device *dev)
+{
+	struct armada_private *priv = dev->dev_private;
+	struct armada_crtc *dcrtc = priv->dcrtc[0];
+
+	spin_lock_irq(&dev->vbl_lock);
+	writel_relaxed(dcrtc->irq_ena, dcrtc->base + LCD_SPU_IRQ_ENA);
+	writel(0, dcrtc->base + LCD_SPU_IRQ_ISR);
+	spin_unlock_irq(&dev->vbl_lock);
+
+	return 0;
+}
+
+static void armada_drm_irq_uninstall(struct drm_device *dev)
+{
+	struct armada_private *priv = dev->dev_private;
+	struct armada_crtc *dcrtc = priv->dcrtc[0];
+
+	writel(0, dcrtc->base + LCD_SPU_IRQ_ENA);
+}
+
+static struct drm_ioctl_desc armada_ioctls[] = {
+	DRM_IOCTL_DEF_DRV(ARMADA_GEM_CREATE, armada_gem_create_ioctl,
+		DRM_UNLOCKED),
+	DRM_IOCTL_DEF_DRV(ARMADA_GEM_MMAP, armada_gem_mmap_ioctl,
+		DRM_UNLOCKED),
+	DRM_IOCTL_DEF_DRV(ARMADA_GEM_PWRITE, armada_gem_pwrite_ioctl,
+		DRM_UNLOCKED),
+};
+
+static const struct file_operations armada_drm_fops = {
+	.owner			= THIS_MODULE,
+	.llseek			= no_llseek,
+	.read			= drm_read,
+	.poll			= drm_poll,
+	.unlocked_ioctl		= drm_ioctl,
+	.mmap			= drm_gem_mmap,
+	.open			= drm_open,
+	.release		= drm_release,
+};
+
+static struct drm_driver armada_drm_driver = {
+	.load			= armada_drm_load,
+	.open			= NULL,
+	.preclose		= NULL,
+	.postclose		= NULL,
+	.lastclose		= NULL,
+	.unload			= armada_drm_unload,
+	.get_vblank_counter	= drm_vblank_count,
+	.enable_vblank		= armada_drm_enable_vblank,
+	.disable_vblank		= armada_drm_disable_vblank,
+	.irq_handler		= armada_drm_irq_handler,
+	.irq_postinstall	= armada_drm_irq_postinstall,
+	.irq_uninstall		= armada_drm_irq_uninstall,
+#ifdef CONFIG_DEBUG_FS
+	.debugfs_init		= armada_drm_debugfs_init,
+	.debugfs_cleanup	= armada_drm_debugfs_cleanup,
+#endif
+	.gem_init_object	= NULL,
+	.gem_free_object	= armada_gem_free_object,
+	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
+	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
+	.gem_prime_export	= armada_gem_prime_export,
+	.gem_prime_import	= armada_gem_prime_import,
+	.dumb_create		= armada_gem_dumb_create,
+	.dumb_map_offset	= armada_gem_dumb_map_offset,
+	.dumb_destroy		= armada_gem_dumb_destroy,
+	.gem_vm_ops		= &armada_gem_vm_ops,
+	.major			= 1,
+	.minor			= 0,
+	.name			= "armada-drm",
+	.desc			= "Armada SoC DRM",
+	.date			= "20120730",
+	.driver_features	= DRIVER_GEM | DRIVER_MODESET |
+				  DRIVER_HAVE_IRQ | DRIVER_PRIME,
+	.ioctls			= armada_ioctls,
+	.fops			= &armada_drm_fops,
+};
+
+static int armada_drm_probe(struct platform_device *pdev)
+{
+	return drm_platform_init(&armada_drm_driver, pdev);
+}
+
+static int armada_drm_remove(struct platform_device *pdev)
+{
+	drm_platform_exit(&armada_drm_driver, pdev);
+	return 0;
+}
+
+static const struct platform_device_id armada_drm_platform_ids[] = {
+	{
+		.name		= "armada-drm",
+		.driver_data	= (unsigned long)&armada510_ops,
+	}, {
+		.name		= "armada-510-drm",
+		.driver_data	= (unsigned long)&armada510_ops,
+	},
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, armada_drm_platform_ids);
+
+static struct platform_driver armada_drm_platform_driver = {
+	.probe	= armada_drm_probe,
+	.remove	= armada_drm_remove,
+	.driver	= {
+		.name	= "armada-drm",
+		.owner	= THIS_MODULE,
+	},
+	.id_table = armada_drm_platform_ids,
+};
+
+static int __init armada_drm_init(void)
+{
+	armada_drm_driver.num_ioctls = DRM_ARRAY_SIZE(armada_ioctls);
+	return platform_driver_register(&armada_drm_platform_driver);
+}
+module_init(armada_drm_init);
+
+static void __exit armada_drm_exit(void)
+{
+	platform_driver_unregister(&armada_drm_platform_driver);
+}
+module_exit(armada_drm_exit);
+
+MODULE_AUTHOR("Russell King <rmk+kernel@arm.linux.org.uk>");
+MODULE_DESCRIPTION("Armada DRM Driver");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:armada-drm");