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, 272 insertions, 0 deletions

diff --git a/drivers/gpu/drm/pl111/pl111_drv.c b/drivers/gpu/drm/pl111/pl111_drv.c
new file mode 100644
index 000000000000..936403f65508
--- /dev/null
+++ b/drivers/gpu/drm/pl111/pl111_drv.c
@@ -0,0 +1,272 @@
+/*
+ * (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.
+ *
+ */
+
+/**
+ * DOC: ARM PrimeCell PL111 CLCD Driver
+ *
+ * The PL111 is a simple LCD controller that can support TFT and STN
+ * displays.  This driver exposes a standard KMS interface for them.
+ *
+ * This driver uses the same Device Tree binding as the fbdev CLCD
+ * driver.  While the fbdev driver supports panels that may be
+ * connected to the CLCD internally to the CLCD driver, in DRM the
+ * panels get split out to drivers/gpu/drm/panels/.  This means that,
+ * in converting from using fbdev to using DRM, you also need to write
+ * a panel driver (which may be as simple as an entry in
+ * panel-simple.c).
+ *
+ * The driver currently doesn't expose the cursor.  The DRM API for
+ * cursors requires support for 64x64 ARGB8888 cursor images, while
+ * the hardware can only support 64x64 monochrome with masking
+ * cursors.  While one could imagine trying to hack something together
+ * to look at the ARGB8888 and program reasonable in monochrome, we
+ * just don't expose the cursor at all instead, and leave cursor
+ * support to the X11 software cursor layer.
+ *
+ * TODO:
+ *
+ * - Fix race between setting plane base address and getting IRQ for
+ *   vsync firing the pageflip completion.
+ *
+ * - Expose the correct set of formats we can support based on the
+ *   "arm,pl11x,tft-r0g0b0-pads" DT property.
+ *
+ * - Use the "max-memory-bandwidth" DT property to filter the
+ *   supported formats.
+ *
+ * - Read back hardware state at boot to skip reprogramming the
+ *   hardware when doing a no-op modeset.
+ *
+ * - Use the internal clock divisor to reduce power consumption by
+ *   using HCLK (apb_pclk) when appropriate.
+ */
+
+#include <linux/amba/bus.h>
+#include <linux/amba/clcd-regs.h>
+#include <linux/version.h>
+#include <linux/shmem_fs.h>
+#include <linux/dma-buf.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#include <drm/drmP.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_fb_cma_helper.h>
+
+#include "pl111_drm.h"
+
+#define DRIVER_DESC      "DRM module for PL111"
+
+struct drm_mode_config_funcs mode_config_funcs = {
+	.fb_create = drm_fb_cma_create,
+	.atomic_check = drm_atomic_helper_check,
+	.atomic_commit = drm_atomic_helper_commit,
+};
+
+static int pl111_modeset_init(struct drm_device *dev)
+{
+	struct drm_mode_config *mode_config;
+	struct pl111_drm_dev_private *priv = dev->dev_private;
+	int ret = 0;
+
+	drm_mode_config_init(dev);
+	mode_config = &dev->mode_config;
+	mode_config->funcs = &mode_config_funcs;
+	mode_config->min_width = 1;
+	mode_config->max_width = 1024;
+	mode_config->min_height = 1;
+	mode_config->max_height = 768;
+
+	ret = pl111_connector_init(dev);
+	if (ret) {
+		dev_err(dev->dev, "Failed to create pl111_drm_connector\n");
+		goto out_config;
+	}
+
+	/* Don't actually attach if we didn't find a drm_panel
+	 * attached to us.  This will allow a kernel to include both
+	 * the fbdev pl111 driver and this one, and choose between
+	 * them based on which subsystem has support for the panel.
+	 */
+	if (!priv->connector.panel) {
+		dev_info(dev->dev,
+			 "Disabling due to lack of DRM panel device.\n");
+		ret = -ENODEV;
+		goto out_config;
+	}
+
+	ret = pl111_display_init(dev);
+	if (ret != 0) {
+		dev_err(dev->dev, "Failed to init display\n");
+		goto out_config;
+	}
+
+	ret = drm_vblank_init(dev, 1);
+	if (ret != 0) {
+		dev_err(dev->dev, "Failed to init vblank\n");
+		goto out_config;
+	}
+
+	drm_mode_config_reset(dev);
+
+	priv->fbdev = drm_fbdev_cma_init(dev, 32,
+					 dev->mode_config.num_connector);
+
+	drm_kms_helper_poll_init(dev);
+
+	goto finish;
+
+out_config:
+	drm_mode_config_cleanup(dev);
+finish:
+	return ret;
+}
+
+DEFINE_DRM_GEM_CMA_FOPS(drm_fops);
+
+static void pl111_lastclose(struct drm_device *dev)
+{
+	struct pl111_drm_dev_private *priv = dev->dev_private;
+
+	drm_fbdev_cma_restore_mode(priv->fbdev);
+}
+
+static struct drm_driver pl111_drm_driver = {
+	.driver_features =
+		DRIVER_MODESET | DRIVER_GEM | DRIVER_PRIME | DRIVER_ATOMIC,
+	.lastclose = pl111_lastclose,
+	.ioctls = NULL,
+	.fops = &drm_fops,
+	.name = "pl111",
+	.desc = DRIVER_DESC,
+	.date = "20170317",
+	.major = 1,
+	.minor = 0,
+	.patchlevel = 0,
+	.dumb_create = drm_gem_cma_dumb_create,
+	.dumb_destroy = drm_gem_dumb_destroy,
+	.dumb_map_offset = drm_gem_cma_dumb_map_offset,
+	.gem_free_object = drm_gem_cma_free_object,
+	.gem_vm_ops = &drm_gem_cma_vm_ops,
+
+	.enable_vblank = pl111_enable_vblank,
+	.disable_vblank = pl111_disable_vblank,
+
+	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
+	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
+	.gem_prime_import = drm_gem_prime_import,
+	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
+	.gem_prime_export = drm_gem_prime_export,
+	.gem_prime_get_sg_table	= drm_gem_cma_prime_get_sg_table,
+};
+
+#ifdef CONFIG_ARM_AMBA
+static int pl111_amba_probe(struct amba_device *amba_dev,
+			    const struct amba_id *id)
+{
+	struct device *dev = &amba_dev->dev;
+	struct pl111_drm_dev_private *priv;
+	struct drm_device *drm;
+	int ret;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	drm = drm_dev_alloc(&pl111_drm_driver, dev);
+	if (IS_ERR(drm))
+		return PTR_ERR(drm);
+	amba_set_drvdata(amba_dev, drm);
+	priv->drm = drm;
+	drm->dev_private = priv;
+
+	priv->clk = devm_clk_get(dev, "clcdclk");
+	if (IS_ERR(priv->clk)) {
+		dev_err(dev, "CLCD: unable to get clk.\n");
+		ret = PTR_ERR(priv->clk);
+		goto dev_unref;
+	}
+
+	priv->regs = devm_ioremap_resource(dev, &amba_dev->res);
+	if (!priv->regs) {
+		dev_err(dev, "%s failed mmio\n", __func__);
+		return -EINVAL;
+	}
+
+	/* turn off interrupts before requesting the irq */
+	writel(0, priv->regs + CLCD_PL111_IENB);
+
+	ret = devm_request_irq(dev, amba_dev->irq[0], pl111_irq, 0,
+			       "pl111", priv);
+	if (ret != 0) {
+		dev_err(dev, "%s failed irq %d\n", __func__, ret);
+		return ret;
+	}
+
+	ret = pl111_modeset_init(drm);
+	if (ret != 0)
+		goto dev_unref;
+
+	ret = drm_dev_register(drm, 0);
+	if (ret < 0)
+		goto dev_unref;
+
+	return 0;
+
+dev_unref:
+	drm_dev_unref(drm);
+	return ret;
+}
+
+static int pl111_amba_remove(struct amba_device *amba_dev)
+{
+	struct drm_device *drm = amba_get_drvdata(amba_dev);
+	struct pl111_drm_dev_private *priv = drm->dev_private;
+
+	drm_dev_unregister(drm);
+	if (priv->fbdev)
+		drm_fbdev_cma_fini(priv->fbdev);
+	drm_mode_config_cleanup(drm);
+	drm_dev_unref(drm);
+
+	return 0;
+}
+
+static struct amba_id pl111_id_table[] = {
+	{
+		.id = 0x00041111,
+		.mask = 0x000fffff,
+	},
+	{0, 0},
+};
+
+static struct amba_driver pl111_amba_driver = {
+	.drv = {
+		.name = "drm-clcd-pl111",
+	},
+	.probe = pl111_amba_probe,
+	.remove = pl111_amba_remove,
+	.id_table = pl111_id_table,
+};
+
+module_amba_driver(pl111_amba_driver);
+#endif /* CONFIG_ARM_AMBA */
+
+MODULE_DESCRIPTION(DRIVER_DESC);
+MODULE_AUTHOR("ARM Ltd.");
+MODULE_LICENSE("GPL");