[PATCH 2/3] drm/armada: add OF reserved memory support

[Russell King]

Existing Armada DRM makes use of reserved memory for allocating
contiguous screen buffers, which currently prevents its use with
DT systems.  Add support for this for DT systems.

Signed-off-by: Russell King <rmk+ker...@armlinux.org.uk>
---
 drivers/gpu/drm/armada/Makefile      |  3 +++
 drivers/gpu/drm/armada/armada_drv.c  | 24 ++++++++++++++++--
 drivers/gpu/drm/armada/armada_rmem.c | 49 ++++++++++++++++++++++++++++++++++++
 3 files changed, 74 insertions(+), 2 deletions(-)
 create mode 100644 drivers/gpu/drm/armada/armada_rmem.c

diff --git a/drivers/gpu/drm/armada/Makefile b/drivers/gpu/drm/armada/Makefile
index ecf25cf9f9f5..0b8bf3b8aa6a 100644
--- a/drivers/gpu/drm/armada/Makefile
+++ b/drivers/gpu/drm/armada/Makefile
@@ -5,3 +5,6 @@ armada-y        += armada_510.o
 armada-$(CONFIG_DEBUG_FS) += armada_debugfs.o
 
 obj-$(CONFIG_DRM_ARMADA) := armada.o
+
+armada-rmem-$(CONFIG_DRM_ARMADA) += armada_rmem.o
+obj-y += $(armada-rmem-y) $(armada-rmem-m)
diff --git a/drivers/gpu/drm/armada/armada_drv.c 
b/drivers/gpu/drm/armada/armada_drv.c
index 217f0590fd61..a9ee492a2810 100644
--- a/drivers/gpu/drm/armada/armada_drv.c
+++ b/drivers/gpu/drm/armada/armada_drv.c
@@ -9,6 +9,7 @@
 #include <linux/component.h>
 #include <linux/module.h>
 #include <linux/of_graph.h>
+#include <linux/of_reserved_mem.h>
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_of.h>
@@ -96,6 +97,9 @@ static int armada_drm_bind(struct device *dev)
                        return -EINVAL;
        }
 
+       if (!mem && dev->of_node)
+               mem = dev->platform_data;
+
        if (!mem)
                return -ENXIO;
 
@@ -250,9 +254,17 @@ static int armada_drm_probe(struct platform_device *pdev)
        struct device *dev = &pdev->dev;
        int ret;
 
-       ret = drm_of_component_probe(dev, compare_dev_name, &armada_master_ops);
-       if (ret != -EINVAL)
+       if (dev->of_node) {
+               ret = of_reserved_mem_device_init(dev);
+               if (ret && ret != -ENODEV)
+                       return ret;
+
+               ret = drm_of_component_probe(dev, compare_of,
+                                            &armada_master_ops);
+               if (ret)
+                       of_reserved_mem_device_release(dev);
                return ret;
+       }
 
        if (dev->platform_data) {
                char **devices = dev->platform_data;
@@ -287,6 +299,7 @@ static int armada_drm_probe(struct platform_device *pdev)
 static int armada_drm_remove(struct platform_device *pdev)
 {
        component_master_del(&pdev->dev, &armada_master_ops);
+       of_reserved_mem_device_release(&pdev->dev);
        return 0;
 }
 
@@ -300,11 +313,18 @@ static const struct platform_device_id 
armada_drm_platform_ids[] = {
 };
 MODULE_DEVICE_TABLE(platform, armada_drm_platform_ids);
 
+static const struct of_device_id armada_drm_dt_ids[] = {
+       { .compatible = "marvell,dove-display-subsystem", },
+       { /* sentinel */ },
+};
+MODULE_DEVICE_TABLE(of, armada_drm_dt_ids);
+
 static struct platform_driver armada_drm_platform_driver = {
        .probe  = armada_drm_probe,
        .remove = armada_drm_remove,
        .driver = {
                .name   = "armada-drm",
+               .of_match_table = armada_drm_dt_ids,
        },
        .id_table = armada_drm_platform_ids,
 };
diff --git a/drivers/gpu/drm/armada/armada_rmem.c 
b/drivers/gpu/drm/armada/armada_rmem.c
new file mode 100644
index 000000000000..36bb20e426b6
--- /dev/null
+++ b/drivers/gpu/drm/armada/armada_rmem.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2017 Russell King
+#include <linux/errno.h>
+#include <linux/of.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/slab.h>
+
+static int armada_rmem_dev_init(struct reserved_mem *rmem, struct device *dev)
+{
+       struct resource *r;
+
+       if (dev->platform_data)
+               return -EBUSY;
+
+       r = kzalloc(sizeof(*r), GFP_KERNEL);
+       if (!r)
+               return -ENOMEM;
+
+       r->start = rmem->base;
+       r->end = rmem->base + rmem->size - 1;
+       r->flags = IORESOURCE_MEM;
+
+       rmem->priv = r;
+       dev->platform_data = r;
+
+       return 0;
+}
+
+static void armada_rmem_dev_release(struct reserved_mem *rmem,
+       struct device *dev)
+{
+       kfree(rmem->priv);
+       rmem->priv = NULL;
+       dev->platform_data = NULL;
+}
+
+static const struct reserved_mem_ops armada_rmem_ops = {
+       .device_init = armada_rmem_dev_init,
+       .device_release = armada_rmem_dev_release,
+};
+
+static int __init armada_rmem_init(struct reserved_mem *rmem)
+{
+       rmem->ops = &armada_rmem_ops;
+       return 0;
+}
+
+RESERVEDMEM_OF_DECLARE(armada_rmem, "marvell,dove-framebuffer",
+                       armada_rmem_init);
-- 
2.7.4

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