Commit 9a10c7e6 authored by Thierry Reding's avatar Thierry Reding
Browse files

drm/simpledrm: Add support for system memory framebuffers 



Simple framebuffers can be set up in system memory, which cannot be
requested and/or I/O remapped using the I/O resource helpers. Add a
separate code path that obtains system memory framebuffers from the
reserved memory region referenced in the memory-region property.

Reviewed-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230120173103.4002342-6-thierry.reding@gmail.com
parent fa904b4c

drivers/gpu/drm/tiny/simpledrm.c

+75 −24
Original line number Diff line number Diff line
@@ -3,6 +3,7 @@ 
#include <linux/clk.h>

#include <linux/of_clk.h>

#include <linux/minmax.h>

#include <linux/of_address.h>

#include <linux/platform_data/simplefb.h>

#include <linux/platform_device.h>

#include <linux/regulator/consumer.h>
@@ -184,6 +185,31 @@ simplefb_get_format_of(struct drm_device *dev, struct device_node *of_node) 
	return simplefb_get_validated_format(dev, format);

}



static struct resource *

simplefb_get_memory_of(struct drm_device *dev, struct device_node *of_node)

{

	struct device_node *np;

	struct resource *res;

	int err;



	np = of_parse_phandle(of_node, "memory-region", 0);

	if (!np)

		return NULL;



	res = devm_kzalloc(dev->dev, sizeof(*res), GFP_KERNEL);

	if (!res)

		return ERR_PTR(-ENOMEM);



	err = of_address_to_resource(np, 0, res);

	if (err)

		return ERR_PTR(err);



	if (of_get_property(of_node, "reg", NULL))

		drm_warn(dev, "preferring \"memory-region\" over \"reg\" property\n");



	return res;

}



/*

 * Simple Framebuffer device

 */
@@ -604,8 +630,7 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, 
	struct drm_device *dev;

	int width, height, stride;

	const struct drm_format_info *format;

	struct resource *res, *mem;

	void __iomem *screen_base;

	struct resource *res, *mem = NULL;

	struct drm_plane *primary_plane;

	struct drm_crtc *crtc;

	struct drm_encoder *encoder;
@@ -657,6 +682,9 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, 
		format = simplefb_get_format_of(dev, of_node);

		if (IS_ERR(format))

			return ERR_CAST(format);

		mem = simplefb_get_memory_of(dev, of_node);

		if (IS_ERR(mem))

			return ERR_CAST(mem);

	} else {

		drm_err(dev, "no simplefb configuration found\n");

		return ERR_PTR(-ENODEV);
@@ -679,17 +707,39 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, 
	 * Memory management

	 */



	if (mem) {

		void *screen_base;



		ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));

		if (ret) {

			drm_err(dev, "could not acquire memory range %pr: %d\n", mem, ret);

			return ERR_PTR(ret);

		}



		drm_dbg(dev, "using system memory framebuffer at %pr\n", mem);



		screen_base = devm_memremap(dev->dev, mem->start, resource_size(mem), MEMREMAP_WC);

		if (!screen_base)

			return ERR_PTR(-ENOMEM);



		iosys_map_set_vaddr(&sdev->screen_base, screen_base);

	} else {

		void __iomem *screen_base;



		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

		if (!res)

			return ERR_PTR(-EINVAL);



		ret = devm_aperture_acquire_from_firmware(dev, res->start, resource_size(res));

		if (ret) {

		drm_err(dev, "could not acquire memory range %pr: error %d\n", res, ret);

			drm_err(dev, "could not acquire memory range %pr: %d\n", &res, ret);

			return ERR_PTR(ret);

		}



	mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res), drv->name);

		drm_dbg(dev, "using I/O memory framebuffer at %pr\n", res);



		mem = devm_request_mem_region(&pdev->dev, res->start, resource_size(res),

					      drv->name);

		if (!mem) {

			/*

			 * We cannot make this fatal. Sometimes this comes from magic
@@ -705,6 +755,7 @@ static struct simpledrm_device *simpledrm_device_create(struct drm_driver *drv, 
			return ERR_PTR(-ENOMEM);



		iosys_map_set_vaddr_iomem(&sdev->screen_base, screen_base);

	}



	/*

	 * Modesetting