1 files changed, 107 insertions, 0 deletions
diff --git a/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c
new file mode 100644
index 000000000000..0b3fb874a51f
--- /dev/null
+++ b/drivers/gpu/drm/sysfb/drm_sysfb_screen_info.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/export.h>
+#include <linux/limits.h>
+#include <linux/minmax.h>
+#include <linux/screen_info.h>
+
+#include <drm/drm_fourcc.h>
+#include <drm/drm_print.h>
+
+#include "drm_sysfb_helper.h"
+
+static s64 drm_sysfb_get_validated_size0(struct drm_device *dev, const char *name,
+					 u64 value, u64 max)
+{
+	if (!value) {
+		drm_warn(dev, "%s of 0 not allowed\n", name);
+		return -EINVAL;
+	} else if (value > min(max, S64_MAX)) {
+		drm_warn(dev, "%s of %llu exceeds maximum of %llu\n", name, value, max);
+		return -EINVAL;
+	}
+	return value;
+}
+
+int drm_sysfb_get_width_si(struct drm_device *dev, const struct screen_info *si)
+{
+	return drm_sysfb_get_validated_int0(dev, "width", si->lfb_width, U16_MAX);
+}
+EXPORT_SYMBOL(drm_sysfb_get_width_si);
+
+int drm_sysfb_get_height_si(struct drm_device *dev, const struct screen_info *si)
+{
+	return drm_sysfb_get_validated_int0(dev, "height", si->lfb_height, U16_MAX);
+}
+EXPORT_SYMBOL(drm_sysfb_get_height_si);
+
+struct resource *drm_sysfb_get_memory_si(struct drm_device *dev,
+					 const struct screen_info *si,
+					 struct resource *res)
+{
+	ssize_t	num;
+
+	num = screen_info_resources(si, res, 1);
+	if (!num) {
+		drm_warn(dev, "memory resource not found\n");
+		return NULL;
+	}
+
+	return res;
+}
+EXPORT_SYMBOL(drm_sysfb_get_memory_si);
+
+int drm_sysfb_get_stride_si(struct drm_device *dev, const struct screen_info *si,
+			    const struct drm_format_info *format,
+			    unsigned int width, unsigned int height, u64 size)
+{
+	u64 lfb_linelength = si->lfb_linelength;
+
+	if (!lfb_linelength)
+		lfb_linelength = drm_format_info_min_pitch(format, 0, width);
+
+	return drm_sysfb_get_validated_int0(dev, "stride", lfb_linelength, div64_u64(size, height));
+}
+EXPORT_SYMBOL(drm_sysfb_get_stride_si);
+
+u64 drm_sysfb_get_visible_size_si(struct drm_device *dev, const struct screen_info *si,
+				  unsigned int height, unsigned int stride, u64 size)
+{
+	u64 vsize = PAGE_ALIGN(height * stride);
+
+	return drm_sysfb_get_validated_size0(dev, "visible size", vsize, size);
+}
+EXPORT_SYMBOL(drm_sysfb_get_visible_size_si);
+
+const struct drm_format_info *drm_sysfb_get_format_si(struct drm_device *dev,
+						      const struct drm_sysfb_format *formats,
+						      size_t nformats,
+						      const struct screen_info *si)
+{
+	const struct drm_format_info *format = NULL;
+	u32 bits_per_pixel;
+	size_t i;
+
+	bits_per_pixel = __screen_info_lfb_bits_per_pixel(si);
+
+	for (i = 0; i < nformats; ++i) {
+		const struct pixel_format *f = &formats[i].pixel;
+
+		if (bits_per_pixel == f->bits_per_pixel &&
+		    si->red_size == f->red.length &&
+		    si->red_pos == f->red.offset &&
+		    si->green_size == f->green.length &&
+		    si->green_pos == f->green.offset &&
+		    si->blue_size == f->blue.length &&
+		    si->blue_pos == f->blue.offset) {
+			format = drm_format_info(formats[i].fourcc);
+			break;
+		}
+	}
+
+	if (!format)
+		drm_warn(dev, "No compatible color format found\n");
+
+	return format;
+}
+EXPORT_SYMBOL(drm_sysfb_get_format_si);