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Diffstat (limited to 'drivers/firmware/sysfb_simplefb.c')
-rw-r--r--drivers/firmware/sysfb_simplefb.c166
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/firmware/sysfb_simplefb.c b/drivers/firmware/sysfb_simplefb.c
new file mode 100644
index 0000000000..74363ed750
--- /dev/null
+++ b/drivers/firmware/sysfb_simplefb.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Generic System Framebuffers
+ * Copyright (c) 2012-2013 David Herrmann <dh.herrmann@gmail.com>
+ */
+
+/*
+ * simple-framebuffer probing
+ * Try to convert "screen_info" into a "simple-framebuffer" compatible mode.
+ * If the mode is incompatible, we return "false" and let the caller create
+ * legacy nodes instead.
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/platform_data/simplefb.h>
+#include <linux/platform_device.h>
+#include <linux/screen_info.h>
+#include <linux/sysfb.h>
+
+static const char simplefb_resname[] = "BOOTFB";
+static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
+
+/* try parsing screen_info into a simple-framebuffer mode struct */
+__init bool sysfb_parse_mode(const struct screen_info *si,
+ struct simplefb_platform_data *mode)
+{
+ __u8 type;
+ u32 bits_per_pixel;
+ unsigned int i;
+
+ type = si->orig_video_isVGA;
+ if (type != VIDEO_TYPE_VLFB && type != VIDEO_TYPE_EFI)
+ return false;
+
+ /*
+ * The meaning of depth and bpp for direct-color formats is
+ * inconsistent:
+ *
+ * - DRM format info specifies depth as the number of color
+ * bits; including alpha, but not including filler bits.
+ * - Linux' EFI platform code computes lfb_depth from the
+ * individual color channels, including the reserved bits.
+ * - VBE 1.1 defines lfb_depth for XRGB1555 as 16, but later
+ * versions use 15.
+ * - On the kernel command line, 'bpp' of 32 is usually
+ * XRGB8888 including the filler bits, but 15 is XRGB1555
+ * not including the filler bit.
+ *
+ * It's not easily possible to fix this in struct screen_info,
+ * as this could break UAPI. The best solution is to compute
+ * bits_per_pixel from the color bits, reserved bits and
+ * reported lfb_depth, whichever is highest. In the loop below,
+ * ignore simplefb formats with alpha bits, as EFI and VESA
+ * don't specify alpha channels.
+ */
+ if (si->lfb_depth > 8) {
+ bits_per_pixel = max(max3(si->red_size + si->red_pos,
+ si->green_size + si->green_pos,
+ si->blue_size + si->blue_pos),
+ si->rsvd_size + si->rsvd_pos);
+ bits_per_pixel = max_t(u32, bits_per_pixel, si->lfb_depth);
+ } else {
+ bits_per_pixel = si->lfb_depth;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(formats); ++i) {
+ const struct simplefb_format *f = &formats[i];
+
+ if (f->transp.length)
+ continue; /* transparent formats are unsupported by VESA/EFI */
+
+ 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) {
+ mode->format = f->name;
+ mode->width = si->lfb_width;
+ mode->height = si->lfb_height;
+ mode->stride = si->lfb_linelength;
+ return true;
+ }
+ }
+
+ return false;
+}
+
+__init struct platform_device *sysfb_create_simplefb(const struct screen_info *si,
+ const struct simplefb_platform_data *mode)
+{
+ struct platform_device *pd;
+ struct resource res;
+ u64 base, size;
+ u32 length;
+ int ret;
+
+ /*
+ * If the 64BIT_BASE capability is set, ext_lfb_base will contain the
+ * upper half of the base address. Assemble the address, then make sure
+ * it is valid and we can actually access it.
+ */
+ base = si->lfb_base;
+ if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE)
+ base |= (u64)si->ext_lfb_base << 32;
+ if (!base || (u64)(resource_size_t)base != base) {
+ printk(KERN_DEBUG "sysfb: inaccessible VRAM base\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ /*
+ * Don't use lfb_size as IORESOURCE size, since it may contain the
+ * entire VMEM, and thus require huge mappings. Use just the part we
+ * need, that is, the part where the framebuffer is located. But verify
+ * that it does not exceed the advertised VMEM.
+ * Note that in case of VBE, the lfb_size is shifted by 16 bits for
+ * historical reasons.
+ */
+ size = si->lfb_size;
+ if (si->orig_video_isVGA == VIDEO_TYPE_VLFB)
+ size <<= 16;
+ length = mode->height * mode->stride;
+ if (length > size) {
+ printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
+ return ERR_PTR(-EINVAL);
+ }
+ length = PAGE_ALIGN(length);
+
+ /* setup IORESOURCE_MEM as framebuffer memory */
+ memset(&res, 0, sizeof(res));
+ res.flags = IORESOURCE_MEM;
+ res.name = simplefb_resname;
+ res.start = base;
+ res.end = res.start + length - 1;
+ if (res.end <= res.start)
+ return ERR_PTR(-EINVAL);
+
+ pd = platform_device_alloc("simple-framebuffer", 0);
+ if (!pd)
+ return ERR_PTR(-ENOMEM);
+
+ sysfb_set_efifb_fwnode(pd);
+
+ ret = platform_device_add_resources(pd, &res, 1);
+ if (ret)
+ goto err_put_device;
+
+ ret = platform_device_add_data(pd, mode, sizeof(*mode));
+ if (ret)
+ goto err_put_device;
+
+ ret = platform_device_add(pd);
+ if (ret)
+ goto err_put_device;
+
+ return pd;
+
+err_put_device:
+ platform_device_put(pd);
+
+ return ERR_PTR(ret);
+}