efifb: Add support for 64-bit frame buffer addresses

The EFI Graphics Output Protocol uses 64-bit frame buffer addresses but these get truncated to 32-bit by the EFI boot stub when storing the address in the 'lfb_base' field of 'struct screen_info'. Add a 'ext_lfb_base' field for the upper 32-bits of the frame buffer address and set VIDEO_TYPE_CAPABILITY_64BIT_BASE when the field is useable. It turns out that the reason no one has required this support so far is that there's actually code in tianocore to "downgrade" PCI resources that have option ROMs and 64-bit BARS from 64-bit to 32-bit to cope with legacy option ROMs that can't handle 64-bit addresses. The upshot is that basically all GOP devices in the wild use a 32-bit frame buffer address. Still, it is possible to build firmware that uses a full 64-bit GOP frame buffer address. Chad did, which led to him reporting this issue. Add support in anticipation of GOP devices using 64-bit addresses more widely, and so that efifb works out of the box when that happens.

Matt Fleming committed 11 years ago

Commit ae2ee621 parent 7968c0e3 files · +46 −7Browse files

Unified · Split

3 files

arch/x86/boot/compressed/eboot.c +20 −4
drivers/video/fbdev/efifb.c +23 −1
include/uapi/linux/screen_info.h +3 −2

arch/x86/boot/compressed/eboot.c+20−4

@@ -624,7 +624,7 @@ setup_pixel_info(struct screen_info *si, u32 pixels_per_scan_line, · 623 unmodified lines
624	624	static efi_status_t
625	625	__gop_query32(struct efi_graphics_output_protocol_32 *gop32,
626	626	struct efi_graphics_output_mode_info **info,
627		− unsigned long size, u32 fb_base)
	627	+ unsigned long size, u64 fb_base)
628	628	{
629	629	struct efi_graphics_output_protocol_mode_32 *mode;
630	630	efi_status_t status;
@@ -650,7 +650,8 @@ setup_gop32(struct screen_info si, efi_guid_t proto, · 19 unmodified lines
650	650	unsigned long nr_gops;
651	651	u16 width, height;
652	652	u32 pixels_per_scan_line;
653		− u32 fb_base;
	653	+ u32 ext_lfb_base;
	654	+ u64 fb_base;
654	655	struct efi_pixel_bitmask pixel_info;
655	656	int pixel_format;
656	657	efi_status_t status;
@@ -713,6 +714,13 @@ setup_gop32(struct screen_info si, efi_guid_t proto, · 56 unmodified lines
713	714	si->lfb_width = width;
714	715	si->lfb_height = height;
715	716	si->lfb_base = fb_base;
	717	+
	718	+ ext_lfb_base = (u64)(unsigned long)fb_base >> 32;
	719	+ if (ext_lfb_base) {
	720	+ si->capabilities \|= VIDEO_CAPABILITY_64BIT_BASE;
	721	+ si->ext_lfb_base = ext_lfb_base;
	722	+ }
	723	+
716	724	si->pages = 1;
717	725
718	726	setup_pixel_info(si, pixels_per_scan_line, pixel_info, pixel_format);
@@ -727,7 +735,7 @@ out: · 8 unmodified lines
727	735	static efi_status_t
728	736	__gop_query64(struct efi_graphics_output_protocol_64 *gop64,
729	737	struct efi_graphics_output_mode_info **info,
730		− unsigned long size, u32 fb_base)
	738	+ unsigned long size, u64 fb_base)
731	739	{
732	740	struct efi_graphics_output_protocol_mode_64 *mode;
733	741	efi_status_t status;
@@ -753,7 +761,8 @@ setup_gop64(struct screen_info si, efi_guid_t proto, · 19 unmodified lines
753	761	unsigned long nr_gops;
754	762	u16 width, height;
755	763	u32 pixels_per_scan_line;
756		− u32 fb_base;
	764	+ u32 ext_lfb_base;
	765	+ u64 fb_base;
757	766	struct efi_pixel_bitmask pixel_info;
758	767	int pixel_format;
759	768	efi_status_t status;
@@ -816,6 +825,13 @@ setup_gop64(struct screen_info si, efi_guid_t proto, · 56 unmodified lines
816	825	si->lfb_width = width;
817	826	si->lfb_height = height;
818	827	si->lfb_base = fb_base;
	828	+
	829	+ ext_lfb_base = (u64)(unsigned long)fb_base >> 32;
	830	+ if (ext_lfb_base) {
	831	+ si->capabilities \|= VIDEO_CAPABILITY_64BIT_BASE;
	832	+ si->ext_lfb_base = ext_lfb_base;
	833	+ }
	834	+
819	835	si->pages = 1;
820	836
821	837	setup_pixel_info(si, pixels_per_scan_line, pixel_info, pixel_format);

drivers/video/fbdev/efifb.c+23−1

@@ -114,6 +114,20 @@ static int efifb_setup(char *options) · 113 unmodified lines
114	114	return 0;
115	115	}
116	116
	117	+static inline bool fb_base_is_valid(void)
	118	+{
	119	+ if (screen_info.lfb_base)
	120	+ return true;
	121	+
	122	+ if (!(screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE))
	123	+ return false;
	124	+
	125	+ if (screen_info.ext_lfb_base)
	126	+ return true;
	127	+
	128	+ return false;
	129	+}
	130	+
117	131	static int efifb_probe(struct platform_device *dev)
118	132	{
119	133	struct fb_info *info;
@@ -141,7 +155,7 @@ static int efifb_probe(struct platform_device *dev) · 21 unmodified lines
141	155	screen_info.lfb_depth = 32;
142	156	if (!screen_info.pages)
143	157	screen_info.pages = 1;
144		− if (!screen_info.lfb_base) {
	158	+ if (!fb_base_is_valid()) {
145	159	printk(KERN_DEBUG "efifb: invalid framebuffer address\n");
146	160	return -ENODEV;
147	161	}
@@ -160,6 +174,14 @@ static int efifb_probe(struct platform_device *dev) · 12 unmodified lines
160	174	}
161	175
162	176	efifb_fix.smem_start = screen_info.lfb_base;
	177	+
	178	+ if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
	179	+ u64 ext_lfb_base;
	180	+
	181	+ ext_lfb_base = (u64)(unsigned long)screen_info.ext_lfb_base << 32;
	182	+ efifb_fix.smem_start \|= ext_lfb_base;
	183	+ }
	184	+
163	185	efifb_defined.bits_per_pixel = screen_info.lfb_depth;
164	186	efifb_defined.xres = screen_info.lfb_width;
165	187	efifb_defined.yres = screen_info.lfb_height;

include/uapi/linux/screen_info.h+3−2

@@ -43,7 +43,8 @@ struct screen_info { · 42 unmodified lines
43	43	__u16 pages; /* 0x32 */
44	44	__u16 vesa_attributes; /* 0x34 */
45	45	__u32 capabilities; /* 0x36 */
46		− __u8 _reserved[6]; /* 0x3a */
	46	+ __u32 ext_lfb_base; /* 0x3a */
	47	+ __u8 _reserved[2]; /* 0x3e */
47	48	} __attribute__((packed));
48	49
49	50	#define VIDEO_TYPE_MDA 0x10 /* Monochrome Text Display */
@@ -69,6 +70,6 @@ struct screen_info { · 19 unmodified lines
69	70	#define VIDEO_FLAGS_NOCURSOR (1 << 0) /* The video mode has no cursor set */
70	71
71	72	#define VIDEO_CAPABILITY_SKIP_QUIRKS (1 << 0)
72		−
	73	+#define VIDEO_CAPABILITY_64BIT_BASE (1 << 1) /* Frame buffer base is 64-bit */
73	74
74	75	#endif /* _UAPI_SCREEN_INFO_H */