uvesafb: the driver core

uvesafb is an enhanced version of vesafb.  It uses a userspace helper (v86d)
to execute calls to the x86 Video BIOS functions.  The driver is not limited
to any specific arch and whether it works on a given arch or not depends on
that arch being supported by the userspace daemon.  It has been tested on
x86_32 and x86_64.

A single BIOS call is represented by an instance of the uvesafb_ktask
structure.  This structure contains a buffer, a completion struct and a
uvesafb_task substructure, containing the values of the x86 registers, a flags
field and a field indicating the length of the buffer.  Whenever a BIOS call
is made in the driver, uvesafb_exec() builds a message using the uvesafb_task
substructure and the contents of the buffer.  This message is then assigned a
random ack number and sent to the userspace daemon using the connector
interface.

The message's sequence number is used as an index for the uvfb_tasks array,
which provides a mapping from the messages coming from userspace to the
in-kernel uvesafb_ktask structs.

The userspace daemon performs the requested operation and sends a reply in the
form of a uvesafb_task struct and, optionally, a buffer.  The seq and ack
numbers in the reply should be exactly the same as those in the request.

Each message from userspace is processed by uvesafb_cn_callback() and after
passing a few sanity checks leads to the completion of a BIOS call request.
Signed-off-by: NMichal Januszewski <spock@gentoo.org>
Signed-off-by: NAntonino Daplas <adaplas@gmail.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Paulo Marques <pmarques@grupopie.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/video/Kconfig

@@ -592,6 +592,24 @@ config FB_TGA
 
 	  Say Y if you have one of those.
 
+config FB_UVESA
+	tristate "Userspace VESA VGA graphics support"
+	depends on FB && CONNECTOR
+	select FB_CFB_FILLRECT
+	select FB_CFB_COPYAREA
+	select FB_CFB_IMAGEBLIT
+	select FB_MODE_HELPERS
+	help
+	  This is the frame buffer driver for generic VBE 2.0 compliant
+	  graphic cards. It can also take advantage of VBE 3.0 features,
+	  such as refresh rate adjustment.
+
+	  This driver generally provides more features than vesafb but
+	  requires a userspace helper application called 'v86d'. See
+	  <file:Documentation/fb/uvesafb.txt> for more information.
+
+	  If unsure, say N.
+
 config FB_VESA
 	bool "VESA VGA graphics support"
 	depends on (FB = y) && X86

drivers/video/Makefile

@@ -115,6 +115,7 @@ obj-$(CONFIG_FB_XILINX)           += xilinxfb.o
 obj-$(CONFIG_FB_OMAP)             += omap/
 
 # Platform or fallback drivers go here
+obj-$(CONFIG_FB_UVESA)            += uvesafb.o
 obj-$(CONFIG_FB_VESA)             += vesafb.o
 obj-$(CONFIG_FB_IMAC)             += imacfb.o
 obj-$(CONFIG_FB_VGA16)            += vga16fb.o

include/video/Kbuild

-unifdef-y += sisfb.h
+unifdef-y += sisfb.h uvesafb.h

include/video/uvesafb.h

+#ifndef _UVESAFB_H
+#define _UVESAFB_H
+
+struct v86_regs {
+	__u32 ebx;
+	__u32 ecx;
+	__u32 edx;
+	__u32 esi;
+	__u32 edi;
+	__u32 ebp;
+	__u32 eax;
+	__u32 eip;
+	__u32 eflags;
+	__u32 esp;
+	__u16 cs;
+	__u16 ss;
+	__u16 es;
+	__u16 ds;
+	__u16 fs;
+	__u16 gs;
+};
+
+/* Task flags */
+#define TF_VBEIB	0x01
+#define TF_BUF_ESDI	0x02
+#define TF_BUF_ESBX	0x04
+#define TF_BUF_RET	0x08
+#define TF_EXIT		0x10
+
+struct uvesafb_task {
+	__u8 flags;
+	int buf_len;
+	struct v86_regs regs;
+};
+
+/* Constants for the capabilities field
+ * in vbe_ib */
+#define VBE_CAP_CAN_SWITCH_DAC	0x01
+#define VBE_CAP_VGACOMPAT	0x02
+
+/* The VBE Info Block */
+struct vbe_ib {
+	char  vbe_signature[4];
+	__u16 vbe_version;
+	__u32 oem_string_ptr;
+	__u32 capabilities;
+	__u32 mode_list_ptr;
+	__u16 total_memory;
+	__u16 oem_software_rev;
+	__u32 oem_vendor_name_ptr;
+	__u32 oem_product_name_ptr;
+	__u32 oem_product_rev_ptr;
+	__u8  reserved[222];
+	char  oem_data[256];
+	char  misc_data[512];
+} __attribute__ ((packed));
+
+#ifdef __KERNEL__
+
+/* VBE CRTC Info Block */
+struct vbe_crtc_ib {
+	u16 horiz_total;
+	u16 horiz_start;
+	u16 horiz_end;
+	u16 vert_total;
+	u16 vert_start;
+	u16 vert_end;
+	u8  flags;
+	u32 pixel_clock;
+	u16 refresh_rate;
+	u8  reserved[40];
+} __attribute__ ((packed));
+
+#define VBE_MODE_VGACOMPAT	0x20
+#define VBE_MODE_COLOR		0x08
+#define VBE_MODE_SUPPORTEDHW	0x01
+#define VBE_MODE_GRAPHICS	0x10
+#define VBE_MODE_LFB		0x80
+
+#define VBE_MODE_MASK		(VBE_MODE_COLOR | VBE_MODE_SUPPORTEDHW | \
+				VBE_MODE_GRAPHICS | VBE_MODE_LFB)
+
+/* VBE Mode Info Block */
+struct vbe_mode_ib {
+	/* for all VBE revisions */
+	u16 mode_attr;
+	u8  winA_attr;
+	u8  winB_attr;
+	u16 win_granularity;
+	u16 win_size;
+	u16 winA_seg;
+	u16 winB_seg;
+	u32 win_func_ptr;
+	u16 bytes_per_scan_line;
+
+	/* for VBE 1.2+ */
+	u16 x_res;
+	u16 y_res;
+	u8  x_char_size;
+	u8  y_char_size;
+	u8  planes;
+	u8  bits_per_pixel;
+	u8  banks;
+	u8  memory_model;
+	u8  bank_size;
+	u8  image_pages;
+	u8  reserved1;
+
+	/* Direct color fields for direct/6 and YUV/7 memory models. */
+	/* Offsets are bit positions of lsb in the mask. */
+	u8  red_len;
+	u8  red_off;
+	u8  green_len;
+	u8  green_off;
+	u8  blue_len;
+	u8  blue_off;
+	u8  rsvd_len;
+	u8  rsvd_off;
+	u8  direct_color_info;	/* direct color mode attributes */
+
+	/* for VBE 2.0+ */
+	u32 phys_base_ptr;
+	u8  reserved2[6];
+
+	/* for VBE 3.0+ */
+	u16 lin_bytes_per_scan_line;
+	u8  bnk_image_pages;
+	u8  lin_image_pages;
+	u8  lin_red_len;
+	u8  lin_red_off;
+	u8  lin_green_len;
+	u8  lin_green_off;
+	u8  lin_blue_len;
+	u8  lin_blue_off;
+	u8  lin_rsvd_len;
+	u8  lin_rsvd_off;
+	u32 max_pixel_clock;
+	u16 mode_id;
+	u8  depth;
+} __attribute__ ((packed));
+
+#define UVESAFB_DEFAULT_MODE "640x480-16"
+
+/* How long to wait for a reply from userspace [ms] */
+#define UVESAFB_TIMEOUT 5000
+
+/* Max number of concurrent tasks */
+#define UVESAFB_TASKS_MAX 16
+
+#define dac_reg	(0x3c8)
+#define dac_val	(0x3c9)
+
+struct uvesafb_pal_entry {
+	u_char blue, green, red, pad;
+} __attribute__ ((packed));
+
+struct uvesafb_ktask {
+	struct uvesafb_task t;
+	void *buf;
+	struct completion *done;
+	u32 ack;
+};
+
+static int uvesafb_exec(struct uvesafb_ktask *tsk);
+
+#define UVESAFB_EXACT_RES	1
+#define UVESAFB_EXACT_DEPTH	2
+
+struct uvesafb_par {
+	struct vbe_ib vbe_ib;		/* VBE Info Block */
+	struct vbe_mode_ib *vbe_modes;	/* list of supported VBE modes */
+	int vbe_modes_cnt;
+
+	u8 nocrtc;
+	u8 ypan;			/* 0 - nothing, 1 - ypan, 2 - ywrap */
+	u8 pmi_setpal;			/* PMI for palette changes */
+	u16 *pmi_base;			/* protected mode interface location */
+	void *pmi_start;
+	void *pmi_pal;
+	u8 *vbe_state_orig;		/*
+					 * original hardware state, before the
+					 * driver was loaded
+					 */
+	u8 *vbe_state_saved;		/* state saved by fb_save_state */
+	int vbe_state_size;
+	atomic_t ref_count;
+
+	int mode_idx;
+	struct vbe_crtc_ib crtc;
+};
+
+#endif /* __KERNEL__ */
+#endif /* _UVESAFB_H */