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: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Antonino 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/video/uvesafb.h b/include/video/uvesafb.h
new file mode 100644
index 0000000..95bcef1
--- /dev/null
+++ b/include/video/uvesafb.h
@@ -0,0 +1,193 @@
+#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 */