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>

1 files changed, 193 insertions, 0 deletions

diff --git a/include/video/uvesafb.h b/include/video/uvesafb.h
new file mode 100644
index 000000000000..95bcef193954
--- /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 */