uvesafb.c

Linux环境下视频显示卡设备的驱动程序源代码

/*
 * A framebuffer driver for VBE 2.0+ compliant video cards
 *
 * (c) 2007 Michal Januszewski <[e-mail]>
 *     Loosely based upon the vesafb driver.
 *
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
#include <linux/completion.h>
#include <linux/connector.h>
#include <linux/random.h>
#include <linux/platform_device.h>
#include <linux/limits.h>
#include <linux/fb.h>
#include <linux/io.h>
#include <linux/mutex.h>
#include <video/edid.h>
#include <video/uvesafb.h>
#ifdef CONFIG_X86
#include <video/vga.h>
#endif
#ifdef CONFIG_MTRR
#include <asm/mtrr.h>
#endif
#include "edid.h"

static struct cb_id uvesafb_cn_id = {
	.idx = CN_IDX_V86D,
	.val = CN_VAL_V86D_UVESAFB
};
static char v86d_path[PATH_MAX] = "/sbin/v86d";
static char v86d_started;	/* has v86d been started by uvesafb? */

static struct fb_fix_screeninfo uvesafb_fix __devinitdata = {
	.id	= "VESA VGA",
	.type	= FB_TYPE_PACKED_PIXELS,
	.accel	= FB_ACCEL_NONE,
	.visual = FB_VISUAL_TRUECOLOR,
};

static int mtrr		__devinitdata = 3; /* enable mtrr by default */
static int blank	= 1;		   /* enable blanking by default */
static int ypan		= 1; 		 /* 0: scroll, 1: ypan, 2: ywrap */
static int pmi_setpal	__devinitdata = 1; /* use PMI for palette changes */
static int nocrtc	__devinitdata; /* ignore CRTC settings */
static int noedid	__devinitdata; /* don't try DDC transfers */
static int vram_remap	__devinitdata; /* set amt. of memory to be used */
static int vram_total	__devinitdata; /* set total amount of memory */
static u16 maxclk	__devinitdata; /* maximum pixel clock */
static u16 maxvf	__devinitdata; /* maximum vertical frequency */
static u16 maxhf	__devinitdata; /* maximum horizontal frequency */
static u16 vbemode	__devinitdata; /* force use of a specific VBE mode */
static char *mode_option __devinitdata;

static struct uvesafb_ktask *uvfb_tasks[UVESAFB_TASKS_MAX];
static DEFINE_MUTEX(uvfb_lock);

/*
 * A handler for replies from userspace.
 *
 * Make sure each message passes consistency checks and if it does,
 * find the kernel part of the task struct, copy the registers and
 * the buffer contents and then complete the task.
 */
static void uvesafb_cn_callback(void *data)
{
	struct cn_msg *msg = data;
	struct uvesafb_task *utask;
	struct uvesafb_ktask *task;

	if (msg->seq >= UVESAFB_TASKS_MAX)
		return;

	mutex_lock(&uvfb_lock);
	task = uvfb_tasks[msg->seq];

	if (!task || msg->ack != task->ack) {
		mutex_unlock(&uvfb_lock);
		return;
	}

	utask = (struct uvesafb_task *)msg->data;

	/* Sanity checks for the buffer length. */
	if (task->t.buf_len < utask->buf_len ||
	    utask->buf_len > msg->len - sizeof(*utask)) {
		mutex_unlock(&uvfb_lock);
		return;
	}

	uvfb_tasks[msg->seq] = NULL;
	mutex_unlock(&uvfb_lock);

	memcpy(&task->t, utask, sizeof(*utask));

	if (task->t.buf_len && task->buf)
		memcpy(task->buf, utask + 1, task->t.buf_len);

	complete(task->done);
	return;
}

static int uvesafb_helper_start(void)
{
	char *envp[] = {
		"HOME=/",
		"PATH=/sbin:/bin",
		NULL,
	};

	char *argv[] = {
		v86d_path,
		NULL,
	};

	return call_usermodehelper(v86d_path, argv, envp, 1);
}

/*
 * Execute a uvesafb task.
 *
 * Returns 0 if the task is executed successfully.
 *
 * A message sent to the userspace consists of the uvesafb_task
 * struct and (optionally) a buffer. The uvesafb_task struct is
 * a simplified version of uvesafb_ktask (its kernel counterpart)
 * containing only the register values, flags and the length of
 * the buffer.
 *
 * Each message is assigned a sequence number (increased linearly)
 * and a random ack number. The sequence number is used as a key
 * for the uvfb_tasks array which holds pointers to uvesafb_ktask
 * structs for all requests.
 */
static int uvesafb_exec(struct uvesafb_ktask *task)
{
	static int seq;
	struct cn_msg *m;
	int err;
	int len = sizeof(task->t) + task->t.buf_len;

	/*
	 * Check whether the message isn't longer than the maximum
	 * allowed by connector.
	 */
	if (sizeof(*m) + len > CONNECTOR_MAX_MSG_SIZE) {
		printk(KERN_WARNING "uvesafb: message too long (%d), "
			"can't execute task\n", (int)(sizeof(*m) + len));
		return -E2BIG;
	}

	m = kzalloc(sizeof(*m) + len, GFP_KERNEL);
	if (!m)
		return -ENOMEM;

	init_completion(task->done);

	memcpy(&m->id, &uvesafb_cn_id, sizeof(m->id));
	m->seq = seq;
	m->len = len;
	m->ack = random32();

	/* uvesafb_task structure */
	memcpy(m + 1, &task->t, sizeof(task->t));

	/* Buffer */
	memcpy((u8 *)(m + 1) + sizeof(task->t), task->buf, task->t.buf_len);

	/*
	 * Save the message ack number so that we can find the kernel
	 * part of this task when a reply is received from userspace.
	 */
	task->ack = m->ack;

	mutex_lock(&uvfb_lock);

	/* If all slots are taken -- bail out. */
	if (uvfb_tasks[seq]) {
		mutex_unlock(&uvfb_lock);
		err = -EBUSY;
		goto out;
	}

	/* Save a pointer to the kernel part of the task struct. */
	uvfb_tasks[seq] = task;
	mutex_unlock(&uvfb_lock);

	err = cn_netlink_send(m, 0, gfp_any());
	if (err == -ESRCH) {
		/*
		 * Try to start the userspace helper if sending
		 * the request failed the first time.
		 */
		err = uvesafb_helper_start();
		if (err) {
			printk(KERN_ERR "uvesafb: failed to execute %s\n",
					v86d_path);
			printk(KERN_ERR "uvesafb: make sure that the v86d "
					"helper is installed and executable\n");
		} else {
			v86d_started = 1;
			err = cn_netlink_send(m, 0, gfp_any());
		}
	}

	if (!err && !(task->t.flags & TF_EXIT))
		err = !wait_for_completion_timeout(task->done,
				msecs_to_jiffies(UVESAFB_TIMEOUT));

	mutex_lock(&uvfb_lock);
	uvfb_tasks[seq] = NULL;
	mutex_unlock(&uvfb_lock);

	seq++;
	if (seq >= UVESAFB_TASKS_MAX)
		seq = 0;
out:
	kfree(m);
	return err;
}

/*
 * Free a uvesafb_ktask struct.
 */
static void uvesafb_free(struct uvesafb_ktask *task)
{
	if (task) {
		if (task->done)
			kfree(task->done);
		kfree(task);
	}
}

/*
 * Prepare a uvesafb_ktask struct to be used again.
 */
static void uvesafb_reset(struct uvesafb_ktask *task)
{
	struct completion *cpl = task->done;

	memset(task, 0, sizeof(*task));
	task->done = cpl;
}

/*
 * Allocate and prepare a uvesafb_ktask struct.
 */
static struct uvesafb_ktask *uvesafb_prep(void)
{
	struct uvesafb_ktask *task;

	task = kzalloc(sizeof(*task), GFP_KERNEL);
	if (task) {
		task->done = kzalloc(sizeof(*task->done), GFP_KERNEL);
		if (!task->done) {
			kfree(task);
			task = NULL;
		}
	}
	return task;
}

static void uvesafb_setup_var(struct fb_var_screeninfo *var,
		struct fb_info *info, struct vbe_mode_ib *mode)
{
	struct uvesafb_par *par = info->par;

	var->vmode = FB_VMODE_NONINTERLACED;
	var->sync = FB_SYNC_VERT_HIGH_ACT;

	var->xres = mode->x_res;
	var->yres = mode->y_res;
	var->xres_virtual = mode->x_res;
	var->yres_virtual = (par->ypan) ?
			info->fix.smem_len / mode->bytes_per_scan_line :
			mode->y_res;
	var->xoffset = 0;
	var->yoffset = 0;
	var->bits_per_pixel = mode->bits_per_pixel;

	if (var->bits_per_pixel == 15)
		var->bits_per_pixel = 16;

	if (var->bits_per_pixel > 8) {
		var->red.offset    = mode->red_off;
		var->red.length    = mode->red_len;
		var->green.offset  = mode->green_off;
		var->green.length  = mode->green_len;
		var->blue.offset   = mode->blue_off;
		var->blue.length   = mode->blue_len;
		var->transp.offset = mode->rsvd_off;
		var->transp.length = mode->rsvd_len;
	} else {
		var->red.offset    = 0;
		var->green.offset  = 0;
		var->blue.offset   = 0;
		var->transp.offset = 0;

		/*
		 * We're assuming that we can switch the DAC to 8 bits. If
		 * this proves to be incorrect, we'll update the fields
		 * later in set_par().
		 */
		if (par->vbe_ib.capabilities & VBE_CAP_CAN_SWITCH_DAC) {
			var->red.length    = 8;
			var->green.length  = 8;
			var->blue.length   = 8;
			var->transp.length = 0;
		} else {
			var->red.length    = 6;
			var->green.length  = 6;
			var->blue.length   = 6;
			var->transp.length = 0;
		}
	}
}

static int uvesafb_vbe_find_mode(struct uvesafb_par *par,
		int xres, int yres, int depth, unsigned char flags)
{
	int i, match = -1, h = 0, d = 0x7fffffff;

	for (i = 0; i < par->vbe_modes_cnt; i++) {
		h = abs(par->vbe_modes[i].x_res - xres) +
		    abs(par->vbe_modes[i].y_res - yres) +
		    abs(depth - par->vbe_modes[i].depth);

		/*
		 * We have an exact match in terms of resolution
		 * and depth.
		 */
		if (h == 0)
			return i;

		if (h < d || (h == d && par->vbe_modes[i].depth > depth)) {
			d = h;
			match = i;
		}
	}
	i = 1;

	if (flags & UVESAFB_EXACT_DEPTH &&
			par->vbe_modes[match].depth != depth)
		i = 0;

	if (flags & UVESAFB_EXACT_RES && d > 24)
		i = 0;

	if (i != 0)
		return match;
	else
		return -1;
}

static u8 *uvesafb_vbe_state_save(struct uvesafb_par *par)
{
	struct uvesafb_ktask *task;
	u8 *state;
	int err;

	if (!par->vbe_state_size)
		return NULL;

	state = kmalloc(par->vbe_state_size, GFP_KERNEL);
	if (!state)
		return NULL;

	task = uvesafb_prep();
	if (!task) {
		kfree(state);
		return NULL;
	}

	task->t.regs.eax = 0x4f04;
	task->t.regs.ecx = 0x000f;
	task->t.regs.edx = 0x0001;
	task->t.flags = TF_BUF_RET | TF_BUF_ESBX;
	task->t.buf_len = par->vbe_state_size;
	task->buf = state;
	err = uvesafb_exec(task);

	if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
		printk(KERN_WARNING "uvesafb: VBE get state call "
				"failed (eax=0x%x, err=%d)\n",
				task->t.regs.eax, err);
		kfree(state);
		state = NULL;
	}

	uvesafb_free(task);
	return state;
}

static void uvesafb_vbe_state_restore(struct uvesafb_par *par, u8 *state_buf)
{
	struct uvesafb_ktask *task;
	int err;

	if (!state_buf)
		return;

	task = uvesafb_prep();
	if (!task)
		return;

	task->t.regs.eax = 0x4f04;
	task->t.regs.ecx = 0x000f;
	task->t.regs.edx = 0x0002;
	task->t.buf_len = par->vbe_state_size;
	task->t.flags = TF_BUF_ESBX;
	task->buf = state_buf;

	err = uvesafb_exec(task);
	if (err || (task->t.regs.eax & 0xffff) != 0x004f)
		printk(KERN_WARNING "uvesafb: VBE state restore call "
				"failed (eax=0x%x, err=%d)\n",
				task->t.regs.eax, err);

	uvesafb_free(task);
}

static int __devinit uvesafb_vbe_getinfo(struct uvesafb_ktask *task,
		struct uvesafb_par *par)
{
	int err;

	task->t.regs.eax = 0x4f00;
	task->t.flags = TF_VBEIB;
	task->t.buf_len = sizeof(struct vbe_ib);
	task->buf = &par->vbe_ib;
	strncpy(par->vbe_ib.vbe_signature, "VBE2", 4);

	err = uvesafb_exec(task);
	if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
		printk(KERN_ERR "uvesafb: Getting VBE info block failed "
				"(eax=0x%x, err=%d)\n", (u32)task->t.regs.eax,
				err);
		return -EINVAL;
	}

	if (par->vbe_ib.vbe_version < 0x0200) {
		printk(KERN_ERR "uvesafb: Sorry, pre-VBE 2.0 cards are "
				"not supported.\n");
		return -EINVAL;
	}

	if (!par->vbe_ib.mode_list_ptr) {
		printk(KERN_ERR "uvesafb: Missing mode list!\n");
		return -EINVAL;
	}

	printk(KERN_INFO "uvesafb: ");

	/*
	 * Convert string pointers and the mode list pointer into
	 * usable addresses. Print informational messages about the
	 * video adapter and its vendor.
	 */
	if (par->vbe_ib.oem_vendor_name_ptr)
		printk("%s, ",
			((char *)task->buf) + par->vbe_ib.oem_vendor_name_ptr);

	if (par->vbe_ib.oem_product_name_ptr)
		printk("%s, ",
			((char *)task->buf) + par->vbe_ib.oem_product_name_ptr);

	if (par->vbe_ib.oem_product_rev_ptr)
		printk("%s, ",
			((char *)task->buf) + par->vbe_ib.oem_product_rev_ptr);

	if (par->vbe_ib.oem_string_ptr)
		printk("OEM: %s, ",
			((char *)task->buf) + par->vbe_ib.oem_string_ptr);

	printk("VBE v%d.%d\n", ((par->vbe_ib.vbe_version & 0xff00) >> 8),
			par->vbe_ib.vbe_version & 0xff);

	return 0;
}

static int __devinit uvesafb_vbe_getmodes(struct uvesafb_ktask *task,
		struct uvesafb_par *par)
{
	int off = 0, err;
	u16 *mode;

	par->vbe_modes_cnt = 0;

	/* Count available modes. */
	mode = (u16 *) (((u8 *)&par->vbe_ib) + par->vbe_ib.mode_list_ptr);
	while (*mode != 0xffff) {
		par->vbe_modes_cnt++;
		mode++;
	}

	par->vbe_modes = kzalloc(sizeof(struct vbe_mode_ib) *
				par->vbe_modes_cnt, GFP_KERNEL);
	if (!par->vbe_modes)
		return -ENOMEM;

	/* Get info about all available modes. */
	mode = (u16 *) (((u8 *)&par->vbe_ib) + par->vbe_ib.mode_list_ptr);
	while (*mode != 0xffff) {
		struct vbe_mode_ib *mib;

		uvesafb_reset(task);
		task->t.regs.eax = 0x4f01;
		task->t.regs.ecx = (u32) *mode;
		task->t.flags = TF_BUF_RET | TF_BUF_ESDI;
		task->t.buf_len = sizeof(struct vbe_mode_ib);
		task->buf = par->vbe_modes + off;

		err = uvesafb_exec(task);
		if (err || (task->t.regs.eax & 0xffff) != 0x004f) {
			printk(KERN_WARNING "uvesafb: Getting mode info block "