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[Xen-devel][PATCH][LINUX] Dynamic modes support for xenfb (2 of 2)

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel][PATCH][LINUX] Dynamic modes support for xenfb (2 of 2)
From: Pat Campbell <plc@xxxxxxxxxx>
Date: Tue, 25 Mar 2008 14:10:28 -0600
Delivery-date: Tue, 25 Mar 2008 13:14:19 -0700
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Attached patch adds dynamic frame buffer resolution support to
the PV xenfb frame buffer driver.

Corresponding backend IOEMU patch is required for functionality but
this patch is not dependent on it, preserving backwards compatibility.

Please apply to tip of linux-2.6.18-xen

Signed-off-by: Pat Campbell <plc@xxxxxxxxxx>

diff -r de57c3f218fb drivers/xen/fbfront/xenfb.c
--- a/drivers/xen/fbfront/xenfb.c       Thu Mar 20 11:35:25 2008 +0000
+++ b/drivers/xen/fbfront/xenfb.c       Tue Mar 25 10:20:01 2008 -0600
@@ -62,15 +62,21 @@ struct xenfb_info
        struct xenfb_page       *page;
        unsigned long           *mfns;
        int                     update_wanted; /* XENFB_TYPE_UPDATE wanted */
+       int                     feature_resize; /* Backend has resize feature */
+       struct xenfb_resize     resize;
+       int                     resize_dpy;
+       spinlock_t              resize_lock;
 
        struct xenbus_device    *xbdev;
 };
 
 /*
- * How the locks work together
- *
- * There are two locks: spinlock dirty_lock protecting the dirty
- * rectangle, and mutex mm_lock protecting mappings.
+ * There are three locks:
+ *    spinlock resize_lock protecting resize_dpy and resize
+ *    spinlock dirty_lock protecting the dirty rectangle
+ *    mutex mm_lock protecting mappings.
+ *
+ * How the dirty and mapping locks work together
  *
  * The problem is that dirty rectangle and mappings aren't
  * independent: the dirty rectangle must cover all faulted pages in
@@ -129,20 +135,41 @@ struct xenfb_info
  *
  * Oh well, we wont be updating the writes to this page anytime soon.
  */
+#define MB_ (1024*1024)
+#define XENFB_DEFAULT_FB_LEN (XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8)
+
+enum {KPARAM_MEM, KPARAM_WIDTH, KPARAM_HEIGHT, KPARAM_CNT};
+static int video[KPARAM_CNT] = {2, XENFB_WIDTH, XENFB_HEIGHT};
+module_param_array(video, int, NULL, 0);
+MODULE_PARM_DESC(video,
+               "Size of video memory in MB and width,height in pixels, default 
= (2,800,600)");
 
 static int xenfb_fps = 20;
-static unsigned long xenfb_mem_len = XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH 
/ 8;
 
 static int xenfb_remove(struct xenbus_device *);
-static void xenfb_init_shared_page(struct xenfb_info *);
+static void xenfb_init_shared_page(struct xenfb_info *, struct fb_info *);
 static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *);
 static void xenfb_disconnect_backend(struct xenfb_info *);
 
+static void xenfb_send_event(struct xenfb_info *info,
+               union xenfb_out_event *event)
+{
+       __u32 prod;
+
+       prod = info->page->out_prod;
+       /* caller ensures !xenfb_queue_full() */
+       mb();                   /* ensure ring space available */
+       XENFB_OUT_RING_REF(info->page, prod) = *event;
+       wmb();                  /* ensure ring contents visible */
+       info->page->out_prod = prod + 1;
+
+       notify_remote_via_irq(info->irq);
+}
+
 static void xenfb_do_update(struct xenfb_info *info,
                            int x, int y, int w, int h)
 {
        union xenfb_out_event event;
-       __u32 prod;
 
        event.type = XENFB_TYPE_UPDATE;
        event.update.x = x;
@@ -150,14 +177,18 @@ static void xenfb_do_update(struct xenfb
        event.update.width = w;
        event.update.height = h;
 
-       prod = info->page->out_prod;
        /* caller ensures !xenfb_queue_full() */
-       mb();                   /* ensure ring space available */
-       XENFB_OUT_RING_REF(info->page, prod) = event;
-       wmb();                  /* ensure ring contents visible */
-       info->page->out_prod = prod + 1;
-
-       notify_remote_via_irq(info->irq);
+       xenfb_send_event(info, &event);
+}
+
+static void xenfb_do_resize(struct xenfb_info *info)
+{
+       union xenfb_out_event event;
+
+       event.resize = info->resize;
+
+       /* caller ensures !xenfb_queue_full() */
+       xenfb_send_event(info, &event);
 }
 
 static int xenfb_queue_full(struct xenfb_info *info)
@@ -209,11 +240,26 @@ static void xenfb_update_screen(struct x
        xenfb_do_update(info, x1, y1, x2 - x1, y2 - y1);
 }
 
+static void xenfb_handle_resize_dpy(struct xenfb_info *info)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&info->resize_lock, flags);
+       if (info->resize_dpy) {
+               if (!xenfb_queue_full(info)) {
+                       info->resize_dpy = 0;
+                       xenfb_do_resize(info);
+               }
+       }
+       spin_unlock_irqrestore(&info->resize_lock, flags);
+}
+
 static int xenfb_thread(void *data)
 {
        struct xenfb_info *info = data;
 
        while (!kthread_should_stop()) {
+               xenfb_handle_resize_dpy(info);
                if (info->dirty) {
                        info->dirty = 0;
                        xenfb_update_screen(info);
@@ -413,6 +459,56 @@ static int xenfb_mmap(struct fb_info *fb
        return 0;
 }
 
+static int
+xenfb_check_var(struct fb_var_screeninfo *var, struct fb_info *info)
+{
+       struct xenfb_info *xenfb_info;
+       int required_mem_len;
+
+       xenfb_info = info->par;
+
+       if (!xenfb_info->feature_resize) {
+               if (var->xres == video[KPARAM_WIDTH] &&
+                       var->yres == video[KPARAM_HEIGHT] &&
+                       var->bits_per_pixel == xenfb_info->page->depth) {
+                       return 0;
+               }
+               return -EINVAL;
+       }
+
+       /* Can't resize past initial width and height */
+       if (var->xres > video[KPARAM_WIDTH] || var->yres > video[KPARAM_HEIGHT])
+               return -EINVAL;
+
+       required_mem_len = var->xres * var->yres * (xenfb_info->page->depth / 
8);
+       if (var->bits_per_pixel == xenfb_info->page->depth &&
+               var->xres <= info->fix.line_length / (XENFB_DEPTH / 8) &&
+               required_mem_len <= info->fix.smem_len) {
+               var->xres_virtual = var->xres;
+               var->yres_virtual = var->yres;
+               return 0;
+       }
+       return -EINVAL;
+}
+
+static int xenfb_set_par(struct fb_info *info)
+{
+       struct xenfb_info *xenfb_info;
+       unsigned long flags;
+
+       xenfb_info = info->par;
+
+       spin_lock_irqsave(&xenfb_info->resize_lock, flags);
+       xenfb_info->resize.type = XENFB_TYPE_RESIZE;
+       xenfb_info->resize.width = info->var.xres;
+       xenfb_info->resize.height = info->var.yres;
+       xenfb_info->resize.stride = info->fix.line_length;
+       xenfb_info->resize.depth = info->var.bits_per_pixel;
+       xenfb_info->resize_dpy = 1;
+       spin_unlock_irqrestore(&xenfb_info->resize_lock, flags);
+       return 0;
+}
+
 static struct fb_ops xenfb_fb_ops = {
        .owner          = THIS_MODULE,
        .fb_setcolreg   = xenfb_setcolreg,
@@ -420,6 +516,8 @@ static struct fb_ops xenfb_fb_ops = {
        .fb_copyarea    = xenfb_copyarea,
        .fb_imageblit   = xenfb_imageblit,
        .fb_mmap        = xenfb_mmap,
+       .fb_check_var   = xenfb_check_var,
+       .fb_set_par     = xenfb_set_par,
 };
 
 static irqreturn_t xenfb_event_handler(int rq, void *dev_id,
@@ -450,6 +548,8 @@ static int __devinit xenfb_probe(struct 
 {
        struct xenfb_info *info;
        struct fb_info *fb_info;
+       int fb_size;
+       int val;
        int ret;
 
        info = kzalloc(sizeof(*info), GFP_KERNEL);
@@ -457,11 +557,27 @@ static int __devinit xenfb_probe(struct 
                xenbus_dev_fatal(dev, -ENOMEM, "allocating info structure");
                return -ENOMEM;
        }
+
+       /* Limit kernel param videoram amount to what is in xenstore */
+       if (xenbus_scanf(XBT_NIL, dev->otherend, "videoram", "%d", &val) == 1) {
+               if (val < video[KPARAM_MEM])
+                       video[KPARAM_MEM] = val;
+       }
+
+       /* If requested res does not fit in available memory, use default */
+       fb_size = video[KPARAM_MEM] * MB_;
+       if (video[KPARAM_WIDTH] * video[KPARAM_HEIGHT] * XENFB_DEPTH/8 > 
fb_size) {
+               video[KPARAM_WIDTH] = XENFB_WIDTH;
+               video[KPARAM_HEIGHT] = XENFB_HEIGHT;
+               fb_size = XENFB_DEFAULT_FB_LEN;
+       }
+
        dev->dev.driver_data = info;
        info->xbdev = dev;
        info->irq = -1;
        info->x1 = info->y1 = INT_MAX;
        spin_lock_init(&info->dirty_lock);
+       spin_lock_init(&info->resize_lock);
        mutex_init(&info->mm_lock);
        init_waitqueue_head(&info->wq);
        init_timer(&info->refresh);
@@ -469,12 +585,12 @@ static int __devinit xenfb_probe(struct 
        info->refresh.data = (unsigned long)info;
        INIT_LIST_HEAD(&info->mappings);
 
-       info->fb = vmalloc(xenfb_mem_len);
+       info->fb = vmalloc(fb_size);
        if (info->fb == NULL)
                goto error_nomem;
-       memset(info->fb, 0, xenfb_mem_len);
-
-       info->nr_pages = (xenfb_mem_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+       memset(info->fb, 0, fb_size);
+
+       info->nr_pages = (fb_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
        info->pages = kmalloc(sizeof(struct page *) * info->nr_pages,
                              GFP_KERNEL);
@@ -489,8 +605,6 @@ static int __devinit xenfb_probe(struct 
        info->page = (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
        if (!info->page)
                goto error_nomem;
-
-       xenfb_init_shared_page(info);
 
        fb_info = framebuffer_alloc(sizeof(u32) * 256, NULL);
                                /* see fishy hackery below */
@@ -504,9 +618,9 @@ static int __devinit xenfb_probe(struct 
        fb_info->screen_base = info->fb;
 
        fb_info->fbops = &xenfb_fb_ops;
-       fb_info->var.xres_virtual = fb_info->var.xres = info->page->width;
-       fb_info->var.yres_virtual = fb_info->var.yres = info->page->height;
-       fb_info->var.bits_per_pixel = info->page->depth;
+       fb_info->var.xres_virtual = fb_info->var.xres = video[KPARAM_WIDTH];
+       fb_info->var.yres_virtual = fb_info->var.yres = video[KPARAM_HEIGHT];
+       fb_info->var.bits_per_pixel = XENFB_DEPTH;
 
        fb_info->var.red = (struct fb_bitfield){16, 8, 0};
        fb_info->var.green = (struct fb_bitfield){8, 8, 0};
@@ -518,9 +632,9 @@ static int __devinit xenfb_probe(struct 
        fb_info->var.vmode = FB_VMODE_NONINTERLACED;
 
        fb_info->fix.visual = FB_VISUAL_TRUECOLOR;
-       fb_info->fix.line_length = info->page->line_length;
+       fb_info->fix.line_length = fb_info->var.xres * (XENFB_DEPTH / 8);
        fb_info->fix.smem_start = 0;
-       fb_info->fix.smem_len = xenfb_mem_len;
+       fb_info->fix.smem_len = fb_size;
        strcpy(fb_info->fix.id, "xen");
        fb_info->fix.type = FB_TYPE_PACKED_PIXELS;
        fb_info->fix.accel = FB_ACCEL_NONE;
@@ -533,6 +647,8 @@ static int __devinit xenfb_probe(struct 
                xenbus_dev_fatal(dev, ret, "fb_alloc_cmap");
                goto error;
        }
+
+       xenfb_init_shared_page(info, fb_info);
 
        ret = register_framebuffer(fb_info);
        if (ret) {
@@ -571,7 +687,7 @@ static int xenfb_resume(struct xenbus_de
        struct xenfb_info *info = dev->dev.driver_data;
 
        xenfb_disconnect_backend(info);
-       xenfb_init_shared_page(info);
+       xenfb_init_shared_page(info, info->fb_info);
        return xenfb_connect_backend(dev, info);
 }
 
@@ -597,9 +713,11 @@ static int xenfb_remove(struct xenbus_de
        return 0;
 }
 
-static void xenfb_init_shared_page(struct xenfb_info *info)
+static void xenfb_init_shared_page(struct xenfb_info *info,
+                                   struct fb_info * fb_info)
 {
        int i;
+       int epd = PAGE_SIZE / sizeof(info->mfns[0]);
 
        for (i = 0; i < info->nr_pages; i++)
                info->pages[i] = vmalloc_to_page(info->fb + i * PAGE_SIZE);
@@ -607,13 +725,14 @@ static void xenfb_init_shared_page(struc
        for (i = 0; i < info->nr_pages; i++)
                info->mfns[i] = vmalloc_to_mfn(info->fb + i * PAGE_SIZE);
 
-       info->page->pd[0] = vmalloc_to_mfn(info->mfns);
-       info->page->pd[1] = 0;
-       info->page->width = XENFB_WIDTH;
-       info->page->height = XENFB_HEIGHT;
-       info->page->depth = XENFB_DEPTH;
-       info->page->line_length = (info->page->depth / 8) * info->page->width;
-       info->page->mem_length = xenfb_mem_len;
+       for (i = 0; i * epd < info->nr_pages; i++)
+               info->page->pd[i] = vmalloc_to_mfn(&info->mfns[i * epd]);
+
+       info->page->width = fb_info->var.xres;
+       info->page->height = fb_info->var.yres;
+       info->page->depth = fb_info->var.bits_per_pixel;
+       info->page->line_length = fb_info->fix.line_length;
+       info->page->mem_length = fb_info->fix.smem_len;
        info->page->in_cons = info->page->in_prod = 0;
        info->page->out_cons = info->page->out_prod = 0;
 }
@@ -712,6 +831,11 @@ static void xenfb_backend_changed(struct
                        val = 0;
                if (val)
                        info->update_wanted = 1;
+
+               if (xenbus_scanf(XBT_NIL, dev->otherend,
+                                       "feature-resize", "%d", &val) < 0)
+                       val = 0;
+               info->feature_resize = val;
                break;
 
        case XenbusStateClosing:
diff -r de57c3f218fb drivers/xen/fbfront/xenkbd.c
--- a/drivers/xen/fbfront/xenkbd.c      Thu Mar 20 11:35:25 2008 +0000
+++ b/drivers/xen/fbfront/xenkbd.c      Tue Mar 25 10:20:01 2008 -0600
@@ -297,6 +297,16 @@ static void xenkbd_backend_changed(struc
                 */
                if (dev->state != XenbusStateConnected)
                        goto InitWait; /* no InitWait seen yet, fudge it */
+
+               /* Set input abs params to match backend screen res */
+               if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+                                  "width", "%d", &val) > 0 )
+                       input_set_abs_params(info->ptr, ABS_X, 0, val, 0, 0);
+
+               if (xenbus_scanf(XBT_NIL, info->xbdev->otherend,
+                                  "height", "%d", &val) > 0 )
+                       input_set_abs_params(info->ptr, ABS_Y, 0, val, 0, 0);
+
                break;
 
        case XenbusStateClosing:
diff -r de57c3f218fb include/xen/interface/io/fbif.h
--- a/include/xen/interface/io/fbif.h   Thu Mar 20 11:35:25 2008 +0000
+++ b/include/xen/interface/io/fbif.h   Tue Mar 25 10:20:01 2008 -0600
@@ -50,12 +50,28 @@ struct xenfb_update
     int32_t height; /* rect height */
 };
 
+/*
+ * Framebuffer resize notification event
+ * Capable backend sets feature-resize in xenstore.
+ */
+#define XENFB_TYPE_RESIZE 3
+
+struct xenfb_resize
+{
+    uint8_t type;    /* XENFB_TYPE_RESIZE */
+    int32_t width;   /* width in pixels */
+    int32_t height;  /* height in pixels */
+    int32_t stride;  /* stride in bytes */
+    int32_t depth;   /* depth in bits */
+};
+
 #define XENFB_OUT_EVENT_SIZE 40
 
 union xenfb_out_event
 {
     uint8_t type;
     struct xenfb_update update;
+    struct xenfb_resize resize;
     char pad[XENFB_OUT_EVENT_SIZE];
 };
 
@@ -109,15 +125,17 @@ struct xenfb_page
      * Each directory page holds PAGE_SIZE / sizeof(*pd)
      * framebuffer pages, and can thus map up to PAGE_SIZE *
      * PAGE_SIZE / sizeof(*pd) bytes.  With PAGE_SIZE == 4096 and
-     * sizeof(unsigned long) == 4, that's 4 Megs.  Two directory
-     * pages should be enough for a while.
+     * sizeof(unsigned long) == 4/8, that's 4 Megs 32 bit and 2 Megs
+     * 64 bit.  256 directories give enough room for a 512 Meg
+     * framebuffer with a max resolution of 12,800x10,240.  Should
+     * be enough for a while with room leftover for expansion.
      */
-    unsigned long pd[2];
+    unsigned long pd[256];
 };
 
 /*
- * Wart: xenkbd needs to know resolution.  Put it here until a better
- * solution is found, but don't leak it to the backend.
+ * Wart: xenkbd needs to know default resolution.  Put it here until a
+ * better solution is found, but don't leak it to the backend.
  */
 #ifdef __KERNEL__
 #define XENFB_WIDTH 800
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