fbdev: add FBIOCOPYAREA ioctl

Based on the patch authored by Ali Gholami Rudi at
    https://lkml.org/lkml/2009/7/13/153

Provide an ioctl for userspace applications, but only if this operation
is hardware accelerated (otherwide it does not make any sense).

Signed-off-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
bcm2708_fb: Add ioctl for reading gpu memory through dma

diff --git a/drivers/video/fbdev/bcm2708_fb.c b/drivers/video/fbdev/bcm2708_fb.c
index 37f60813fe1dd95d9f5f725c07ec2e75c09857bf..a048c964b11508042ffc582f452f2a4c43d0770f 100644 (file)
--- a/drivers/video/fbdev/bcm2708_fb.c
+++ b/drivers/video/fbdev/bcm2708_fb.c
@@ -31,8 +31,10 @@
 #include <linux/console.h>
 #include <linux/debugfs.h>
 #include <asm/sizes.h>
+#include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/dma-mapping.h>
+#include <linux/cred.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>
 
 //#define BCM2708_FB_DEBUG
@@ -94,6 +96,7 @@ struct bcm2708_fb {
        wait_queue_head_t dma_waitq;
        struct bcm2708_fb_stats stats;
        unsigned long fb_bus_address;
+       struct { u32 base, length; } gpu;
 };
 
 #define to_bcm2708(info)       container_of(info, struct bcm2708_fb, fb)
@@ -426,6 +429,106 @@ static int bcm2708_fb_pan_display(struct fb_var_screeninfo *var, struct fb_info
        return result;
 }
 
+static void dma_memcpy(struct bcm2708_fb *fb, dma_addr_t dst, dma_addr_t src, int size)
+{
+       int burst_size = (fb->dma_chan == 0) ? 8 : 2;
+       struct bcm2708_dma_cb *cb = fb->cb_base;
+
+       cb->info = BCM2708_DMA_BURST(burst_size) | BCM2708_DMA_S_WIDTH |
+                  BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
+                  BCM2708_DMA_D_INC;
+       cb->dst = dst;
+       cb->src = src;
+       cb->length = size;
+       cb->stride = 0;
+       cb->pad[0] = 0;
+       cb->pad[1] = 0;
+       cb->next = 0;
+
+       if (size < dma_busy_wait_threshold) {
+               bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
+               bcm_dma_wait_idle(fb->dma_chan_base);
+       } else {
+               void __iomem *dma_chan = fb->dma_chan_base;
+               cb->info |= BCM2708_DMA_INT_EN;
+               bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
+               while (bcm_dma_is_busy(dma_chan)) {
+                       wait_event_interruptible(
+                               fb->dma_waitq,
+                               !bcm_dma_is_busy(dma_chan));
+               }
+               fb->stats.dma_irqs++;
+       }
+       fb->stats.dma_copies++;
+}
+
+#define INTALIAS_NORMAL(x) ((x)&~0xc0000000) // address with no aliases
+#define INTALIAS_L1L2_NONALLOCATING(x) (((x)&~0xc0000000)|0x80000000) // cache coherent but non-allocating in L1 and L2
+
+static long vc_mem_copy(struct bcm2708_fb *fb, unsigned long arg)
+{
+       struct fb_dmacopy ioparam;
+       size_t size = PAGE_SIZE;
+       u32 *buf = NULL;
+       dma_addr_t bus_addr;
+       long rc = 0;
+       size_t offset;
+
+       /* restrict this to root user */
+       if (!uid_eq(current_euid(), GLOBAL_ROOT_UID))
+       {
+               rc = -EFAULT;
+               goto out;
+       }
+
+       /* Get the parameter data.
+        */
+       if (copy_from_user
+           (&ioparam, (void *)arg, sizeof(ioparam)) != 0) {
+               pr_err("[%s]: failed to copy-from-user\n",
+                               __func__);
+               rc = -EFAULT;
+               goto out;
+       }
+
+       if (fb->gpu.base == 0 || fb->gpu.length == 0) {
+               pr_err("[%s]: Unable to determine gpu memory (%x,%x)\n", __func__, fb->gpu.base, fb->gpu.length);
+               return -EFAULT;
+       }
+
+       if (INTALIAS_NORMAL(ioparam.src) < fb->gpu.base || INTALIAS_NORMAL(ioparam.src) >= fb->gpu.base + fb->gpu.length) {
+               pr_err("[%s]: Invalid memory access %x (%x-%x)", __func__, INTALIAS_NORMAL(ioparam.src), fb->gpu.base, fb->gpu.base + fb->gpu.length);
+               return -EFAULT;
+       }
+
+       buf = dma_alloc_coherent(fb->fb.device, PAGE_ALIGN(size), &bus_addr,
+                                GFP_ATOMIC);
+       if (!buf) {
+               pr_err("[%s]: failed to dma_alloc_coherent(%d)\n",
+                               __func__, size);
+               rc = -ENOMEM;
+               goto out;
+       }
+
+       for (offset = 0; offset < ioparam.length; offset += size) {
+               size_t remaining = ioparam.length - offset;
+               size_t s = min(size, remaining);
+               unsigned char *p = (unsigned char *)ioparam.src + offset;
+               unsigned char *q = (unsigned char *)ioparam.dst + offset;
+               dma_memcpy(fb, bus_addr, INTALIAS_L1L2_NONALLOCATING((dma_addr_t)p), size);
+               if (copy_to_user(q, buf, s) != 0) {
+                       pr_err("[%s]: failed to copy-to-user\n",
+                                       __func__);
+                       rc = -EFAULT;
+                       goto out;
+               }
+       }
+out:
+       if (buf)
+               dma_free_coherent(fb->fb.device, PAGE_ALIGN(size), buf, bus_addr);
+       return rc;
+}
+
 static int bcm2708_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
 {
        struct bcm2708_fb *fb = to_bcm2708(info);
@@ -438,6 +541,9 @@ static int bcm2708_ioctl(struct fb_info *info, unsigned int cmd, unsigned long a
                                            RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC,
                                            &dummy, sizeof(dummy));
                break;
+       case FBIODMACOPY:
+               ret = vc_mem_copy(fb, arg);
+               break;
        default:
                dev_dbg(info->device, "Unknown ioctl 0x%x\n", cmd);
                return -ENOTTY;
@@ -760,6 +866,11 @@ static int bcm2708_fb_probe(struct platform_device *dev)
        fb->dev = dev;
        fb->fb.device = &dev->dev;
 
+       // failure here isn't fatal, but we'll fail in vc_mem_copy if fb->gpu is not valid
+       rpi_firmware_property(fb->fw,
+                                   RPI_FIRMWARE_GET_VC_MEMORY,
+                                   &fb->gpu, sizeof(fb->gpu));
+
        ret = bcm2708_fb_register(fb);
        if (ret == 0) {
                platform_set_drvdata(dev, fb);

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 7a42238db446b0093323505b710963ac94a53e15..6e3be5680f33a564cebec408d1e15ffddbe0f890 100644 (file)
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1084,6 +1084,31 @@ fb_blank(struct fb_info *info, int blank)
 }
 EXPORT_SYMBOL(fb_blank);
 
+static int fb_copyarea_user(struct fb_info *info,
+                           struct fb_copyarea *copy)
+{
+       int ret = 0;
+       if (!lock_fb_info(info))
+               return -ENODEV;
+       if (copy->dx >= info->var.xres ||
+           copy->sx >= info->var.xres ||
+           copy->width > info->var.xres ||
+           copy->dy >= info->var.yres ||
+           copy->sy >= info->var.yres ||
+           copy->height > info->var.yres ||
+           copy->dx + copy->width > info->var.xres ||
+           copy->sx + copy->width > info->var.xres ||
+           copy->dy + copy->height > info->var.yres ||
+           copy->sy + copy->height > info->var.yres) {
+               ret = -EINVAL;
+               goto out;
+       }
+       info->fbops->fb_copyarea(info, copy);
+out:
+       unlock_fb_info(info);
+       return ret;
+}
+
 static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
                        unsigned long arg)
 {
@@ -1094,6 +1119,7 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
        struct fb_cmap cmap_from;
        struct fb_cmap_user cmap;
        struct fb_event event;
+       struct fb_copyarea copy;
        void __user *argp = (void __user *)arg;
        long ret = 0;
 
@@ -1211,6 +1237,15 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
                unlock_fb_info(info);
                console_unlock();
                break;
+       case FBIOCOPYAREA:
+               if (info->flags & FBINFO_HWACCEL_COPYAREA) {
+                       /* only provide this ioctl if it is accelerated */
+                       if (copy_from_user(&copy, argp, sizeof(copy)))
+                               return -EFAULT;
+                       ret = fb_copyarea_user(info, &copy);
+                       break;
+               }
+               /* fall through */
        default:
                if (!lock_fb_info(info))
                        return -ENODEV;
@@ -1356,6 +1391,7 @@ static long fb_compat_ioctl(struct file *file, unsigned int cmd,
        case FBIOPAN_DISPLAY:
        case FBIOGET_CON2FBMAP:
        case FBIOPUT_CON2FBMAP:
+       case FBIOCOPYAREA:
                arg = (unsigned long) compat_ptr(arg);
        case FBIOBLANK:
                ret = do_fb_ioctl(info, cmd, arg);

diff --git a/include/uapi/linux/fb.h b/include/uapi/linux/fb.h
index fb795c3b3c178ad3cd7c9e9e4547ffd492bac181..703fa8a70574323abe2fb32599254582cd5d891f 100644 (file)
--- a/include/uapi/linux/fb.h
+++ b/include/uapi/linux/fb.h
@@ -34,6 +34,12 @@
 #define FBIOPUT_MODEINFO        0x4617
 #define FBIOGET_DISPINFO        0x4618
 #define FBIO_WAITFORVSYNC      _IOW('F', 0x20, __u32)
+/*
+ * HACK: use 'z' in order not to clash with any other ioctl numbers which might
+ * be concurrently added to the mainline kernel
+ */
+#define FBIOCOPYAREA           _IOW('z', 0x21, struct fb_copyarea)
+#define FBIODMACOPY            _IOW('z', 0x22, struct fb_dmacopy)
 
 #define FB_TYPE_PACKED_PIXELS          0       /* Packed Pixels        */
 #define FB_TYPE_PLANES                 1       /* Non interleaved planes */
@@ -346,6 +352,12 @@ struct fb_copyarea {
        __u32 sy;
 };
 
+struct fb_dmacopy {
+       void *dst;
+       __u32 src;
+       __u32 length;
+};
+
 struct fb_fillrect {
        __u32 dx;       /* screen-relative */
        __u32 dy;