target/linux/brcm2708/patches-4.4/0531-bcm2708_fb-Add-ioctl-for-reading-gpu-memory-through-.patch

   1 From 26a7e2d3d11c23acc6f87414da736c07a3b9cc52 Mon Sep 17 00:00:00 2001
   2 From: popcornmix <popcornmix@gmail.com>
   3 Date: Sat, 5 Nov 2016 14:14:43 +0000
   4 Subject: [PATCH] bcm2708_fb: Add ioctl for reading gpu memory through dma
   5
   6 ---
   7  drivers/video/fbdev/bcm2708_fb.c | 109 +++++++++++++++++++++++++++++++++++++++
   8  include/uapi/linux/fb.h          |   7 +++
   9  2 files changed, 116 insertions(+)
  10
  11 --- a/drivers/video/fbdev/bcm2708_fb.c
  12 +++ b/drivers/video/fbdev/bcm2708_fb.c
  13 @@ -31,8 +31,10 @@
  14  #include <linux/console.h>
  15  #include <linux/debugfs.h>
  16  #include <asm/sizes.h>
  17 +#include <asm/uaccess.h>
  18  #include <linux/io.h>
  19  #include <linux/dma-mapping.h>
  20 +#include <linux/cred.h>
  21  #include <soc/bcm2835/raspberrypi-firmware.h>
  22
  23  //#define BCM2708_FB_DEBUG
  24 @@ -429,6 +431,110 @@ static int bcm2708_fb_pan_display(struct
  25         return result;
  26  }
  27
  28 +static void dma_memcpy(struct bcm2708_fb *fb, dma_addr_t dst, dma_addr_t src, int size)
  29 +{
  30 +       int burst_size = (fb->dma_chan == 0) ? 8 : 2;
  31 +       struct bcm2708_dma_cb *cb = fb->cb_base;
  32 +
  33 +       cb->info = BCM2708_DMA_BURST(burst_size) | BCM2708_DMA_S_WIDTH |
  34 +                  BCM2708_DMA_S_INC | BCM2708_DMA_D_WIDTH |
  35 +                  BCM2708_DMA_D_INC | BCM2708_DMA_TDMODE;
  36 +       cb->dst = dst;
  37 +       cb->src = src;
  38 +       cb->length = size;
  39 +       cb->stride = 0;
  40 +       cb->pad[0] = 0;
  41 +       cb->pad[1] = 0;
  42 +       cb->next = 0;
  43 +
  44 +       if (size < dma_busy_wait_threshold) {
  45 +               bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
  46 +               bcm_dma_wait_idle(fb->dma_chan_base);
  47 +       } else {
  48 +               void __iomem *dma_chan = fb->dma_chan_base;
  49 +               cb->info |= BCM2708_DMA_INT_EN;
  50 +               bcm_dma_start(fb->dma_chan_base, fb->cb_handle);
  51 +               while (bcm_dma_is_busy(dma_chan)) {
  52 +                       wait_event_interruptible(
  53 +                               fb->dma_waitq,
  54 +                               !bcm_dma_is_busy(dma_chan));
  55 +               }
  56 +               fb->stats.dma_irqs++;
  57 +       }
  58 +       fb->stats.dma_copies++;
  59 +}
  60 +
  61 +#define INTALIAS_NORMAL(x) ((x)&~0xc0000000) // address with no aliases
  62 +#define INTALIAS_L1L2_NONALLOCATING(x) (((x)&~0xc0000000)|0x80000000) // cache coherent but non-allocating in L1 and L2
  63 +
  64 +static long vc_mem_copy(struct bcm2708_fb *fb, unsigned long arg)
  65 +{
  66 +       struct fb_dmacopy ioparam;
  67 +       size_t size = PAGE_SIZE;
  68 +       u32 *buf = NULL;
  69 +       dma_addr_t bus_addr;
  70 +       long rc = 0;
  71 +       size_t offset;
  72 +       struct { u32 base, length; } gpu = {};
  73 +
  74 +       /* restrict this to root user */
  75 +       if (!uid_eq(current_euid(), GLOBAL_ROOT_UID))
  76 +       {
  77 +               rc = -EFAULT;
  78 +               goto out;
  79 +       }
  80 +
  81 +       /* Get the parameter data.
  82 +        */
  83 +       if (copy_from_user
  84 +           (&ioparam, (void *)arg, sizeof(ioparam)) != 0) {
  85 +               pr_err("[%s]: failed to copy-from-user\n",
  86 +                               __func__);
  87 +               rc = -EFAULT;
  88 +               goto out;
  89 +       }
  90 +
  91 +       rc = rpi_firmware_property(fb->fw,
  92 +                                   RPI_FIRMWARE_GET_VC_MEMORY,
  93 +                                   &gpu, sizeof(gpu));
  94 +       if (rc != 0 || gpu.base == 0 || gpu.length == 0) {
  95 +               pr_err("[%s]: Unable to determine gpu memory %ld,%x,%x)\n", __func__, rc, gpu.base, gpu.length);
  96 +               return -EFAULT;
  97 +       }
  98 +
  99 +       if (INTALIAS_NORMAL(ioparam.src) < gpu.base || INTALIAS_NORMAL(ioparam.src) >= gpu.base + gpu.length) {
 100 +               pr_err("[%s]: Invalid memory access %x (%x-%x)", __func__, INTALIAS_NORMAL(ioparam.src), gpu.base, gpu.base + gpu.length);
 101 +               return -EFAULT;
 102 +       }
 103 +
 104 +       buf = dma_alloc_coherent(NULL, PAGE_ALIGN(size), &bus_addr,
 105 +                                GFP_ATOMIC);
 106 +       if (!buf) {
 107 +               pr_err("[%s]: failed to dma_alloc_coherent(%d)\n",
 108 +                               __func__, size);
 109 +               rc = -ENOMEM;
 110 +               goto out;
 111 +       }
 112 +
 113 +       for (offset = 0; offset < ioparam.length; offset += size) {
 114 +               size_t remaining = ioparam.length - offset;
 115 +               size_t s = min(size, remaining);
 116 +               unsigned char *p = (unsigned char *)ioparam.src + offset;
 117 +               unsigned char *q = (unsigned char *)ioparam.dst + offset;
 118 +               dma_memcpy(fb, (dma_addr_t)buf, INTALIAS_L1L2_NONALLOCATING((dma_addr_t)p), size);
 119 +               if (copy_to_user(q, buf, s) != 0) {
 120 +                       pr_err("[%s]: failed to copy-to-user\n",
 121 +                                       __func__);
 122 +                       rc = -EFAULT;
 123 +                       goto out;
 124 +               }
 125 +       }
 126 +out:
 127 +       if (buf)
 128 +               dma_free_coherent(NULL, PAGE_ALIGN(size), buf, bus_addr);
 129 +       return rc;
 130 +}
 131 +
 132  static int bcm2708_ioctl(struct fb_info *info, unsigned int cmd, unsigned long arg)
 133  {
 134         struct bcm2708_fb *fb = to_bcm2708(info);
 135 @@ -441,6 +547,9 @@ static int bcm2708_ioctl(struct fb_info
 136                                             RPI_FIRMWARE_FRAMEBUFFER_SET_VSYNC,
 137                                             &dummy, sizeof(dummy));
 138                 break;
 139 +       case FBIODMACOPY:
 140 +               ret = vc_mem_copy(fb, arg);
 141 +               break;
 142         default:
 143                 dev_dbg(info->device, "Unknown ioctl 0x%x\n", cmd);
 144                 return -ENOTTY;
 145 --- a/include/uapi/linux/fb.h
 146 +++ b/include/uapi/linux/fb.h
 147 @@ -39,6 +39,7 @@
 148   * be concurrently added to the mainline kernel
 149   */
 150  #define FBIOCOPYAREA           _IOW('z', 0x21, struct fb_copyarea)
 151 +#define FBIODMACOPY            _IOW('z', 0x22, struct fb_dmacopy)
 152
 153  #define FB_TYPE_PACKED_PIXELS          0       /* Packed Pixels        */
 154  #define FB_TYPE_PLANES                 1       /* Non interleaved planes */
 155 @@ -351,6 +352,12 @@ struct fb_copyarea {
 156         __u32 sy;
 157  };
 158
 159 +struct fb_dmacopy {
 160 +       dma_addr_t dst;
 161 +       dma_addr_t src;
 162 +       __u32 length;
 163 +};
 164 +
 165  struct fb_fillrect {
 166         __u32 dx;       /* screen-relative */
 167         __u32 dy;