From 2165408c7f64fcaa66a024fada65639f4a334347 Mon Sep 17 00:00:00 2001
From: popcornmix <popcornmix@gmail.com>
Date: Mon, 14 Nov 2016 16:01:04 +0000
Subject: [PATCH] vcdbg: Use dma driver to access gpu memory

---
 .../linux/libs/debug_sym/debug_sym.c          | 44 +++++++++++++++++++
 host_support/include/vc_mem.h                 |  1 +
 2 files changed, 45 insertions(+)

diff --git a/host_applications/linux/libs/debug_sym/debug_sym.c b/host_applications/linux/libs/debug_sym/debug_sym.c
index 655a0f4..51ee49a 100755
--- a/host_applications/linux/libs/debug_sym/debug_sym.c
+++ b/host_applications/linux/libs/debug_sym/debug_sym.c
@@ -139,6 +139,40 @@ int OpenVideoCoreMemory( VC_MEM_ACCESS_HANDLE_T *vcHandlePtr  )
 *
 ***************************************************************************/
 
+struct fb_dmacopy {
+	uint32_t dst;
+	uint32_t src;
+	uint32_t length;
+};
+#define FBIODMACOPY _IOW('z', 0x22, struct fb_dmacopy)
+
+static int vc_mem_copy(uint32_t dst, uint32_t src, uint32_t length)
+{
+    const char *filename = "/dev/fb0";
+    int memFd;
+    struct fb_dmacopy ioparam;
+
+    ioparam.dst = dst;
+    ioparam.src = src;
+    ioparam.length = length;
+
+    if (( memFd = open( filename, O_RDWR | O_SYNC )) < 0 )
+    {
+        ERR( "Unable to open '%s': %s(%d)\n", filename, strerror( errno ), errno );
+        return -errno;
+    }
+
+    if ( ioctl( memFd, FBIODMACOPY, &ioparam ) != 0 )
+    {
+        ERR( "Failed to get memory size via ioctl: %s(%d)\n",
+            strerror( errno ), errno );
+        close( memFd );
+        return -errno;
+    }
+    close( memFd );
+    return 0;
+}
+
 int OpenVideoCoreMemoryFile( const char *filename, VC_MEM_ACCESS_HANDLE_T *vcHandlePtr )
 {
     return OpenVideoCoreMemoryFileWithOffset( filename, vcHandlePtr, 0 );
@@ -533,6 +567,7 @@ static int AccessVideoCoreMemory( VC_MEM_ACCESS_HANDLE_T vcHandle,
                                   VC_MEM_ADDR_T          vcMemAddr,
                                   size_t                 numBytes )
 {
+    VC_MEM_ADDR_T origVcMemAddr = vcMemAddr;
     DBG( "%s %zu bytes @ 0x%08x", mem_op == WRITE_MEM ? "Write" : "Read", numBytes, vcMemAddr );
 
     /*
@@ -587,6 +622,15 @@ static int AccessVideoCoreMemory( VC_MEM_ACCESS_HANDLE_T vcHandle,
         return 0;
     }
 #else
+    // DMA allows memory to be accessed above 1008M and is more coherent so try this first
+    if (mem_op == READ_MEM)
+    {
+        DBG( "AccessVideoCoreMemory: %p, %x, %d", buf, origVcMemAddr, numBytes );
+        int s = vc_mem_copy((uint32_t)buf, (uint32_t)origVcMemAddr, numBytes);
+        if (s == 0)
+            return 1;
+    }
+
     {
         uint8_t    *mapAddr;
         size_t      mapSize;
diff --git a/host_support/include/vc_mem.h b/host_support/include/vc_mem.h
index 0b5a53c..7de7e0b 100755
--- a/host_support/include/vc_mem.h
+++ b/host_support/include/vc_mem.h
@@ -35,6 +35,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #define VC_MEM_IOC_MEM_SIZE         _IOR( VC_MEM_IOC_MAGIC, 1, unsigned int )
 #define VC_MEM_IOC_MEM_BASE         _IOR( VC_MEM_IOC_MAGIC, 2, unsigned int )
 #define VC_MEM_IOC_MEM_LOAD         _IOR( VC_MEM_IOC_MAGIC, 3, unsigned int )
+#define VC_MEM_IOC_MEM_COPY         _IOWR( VC_MEM_IOC_MAGIC, 4, char *)
 
 #if defined( __KERNEL__ )
 #define VC_MEM_TO_ARM_ADDR_MASK 0x3FFFFFFF