dde_kit: support to allocate DMA buffer per device

os/include/dde_kit/pci.h

@@ -135,6 +135,19 @@ int dde_kit_pci_first_device(int *bus, int *dev, int *fun);
  */
 int dde_kit_pci_next_device(int *bus, int *dev, int *fun);
 
+/**
+ * Allocate a DMA buffer and map it. If an IOMMU is available this functions
+ * takes care that DMA to this buffer for the given PCI device is permitted.
+ *
+ * \retval bus  bus number
+ * \retval dev  device number
+ * \retval fun  function number
+ * 
+ * \return 0 in case of failure, otherwise the virtual address of the buffer.
+ */
+dde_kit_addr_t dde_kit_pci_alloc_dma_buffer(int bus, int dev, int fun,
+                                            dde_kit_size_t size);
+
 /**
  * Initialize PCI subsystem
  *

os/src/lib/dde_kit/pci.cc

@@ -21,9 +21,11 @@
  */
 
 #include <base/printf.h>
+#include <dataspace/client.h>
 
 extern "C" {
 #include <dde_kit/pci.h>
+#include <dde_kit/pgtab.h>
 }
 
 #include "pci_tree.h"
@@ -137,6 +139,26 @@ extern "C" int dde_kit_pci_next_device(int *bus, int *dev, int *fun)
 	}
 }
 
+extern "C" dde_kit_addr_t dde_kit_pci_alloc_dma_buffer(int bus, int dev,
+                                                       int fun, 
+                                                       dde_kit_size_t size)
+{
+	try {
+		using namespace Genode;
+
+		Ram_dataspace_capability ram_cap;
+		ram_cap = pci_tree()->alloc_dma_buffer(bus, dev, fun, size);
+		addr_t base = (addr_t)env()->rm_session()->attach(ram_cap);
+
+		/* add to DDE-kit page tables */
+		addr_t phys = Dataspace_client(ram_cap).phys_addr();
+		dde_kit_pgtab_set_region_with_size((void *)base, phys, size);
+
+		return base;
+	} catch (...) {
+		return 0;
+	}
+}
 
 /********************
  ** Initialization **

os/src/lib/dde_kit/pci_tree.h

@@ -40,12 +40,14 @@ namespace Dde_kit {
 
 		private:
 
-			Pci::Device_client _device;
-			unsigned short     _bdf;    /* bus:device:function */
+			Pci::Device_client     _device;
+			unsigned short         _bdf;    /* bus:device:function */
 
 		public:
 
-			Pci_device(Pci::Device_capability device_cap) : _device(device_cap)
+			Pci_device(Pci::Device_capability device_cap)
+			:
+				_device(device_cap)
 			{
 				unsigned char bus = ~0, dev = ~0, fun = ~0;
 
@@ -118,6 +120,14 @@ namespace Dde_kit {
 
 				if (child(RIGHT)) child(RIGHT)->show();
 			}
+
+			Ram_dataspace_capability alloc_dma_buffer(Pci::Connection &pci_drv,
+			                                          size_t size)
+			{
+				/* trigger that the device gets assigned to this driver */
+				pci_drv.config_extended(_device);
+				return pci_drv.alloc_dma_buffer(_device, size);
+			}
 	};
 
 	class Pci_tree
@@ -241,6 +251,16 @@ namespace Dde_kit {
 
 				_next_bdf(d, bus, dev, fun);
 			}
+
+			Ram_dataspace_capability alloc_dma_buffer(int bus, int dev,
+			                                          int fun, size_t size)
+			{
+				Lock::Guard lock_guard(_lock);
+
+				unsigned short bdf = Pci_device::knit_bdf(bus, dev, fun);
+
+				return _lookup(bdf)->alloc_dma_buffer(_pci_drv, size);
+			}
 	};
 }