[PATCH rdma-core 21/27] pyverbs: Add auxiliary memory functions

[Yishai Hadas <yishaih@nvidia.com>]

From: Edward Srouji <edwards@nvidia.com>

Add some auxiliary functions to mem_alloc module to expose to Python
users the ability to read/write from/to memory, with chuncks of 4/8
bytes.
In addition, expose udma memory barriers and the ability to write on
MMIO.

Reviewed-by: Ido Kalir <idok@nvidia.com>
Signed-off-by: Edward Srouji <edwards@nvidia.com>
---
 pyverbs/CMakeLists.txt |  7 +++++++
 pyverbs/dma_util.pyx   | 25 +++++++++++++++++++++++++
 pyverbs/mem_alloc.pyx  | 46 +++++++++++++++++++++++++++++++++++++++++++++-
 3 files changed, 77 insertions(+), 1 deletion(-)
 create mode 100644 pyverbs/dma_util.pyx

diff --git a/pyverbs/CMakeLists.txt b/pyverbs/CMakeLists.txt
index c532b4c..f403719 100644
--- a/pyverbs/CMakeLists.txt
+++ b/pyverbs/CMakeLists.txt
@@ -12,6 +12,12 @@ else()
   set(DMABUF_ALLOC dmabuf_alloc_stub.c)
 endif()
 
+if (HAVE_COHERENT_DMA)
+  set(DMA_UTIL dma_util.pyx)
+else()
+  set(DMA_UTIL "")
+endif()
+
 rdma_cython_module(pyverbs ""
   addr.pyx
   base.pyx
@@ -19,6 +25,7 @@ rdma_cython_module(pyverbs ""
   cmid.pyx
   cq.pyx
   device.pyx
+  ${DMA_UTIL}
   dmabuf.pyx
   ${DMABUF_ALLOC}
   enums.pyx
diff --git a/pyverbs/dma_util.pyx b/pyverbs/dma_util.pyx
new file mode 100644
index 0000000..36d5f9b
--- /dev/null
+++ b/pyverbs/dma_util.pyx
@@ -0,0 +1,25 @@
+# SPDX-License-Identifier: (GPL-2.0 OR Linux-OpenIB)
+# Copyright (c) 2021 Nvidia, Inc. All rights reserved. See COPYING file
+
+#cython: language_level=3
+
+from libc.stdint cimport uintptr_t, uint64_t
+
+cdef extern from 'util/udma_barrier.h':
+    cdef void udma_to_device_barrier()
+    cdef void udma_from_device_barrier()
+
+cdef extern from 'util/mmio.h':
+   cdef void mmio_write64_be(void *addr, uint64_t val)
+
+
+def udma_to_dev_barrier():
+    udma_to_device_barrier()
+
+
+def udma_from_dev_barrier():
+    udma_from_device_barrier()
+
+
+def mmio_write64_as_be(addr, val):
+    mmio_write64_be(<void*><uintptr_t> addr, val)
diff --git a/pyverbs/mem_alloc.pyx b/pyverbs/mem_alloc.pyx
index 24be4f1..c6290f7 100644
--- a/pyverbs/mem_alloc.pyx
+++ b/pyverbs/mem_alloc.pyx
@@ -6,13 +6,17 @@
 from posix.stdlib cimport posix_memalign as c_posix_memalign
 from libc.stdlib cimport malloc as c_malloc, free as c_free
 from posix.mman cimport mmap as c_mmap, munmap as c_munmap
-from libc.stdint cimport uintptr_t
+from libc.stdint cimport uintptr_t, uint32_t, uint64_t
 from libc.string cimport memset
 cimport posix.mman as mm
 
 cdef extern from 'sys/mman.h':
     cdef void* MAP_FAILED
 
+cdef extern from 'endian.h':
+    unsigned long htobe32(unsigned long host_32bits)
+    unsigned long htobe64(unsigned long host_64bits)
+
 
 def mmap(addr=0, length=100, prot=mm.PROT_READ | mm.PROT_WRITE,
          flags=mm.MAP_PRIVATE | mm.MAP_ANONYMOUS, fd=0, offset=0):
@@ -82,6 +86,46 @@ def free(ptr):
     c_free(<void*><uintptr_t>ptr)
 
 
+def writebe32(addr, val, offset=0):
+    """
+    Write 32-bit value <val> as Big Endian to address <addr> and offset <offset>
+    :param addr: The start of the address to write the value to
+    :param val: Value to write
+    :param offset: Offset of the address  to write the value to (in 4-bytes)
+    """
+    (<uint32_t*><void*><uintptr_t>addr)[offset] = htobe32(val)
+
+
+def writebe64(addr, val, offset=0):
+    """
+    Write 64-bit value <val> as Big Endian to address <addr> and offset <offset>
+    :param addr: The start of the address to write the value to
+    :param val: Value to write
+    :param offset: Offset of the address  to write the value to (in 8-bytes)
+    """
+    (<uint64_t*><void*><uintptr_t>addr)[offset] = htobe64(val)
+
+
+def read32(addr, offset=0):
+    """
+    Read 32-bit value from address <addr> and offset <offset>
+    :param addr: The start of the address to read from
+    :param offset: Offset of the address to read from (in 4-bytes)
+    :return: The read value
+    """
+    return (<uint32_t*><uintptr_t>addr)[offset]
+
+
+def read64(addr, offset=0):
+    """
+    Read 64-bit value from address <addr> and offset <offset>
+    :param addr: The start of the address to read from
+    :param offset: Offset of the address to read from (in 8-bytes)
+    :return: The read value
+    """
+    return (<uint64_t*><uintptr_t>addr)[offset]
+
+
 # protection bits for mmap/mprotect
 PROT_EXEC_ = mm.PROT_EXEC
 PROT_READ_ = mm.PROT_READ
-- 
1.8.3.1