Re: [Xenomai-help] RTDM mmap and DMA

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

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Fillod Stephane wrote:
 > Perrine Martignoni wrote:
 > >Currently, I write an RTDM module and I would like to do DMA and mmap
 > to perform transfers who have hard constraints.
 > >I would like to know if there is an example in a driver who would help
 > me to do this.
 > 
 > I'm looking for the same need, except I'm not using RTDM, and everything
 > is in userland. Using the attached patch against Xenomai 2.4.0, I hope
 > to make it to work with something like this:

I propose the attached modifications. Is it Ok for you ?

-- 


					    Gilles Chanteperdrix.

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Index: ksrc/nucleus/heap.c
===================================================================
--- ksrc/nucleus/heap.c	(revision 3301)
+++ ksrc/nucleus/heap.c	(working copy)
@@ -1180,7 +1180,11 @@
 		 * space. Assume that we can wait to get the required memory.
 		 */
 
-		ptr = kmalloc(size, kmflags | GFP_KERNEL);
+		if (size <= KMALLOC_MAX_SIZE)
+			ptr = kmalloc(size, kmflags | GFP_KERNEL);
+		else
+			ptr = (void*) __get_free_pages(kmflags | GFP_KERNEL,
+						       get_order(size));
 
 		if (!ptr)
 			return NULL;
@@ -1212,7 +1216,10 @@
 		for (vaddr = vabase; vaddr < vabase + size; vaddr += PAGE_SIZE)
 			ClearPageReserved(virt_to_page(vaddr));
 
-		kfree(ptr);
+		if (size <= KMALLOC_MAX_SIZE)
+			kfree(ptr);
+		else
+			free_pages((unsigned long)ptr, get_order(size));
 	}
 }
 
Index: ksrc/skins/native/heap.c
===================================================================
--- ksrc/skins/native/heap.c	(revision 3301)
+++ ksrc/skins/native/heap.c	(working copy)
@@ -730,6 +730,7 @@
 	info->usablemem = xnheap_usable_mem(&heap->heap_base);
 	info->usedmem = xnheap_used_mem(&heap->heap_base);
 	info->mode = heap->mode;
+	info->phys_addr = (heap->mode & H_SINGLE) ? virt_to_phys(heap->sba):0;
 
       unlock_and_exit:
 
Index: include/native/heap.h
===================================================================
--- include/native/heap.h	(revision 3301)
+++ include/native/heap.h	(working copy)
@@ -48,6 +48,8 @@
 
     char name[XNOBJECT_NAME_LEN]; /* !< Symbolic name. */
 
+    unsigned long phys_addr;	/* !< Physical address. */
+
 } RT_HEAP_INFO;
 
 typedef struct rt_heap_placeholder {
Index: include/asm-generic/wrappers.h
===================================================================
--- include/asm-generic/wrappers.h	(revision 3301)
+++ include/asm-generic/wrappers.h	(working copy)
@@ -27,6 +27,7 @@
 
 #include <linux/version.h>
 #include <linux/module.h>
+#include <linux/slab.h>
 #include <asm/io.h>
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,0)
@@ -281,4 +282,8 @@
 #define trace_mark(ev, fmt, args...)	do { } while (0)
 #endif /* CONFIG_MARKERS */
 
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,22)
+#define KMALLOC_MAX_SIZE 131072
+#endif /* !KMALLOC_MAX_SIZE */
+
 #endif /* _XENO_ASM_GENERIC_WRAPPERS_H */