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Subject[PATCH 5/5] [PPC] provide walk_memory_resource() for ppc
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Provide walk_memory_resource() for ppc64. PPC maintains 
logic memory region mapping in lmb.memory structures. Walk
through these structures and do the callbacks for the
contiguous chunks.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
---
arch/powerpc/mm/mem.c | 30 +++++++++++++++++++++++-------
include/linux/lmb.h | 1 +
lib/lmb.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 57 insertions(+), 7 deletions(-)

Index: linux-2.6.25-rc3/lib/lmb.c
===================================================================
--- linux-2.6.25-rc3.orig/lib/lmb.c 2008-03-05 10:28:55.000000000 -0800
+++ linux-2.6.25-rc3/lib/lmb.c 2008-03-05 10:34:01.000000000 -0800
@@ -416,3 +416,36 @@ int __init lmb_is_reserved(u64 addr)
}
return 0;
}
+
+/*
+ * Given a <base, len>, find which memory regions belong to this range.
+ * Adjust the request and return a contiguous chunk.
+ */
+int lmb_find(struct lmb_property *res)
+{
+ int i;
+ u64 rstart, rend;
+
+ rstart = res->base;
+ rend = rstart + res->size - 1;
+
+ for (i = 0; i < lmb.memory.cnt; i++) {
+ u64 start = lmb.memory.region[i].base;
+ u64 end = start + lmb.memory.region[i].size - 1;
+
+ if (start > rend)
+ return -1;
+
+ if ((end >= rstart) && (start < rend)) {
+ /* adjust the request */
+ if (rstart < start)
+ rstart = start;
+ if (rend > end)
+ rend = end;
+ res->base = rstart;
+ res->size = rend - rstart + 1;
+ return 0;
+ }
+ }
+ return -1;
+}
Index: linux-2.6.25-rc3/arch/powerpc/mm/mem.c
===================================================================
--- linux-2.6.25-rc3.orig/arch/powerpc/mm/mem.c 2008-03-05 10:14:28.000000000 -0800
+++ linux-2.6.25-rc3/arch/powerpc/mm/mem.c 2008-03-05 10:32:16.000000000 -0800
@@ -148,19 +148,35 @@ out:

/*
* walk_memory_resource() needs to make sure there is no holes in a given
- * memory range. On PPC64, since this range comes from /sysfs, the range
- * is guaranteed to be valid, non-overlapping and can not contain any
- * holes. By the time we get here (memory add or remove), /proc/device-tree
- * is updated and correct. Only reason we need to check against device-tree
- * would be if we allow user-land to specify a memory range through a
- * system call/ioctl etc. instead of doing offline/online through /sysfs.
+ * memory range. PPC64 does not maintain the memory layout in /proc/iomem.
+ * Instead it maintains it in lmb.memory structures. Walk through the
+ * memory regions, find holes and callback for contiguous regions.
*/
int
walk_memory_resource(unsigned long start_pfn, unsigned long nr_pages, void *arg,
int (*func)(unsigned long, unsigned long, void *))
{
- return (*func)(start_pfn, nr_pages, arg);
+ struct lmb_property res;
+ unsigned long pfn, len;
+ u64 end;
+ int ret = -1;
+
+ res.base = (u64) start_pfn << PAGE_SHIFT;
+ res.size = (u64) nr_pages << PAGE_SHIFT;
+
+ end = res.base + res.size - 1;
+ while ((res.base < end) && (lmb_find(&res) >= 0)) {
+ pfn = (unsigned long)(res.base >> PAGE_SHIFT);
+ len = (unsigned long)(res.size >> PAGE_SHIFT);
+ ret = (*func)(pfn, len, arg);
+ if (ret)
+ break;
+ res.base += (res.size + 1);
+ res.size = (end - res.base + 1);
+ }
+ return ret;
}
+EXPORT_SYMBOL_GPL(walk_memory_resource);

#endif /* CONFIG_MEMORY_HOTPLUG */

Index: linux-2.6.25-rc3/include/linux/lmb.h
===================================================================
--- linux-2.6.25-rc3.orig/include/linux/lmb.h 2008-03-05 10:30:06.000000000 -0800
+++ linux-2.6.25-rc3/include/linux/lmb.h 2008-03-05 10:33:12.000000000 -0800
@@ -52,6 +52,7 @@ extern u64 __init lmb_phys_mem_size(void
extern u64 __init lmb_end_of_DRAM(void);
extern void __init lmb_enforce_memory_limit(u64 memory_limit);
extern int __init lmb_is_reserved(u64 addr);
+extern int lmb_find(struct lmb_property *res);

extern void lmb_dump_all(void);




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