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Subject[PATCH 4/5] [PPC] update lmb for hotplug memory add/remove
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ppc kernel maintains information about logical memory blocks in
lmb.memory structure at the boot time. Its not updated for
hotplug memory add/remove. hotplug memory notifier for memory
add/remove now updates lmb.memory.

This information is useful for eHEA driver to find out the memory
layout and holes.

NOTE: Calls to lmb_add() and lmb_remove() needs to be serialized by
the caller. In this case blocking_notifier_chain(pSeries_reconfig_chain)
does that.

Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
---
arch/powerpc/platforms/pseries/hotplug-memory.c | 43 +++++++++++++++
include/linux/lmb.h | 3 -
lib/lmb.c | 66 ++++++++++++++++++++----
3 files changed, 102 insertions(+), 10 deletions(-)

Index: linux-2.6.25-rc3/lib/lmb.c
===================================================================
--- linux-2.6.25-rc3.orig/lib/lmb.c 2008-03-05 10:44:29.000000000 -0800
+++ linux-2.6.25-rc3/lib/lmb.c 2008-03-05 10:44:56.000000000 -0800
@@ -54,14 +54,13 @@ void lmb_dump_all(void)
#endif /* DEBUG */
}

-static unsigned long __init lmb_addrs_overlap(u64 base1,
- u64 size1, u64 base2, u64 size2)
+static unsigned long lmb_addrs_overlap(u64 base1, u64 size1, u64 base2,
+ u64 size2)
{
return ((base1 < (base2+size2)) && (base2 < (base1+size1)));
}

-static long __init lmb_addrs_adjacent(u64 base1, u64 size1,
- u64 base2, u64 size2)
+static long lmb_addrs_adjacent(u64 base1, u64 size1, u64 base2, u64 size2)
{
if (base2 == base1 + size1)
return 1;
@@ -71,7 +70,7 @@ static long __init lmb_addrs_adjacent(u6
return 0;
}

-static long __init lmb_regions_adjacent(struct lmb_region *rgn,
+static long lmb_regions_adjacent(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
u64 base1 = rgn->region[r1].base;
@@ -82,7 +81,7 @@ static long __init lmb_regions_adjacent(
return lmb_addrs_adjacent(base1, size1, base2, size2);
}

-static void __init lmb_remove_region(struct lmb_region *rgn, unsigned long r)
+static void lmb_remove_region(struct lmb_region *rgn, unsigned long r)
{
unsigned long i;

@@ -94,7 +93,7 @@ static void __init lmb_remove_region(str
}

/* Assumption: base addr of region 1 < base addr of region 2 */
-static void __init lmb_coalesce_regions(struct lmb_region *rgn,
+static void lmb_coalesce_regions(struct lmb_region *rgn,
unsigned long r1, unsigned long r2)
{
rgn->region[r1].size += rgn->region[r2].size;
@@ -129,7 +128,7 @@ void __init lmb_analyze(void)
}

/* This routine called with relocation disabled. */
-static long __init lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
+static long lmb_add_region(struct lmb_region *rgn, u64 base, u64 size)
{
unsigned long coalesced = 0;
long adjacent, i;
@@ -195,7 +194,7 @@ static long __init lmb_add_region(struct
}

/* This routine may be called with relocation disabled. */
-long __init lmb_add(u64 base, u64 size)
+long lmb_add(u64 base, u64 size)
{
struct lmb_region *_rgn = &(lmb.memory);

@@ -207,6 +206,55 @@ long __init lmb_add(u64 base, u64 size)

}

+long lmb_remove(u64 base, u64 size)
+{
+ struct lmb_region *rgn = &(lmb.memory);
+ u64 rgnbegin, rgnend;
+ u64 end = base + size;
+ int i;
+
+ rgnbegin = rgnend = 0; /* supress gcc warnings */
+
+ /* Find the region where (base, size) belongs to */
+ for (i=0; i < rgn->cnt; i++) {
+ rgnbegin = rgn->region[i].base;
+ rgnend = rgnbegin + rgn->region[i].size;
+
+ if ((rgnbegin <= base) && (end <= rgnend))
+ break;
+ }
+
+ /* Didn't find the region */
+ if (i == rgn->cnt)
+ return -1;
+
+ /* Check to see if we are removing entire region */
+ if ((rgnbegin == base) && (rgnend == end)) {
+ lmb_remove_region(rgn, i);
+ return 0;
+ }
+
+ /* Check to see if region is matching at the front */
+ if (rgnbegin == base) {
+ rgn->region[i].base = end;
+ rgn->region[i].size -= size;
+ return 0;
+ }
+
+ /* Check to see if the region is matching at the end */
+ if (rgnend == end) {
+ rgn->region[i].size -= size;
+ return 0;
+ }
+
+ /*
+ * We need to split the entry - adjust the current one to the
+ * beginging of the hole and add the region after hole.
+ */
+ rgn->region[i].size = base - rgn->region[i].base;
+ return lmb_add_region(rgn, end, rgnend - end);
+}
+
long __init lmb_reserve(u64 base, u64 size)
{
struct lmb_region *_rgn = &(lmb.reserved);
Index: linux-2.6.25-rc3/arch/powerpc/platforms/pseries/hotplug-memory.c
===================================================================
--- linux-2.6.25-rc3.orig/arch/powerpc/platforms/pseries/hotplug-memory.c 2008-03-05 10:44:51.000000000 -0800
+++ linux-2.6.25-rc3/arch/powerpc/platforms/pseries/hotplug-memory.c 2008-03-05 10:45:06.000000000 -0800
@@ -10,6 +10,7 @@
*/

#include <linux/of.h>
+#include <linux/lmb.h>
#include <asm/firmware.h>
#include <asm/machdep.h>
#include <asm/pSeries_reconfig.h>
@@ -58,6 +59,11 @@ static int pseries_remove_memory(struct
return ret;

/*
+ * Update memory regions for memory remove
+ */
+ lmb_remove(start_pfn << PAGE_SHIFT, regs[3]);
+
+ /*
* Remove htab bolted mappings for this section of memory
*/
start = (unsigned long)__va(start_pfn << PAGE_SHIFT);
@@ -65,6 +71,41 @@ static int pseries_remove_memory(struct
return ret;
}

+static int pseries_add_memory(struct device_node *np)
+{
+ const char *type;
+ const unsigned int *my_index;
+ const unsigned int *regs;
+ u64 start_pfn;
+ int ret = -EINVAL;
+
+ /*
+ * Check to see if we are actually adding memory
+ */
+ type = of_get_property(np, "device_type", NULL);
+ if (type == NULL || strcmp(type, "memory") != 0)
+ return 0;
+
+ /*
+ * Find the memory index and size of the removing section
+ */
+ my_index = of_get_property(np, "ibm,my-drc-index", NULL);
+ if (!my_index)
+ return ret;
+
+ regs = of_get_property(np, "reg", NULL);
+ if (!regs)
+ return ret;
+
+ start_pfn = section_nr_to_pfn(*my_index & 0xffff);
+
+ /*
+ * Update memory region to represent the memory add
+ */
+ lmb_add(start_pfn << PAGE_SHIFT, regs[3]);
+ return 0;
+}
+
static int pseries_memory_notifier(struct notifier_block *nb,
unsigned long action, void *node)
{
@@ -72,6 +113,8 @@ static int pseries_memory_notifier(struc

switch (action) {
case PSERIES_RECONFIG_ADD:
+ if (pseries_add_memory(node))
+ err = NOTIFY_BAD;
break;
case PSERIES_RECONFIG_REMOVE:
if (pseries_remove_memory(node))
Index: linux-2.6.25-rc3/include/linux/lmb.h
===================================================================
--- linux-2.6.25-rc3.orig/include/linux/lmb.h 2008-03-05 10:44:29.000000000 -0800
+++ linux-2.6.25-rc3/include/linux/lmb.h 2008-03-05 10:44:56.000000000 -0800
@@ -40,7 +40,8 @@ extern struct lmb lmb;

extern void __init lmb_init(void);
extern void __init lmb_analyze(void);
-extern long __init lmb_add(u64 base, u64 size);
+extern long lmb_add(u64 base, u64 size);
+extern long lmb_remove(u64 base, u64 size);
extern long __init lmb_reserve(u64 base, u64 size);
extern u64 __init lmb_alloc(u64 size, u64 align);
extern u64 __init lmb_alloc_base(u64 size,



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