powerpc/pseries: Update memory hotplug code to use drmem LMB array

Update the pseries memory hotplug code to use the newly added
dynamic reconfiguration LMB array. Doing this is required for the
upcoming support of version 2 of the dynamic reconfiguration
device tree property.

In addition, making this change cleans up the code that parses the
LMB information as we no longer need to worry about device tree
format. This allows us to discard one of the first steps on memory
hotplug where we make a working copy of the device tree property and
convert the entire property to cpu format. Instead we just use the
LMB array directly while holding the memory hotplug lock.

This patch also moves the updating of the device tree property to
powerpc/mm/drmem.c. This allows to the hotplug code to work without
needing to know the device tree format and provides a single
routine for updating the device tree property. This new routine
will handle determination of the proper device tree format and
generate a properly formatted device tree property.
Signed-off-by: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/include/asm/drmem.h

@@ -40,9 +40,27 @@ static inline u32 drmem_lmb_size(void)
 	return drmem_info->lmb_size;
 }
 
+#define DRMEM_LMB_RESERVED	0x80000000
+
+static inline void drmem_mark_lmb_reserved(struct drmem_lmb *lmb)
+{
+	lmb->flags |= DRMEM_LMB_RESERVED;
+}
+
+static inline void drmem_remove_lmb_reservation(struct drmem_lmb *lmb)
+{
+	lmb->flags &= ~DRMEM_LMB_RESERVED;
+}
+
+static inline bool drmem_lmb_reserved(struct drmem_lmb *lmb)
+{
+	return lmb->flags & DRMEM_LMB_RESERVED;
+}
+
 u64 drmem_lmb_memory_max(void);
 void __init walk_drmem_lmbs(struct device_node *dn,
 			void (*func)(struct drmem_lmb *, const __be32 **));
+int drmem_update_dt(void);
 
 #ifdef CONFIG_PPC_PSERIES
 void __init walk_drmem_lmbs_early(unsigned long node,

arch/powerpc/mm/drmem.c

@@ -29,6 +29,87 @@ u64 drmem_lmb_memory_max(void)
 	return last_lmb->base_addr + drmem_lmb_size();
 }
 
+static u32 drmem_lmb_flags(struct drmem_lmb *lmb)
+{
+	/*
+	 * Return the value of the lmb flags field minus the reserved
+	 * bit used internally for hotplug processing.
+	 */
+	return lmb->flags & ~DRMEM_LMB_RESERVED;
+}
+
+static struct property *clone_property(struct property *prop, u32 prop_sz)
+{
+	struct property *new_prop;
+
+	new_prop = kzalloc(sizeof(*new_prop), GFP_KERNEL);
+	if (!new_prop)
+		return NULL;
+
+	new_prop->name = kstrdup(prop->name, GFP_KERNEL);
+	new_prop->value = kzalloc(prop_sz, GFP_KERNEL);
+	if (!new_prop->name || !new_prop->value) {
+		kfree(new_prop->name);
+		kfree(new_prop->value);
+		kfree(new_prop);
+		return NULL;
+	}
+
+	new_prop->length = prop_sz;
+#if defined(CONFIG_OF_DYNAMIC)
+	of_property_set_flag(new_prop, OF_DYNAMIC);
+#endif
+	return new_prop;
+}
+
+static int drmem_update_dt_v1(struct device_node *memory,
+			      struct property *prop)
+{
+	struct property *new_prop;
+	struct of_drconf_cell *dr_cell;
+	struct drmem_lmb *lmb;
+	u32 *p;
+
+	new_prop = clone_property(prop, prop->length);
+	if (!new_prop)
+		return -1;
+
+	p = new_prop->value;
+	*p++ = cpu_to_be32(drmem_info->n_lmbs);
+
+	dr_cell = (struct of_drconf_cell *)p;
+
+	for_each_drmem_lmb(lmb) {
+		dr_cell->base_addr = cpu_to_be64(lmb->base_addr);
+		dr_cell->drc_index = cpu_to_be32(lmb->drc_index);
+		dr_cell->aa_index = cpu_to_be32(lmb->aa_index);
+		dr_cell->flags = cpu_to_be32(drmem_lmb_flags(lmb));
+
+		dr_cell++;
+	}
+
+	of_update_property(memory, new_prop);
+	return 0;
+}
+
+int drmem_update_dt(void)
+{
+	struct device_node *memory;
+	struct property *prop;
+	int rc = -1;
+
+	memory = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
+	if (!memory)
+		return -1;
+
+	prop = of_find_property(memory, "ibm,dynamic-memory", NULL);
+	if (prop)
+		rc = drmem_update_dt_v1(memory, prop);
+
+	of_node_put(memory);
+	return rc;
+}
+
 static void __init read_drconf_v1_cell(struct drmem_lmb *lmb,
 				       const __be32 **prop)
 {