powerpc/drmem: Add support for ibm, dynamic-memory-v2 property

The Power Hypervisor has introduced a new device tree format for
the property describing the dynamic reconfiguration LMBs for a system,
ibm,dynamic-memory-v2. This new format condenses the size of the
property, especially on large memory systems, by reporting sets
of LMBs that have the same properties (flags and associativity array
index).

This patch updates the powerpc/mm/drmem.c code to provide routines
that can parse the new device tree format during the walk_drmem_lmb*
routines used during boot, the creation of the LMB array, and updating
the device tree to create a new property in the proper format for
ibm,dynamic-memory-v2.

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

@@ -50,6 +50,19 @@ struct of_drconf_cell_v1 {
 	__be32	flags;
 };
 
+/*
+ * Version 2 of the ibm,dynamic-memory property is defined as a
+ * 32-bit value specifying the number of LMB sets followed by an
+ * array of of_drconf_cell_v2 entries, one per LMB set.
+ */
+struct of_drconf_cell_v2 {
+	u32	seq_lmbs;
+	u64	base_addr;
+	u32	drc_index;
+	u32	aa_index;
+	u32	flags;
+} __packed;
+
 #define DRCONF_MEM_ASSIGNED	0x00000008
 #define DRCONF_MEM_AI_INVALID	0x00000040
 #define DRCONF_MEM_RESERVED	0x00000080

arch/powerpc/mm/drmem.c

@@ -92,6 +92,84 @@ static int drmem_update_dt_v1(struct device_node *memory,
 	return 0;
 }
 
+static void init_drconf_v2_cell(struct of_drconf_cell_v2 *dr_cell,
+				struct 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(lmb->flags);
+}
+
+static int drmem_update_dt_v2(struct device_node *memory,
+			      struct property *prop)
+{
+	struct property *new_prop;
+	struct of_drconf_cell_v2 *dr_cell;
+	struct drmem_lmb *lmb, *prev_lmb;
+	u32 lmb_sets, prop_sz, seq_lmbs;
+	u32 *p;
+
+	/* First pass, determine how many LMB sets are needed. */
+	lmb_sets = 0;
+	prev_lmb = NULL;
+	for_each_drmem_lmb(lmb) {
+		if (!prev_lmb) {
+			prev_lmb = lmb;
+			lmb_sets++;
+			continue;
+		}
+
+		if (prev_lmb->aa_index != lmb->aa_index ||
+		    prev_lmb->flags != lmb->flags)
+			lmb_sets++;
+
+		prev_lmb = lmb;
+	}
+
+	prop_sz = lmb_sets * sizeof(*dr_cell) + sizeof(__be32);
+	new_prop = clone_property(prop, prop_sz);
+	if (!new_prop)
+		return -1;
+
+	p = new_prop->value;
+	*p++ = cpu_to_be32(lmb_sets);
+
+	dr_cell = (struct of_drconf_cell_v2 *)p;
+
+	/* Second pass, populate the LMB set data */
+	prev_lmb = NULL;
+	seq_lmbs = 0;
+	for_each_drmem_lmb(lmb) {
+		if (prev_lmb == NULL) {
+			/* Start of first LMB set */
+			prev_lmb = lmb;
+			init_drconf_v2_cell(dr_cell, lmb);
+			seq_lmbs++;
+			continue;
+		}
+
+		if (prev_lmb->aa_index != lmb->aa_index ||
+		    prev_lmb->flags != lmb->flags) {
+			/* end of one set, start of another */
+			dr_cell->seq_lmbs = cpu_to_be32(seq_lmbs);
+			dr_cell++;
+
+			init_drconf_v2_cell(dr_cell, lmb);
+			seq_lmbs = 1;
+		} else {
+			seq_lmbs++;
+		}
+
+		prev_lmb = lmb;
+	}
+
+	/* close out last LMB set */
+	dr_cell->seq_lmbs = cpu_to_be32(seq_lmbs);
+	of_update_property(memory, new_prop);
+	return 0;
+}
+
 int drmem_update_dt(void)
 {
 	struct device_node *memory;
@@ -103,8 +181,13 @@ int drmem_update_dt(void)
 		return -1;
 
 	prop = of_find_property(memory, "ibm,dynamic-memory", NULL);
-	if (prop)
+	if (prop) {
 		rc = drmem_update_dt_v1(memory, prop);
+	} else {
+		prop = of_find_property(memory, "ibm,dynamic-memory-v2", NULL);
+		if (prop)
+			rc = drmem_update_dt_v2(memory, prop);
+	}
 
 	of_node_put(memory);
 	return rc;
@@ -140,6 +223,47 @@ static void __init __walk_drmem_v1_lmbs(const __be32 *prop, const __be32 *usm,
 	}
 }
 
+static void __init read_drconf_v2_cell(struct of_drconf_cell_v2 *dr_cell,
+				       const __be32 **prop)
+{
+	const __be32 *p = *prop;
+
+	dr_cell->seq_lmbs = of_read_number(p++, 1);
+	dr_cell->base_addr = dt_mem_next_cell(dt_root_addr_cells, &p);
+	dr_cell->drc_index = of_read_number(p++, 1);
+	dr_cell->aa_index = of_read_number(p++, 1);
+	dr_cell->flags = of_read_number(p++, 1);
+
+	*prop = p;
+}
+
+static void __init __walk_drmem_v2_lmbs(const __be32 *prop, const __be32 *usm,
+			void (*func)(struct drmem_lmb *, const __be32 **))
+{
+	struct of_drconf_cell_v2 dr_cell;
+	struct drmem_lmb lmb;
+	u32 i, j, lmb_sets;
+
+	lmb_sets = of_read_number(prop++, 1);
+
+	for (i = 0; i < lmb_sets; i++) {
+		read_drconf_v2_cell(&dr_cell, &prop);
+
+		for (j = 0; j < dr_cell.seq_lmbs; j++) {
+			lmb.base_addr = dr_cell.base_addr;
+			dr_cell.base_addr += drmem_lmb_size();
+
+			lmb.drc_index = dr_cell.drc_index;
+			dr_cell.drc_index++;
+
+			lmb.aa_index = dr_cell.aa_index;
+			lmb.flags = dr_cell.flags;
+
+			func(&lmb, &usm);
+		}
+	}
+}
+
 #ifdef CONFIG_PPC_PSERIES
 void __init walk_drmem_lmbs_early(unsigned long node,
 			void (*func)(struct drmem_lmb *, const __be32 **))
@@ -156,8 +280,14 @@ void __init walk_drmem_lmbs_early(unsigned long node,
 	usm = of_get_flat_dt_prop(node, "linux,drconf-usable-memory", &len);
 
 	prop = of_get_flat_dt_prop(node, "ibm,dynamic-memory", &len);
-	if (prop)
+	if (prop) {
 		__walk_drmem_v1_lmbs(prop, usm, func);
+	} else {
+		prop = of_get_flat_dt_prop(node, "ibm,dynamic-memory-v2",
+					   &len);
+		if (prop)
+			__walk_drmem_v2_lmbs(prop, usm, func);
+	}
 
 	memblock_dump_all();
 }
@@ -210,8 +340,13 @@ void __init walk_drmem_lmbs(struct device_node *dn,
 	usm = of_get_usable_memory(dn);
 
 	prop = of_get_property(dn, "ibm,dynamic-memory", NULL);
-	if (prop)
+	if (prop) {
 		__walk_drmem_v1_lmbs(prop, usm, func);
+	} else {
+		prop = of_get_property(dn, "ibm,dynamic-memory-v2", NULL);
+		if (prop)
+			__walk_drmem_v2_lmbs(prop, usm, func);
+	}
 }
 
 static void __init init_drmem_v1_lmbs(const __be32 *prop)
@@ -229,6 +364,50 @@ static void __init init_drmem_v1_lmbs(const __be32 *prop)
 		read_drconf_v1_cell(lmb, &prop);
 }
 
+static void __init init_drmem_v2_lmbs(const __be32 *prop)
+{
+	struct drmem_lmb *lmb;
+	struct of_drconf_cell_v2 dr_cell;
+	const __be32 *p;
+	u32 i, j, lmb_sets;
+	int lmb_index;
+
+	lmb_sets = of_read_number(prop++, 1);
+
+	/* first pass, calculate the number of LMBs */
+	p = prop;
+	for (i = 0; i < lmb_sets; i++) {
+		read_drconf_v2_cell(&dr_cell, &p);
+		drmem_info->n_lmbs += dr_cell.seq_lmbs;
+	}
+
+	drmem_info->lmbs = kcalloc(drmem_info->n_lmbs, sizeof(*lmb),
+				   GFP_KERNEL);
+	if (!drmem_info->lmbs)
+		return;
+
+	/* second pass, read in the LMB information */
+	lmb_index = 0;
+	p = prop;
+
+	for (i = 0; i < lmb_sets; i++) {
+		read_drconf_v2_cell(&dr_cell, &p);
+
+		for (j = 0; j < dr_cell.seq_lmbs; j++) {
+			lmb = &drmem_info->lmbs[lmb_index++];
+
+			lmb->base_addr = dr_cell.base_addr;
+			dr_cell.base_addr += drmem_info->lmb_size;
+
+			lmb->drc_index = dr_cell.drc_index;
+			dr_cell.drc_index++;
+
+			lmb->aa_index = dr_cell.aa_index;
+			lmb->flags = dr_cell.flags;
+		}
+	}
+}
+
 static int __init drmem_init(void)
 {
 	struct device_node *dn;
@@ -246,8 +425,13 @@ static int __init drmem_init(void)
 	}
 
 	prop = of_get_property(dn, "ibm,dynamic-memory", NULL);
-	if (prop)
+	if (prop) {
 		init_drmem_v1_lmbs(prop);
+	} else {
+		prop = of_get_property(dn, "ibm,dynamic-memory-v2", NULL);
+		if (prop)
+			init_drmem_v2_lmbs(prop);
+	}
 
 	of_node_put(dn);
 	return 0;