regmap: implement register striding

regmap_config.reg_stride is introduced. All extant register addresses
are a multiple of this value. Users of serial-oriented regmap busses will
typically set this to 1. Users of the MMIO regmap bus will typically set
this based on the value size of their registers, in bytes, so 4 for a
32-bit register.

Throughout the regmap code, actual register addresses are used. Wherever
the register address is used to index some array of values, the address
is divided by the stride to determine the index, or vice-versa. Error-
checking is added to all entry-points for register address data to ensure
that register addresses actually satisfy the specified stride. The MMIO
bus ensures that the specified stride is large enough for the register
size.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 23 insertions, 17 deletions

diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index e49e71fab184..e6732cf7c06e 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -39,11 +39,12 @@ struct regcache_rbtree_ctx {
 };
 
 static inline void regcache_rbtree_get_base_top_reg(
+	struct regmap *map,
 	struct regcache_rbtree_node *rbnode,
 	unsigned int *base, unsigned int *top)
 {
 	*base = rbnode->base_reg;
-	*top = rbnode->base_reg + rbnode->blklen - 1;
+	*top = rbnode->base_reg + ((rbnode->blklen - 1) * map->reg_stride);
 }
 
 static unsigned int regcache_rbtree_get_register(
@@ -70,7 +71,8 @@ static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
 
 	rbnode = rbtree_ctx->cached_rbnode;
 	if (rbnode) {
-		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
+		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
+						 &top_reg);
 		if (reg >= base_reg && reg <= top_reg)
 			return rbnode;
 	}
@@ -78,7 +80,8 @@ static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
 	node = rbtree_ctx->root.rb_node;
 	while (node) {
 		rbnode = container_of(node, struct regcache_rbtree_node, node);
-		regcache_rbtree_get_base_top_reg(rbnode, &base_reg, &top_reg);
+		regcache_rbtree_get_base_top_reg(map, rbnode, &base_reg,
+						 &top_reg);
 		if (reg >= base_reg && reg <= top_reg) {
 			rbtree_ctx->cached_rbnode = rbnode;
 			return rbnode;
@@ -92,7 +95,7 @@ static struct regcache_rbtree_node *regcache_rbtree_lookup(struct regmap *map,
 	return NULL;
 }
 
-static int regcache_rbtree_insert(struct rb_root *root,
+static int regcache_rbtree_insert(struct regmap *map, struct rb_root *root,
 				  struct regcache_rbtree_node *rbnode)
 {
 	struct rb_node **new, *parent;
@@ -106,7 +109,7 @@ static int regcache_rbtree_insert(struct rb_root *root,
 		rbnode_tmp = container_of(*new, struct regcache_rbtree_node,
 					  node);
 		/* base and top registers of the current rbnode */
-		regcache_rbtree_get_base_top_reg(rbnode_tmp, &base_reg_tmp,
+		regcache_rbtree_get_base_top_reg(map, rbnode_tmp, &base_reg_tmp,
 						 &top_reg_tmp);
 		/* base register of the rbnode to be added */
 		base_reg = rbnode->base_reg;
@@ -138,7 +141,7 @@ static int rbtree_show(struct seq_file *s, void *ignored)
 	unsigned int base, top;
 	int nodes = 0;
 	int registers = 0;
-	int average;
+	int this_registers, average;
 
 	map->lock(map);
 
@@ -146,11 +149,12 @@ static int rbtree_show(struct seq_file *s, void *ignored)
 	     node = rb_next(node)) {
 		n = container_of(node, struct regcache_rbtree_node, node);
 
-		regcache_rbtree_get_base_top_reg(n, &base, &top);
-		seq_printf(s, "%x-%x (%d)\n", base, top, top - base + 1);
+		regcache_rbtree_get_base_top_reg(map, n, &base, &top);
+		this_registers = ((top - base) / map->reg_stride) + 1;
+		seq_printf(s, "%x-%x (%d)\n", base, top, this_registers);
 
 		nodes++;
-		registers += top - base + 1;
+		registers += this_registers;
 	}
 
 	if (nodes)
@@ -255,7 +259,7 @@ static int regcache_rbtree_read(struct regmap *map,
 
 	rbnode = regcache_rbtree_lookup(map, reg);
 	if (rbnode) {
-		reg_tmp = reg - rbnode->base_reg;
+		reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 		*value = regcache_rbtree_get_register(rbnode, reg_tmp,
 						      map->cache_word_size);
 	} else {
@@ -310,7 +314,7 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 	 */
 	rbnode = regcache_rbtree_lookup(map, reg);
 	if (rbnode) {
-		reg_tmp = reg - rbnode->base_reg;
+		reg_tmp = (reg - rbnode->base_reg) / map->reg_stride;
 		val = regcache_rbtree_get_register(rbnode, reg_tmp,
 						   map->cache_word_size);
 		if (val == value)
@@ -321,13 +325,15 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 		/* look for an adjacent register to the one we are about to add */
 		for (node = rb_first(&rbtree_ctx->root); node;
 		     node = rb_next(node)) {
-			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node, node);
+			rbnode_tmp = rb_entry(node, struct regcache_rbtree_node,
+					      node);
 			for (i = 0; i < rbnode_tmp->blklen; i++) {
-				reg_tmp = rbnode_tmp->base_reg + i;
-				if (abs(reg_tmp - reg) != 1)
+				reg_tmp = rbnode_tmp->base_reg +
+						(i * map->reg_stride);
+				if (abs(reg_tmp - reg) != map->reg_stride)
 					continue;
 				/* decide where in the block to place our register */
-				if (reg_tmp + 1 == reg)
+				if (reg_tmp + map->reg_stride == reg)
 					pos = i + 1;
 				else
 					pos = i;
@@ -357,7 +363,7 @@ static int regcache_rbtree_write(struct regmap *map, unsigned int reg,
 			return -ENOMEM;
 		}
 		regcache_rbtree_set_register(rbnode, 0, value, map->cache_word_size);
-		regcache_rbtree_insert(&rbtree_ctx->root, rbnode);
+		regcache_rbtree_insert(map, &rbtree_ctx->root, rbnode);
 		rbtree_ctx->cached_rbnode = rbnode;
 	}
 
@@ -397,7 +403,7 @@ static int regcache_rbtree_sync(struct regmap *map, unsigned int min,
 			end = rbnode->blklen;
 
 		for (i = base; i < end; i++) {
-			regtmp = rbnode->base_reg + i;
+			regtmp = rbnode->base_reg + (i * map->reg_stride);
 			val = regcache_rbtree_get_register(rbnode, i,
 							   map->cache_word_size);