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, 11 deletions

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index 1befaa7a31cb..56b8136eb36a 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -58,11 +58,12 @@ static void regmap_irq_sync_unlock(struct irq_data *data)
 	 * suppress pointless writes.
 	 */
 	for (i = 0; i < d->chip->num_regs; i++) {
-		ret = regmap_update_bits(d->map, d->chip->mask_base + i,
+		ret = regmap_update_bits(d->map, d->chip->mask_base +
+						(i * map->map->reg_stride),
 					 d->mask_buf_def[i], d->mask_buf[i]);
 		if (ret != 0)
 			dev_err(d->map->dev, "Failed to sync masks in %x\n",
-				d->chip->mask_base + i);
+				d->chip->mask_base + (i * map->reg_stride));
 	}
 
 	mutex_unlock(&d->lock);
@@ -73,7 +74,7 @@ static void regmap_irq_enable(struct irq_data *data)
 	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
 	const struct regmap_irq *irq_data = irq_to_regmap_irq(d, data->irq);
 
-	d->mask_buf[irq_data->reg_offset] &= ~irq_data->mask;
+	d->mask_buf[irq_data->reg_offset / map->reg_stride] &= ~irq_data->mask;
 }
 
 static void regmap_irq_disable(struct irq_data *data)
@@ -81,7 +82,7 @@ static void regmap_irq_disable(struct irq_data *data)
 	struct regmap_irq_chip_data *d = irq_data_get_irq_chip_data(data);
 	const struct regmap_irq *irq_data = irq_to_regmap_irq(d, data->irq);
 
-	d->mask_buf[irq_data->reg_offset] |= irq_data->mask;
+	d->mask_buf[irq_data->reg_offset / map->reg_stride] |= irq_data->mask;
 }
 
 static struct irq_chip regmap_irq_chip = {
@@ -136,17 +137,19 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 		data->status_buf[i] &= ~data->mask_buf[i];
 
 		if (data->status_buf[i] && chip->ack_base) {
-			ret = regmap_write(map, chip->ack_base + i,
+			ret = regmap_write(map, chip->ack_base +
+						(i * map->reg_stride),
 					   data->status_buf[i]);
 			if (ret != 0)
 				dev_err(map->dev, "Failed to ack 0x%x: %d\n",
-					chip->ack_base + i, ret);
+					chip->ack_base + (i * map->reg_stride),
+					ret);
 		}
 	}
 
 	for (i = 0; i < chip->num_irqs; i++) {
-		if (data->status_buf[chip->irqs[i].reg_offset] &
-		    chip->irqs[i].mask) {
+		if (data->status_buf[chip->irqs[i].reg_offset /
+				     map->reg_stride] & chip->irqs[i].mask) {
 			handle_nested_irq(data->irq_base + i);
 			handled = true;
 		}
@@ -181,6 +184,14 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
 	int cur_irq, i;
 	int ret = -ENOMEM;
 
+	for (i = 0; i < chip->num_irqs; i++) {
+		if (chip->irqs[i].reg_offset % map->reg_stride)
+			return -EINVAL;
+		if (chip->irqs[i].reg_offset / map->reg_stride >=
+		    chip->num_regs)
+			return -EINVAL;
+	}
+
 	irq_base = irq_alloc_descs(irq_base, 0, chip->num_irqs, 0);
 	if (irq_base < 0) {
 		dev_warn(map->dev, "Failed to allocate IRQs: %d\n",
@@ -218,16 +229,17 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
 	mutex_init(&d->lock);
 
 	for (i = 0; i < chip->num_irqs; i++)
-		d->mask_buf_def[chip->irqs[i].reg_offset]
+		d->mask_buf_def[chip->irqs[i].reg_offset / map->reg_stride]
 			|= chip->irqs[i].mask;
 
 	/* Mask all the interrupts by default */
 	for (i = 0; i < chip->num_regs; i++) {
 		d->mask_buf[i] = d->mask_buf_def[i];
-		ret = regmap_write(map, chip->mask_base + i, d->mask_buf[i]);
+		ret = regmap_write(map, chip->mask_base + (i * map->reg_stride),
+				   d->mask_buf[i]);
 		if (ret != 0) {
 			dev_err(map->dev, "Failed to set masks in 0x%x: %d\n",
-				chip->mask_base + i, ret);
+				chip->mask_base + (i * map->reg_stride), ret);
 			goto err_alloc;
 		}
 	}