[U-Boot] [PATCH v4 07/13] regmap: Add raw read/write functions

Mario Six
2018-08-03T08:01:12Z

The regmap functions currently assume that all register map accesses
have a data width of 32 bits, but there are maps that have different
widths.

To rectify this, implement the regmap_raw_read and regmap_raw_write
functions from the Linux kernel API that specify the width of a desired
read or write operation on a regmap.

Implement the regmap_read and regmap_write functions using these raw
functions in a backwards-compatible manner.

Reviewed-by: Anatolij Gustschin <agust@denx.de>
Signed-off-by: Mario Six <mario.six@gdsys.cc>

---

v3 -> v4:
* Switched 'ranges[0] + offset' to 'ranges[0].start + offset'
* Explained the difference between the raw and non-raw read/write
functions better in the docs

v2 -> v3:
* Implement the "raw" functions from Linux instead of adding a size
parameter to the regmap_{read,write} functions
* Fixed style violation
* Improved error handling

v1 -> v2:
New in v2

---
drivers/core/regmap.c | 54 ++++++++++++++++++++++++++++++++++++++++++-------
include/regmap.h | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+), 7 deletions(-)

diff --git a/drivers/core/regmap.c b/drivers/core/regmap.c
index 154426269d9..87c4c950a63 100644
--- a/drivers/core/regmap.c
+++ b/drivers/core/regmap.c
@@ -188,22 +188,62 @@ int regmap_uninit(struct regmap *map)
return 0;
}

+int regmap_raw_read(struct regmap *map, uint offset, void *valp, size_t val_len)
+{
+ void *ptr;
+
+ ptr = map_physmem(map->ranges[0].start + offset, val_len, MAP_NOCACHE);
+
+ switch (val_len) {
+ case REGMAP_SIZE_8:
+ *((u8 *)valp) = in_8((u8 *)ptr);
+ break;
+ case REGMAP_SIZE_16:
+ *((u16 *)valp) = in_le16((u16 *)ptr);
+ break;
+ case REGMAP_SIZE_32:
+ *((u32 *)valp) = in_le32((u32 *)ptr);
+ break;
+ default:
+ debug("%s: regmap size %u unknown\n", __func__, val_len);
+ return -EINVAL;
+ }
+ return 0;
+}
+
int regmap_read(struct regmap *map, uint offset, uint *valp)
{
- u32 *ptr = map_physmem(map->ranges[0].start + offset, 4, MAP_NOCACHE);
+ return regmap_raw_read(map, offset, valp, REGMAP_SIZE_32);
+}

- *valp = le32_to_cpu(readl(ptr));
+int regmap_raw_write(struct regmap *map, uint offset, const void *val,
+ size_t val_len)
+{
+ void *ptr;
+
+ ptr = map_physmem(map->ranges[0].start + offset, val_len, MAP_NOCACHE);
+
+ switch (val_len) {
+ case REGMAP_SIZE_8:
+ out_8((u8 *)ptr, *((u8 *)val));
+ break;
+ case REGMAP_SIZE_16:
+ out_le16((u16 *)ptr, *((u16 *)val));
+ break;
+ case REGMAP_SIZE_32:
+ out_le32((u32 *)ptr, *((u32 *)val));
+ break;
+ default:
+ debug("%s: regmap size %u unknown\n", __func__, val_len);
+ return -EINVAL;
+ }

return 0;
}

int regmap_write(struct regmap *map, uint offset, uint val)
{
- u32 *ptr = map_physmem(map->ranges[0].start + offset, 4, MAP_NOCACHE);
-
- writel(cpu_to_le32(val), ptr);
-
- return 0;
+ return regmap_raw_write(map, offset, &val, REGMAP_SIZE_32);
}

int regmap_update_bits(struct regmap *map, uint offset, uint mask, uint val)
diff --git a/include/regmap.h b/include/regmap.h
index 32f75e06f59..46ae4ed0a03 100644
--- a/include/regmap.h
+++ b/include/regmap.h
@@ -8,6 +8,19 @@
#define __REGMAP_H

/**
+ * enum regmap_size_t - Access sizes for fpgamap reads and writes
+ *
+ * @REGMAP_SIZE_8: 8-bit read/write access size
+ * @REGMAP_SIZE_16: 16-bit read/write access size
+ * @REGMAP_SIZE_32: 32-bit read/write access size
+ */
+enum regmap_size_t {
+ REGMAP_SIZE_8 = 1,
+ REGMAP_SIZE_16 = 2,
+ REGMAP_SIZE_32 = 4,
+};
+
+/**
* struct regmap_range - a register map range
*
* @start: Start address
@@ -41,6 +54,10 @@ struct regmap {
* @offset: Offset in the regmap to write to
* @val: Data to write to the regmap at the specified offset
*
+ * Note that this function will only write values of 32 bit width to the
+ * regmap; if the size of data to be read is different, the regmap_raw_write
+ * function can be used.
+ *
* Return: 0 if OK, -ve on error
*/
int regmap_write(struct regmap *map, uint offset, uint val);
@@ -53,10 +70,49 @@ int regmap_write(struct regmap *map, uint offset, uint val);
* @valp: Pointer to the buffer to receive the data read from the regmap
* at the specified offset
*
+ * Note that this function will only read values of 32 bit width from the
+ * regmap; if the size of data to be read is different, the regmap_raw_read
+ * function can be used.
+ *
* Return: 0 if OK, -ve on error
*/
int regmap_read(struct regmap *map, uint offset, uint *valp);

+/**
+ * regmap_raw_write() - Write a value of specified length to a regmap
+ *
+ * @map: Regmap to write to
+ * @offset: Offset in the regmap to write to
+ * @val: Value to write to the regmap at the specified offset
+ * @val_len: Length of the data to be written to the regmap
+ *
+ * Note that this function will, as opposed to regmap_write, write data of
+ * arbitrary length to the regmap, and not just 32-bit values, and is thus a
+ * generalized version of regmap_write.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int regmap_raw_write(struct regmap *map, uint offset, const void *val,
+ size_t val_len);
+
+/**
+ * regmap_raw_read() - Read a value of specified length from a regmap
+ *
+ * @map: Regmap to read from
+ * @offset: Offset in the regmap to read from
+ * @valp: Pointer to the buffer to receive the data read from the regmap
+ * at the specified offset
+ * @val_len: Length of the data to be read from the regmap
+ *
+ * Note that this function will, as opposed to regmap_read, read data of
+ * arbitrary length from the regmap, and not just 32-bit values, and is thus a
+ * generalized version of regmap_read.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+int regmap_raw_read(struct regmap *map, uint offset, void *valp,
+ size_t val_len);
+
#define regmap_write32(map, ptr, member, val) \
regmap_write(map, (uint32_t *)(ptr)->member - (uint32_t *)(ptr), val)

--
2.11.0