unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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regmap: allow busses to request formatting with specific endianness

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Add a field to struct regmap_bus that allows bus drivers to request that
register addresses and values be formatted with a specific endianness.

The default endianness is unchanged from current operation: Big.

Implement native endian formatting/parsing for 16- and 32-bit values.
This will be enough to support regmap-mmio.c.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Stephen Warren 2012-05-24 10:47:26 -06:00 committed by Mark Brown
parent f8f5701bda
commit 141eba2e00
2 changed files with 115 additions and 11 deletions
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101
drivers/base/regmap/regmap.c
View file

@ -119,13 +119,19 @@ static void regmap_format_8(void *buf, unsigned int val, unsigned int shift)
b[0] = val << shift; b[0] = val << shift;
} }
static void regmap_format_16(void *buf, unsigned int val, unsigned int shift) static void regmap_format_16_be(void *buf, unsigned int val, unsigned int shift)
{ {
__be16 *b = buf; __be16 *b = buf;
b[0] = cpu_to_be16(val << shift); b[0] = cpu_to_be16(val << shift);
} }
static void regmap_format_16_native(void *buf, unsigned int val,
unsigned int shift)
{
*(u16 *)buf = val << shift;
}
static void regmap_format_24(void *buf, unsigned int val, unsigned int shift) static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)
{ {
u8 *b = buf; u8 *b = buf;
@ -137,13 +143,19 @@ static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)
b[2] = val; b[2] = val;
} }
static void regmap_format_32(void *buf, unsigned int val, unsigned int shift) static void regmap_format_32_be(void *buf, unsigned int val, unsigned int shift)
{ {
__be32 *b = buf; __be32 *b = buf;
b[0] = cpu_to_be32(val << shift); b[0] = cpu_to_be32(val << shift);
} }
static void regmap_format_32_native(void *buf, unsigned int val,
unsigned int shift)
{
*(u32 *)buf = val << shift;
}
static unsigned int regmap_parse_8(void *buf) static unsigned int regmap_parse_8(void *buf)
{ {
u8 *b = buf; u8 *b = buf;
@ -151,7 +163,7 @@ static unsigned int regmap_parse_8(void *buf)
return b[0]; return b[0];
} }
static unsigned int regmap_parse_16(void *buf) static unsigned int regmap_parse_16_be(void *buf)
{ {
__be16 *b = buf; __be16 *b = buf;
@ -160,6 +172,11 @@ static unsigned int regmap_parse_16(void *buf)
return b[0]; return b[0];
} }
static unsigned int regmap_parse_16_native(void *buf)
{
return *(u16 *)buf;
}
static unsigned int regmap_parse_24(void *buf) static unsigned int regmap_parse_24(void *buf)
{ {
u8 *b = buf; u8 *b = buf;
@ -170,7 +187,7 @@ static unsigned int regmap_parse_24(void *buf)
return ret; return ret;
} }
static unsigned int regmap_parse_32(void *buf) static unsigned int regmap_parse_32_be(void *buf)
{ {
__be32 *b = buf; __be32 *b = buf;
@ -179,6 +196,11 @@ static unsigned int regmap_parse_32(void *buf)
return b[0]; return b[0];
} }
static unsigned int regmap_parse_32_native(void *buf)
{
return *(u32 *)buf;
}
static void regmap_lock_mutex(struct regmap *map) static void regmap_lock_mutex(struct regmap *map)
{ {
mutex_lock(&map->mutex); mutex_lock(&map->mutex);
@ -227,6 +249,7 @@ struct regmap *regmap_init(struct device *dev,
{ {
struct regmap *map, **m; struct regmap *map, **m;
int ret = -EINVAL; int ret = -EINVAL;
enum regmap_endian reg_endian, val_endian;
if (!bus || !config) if (!bus || !config)
goto err; goto err;
@ -275,6 +298,18 @@ struct regmap *regmap_init(struct device *dev,
map->read_flag_mask = bus->read_flag_mask; map->read_flag_mask = bus->read_flag_mask;
} }
reg_endian = config->reg_format_endian;
if (reg_endian == REGMAP_ENDIAN_DEFAULT)
reg_endian = bus->reg_format_endian_default;
if (reg_endian == REGMAP_ENDIAN_DEFAULT)
reg_endian = REGMAP_ENDIAN_BIG;
val_endian = config->val_format_endian;
if (val_endian == REGMAP_ENDIAN_DEFAULT)
val_endian = bus->val_format_endian_default;
if (val_endian == REGMAP_ENDIAN_DEFAULT)
val_endian = REGMAP_ENDIAN_BIG;
switch (config->reg_bits + map->reg_shift) { switch (config->reg_bits + map->reg_shift) {
case 2: case 2:
switch (config->val_bits) { switch (config->val_bits) {
@ -321,11 +356,29 @@ struct regmap *regmap_init(struct device *dev,
break; break;
case 16: case 16:
map->format.format_reg = regmap_format_16; switch (reg_endian) {
case REGMAP_ENDIAN_BIG:
map->format.format_reg = regmap_format_16_be;
break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_reg = regmap_format_16_native;
break;
default:
goto err_map;
}
break; break;
case 32: case 32:
map->format.format_reg = regmap_format_32; switch (reg_endian) {
case REGMAP_ENDIAN_BIG:
map->format.format_reg = regmap_format_32_be;
break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_reg = regmap_format_32_native;
break;
default:
goto err_map;
}
break; break;
default: default:
@ -338,21 +391,47 @@ struct regmap *regmap_init(struct device *dev,
map->format.parse_val = regmap_parse_8; map->format.parse_val = regmap_parse_8;
break; break;
case 16: case 16:
map->format.format_val = regmap_format_16; switch (val_endian) {
map->format.parse_val = regmap_parse_16; case REGMAP_ENDIAN_BIG:
map->format.format_val = regmap_format_16_be;
map->format.parse_val = regmap_parse_16_be;
break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_val = regmap_format_16_native;
map->format.parse_val = regmap_parse_16_native;
break;
default:
goto err_map;
}
break; break;
case 24: case 24:
if (val_endian != REGMAP_ENDIAN_BIG)
goto err_map;
map->format.format_val = regmap_format_24; map->format.format_val = regmap_format_24;
map->format.parse_val = regmap_parse_24; map->format.parse_val = regmap_parse_24;
break; break;
case 32: case 32:
map->format.format_val = regmap_format_32; switch (val_endian) {
map->format.parse_val = regmap_parse_32; case REGMAP_ENDIAN_BIG:
map->format.format_val = regmap_format_32_be;
map->format.parse_val = regmap_parse_32_be;
break;
case REGMAP_ENDIAN_NATIVE:
map->format.format_val = regmap_format_32_native;
map->format.parse_val = regmap_parse_32_native;
break;
default:
goto err_map;
}
break; break;
} }
if (map->format.format_write) if (map->format.format_write) {
if ((reg_endian != REGMAP_ENDIAN_BIG) ||
(val_endian != REGMAP_ENDIAN_BIG))
goto err_map;
map->use_single_rw = true; map->use_single_rw = true;
}
if (!map->format.format_write && if (!map->format.format_write &&
!(map->format.format_reg && map->format.format_val)) !(map->format.format_reg && map->format.format_val))

25
include/linux/regmap.h
View file

@ -43,6 +43,14 @@ struct reg_default {
#ifdef CONFIG_REGMAP #ifdef CONFIG_REGMAP
enum regmap_endian {
/* Unspecified -> 0 -> Backwards compatible default */
REGMAP_ENDIAN_DEFAULT = 0,
REGMAP_ENDIAN_BIG,
REGMAP_ENDIAN_LITTLE,
REGMAP_ENDIAN_NATIVE,
};
/** /**
* Configuration for the register map of a device. * Configuration for the register map of a device.
* *
@ -84,6 +92,12 @@ struct reg_default {
* @reg_defaults_raw: Power on reset values for registers (for use with * @reg_defaults_raw: Power on reset values for registers (for use with
* register cache support). * register cache support).
* @num_reg_defaults_raw: Number of elements in reg_defaults_raw. * @num_reg_defaults_raw: Number of elements in reg_defaults_raw.
* @reg_format_endian: Endianness for formatted register addresses. If this is
* DEFAULT, the @reg_format_endian_default value from the
* regmap bus is used.
* @val_format_endian: Endianness for formatted register values. If this is
* DEFAULT, the @reg_format_endian_default value from the
* regmap bus is used.
*/ */
struct regmap_config { struct regmap_config {
const char *name; const char *name;
@ -109,6 +123,9 @@ struct regmap_config {
u8 write_flag_mask; u8 write_flag_mask;
bool use_single_rw; bool use_single_rw;
enum regmap_endian reg_format_endian;
enum regmap_endian val_format_endian;
}; };
typedef int (*regmap_hw_write)(void *context, const void *data, typedef int (*regmap_hw_write)(void *context, const void *data,
@ -133,6 +150,12 @@ typedef void (*regmap_hw_free_context)(void *context);
* data. * data.
* @read_flag_mask: Mask to be set in the top byte of the register when doing * @read_flag_mask: Mask to be set in the top byte of the register when doing
* a read. * a read.
* @reg_format_endian_default: Default endianness for formatted register
* addresses. Used when the regmap_config specifies DEFAULT. If this is
* DEFAULT, BIG is assumed.
* @val_format_endian_default: Default endianness for formatted register
* values. Used when the regmap_config specifies DEFAULT. If this is
* DEFAULT, BIG is assumed.
*/ */
struct regmap_bus { struct regmap_bus {
bool fast_io; bool fast_io;
@ -141,6 +164,8 @@ struct regmap_bus {
regmap_hw_read read; regmap_hw_read read;
regmap_hw_free_context free_context; regmap_hw_free_context free_context;
u8 read_flag_mask; u8 read_flag_mask;
enum regmap_endian reg_format_endian_default;
enum regmap_endian val_format_endian_default;
}; };
struct regmap *regmap_init(struct device *dev, struct regmap *regmap_init(struct device *dev,