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hw/registerfields: Add shared fields macros

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Occasionally a peripheral will have different operating modes, where the
MMIO layout changes, but some of the register fields have the same offsets
and behaviors.

To help support this, we add SHARED_FIELD_XX macros that create SHIFT,
LENGTH, and MASK macros for the fields that are shared across registers,
and accessors for these fields.

An example use may look as follows:
There is a peripheral with registers REG_MODE1 and REG_MODE2 at
different addreses, and both have a field FIELD1 initialized by
SHARED_FIELD().

Depending on what mode the peripheral is operating in, the user could
extract FIELD1 via
SHARED_ARRAY_FIELD_EX32(s->regs, R_REG_MODE1, FIELD1)
or
SHARED_ARRAY_FIELD_EX32(s->regs, R_REG_MODE2, FIELD1)

Signed-off-by: Joe Komlodi <komlodi@google.com>
Change-Id: Id3dc53e7d2f8741c95697cbae69a81bb699fa3cb
Message-Id: <20220331043248.2237838-2-komlodi@google.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
This commit is contained in:
Joe Komlodi 2022-06-13 14:05:48 +02:00 committed by Cédric Le Goater
parent 3302184f7f
commit 4a71d6d32e
1 changed files with 70 additions and 0 deletions
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70
include/hw/registerfields.h
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@ -154,4 +154,74 @@
#define ARRAY_FIELD_DP64(regs, reg, field, val) \
(regs)[R_ ## reg] = FIELD_DP64((regs)[R_ ## reg], reg, field, val);
/*
* These macros can be used for defining and extracting fields that have the
* same bit position across multiple registers.
*/
/* Define shared SHIFT, LENGTH, and MASK constants */
#define SHARED_FIELD(name, shift, length) \
enum { name ## _ ## SHIFT = (shift)}; \
enum { name ## _ ## LENGTH = (length)}; \
enum { name ## _ ## MASK = MAKE_64BIT_MASK(shift, length)};
/* Extract a shared field */
#define SHARED_FIELD_EX8(storage, field) \
extract8((storage), field ## _SHIFT, field ## _LENGTH)
#define SHARED_FIELD_EX16(storage, field) \
extract16((storage), field ## _SHIFT, field ## _LENGTH)
#define SHARED_FIELD_EX32(storage, field) \
extract32((storage), field ## _SHIFT, field ## _LENGTH)
#define SHARED_FIELD_EX64(storage, field) \
extract64((storage), field ## _SHIFT, field ## _LENGTH)
/* Extract a shared field from a register array */
#define SHARED_ARRAY_FIELD_EX32(regs, offset, field) \
SHARED_FIELD_EX32((regs)[(offset)], field)
#define SHARED_ARRAY_FIELD_EX64(regs, offset, field) \
SHARED_FIELD_EX64((regs)[(offset)], field)
/* Deposit a shared field */
#define SHARED_FIELD_DP8(storage, field, val) ({ \
struct { \
unsigned int v:field ## _LENGTH; \
} _v = { .v = val }; \
uint8_t _d; \
_d = deposit32((storage), field ## _SHIFT, field ## _LENGTH, _v.v); \
_d; })
#define SHARED_FIELD_DP16(storage, field, val) ({ \
struct { \
unsigned int v:field ## _LENGTH; \
} _v = { .v = val }; \
uint16_t _d; \
_d = deposit32((storage), field ## _SHIFT, field ## _LENGTH, _v.v); \
_d; })
#define SHARED_FIELD_DP32(storage, field, val) ({ \
struct { \
unsigned int v:field ## _LENGTH; \
} _v = { .v = val }; \
uint32_t _d; \
_d = deposit32((storage), field ## _SHIFT, field ## _LENGTH, _v.v); \
_d; })
#define SHARED_FIELD_DP64(storage, field, val) ({ \
struct { \
uint64_t v:field ## _LENGTH; \
} _v = { .v = val }; \
uint64_t _d; \
_d = deposit64((storage), field ## _SHIFT, field ## _LENGTH, _v.v); \
_d; })
/* Deposit a shared field to a register array */
#define SHARED_ARRAY_FIELD_DP32(regs, offset, field, val) \
(regs)[(offset)] = SHARED_FIELD_DP32((regs)[(offset)], field, val);
#define SHARED_ARRAY_FIELD_DP64(regs, offset, field, val) \
(regs)[(offset)] = SHARED_FIELD_DP64((regs)[(offset)], field, val);
#endif