From: Peter Crosthwaite <peter.crosthwa...@xilinx.com> Define some macros that can be used for defining registers and fields.
The REG32 macro will define A_FOO, for the byte address of a register as well as R_FOO for the uint32_t[] register number (A_FOO / 4). The FIELD macro will define FOO_BAR_MASK, FOO_BAR_SHIFT and FOO_BAR_LENGTH constants for field BAR in register FOO. Finally, there are some shorthand helpers for extracting/depositing fields from registers based on these naming schemes. Usage can greatly reduce the verbosity of device code. The deposit and extract macros (eg F_EX32, AF_DP32 etc.) can be used to generate extract and deposits without any repetition of the name stems. Signed-off-by: Peter Crosthwaite <peter.crosthwa...@xilinx.com> [ EI Changes: * Add Deposit macros ] Signed-off-by: Edgar E. Iglesias <edgar.igles...@xilinx.com> Signed-off-by: Alistair Francis <alistair.fran...@xilinx.com> --- E.g. Currently you have to define something like: \#define R_FOOREG (0x84/4) \#define R_FOOREG_BARFIELD_SHIFT 10 \#define R_FOOREG_BARFIELD_LENGTH 5 uint32_t foobar_val = extract32(s->regs[R_FOOREG], R_FOOREG_BARFIELD_SHIFT, R_FOOREG_BARFIELD_LENGTH); Which has: 2 macro definitions per field 3 register names ("FOOREG") per extract 2 field names ("BARFIELD") per extract With these macros this becomes: REG32(FOOREG, 0x84) FIELD(FOOREG, BARFIELD, 10, 5) uint32_t foobar_val = AF_EX32(s->regs, FOOREG, BARFIELD) Which has: 1 macro definition per field 1 register name per extract 1 field name per extract If you are not using arrays for the register data you can just use the non-array "F_" variants and still save 2 name stems: uint32_t foobar_val = F_EX32(s->fooreg, FOOREG, BARFIELD) Deposit is similar for depositing values. Deposit has compile-time overflow checking for literals. For example: REG32(XYZ1, 0x84) FIELD(XYZ1, TRC, 0, 4) /* Correctly set XYZ1.TRC = 5. */ AF_DP32(s->regs, XYZ1, TRC, 5); /* Incorrectly set XYZ1.TRC = 16. */ AF_DP32(s->regs, XYZ1, TRC, 16); The latter assignment results in: warning: large integer implicitly truncated to unsigned type [-Woverflow] include/hw/register.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) diff --git a/include/hw/register.h b/include/hw/register.h index 786707b..e0aac91 100644 --- a/include/hw/register.h +++ b/include/hw/register.h @@ -157,4 +157,42 @@ void register_write_memory_le(void *opaque, hwaddr addr, uint64_t value, uint64_t register_read_memory_be(void *opaque, hwaddr addr, unsigned size); uint64_t register_read_memory_le(void *opaque, hwaddr addr, unsigned size); +/* Define constants for a 32 bit register */ +#define REG32(reg, addr) \ + enum { A_ ## reg = (addr) }; \ + enum { R_ ## reg = (addr) / 4 }; + +/* Define SHIFT, LEGTH and MASK constants for a field within a register */ +#define FIELD(reg, field, shift, length) \ + enum { R_ ## reg ## _ ## field ## _SHIFT = (shift)}; \ + enum { R_ ## reg ## _ ## field ## _LENGTH = (length)}; \ + enum { R_ ## reg ## _ ## field ## _MASK = (((1ULL << (length)) - 1) \ + << (shift)) }; + +/* Extract a field from a register */ + +#define F_EX32(storage, reg, field) \ + extract32((storage), R_ ## reg ## _ ## field ## _SHIFT, \ + R_ ## reg ## _ ## field ## _LENGTH) + +/* Extract a field from an array of registers */ + +#define AF_EX32(regs, reg, field) \ + F_EX32((regs)[R_ ## reg], reg, field) + +/* Deposit a register field. */ + +#define F_DP32(storage, reg, field, val) ({ \ + struct { \ + unsigned int v:R_ ## reg ## _ ## field ## _LENGTH; \ + } v = { .v = val }; \ + uint32_t d; \ + d = deposit32((storage), R_ ## reg ## _ ## field ## _SHIFT, \ + R_ ## reg ## _ ## field ## _LENGTH, v.v); \ + d; }) + +/* Deposit a field to array of registers. */ + +#define AF_DP32(regs, reg, field, val) \ + (regs)[R_ ## reg] = F_DP32((regs)[R_ ## reg], reg, field, val); #endif -- 2.7.4