diff options
| -rw-r--r-- | src/include/device/mmio.h | 120 |
1 files changed, 120 insertions, 0 deletions
diff --git a/src/include/device/mmio.h b/src/include/device/mmio.h index e40b40f49f..7b95a3cd74 100644 --- a/src/include/device/mmio.h +++ b/src/include/device/mmio.h @@ -51,6 +51,126 @@ static inline void buffer_to_fifo32(void *buffer, size_t size, void *fifo, buffer_to_fifo32_prefix(buffer, size, 0, 0, fifo, fifo_stride, fifo_width); } + +/* + * Utilities to help processing bit fields. + * + * To define a bit field (usually inside a register), do: + * + * DEFINE_BITFIELD(name, high_bit, low_bit) + * + * - name: Name of the field to access. + * - high_bit: highest bit that's part of the bit field. + * - low_bit: lowest bit in the bit field. + * + * To extract one field value from a raw reg value: + * + * EXTRACT_BITFIELD(value, name); + * + * To read from an MMIO register and extract one field from it: + * + * READ32_BITFIELD(®, name); + * + * To write into an MMIO register, set given fields (by names) to specified + * values, and all other bits to zero (usually used for resetting a register): + * + * WRITE32_BITFIELDS(®, name, value, [name, value, ...]) + * + * To write into an MMIO register, set given fields (by names) to specified + * values, and leaving all others "unchanged" (usually used for updating some + * settings): + * + * SET32_BITFIELDS(®, name, value, [name, value, ...]) + * + * Examples: + * + * DEFINE_BITFIELD(DISP_TYPE, 2, 1) + * DEFINE_BITFIELD(DISP_EN, 0, 0) + * + * SET32_BITFIELDS(&disp_regs.ctrl, DISP_TYPE, 2); + * SET32_BITFIELDS(&disp_regs.ctrl, DISP_EN, 0); + * + * SET32_BITFIELDS(&disp_regs.ctrl, DISP_TYPE, 1, DISP_EN, 1); + * WRITE32_BITFIELDS(&disp_regs.ctrl, DISP_TYPE, 1, DISP_EN, 1); + * + * READ32_BITFIELD(®, DISP_TYPE) + * EXTRACT_BITFIELD(value, DISP_TYPE) + * + * These will be translated to: + * + * clrsetbits_le32(&disp_regs.ctrl, 0x6, 0x4); + * clrsetbits_le32(&disp_regs.ctrl, 0x1, 0x0); + * + * clrsetbits_le32(&disp_regs.ctrl, 0x7, 0x3); + * write32(&disp_regs.ctrl, 0x3); + * + * (read32(®) & 0x6) >> 1 + * (value & 0x6) >> 1 + * + * The {WRITE,SET}32_BITFIELDS currently only allows setting up to 8 fields at + * one invocation. + */ + +#define DEFINE_BITFIELD(name, high_bit, low_bit) \ + _Static_assert(high_bit >= low_bit, "invalid bit field range"); \ + enum { \ + name##_BITFIELD_SHIFT = (low_bit), \ + name##_BITFIELD_SIZE = (high_bit) - (low_bit) + 1, \ + }; + +#define _BF_MASK(name, value) \ + (((1 << name##_BITFIELD_SIZE) - 1) << name##_BITFIELD_SHIFT) + +#define _BF_VALUE(name, value) \ + ((value) << name##_BITFIELD_SHIFT) + +#define _BF_APPLY1(op, name, value, ...) (op(name, value)) +#define _BF_APPLY2(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY1(op, __VA_ARGS__)) +#define _BF_APPLY3(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY2(op, __VA_ARGS__)) +#define _BF_APPLY4(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY3(op, __VA_ARGS__)) +#define _BF_APPLY5(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY4(op, __VA_ARGS__)) +#define _BF_APPLY6(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY5(op, __VA_ARGS__)) +#define _BF_APPLY7(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY6(op, __VA_ARGS__)) +#define _BF_APPLY8(op, name, value, ...) ((op(name, value)) | \ + _BF_APPLY7(op, __VA_ARGS__)) +#define _BF_APPLYINVALID(...) \ + _Static_assert(0, "Invalid arguments for {WRITE,SET}*_BITFIELDS") + +#define _BF_IMPL2(op, addr, \ + n1, v1, n2, v2, n3, v3, n4, v4, n5, v5, n6, v6, n7, v7, n8, v8, \ + NARGS, ...) \ + \ + op(addr, \ + _BF_APPLY##NARGS(_BF_MASK, n1, v1, n2, v2, n3, v3, n4, v4, \ + n5, v5, n6, v6, n7, v7, n8, v8), \ + _BF_APPLY##NARGS(_BF_VALUE, n1, v1, n2, v2, n3, v3, n4, v4, \ + n5, v5, n6, v6, n7, v7, n8, v8)) + +#define _BF_IMPL(op, addr, ...) \ + _BF_IMPL2(op, addr, __VA_ARGS__, \ + 8, INVALID, 7, INVALID, 6, INVALID, 5, INVALID, \ + 4, INVALID, 3, INVALID, 2, INVALID, 1, INVALID) + +#define _WRITE32_BITFIELDS_IMPL(addr, masks, values) write32(addr, values) + +#define WRITE32_BITFIELDS(addr, ...) \ + _BF_IMPL(_WRITE32_BITFIELDS_IMPL, addr, __VA_ARGS__) + +#define SET32_BITFIELDS(addr, ...) \ + _BF_IMPL(clrsetbits_le32, addr, __VA_ARGS__) + +#define EXTRACT_BITFIELD(value, name) \ + (((value) & _BF_MASK(name, 0)) >> name##_BITFIELD_SHIFT) + +#define READ32_BITFIELD(addr, name) \ + EXTRACT_BITFIELD(read32(addr), name) + #endif /* !__ROMCC__ */ #endif /* __DEVICE_MMIO_H__ */ |