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Stub 'continuous write' functionality

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This commit is contained in:
Jeff Epler 2022-04-19 11:35:43 -05:00
parent 6425e937b5
commit 33f5598acc
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GPG Key ID: D5BF15AB975AB4DE
3 changed files with 87 additions and 0 deletions
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77
ports/raspberrypi/bindings/rp2pio/StateMachine.c
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@ -426,7 +426,82 @@ STATIC mp_obj_t rp2pio_statemachine_write(size_t n_args, const mp_obj_t *pos_arg
}
MP_DEFINE_CONST_FUN_OBJ_KW(rp2pio_statemachine_write_obj, 2, rp2pio_statemachine_write);
//| def continuous_write(self, buffer: Optional[ReadableBuffer], *, start: int = 0, end: Optional[int] = None) -> None:
//| """Write the data contained in ``buffer`` to the state machine repeatedly until stopped. If the buffer is empty or None, an existing continuous_write is canceled.
//|
//| Writes to the FIFO will match the input buffer's element size. For example, bytearray elements
//| will perform 8 bit writes to the PIO FIFO. The RP2040's memory bus will duplicate the value into
//| the other byte positions. So, pulling more data in the PIO assembly will read the duplicated values.
//|
//| To perform 16 or 32 bits writes into the FIFO use an `array.array` with a type code of the desired
//| size.
//|
//| To atomically change from one buffer to another, simply call
//| `StateMachine.continuous_write` again with a different buffer.
//| The call will only return once outputting the new buffer has started.
//|
//| If the buffer is modified while it is being written out, the updated
//| values will be used. However, because of interactions between CPU
//| writes, DMA and the PIO FIFO are complex, it is difficult to predict
//| the result of modifying multiple values. Instead, alternate between
//| a pair of buffers.
//|
//| :param ~circuitpython_typing.ReadableBuffer buffer: Write out the data in this buffer
//| :param int start: Start of the slice of ``buffer`` to write out: ``buffer[start:end]``
//| :param int end: End of the slice; this index is not included. Defaults to ``len(buffer)``"""
//| ...
//|
STATIC mp_obj_t rp2pio_statemachine_start_continuous_write(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_buffer, ARG_start, ARG_end };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_buffer, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
rp2pio_statemachine_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
check_for_deinit(self);
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args - 1, pos_args + 1, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
mp_buffer_info_t bufinfo = {};
if (args[ARG_buffer].u_obj != mp_const_none) {
mp_get_buffer_raise(args[ARG_buffer].u_obj, &bufinfo, MP_BUFFER_READ);
}
int32_t start = args[ARG_start].u_int;
size_t length = bufinfo.len;
normalize_buffer_bounds(&start, args[ARG_end].u_int, &length);
bool ok = true;
if (length == 0) {
ok = common_hal_rp2pio_statemachine_end_continuous_write(self);
} else {
uint8_t *original_pointer = bufinfo.buf;
int stride_in_bytes = mp_binary_get_size('@', bufinfo.typecode, NULL);
if (stride_in_bytes > 4) {
mp_raise_ValueError(translate("Buffer elements must be 4 bytes long or less"));
}
ok = common_hal_rp2pio_statemachine_start_continuous_write(self, ((uint8_t *)bufinfo.buf) + start, length, stride_in_bytes);
}
if (!ok) {
mp_raise_OSError(MP_EIO);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(rp2pio_statemachine_start_continuous_write_obj, 2, rp2pio_statemachine_start_continuous_write);
//| def end_continuous_write(self) -> None:
//| """Stop a continuous write, if one is in progress."""
//|
STATIC mp_obj_t rp2pio_statemachine_obj_end_continuous_write(mp_obj_t self_in) {
rp2pio_statemachine_obj_t *self = MP_OBJ_TO_PTR(self_in);
bool ok = common_hal_rp2pio_statemachine_end_continuous_write(self);
if (!ok) {
mp_raise_OSError(MP_EIO);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_1(rp2pio_statemachine_end_continuous_write_obj, rp2pio_statemachine_obj_end_continuous_write);
//| def readinto(self, buffer: WriteableBuffer, *, start: int = 0, end: Optional[int] = None) -> None:
//| """Read into ``buffer``. If the number of bytes to read is 0, nothing happens. The buffer
//| includes any data added to the fifo even if it was added before this was called.
@ -646,6 +721,8 @@ STATIC const mp_rom_map_elem_t rp2pio_statemachine_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&rp2pio_statemachine_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&rp2pio_statemachine_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&rp2pio_statemachine_write_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_start_continuous_write), MP_ROM_PTR(&rp2pio_statemachine_start_continuous_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_end_continuous_write), MP_ROM_PTR(&rp2pio_statemachine_end_continuous_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_frequency), MP_ROM_PTR(&rp2pio_statemachine_frequency_obj) },
{ MP_ROM_QSTR(MP_QSTR_rxstall), MP_ROM_PTR(&rp2pio_statemachine_rxstall_obj) },

2
ports/raspberrypi/bindings/rp2pio/StateMachine.h
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@ -65,6 +65,8 @@ void common_hal_rp2pio_statemachine_run(rp2pio_statemachine_obj_t *self, const u
// Writes out the given data.
bool common_hal_rp2pio_statemachine_write(rp2pio_statemachine_obj_t *self, const uint8_t *data, size_t len, uint8_t stride_in_bytes);
bool common_hal_rp2pio_statemachine_start_continuous_write(rp2pio_statemachine_obj_t *self, const uint8_t *data, size_t len, uint8_t stride_in_bytes);
bool common_hal_rp2pio_statemachine_end_continuous_write(rp2pio_statemachine_obj_t *self);
bool common_hal_rp2pio_statemachine_readinto(rp2pio_statemachine_obj_t *self, uint8_t *data, size_t len, uint8_t stride_in_bytes);
bool common_hal_rp2pio_statemachine_write_readinto(rp2pio_statemachine_obj_t *self,
const uint8_t *data_out, size_t out_len, uint8_t out_stride_in_bytes,

8
ports/raspberrypi/common-hal/rp2pio/StateMachine.c
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@ -848,3 +848,11 @@ uint8_t rp2pio_statemachine_program_offset(rp2pio_statemachine_obj_t *self) {
uint8_t sm = self->state_machine;
return _current_program_offset[pio_index][sm];
}
bool common_hal_rp2pio_statemachine_start_continuous_write(rp2pio_statemachine_obj_t *self, const uint8_t *data, size_t len, uint8_t stride_in_bytes) {
return false;
}
bool common_hal_rp2pio_statemachine_end_continuous_write(rp2pio_statemachine_obj_t *self) {
return false;
}