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add SPI.write_readinto() - bidirectional SPI

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This commit is contained in:
Dan Halbert 2017-12-04 21:49:31 -05:00 committed by Scott Shawcroft
parent 9ac6890d20
commit e75fd0e166
5 changed files with 103 additions and 15 deletions
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13
atmel-samd/common-hal/busio/SPI.c
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@ -257,3 +257,16 @@ bool common_hal_busio_spi_read(busio_spi_obj_t *self,
}
return status == STATUS_OK;
}
bool common_hal_busio_spi_transfer(busio_spi_obj_t *self, uint8_t *data_out, uint8_t *data_in, size_t len) {
if (len == 0) {
return true;
}
enum status_code status;
if (len >= 16) {
status = shared_dma_transfer(self->spi_master_instance.hw, data_out, data_in, len, 0 /*ignored*/);
} else {
status = spi_transceive_buffer_wait(&self->spi_master_instance, data_out, data_in, len);
}
return status == STATUS_OK;
}

18
atmel-samd/shared_dma.c
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@ -103,7 +103,7 @@ enum status_code shared_dma_write(Sercom* sercom, const uint8_t* buffer, uint32_
}
dma_configure(general_dma_tx.channel_id, sercom_index(sercom) * 2 + 2, false);
// Set up TX second.
// Set up TX. There is no RX job.
struct dma_descriptor_config descriptor_config;
dma_descriptor_get_config_defaults(&descriptor_config);
descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE;
@ -137,6 +137,12 @@ enum status_code shared_dma_write(Sercom* sercom, const uint8_t* buffer, uint32_
}
enum status_code shared_dma_read(Sercom* sercom, uint8_t* buffer, uint32_t length, uint8_t tx) {
return shared_dma_transfer(sercom, NULL, buffer, length, tx);
}
// Do write and read simultaneously. If buffer_out is NULL, write the tx byte over and over.
// If buffer_out is a real buffer, ignore tx.
enum status_code shared_dma_transfer(Sercom* sercom, uint8_t* buffer_out, uint8_t* buffer_in, uint32_t length, uint8_t tx) {
if (general_dma_tx.job_status != STATUS_OK) {
return general_dma_tx.job_status;
}
@ -153,17 +159,19 @@ enum status_code shared_dma_read(Sercom* sercom, uint8_t* buffer, uint32_t lengt
descriptor_config.block_transfer_count = length;
// DATA register is consistently addressed across all SERCOM modes.
descriptor_config.source_address = ((uint32_t)&sercom->SPI.DATA.reg);
descriptor_config.destination_address = ((uint32_t)buffer + length);
descriptor_config.destination_address = ((uint32_t)buffer_in + length);
dma_descriptor_create(general_dma_rx.descriptor, &descriptor_config);
// Set up TX to retransmit the same byte over and over.
// Set up TX second.
dma_descriptor_get_config_defaults(&descriptor_config);
descriptor_config.beat_size = DMA_BEAT_SIZE_BYTE;
descriptor_config.src_increment_enable = false;
// Increment write address only if we have a real buffer.
descriptor_config.src_increment_enable = buffer_out != NULL;
descriptor_config.dst_increment_enable = false;
descriptor_config.block_transfer_count = length;
descriptor_config.source_address = ((uint32_t)&tx);
//
descriptor_config.source_address = ((uint32_t) (buffer_out != NULL ? buffer_out + length : &tx));
// DATA register is consistently addressed across all SERCOM modes.
descriptor_config.destination_address = ((uint32_t)&sercom->SPI.DATA.reg);

1
atmel-samd/shared_dma.h
View File

@ -39,6 +39,7 @@ void init_shared_dma(void);
enum status_code shared_dma_write(Sercom* sercom, const uint8_t* buffer, uint32_t length);
enum status_code shared_dma_read(Sercom* sercom, uint8_t* buffer, uint32_t length, uint8_t tx);
enum status_code shared_dma_transfer(Sercom* sercom, uint8_t* buffer_out, uint8_t* buffer_in, uint32_t length, uint8_t tx);
// Allocate a counter to track how far along we are in a DMA double buffer.
bool allocate_block_counter(void);

83
shared-bindings/busio/SPI.c
View File

@ -206,12 +206,12 @@ MP_DEFINE_CONST_FUN_OBJ_1(busio_spi_unlock_obj, busio_spi_obj_unlock);
//| .. method:: SPI.write(buffer, \*, start=0, end=len(buffer))
//|
//| Write the data contained in ``buf``. Requires the SPI being locked.
//| Write the data contained in ``buffer``. The SPI object must be locked.
//| If the buffer is empty, nothing happens.
//|
//| :param bytearray buffer: buffer containing the bytes to write
//| :param int start: Index to start writing from
//| :param int end: Index to read up to but not include
//| :param bytearray 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
//|
STATIC mp_obj_t busio_spi_write(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_buffer, ARG_start, ARG_end };
@ -247,14 +247,14 @@ MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_obj, 2, busio_spi_write);
//| .. method:: SPI.readinto(buffer, \*, start=0, end=len(buffer), write_value=0)
//|
//| Read into the buffer specified by ``buf`` while writing zeroes.
//| Requires the SPI being locked.
//| Read into ``buffer`` while writing ``write_value`` for each byte read.
//| The SPI object must be locked.
//| If the number of bytes to read is 0, nothing happens.
//|
//| :param bytearray buffer: buffer to write into
//| :param int start: Index to start writing at
//| :param int end: Index to write up to but not include
//| :param int write_value: Value to write reading. (Usually ignored.)
//| :param bytearray buffer: Read data into this buffer
//| :param int start: Start of the slice of ``buffer`` to read into: ``buffer[start:end]``
//| :param int end: End of the slice; this index is not included
//| :param int write_value: Value to write while reading. (Usually ignored.)
//|
STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_buffer, ARG_start, ARG_end, ARG_write_value };
@ -288,6 +288,68 @@ STATIC mp_obj_t busio_spi_readinto(size_t n_args, const mp_obj_t *pos_args, mp_m
}
MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_readinto_obj, 2, busio_spi_readinto);
//| .. method:: SPI.write_readinto(buffer_out, buffer_in, \*, out_start=0, out_end=len(buffer_out), in_start=0, in_end=len(buffer_in))
//|
//| Write out the data in ``buffer_out`` while simultaneously reading data into ``buffer_in``.
//| The SPI object must be locked.
//| The lengths of the slices defined by ``buffer_out[out_start:out_end]`` and ``buffer_in[in_start:in_end]``
//| must be equal.
//| If buffer slice lengths are both 0, nothing happens.
//|
//| :param bytearray buffer_out: Write out the data in this buffer
//| :param bytearray buffer_in: Read data into this buffer
//| :param int out_start: Start of the slice of buffer_out to write out: ``buffer_out[out_start:out_end]``
//| :param int out_end: End of the slice; this index is not included
//| :param int in_start: Start of the slice of ``buffer_in`` to read into: ``buffer_in[in_start:in_end]``
//| :param int in_end: End of the slice; this index is not included
//|
STATIC mp_obj_t busio_spi_write_readinto(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_buffer_out, ARG_buffer_in, ARG_out_start, ARG_out_end, ARG_in_start, ARG_in_end };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_buffer_out, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_buffer_in, MP_ARG_REQUIRED | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_out_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_out_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
{ MP_QSTR_in_start, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
{ MP_QSTR_in_end, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = INT_MAX} },
};
busio_spi_obj_t *self = MP_OBJ_TO_PTR(pos_args[0]);
raise_error_if_deinited(common_hal_busio_spi_deinited(self));
check_lock(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 buf_out_info;
mp_get_buffer_raise(args[ARG_buffer_out].u_obj, &buf_out_info, MP_BUFFER_READ);
int32_t out_start = args[ARG_out_start].u_int;
uint32_t out_length = buf_out_info.len;
normalize_buffer_bounds(&out_start, args[ARG_out_end].u_int, &out_length);
mp_buffer_info_t buf_in_info;
mp_get_buffer_raise(args[ARG_buffer_in].u_obj, &buf_in_info, MP_BUFFER_WRITE);
int32_t in_start = args[ARG_in_start].u_int;
uint32_t in_length = buf_in_info.len;
normalize_buffer_bounds(&in_start, args[ARG_in_end].u_int, &in_length);
if (out_length != in_length) {
mp_raise_ValueError("buffer slices must be of equal length");
}
if (out_length == 0) {
return mp_const_none;
}
bool ok = common_hal_busio_spi_transfer(self,
((uint8_t*)buf_out_info.buf) + out_start,
((uint8_t*)buf_in_info.buf) + in_start,
out_length);
if (!ok) {
mp_raise_OSError(MP_EIO);
}
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(busio_spi_write_readinto_obj, 2, busio_spi_write_readinto);
STATIC const mp_rom_map_elem_t busio_spi_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&busio_spi_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&default___enter___obj) },
@ -299,6 +361,7 @@ STATIC const mp_rom_map_elem_t busio_spi_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&busio_spi_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&busio_spi_write_obj) },
{ MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&busio_spi_write_readinto_obj) },
};
STATIC MP_DEFINE_CONST_DICT(busio_spi_locals_dict, busio_spi_locals_dict_table);

3
shared-bindings/busio/SPI.h
View File

@ -55,4 +55,7 @@ extern bool common_hal_busio_spi_write(busio_spi_obj_t *self, const uint8_t *dat
// Reads in len bytes while outputting zeroes.
extern bool common_hal_busio_spi_read(busio_spi_obj_t *self, uint8_t *data, size_t len, uint8_t write_value);
// Reads and write len bytes simultaneously.
extern bool common_hal_busio_spi_transfer(busio_spi_obj_t *self, uint8_t *data_out, uint8_t *data_in, size_t len);
#endif // MICROPY_INCLUDED_SHARED_BINDINGS_BUSIO_SPI_H