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extmod/machine_spi: Simplify SPI xfer function to only take one buf len. 

There is no need to take src_len and dest_len arguments.  The case of
reading-only with a single output byte (originally src_len=1, dest_len>1)
is now handled by using the output buffer as the input buffer, and using
memset to fill the output byte into this buffer.  This simplifies the
implementations of the spi_transfer protocol function.
This commit is contained in:
Damien George 2016-10-03 12:39:31 +11:00
parent a0d97fe408
commit 5bb28c7f10
5 changed files with 28 additions and 57 deletions
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32
esp8266/modpybhspi.c
View File

@ -50,23 +50,23 @@ typedef struct _pyb_hspi_obj_t {
} pyb_hspi_obj_t;
STATIC void hspi_transfer(mp_obj_base_t *self_in, size_t src_len, const uint8_t *src_buf, size_t dest_len, uint8_t *dest_buf) {
STATIC void hspi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
(void)self_in;
if (dest_len == 0) {
if (dest == NULL) {
// fast case when we only need to write data
size_t chunk_size = 1024;
size_t count = src_len / chunk_size;
size_t count = len / chunk_size;
size_t i = 0;
for (size_t j = 0; j < count; ++j) {
for (size_t k = 0; k < chunk_size; ++k) {
spi_tx8fast(HSPI, src_buf[i]);
spi_tx8fast(HSPI, src[i]);
++i;
}
ets_loop_iter();
}
while (i < src_len) {
spi_tx8fast(HSPI, src_buf[i]);
while (i < len) {
spi_tx8fast(HSPI, src[i]);
++i;
}
} else {
@ -74,29 +74,17 @@ STATIC void hspi_transfer(mp_obj_base_t *self_in, size_t src_len, const uint8_t
// Process data in chunks, let the pending tasks run in between
size_t chunk_size = 1024; // TODO this should depend on baudrate
size_t count = dest_len / chunk_size;
size_t count = len / chunk_size;
size_t i = 0;
for (size_t j = 0; j < count; ++j) {
for (size_t k = 0; k < chunk_size; ++k) {
uint32_t data_out;
if (src_len == 1) {
data_out = src_buf[0];
} else {
data_out = src_buf[i];
}
dest_buf[i] = spi_transaction(HSPI, 0, 0, 0, 0, 8, data_out, 8, 0);
dest[i] = spi_transaction(HSPI, 0, 0, 0, 0, 8, src[i], 8, 0);
++i;
}
ets_loop_iter();
}
while (i < dest_len) {
uint32_t data_out;
if (src_len == 1) {
data_out = src_buf[0];
} else {
data_out = src_buf[i];
}
dest_buf[i] = spi_transaction(HSPI, 0, 0, 0, 0, 8, data_out, 8, 0);
while (i < len) {
dest[i] = spi_transaction(HSPI, 0, 0, 0, 0, 8, src[i], 8, 0);
++i;
}
}

15
esp8266/modpybspi.c
View File

@ -47,17 +47,12 @@ typedef struct _pyb_spi_obj_t {
mp_hal_pin_obj_t miso;
} pyb_spi_obj_t;
STATIC void mp_hal_spi_transfer(mp_obj_base_t *self_in, size_t src_len, const uint8_t *src_buf, size_t dest_len, uint8_t *dest_buf) {
STATIC void mp_hal_spi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
pyb_spi_obj_t *self = (pyb_spi_obj_t*)self_in;
// only MSB transfer is implemented
uint32_t delay_half = 500000 / self->baudrate + 1;
for (size_t i = 0; i < src_len || i < dest_len; ++i) {
uint8_t data_out;
if (src_len == 1) {
data_out = src_buf[0];
} else {
data_out = src_buf[i];
}
for (size_t i = 0; i < len; ++i) {
uint8_t data_out = src[i];
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j, data_out <<= 1) {
mp_hal_pin_write(self->mosi, (data_out >> 7) & 1);
@ -77,8 +72,8 @@ STATIC void mp_hal_spi_transfer(mp_obj_base_t *self_in, size_t src_len, const ui
ets_delay_us(delay_half);
}
}
if (dest_len != 0) {
dest_buf[i] = data_in;
if (dest != NULL) {
dest[i] = data_in;
}
// make sure pending tasks have a chance to run
ets_loop_iter();

25
extmod/machine_spi.c
View File

@ -25,26 +25,24 @@
*/
#include <stdio.h>
#include <string.h>
#include "py/runtime.h"
#include "extmod/machine_spi.h"
#if MICROPY_PY_MACHINE_SPI
STATIC void mp_machine_spi_transfer(mp_obj_t self, size_t slen, const uint8_t *src, size_t dlen, uint8_t *dest) {
STATIC void mp_machine_spi_transfer(mp_obj_t self, size_t len, const void *src, void *dest) {
mp_obj_base_t *s = (mp_obj_base_t*)MP_OBJ_TO_PTR(self);
mp_machine_spi_p_t *spi_p = (mp_machine_spi_p_t*)s->type->protocol;
spi_p->transfer(s, slen, src, dlen, dest);
spi_p->transfer(s, len, src, dest);
}
STATIC mp_obj_t mp_machine_spi_read(size_t n_args, const mp_obj_t *args) {
uint8_t write_byte = 0;
if (n_args == 3) {
write_byte = mp_obj_get_int(args[2]);
}
vstr_t vstr;
vstr_init_len(&vstr, mp_obj_get_int(args[1]));
mp_machine_spi_transfer(args[0], 1, &write_byte, vstr.len, (uint8_t*)vstr.buf);
memset(vstr.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, vstr.len);
mp_machine_spi_transfer(args[0], vstr.len, vstr.buf, vstr.buf);
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_read_obj, 2, 3, mp_machine_spi_read);
@ -52,11 +50,8 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_read_obj, 2, 3, mp_machine_sp
STATIC mp_obj_t mp_machine_spi_readinto(size_t n_args, const mp_obj_t *args) {
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
uint8_t write_byte = 0;
if (n_args == 3) {
write_byte = mp_obj_get_int(args[2]);
}
mp_machine_spi_transfer(args[0], 1, &write_byte, bufinfo.len, (uint8_t*)bufinfo.buf);
memset(bufinfo.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, bufinfo.len);
mp_machine_spi_transfer(args[0], bufinfo.len, bufinfo.buf, bufinfo.buf);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_readinto_obj, 2, 3, mp_machine_spi_readinto);
@ -64,7 +59,7 @@ MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_readinto_obj, 2, 3, mp_machin
STATIC mp_obj_t mp_machine_spi_write(mp_obj_t self, mp_obj_t wr_buf) {
mp_buffer_info_t src;
mp_get_buffer_raise(wr_buf, &src, MP_BUFFER_READ);
mp_machine_spi_transfer(self, src.len, (const uint8_t*)src.buf, 0, NULL);
mp_machine_spi_transfer(self, src.len, (const uint8_t*)src.buf, NULL);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(mp_machine_spi_write_obj, mp_machine_spi_write);
@ -75,9 +70,9 @@ STATIC mp_obj_t mp_machine_spi_write_readinto(mp_obj_t self, mp_obj_t wr_buf, mp
mp_buffer_info_t dest;
mp_get_buffer_raise(rd_buf, &dest, MP_BUFFER_WRITE);
if (src.len != dest.len) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "buffers must be the same length"));
mp_raise_ValueError("buffers must be the same length");
}
mp_machine_spi_transfer(self, src.len, (const uint8_t*)src.buf, dest.len, (uint8_t*)dest.buf);
mp_machine_spi_transfer(self, src.len, src.buf, dest.buf);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_3(mp_machine_spi_write_readinto_obj, mp_machine_spi_write_readinto);

2
extmod/machine_spi.h
View File

@ -31,7 +31,7 @@
// SPI protocol
typedef struct _mp_machine_spi_p_t {
void (*transfer)(mp_obj_base_t *obj, size_t slen, const uint8_t *src, size_t dlen, uint8_t *dest);
void (*transfer)(mp_obj_base_t *obj, size_t len, const uint8_t *src, uint8_t *dest);
} mp_machine_spi_p_t;
MP_DECLARE_CONST_FUN_OBJ(mp_machine_spi_read_obj);

11
stmhal/spi.c
View File

@ -401,15 +401,8 @@ STATIC void spi_transfer(mp_obj_base_t *self_in, size_t src_len, const uint8_t *
}
}
STATIC void spi_transfer_machine(mp_obj_base_t *self_in, size_t src_len, const uint8_t *src_buf, size_t dest_len, uint8_t *dest_buf) {
if (src_len == 1 && dest_len > 1) {
// this catches read and readinto
// copy the single output byte to the dest buffer and use that as source
memset(dest_buf, src_buf[0], dest_len);
src_len = dest_len;
src_buf = dest_buf;
}
spi_transfer(self_in, src_len, src_buf, dest_len, dest_buf, 100);
STATIC void spi_transfer_machine(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
spi_transfer(self_in, len, src, dest == NULL ? 0 : len, dest, 100);
}
/******************************************************************************/