ports/rp2: Provide direct memory access to PIO FIFOs via proxy arrays.

nickovs · nickovs · commit 96fd89adf886 · 2023-10-15T17:05:24.000-06:00
Signed-off-by: Nicko van Someren &lt;nicko@nicko.org&gt;
diff --git a/ports/rp2/rp2_pio.c b/ports/rp2/rp2_pio.c
@@ -30,6 +30,7 @@
 #include "py/runtime.h"
 #include "py/mperrno.h"
 #include "py/mphal.h"
+#include "py/objarray.h"
 #include "shared/runtime/mpirq.h"
 #include "modrp2.h"
 
@@ -809,6 +810,24 @@ STATIC mp_obj_t rp2_state_machine_tx_fifo(mp_obj_t self_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(rp2_state_machine_tx_fifo_obj, rp2_state_machine_tx_fifo);
 
+STATIC mp_obj_t rp2_state_machine_get_fifo_proxy(mp_obj_t self_in, mp_obj_t read_not_write) {
+    rp2_state_machine_obj_t *self = MP_OBJ_TO_PTR(self_in);
+
+    mp_obj_array_t *proxy = m_new_obj(mp_obj_array_t);
+    proxy->base.type = &mp_type_array;
+    proxy->typecode = 'I';
+    proxy->free = 0;
+    proxy->len = 1;
+    if (mp_obj_is_true(read_not_write)) {
+        proxy->items = (void *)&self->pio->rxf[self->sm];
+    } else {
+        proxy->items = (void *)&self->pio->txf[self->sm];
+    }
+
+    return MP_OBJ_FROM_PTR(proxy);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(rp2_state_machine_get_fifo_proxy_obj, rp2_state_machine_get_fifo_proxy);
+
 // StateMachine.irq(handler=None, trigger=0|1, hard=False)
 STATIC mp_obj_t rp2_state_machine_irq(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
     enum { ARG_handler, ARG_trigger, ARG_hard };
@@ -874,6 +893,7 @@ STATIC const mp_rom_map_elem_t rp2_state_machine_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_put), MP_ROM_PTR(&rp2_state_machine_put_obj) },
     { MP_ROM_QSTR(MP_QSTR_rx_fifo), MP_ROM_PTR(&rp2_state_machine_rx_fifo_obj) },
     { MP_ROM_QSTR(MP_QSTR_tx_fifo), MP_ROM_PTR(&rp2_state_machine_tx_fifo_obj) },
+    { MP_ROM_QSTR(MP_QSTR_get_fifo_proxy), MP_ROM_PTR(&rp2_state_machine_get_fifo_proxy_obj) },
     { MP_ROM_QSTR(MP_QSTR_irq), MP_ROM_PTR(&rp2_state_machine_irq_obj) },
 };
 STATIC MP_DEFINE_CONST_DICT(rp2_state_machine_locals_dict, rp2_state_machine_locals_dict_table);
