Merge pull request #9 from pimoroni/patch-dma-abort

CI: HACK: Add temporary DMA workaround.

boards/pico2_w_cyw43.patch

@@ -0,0 +1,43 @@
+From ea32e6dfb5232ad7d0ebba7da40dda68da05bc76 Mon Sep 17 00:00:00 2001
+From: Peter Harper <peter.harper@raspberrypi.com>
+Date: Fri, 24 Jan 2025 18:47:52 +0000
+Subject: [PATCH] Fix unreliable writes to cyw43.
+
+We use a pio and dma to write to the cyw43 chip using spi. Normally you
+write an address and then read the data from that address, so the pio
+program does does a write then read.
+
+If you just want to write data in the case of uploading firmware we
+use the fdebug_tx_stall flag to work out if the pio has stalled waiting
+to write more data.
+
+The theory is that this flag will also get set if the bus is busy. So
+we mistakenly think a write to cyw43 has completed.
+
+Wait for the dma write to complete before waiting for the pio to stall.
+
+Fixes #2206
+---
+ src/rp2_common/pico_cyw43_driver/cyw43_bus_pio_spi.c | 6 ++++--
+ 1 file changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/src/rp2_common/pico_cyw43_driver/cyw43_bus_pio_spi.c b/src/rp2_common/pico_cyw43_driver/cyw43_bus_pio_spi.c
+index bcc7284f1..787eeff5d 100644
+--- a/src/rp2_common/pico_cyw43_driver/cyw43_bus_pio_spi.c
++++ b/src/rp2_common/pico_cyw43_driver/cyw43_bus_pio_spi.c
+@@ -308,11 +308,13 @@ int cyw43_spi_transfer(cyw43_int_t *self, const uint8_t *tx, size_t tx_length, u
+ 
+         dma_channel_configure(bus_data->dma_out, &out_config, &bus_data->pio->txf[bus_data->pio_sm], tx, tx_length / 4, true);
+ 
++        pio_sm_set_enabled(bus_data->pio, bus_data->pio_sm, true);
++        dma_channel_wait_for_finish_blocking(bus_data->dma_out);
++
+         uint32_t fdebug_tx_stall = 1u << (PIO_FDEBUG_TXSTALL_LSB + bus_data->pio_sm);
+         bus_data->pio->fdebug = fdebug_tx_stall;
+-        pio_sm_set_enabled(bus_data->pio, bus_data->pio_sm, true);
+         while (!(bus_data->pio->fdebug & fdebug_tx_stall)) {
+-            tight_loop_contents(); // todo timeout
++            tight_loop_contents();
+         }
+         __compiler_memory_barrier();
+         pio_sm_set_enabled(bus_data->pio, bus_data->pio_sm, false);

ci/micropython.sh

@@ -52,6 +52,9 @@ function ci_micropython_clone {
     git submodule update --init lib/micropython-lib
     git submodule update --init lib/tinyusb
     git submodule update --init lib/btstack
+    log_inform "HACK: Patching dma aborts for Pico2 W."
+    cd "$CI_BUILD_ROOT/micropython/lib/pico-sdk"
+    git apply "$CI_PROJECT_ROOT/boards/pico2_w_cyw43.patch"
     cd "$CI_BUILD_ROOT"
 }