From 281672d418bdc093716b069198c8852ad87eabb2 Mon Sep 17 00:00:00 2001
From: Josh Rahm <joshuarahm@gmail.com>
Date: Wed, 27 Nov 2024 17:56:47 -0700
Subject: Got the DMA to work! (That was surprisingly easy).

---
 src/spi.c | 49 +++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 41 insertions(+), 8 deletions(-)

(limited to 'src/spi.c')

diff --git a/src/spi.c b/src/spi.c
index 3105f1b..6d9fb2a 100644
--- a/src/spi.c
+++ b/src/spi.c
@@ -5,6 +5,8 @@
 #include "ch573/gpio.h"
 #include "ch573/spi.h"
 
+#define MAX_SPI_FIFO 8
+
 #define SPI CH573_SPI__SPI_T_INTF
 #define SPI0 ch573_spi__spi0
 
@@ -37,7 +39,7 @@ void enable_spi(void)
   GPIO_PORT.dir.set(GPIO_PORT_A, DIR_IN, 13);
   GPIO_PORT.dir.set(GPIO_PORT_A, DIR_IN, 15);
 
-  SPI.clock_div.set(SPI0, 16);
+  SPI.clock_div.set(SPI0, 25);
   SPI.ctrl_mod.all_clear.set(SPI0, 1);
   // SPI.ctrl_mod.set(SPI0, 0xe0);  // Set mosi and sck
 
@@ -47,16 +49,47 @@ void enable_spi(void)
   SPI.ctrl_cfg.dma_enable.set(SPI0, OFF);
 }
 
+// void write_color(uint8_t r, uint8_t g, uint8_t b)
+// {
+//
+//
+//   while (!SPI.int_flag.if_fifo_hf.get(SPI0));
+//   SPI.fifo.set(SPI0, r);
+//   SPI.fifo.set(SPI0, g);
+//   SPI.fifo.set(SPI0, b);
+// }
+
+void dma_transfer(void* output_buffer, size_t len)
+{
+  // Clear everything.
+  SPI.ctrl_mod.all_clear.set(SPI0, 1);
+  SPI.ctrl_mod.all_clear.set(SPI0, 0);
+
+  SPI.ctrl_mod.fifo_dir.set(SPI0, FIFO_DIR_OUTPUT);
+  SPI.dma_beg.set(SPI0, (uint32_t)output_buffer);
+  SPI.dma_end.set(SPI0, (uint32_t)(output_buffer + len));
+
+  SPI.total_count.set(SPI0, len);
+
+  // Start DMA.
+  SPI.ctrl_cfg.dma_enable.set(SPI0, ON);
+}
+
+void wait_for_dma()
+{
+  while (SPI.total_count.get(SPI0) > 0);
+}
+
 void run_spi(void)
 {
   GPIO_PORT.out.set(GPIO_PORT_A, ON, 12);
   while (1) {
-    GPIO_PORT_A->clr |= 1 << 12;
-    SPI.ctrl_mod.fifo_dir.set(SPI0, FIFO_DIR_OUTPUT);
-    // R8_SPI0_CTRL_MOD &= ~RB_SPI_FIFO_DIR;
-    SPI.data_buf.set(SPI0, 0xaa);
-    // R8_SPI0_BUFFER = 0xaa;
-    while (!SPI.int_flag.free.get(SPI0));
-    GPIO_PORT.out.set(GPIO_PORT_A, ON, 12);
+    SPI.total_count.set(SPI0, 1024);
+    // GPIO_PORT_A->clr |= 1 << 12;
+
+    while (SPI.fifo_count.get(SPI0) == 8);
+
+    SPI.fifo.set(SPI0, 0xaa);
+    SPI.total_count.set(SPI0, 1024);
   }
 }
-- 
cgit