1 files changed, 110 insertions, 0 deletions
diff --git a/firmware/zpu/lib/spi.c b/firmware/zpu/lib/spi.c
new file mode 100644
index 000000000..af0d8a68f
--- /dev/null
+++ b/firmware/zpu/lib/spi.c
@@ -0,0 +1,110 @@
+/*
+ * Copyright 2007,2008 Free Software Foundation, Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "spi.h"
+#include "memory_map.h"
+#include "pic.h"
+#include "nonstdio.h"
+
+//void (*volatile spi_callback)(void); //SPI callback when xfer complete.
+
+//static void spi_irq_handler(unsigned irq);
+
+void
+spi_init(void) 
+{
+  /*
+   * f_sclk = f_wb / ((div + 1) * 2)
+   */
+  spi_regs->div = 1;  // 0 = Div by 2 (25 MHz); 1 = Div-by-4 (12.5 MHz)
+}
+
+void
+spi_wait(void) 
+{
+  while (spi_regs->ctrl & SPI_CTRL_GO_BSY)
+    ;
+}
+
+uint32_t
+spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags) 
+{
+  flags &= (SPI_CTRL_TXNEG | SPI_CTRL_RXNEG);
+  int ctrl = SPI_CTRL_ASS | (SPI_CTRL_CHAR_LEN_MASK & length) | flags;
+
+  spi_wait();
+
+  // Tell it which SPI slave device to access
+  spi_regs->ss = slave & 0xffff;
+
+  // Data we will send
+  spi_regs->txrx0 = data;
+
+  // Run it -- write once and rewrite with GO set
+  spi_regs->ctrl = ctrl;
+  spi_regs->ctrl = ctrl | SPI_CTRL_GO_BSY;
+
+  if(readback) {
+    spi_wait();
+    return spi_regs->txrx0;
+  }
+  else
+    return 0;
+}
+
+/*
+void spi_register_callback(void (*volatile callback)(void)) {
+  spi_callback = callback;
+}
+
+static void spi_irq_handler(unsigned irq) {
+//  printf("SPI IRQ handler\n");
+//  uint32_t wat = spi_regs->ctrl; //read a register just to clear the interrupt
+  //spi_regs->ctrl &= ~SPI_CTRL_IE;
+  if(spi_callback) spi_callback(); //we could just use the PIC to register the user's callback, but this provides the ability to do other things later
+}
+
+uint32_t spi_get_data(void) {
+  return spi_regs->txrx0;
+}
+
+bool 
+spi_async_transact(int slave, uint32_t data, int length, uint32_t flags, void (*volatile callback)(void)) {
+  flags &= (SPI_CTRL_TXNEG | SPI_CTRL_RXNEG);
+  int ctrl = SPI_CTRL_ASS | SPI_CTRL_IE | (SPI_CTRL_CHAR_LEN_MASK & length) | flags;
+
+  if(spi_regs->ctrl & SPI_CTRL_GO_BSY) {
+    printf("Async SPI busy!\n");
+    return false; //we don't wait on busy, we just return failure. we count on the host to not set up another transaction before the last one finishes.
+  }
+
+  // Tell it which SPI slave device to access
+  spi_regs->ss = slave & 0xffff;
+
+  // Data we will send
+  spi_regs->txrx0 = data;
+
+  spi_register_callback(callback);
+  pic_register_handler(IRQ_SPI, spi_irq_handler);
+
+  // Run it -- write once and rewrite with GO set
+  spi_regs->ctrl = ctrl;
+  spi_regs->ctrl = ctrl | SPI_CTRL_GO_BSY;
+
+  return true;
+}
+*/