altos: Add SPI-based companion board support

[fw/altos] / src / ao_spi.c

diff --git a/src/ao_spi.c b/src/ao_spi.c
index bd52a0d45694516fa643a9d7c376ac8c68543192..fbe613c759762bc4766f8ab47e9c56362fcc2d88 100644 (file)
--- a/src/ao_spi.c
+++ b/src/ao_spi.c
@@ -17,6 +17,10 @@
 
 #include "ao.h"
 
+/* Shared mutex to protect SPI bus, must cover the entire
+ * operation, from CS low to CS high. This means that any SPI
+ * user must protect the SPI bus with this mutex
+ */
 __xdata uint8_t        ao_spi_mutex;
 __xdata uint8_t ao_spi_dma_in_done;
 __xdata uint8_t ao_spi_dma_out_done;
@@ -36,7 +40,6 @@ static __xdata uint8_t ao_spi_const = 0xff;
 void
 ao_spi_send(void __xdata *block, uint16_t len) __reentrant
 {
-       ao_mutex_get(&ao_spi_mutex);
        ao_dma_set_transfer(ao_spi_dma_in_id,
                            &U0DBUFXADDR,
                            &ao_spi_const,
@@ -64,7 +67,6 @@ ao_spi_send(void __xdata *block, uint16_t len) __reentrant
        ao_dma_trigger(ao_spi_dma_out_id);
        __critical while (!ao_spi_dma_in_done)
                ao_sleep(&ao_spi_dma_in_done);
-       ao_mutex_put(&ao_spi_mutex);
 }
 
 /* Receive bytes over SPI.
@@ -76,7 +78,6 @@ ao_spi_send(void __xdata *block, uint16_t len) __reentrant
 void
 ao_spi_recv(void __xdata *block, uint16_t len) __reentrant
 {
-       ao_mutex_get(&ao_spi_mutex);
        ao_dma_set_transfer(ao_spi_dma_in_id,
                            &U0DBUFXADDR,
                            block,
@@ -104,7 +105,6 @@ ao_spi_recv(void __xdata *block, uint16_t len) __reentrant
        ao_dma_trigger(ao_spi_dma_out_id);
        __critical while (!ao_spi_dma_in_done)
                ao_sleep(&ao_spi_dma_in_done);
-       ao_mutex_put(&ao_spi_mutex);
 }
 
 /*