altos/lpc: Give up on interrupt-driven SPI driver

[fw/altos] / src / lpc / ao_spi_lpc.c

diff --git a/src/lpc/ao_spi_lpc.c b/src/lpc/ao_spi_lpc.c
index 5a358919937c7027e5af06b71fd97dac95168cdb..f091c89c570963542f602c0e7f6d8957116895d4 100644 (file)
--- a/src/lpc/ao_spi_lpc.c
+++ b/src/lpc/ao_spi_lpc.c
@@ -19,130 +19,56 @@
 
 static uint8_t         ao_spi_mutex[LPC_NUM_SPI];
 
-struct ao_lpc_ssp_state {
-       int             tx_count;
-       const uint8_t   *tx;
-       int             tx_inc;
-       int             rx_count;
-       uint8_t         *rx;
-       int             rx_inc;
-};
-
-static struct ao_lpc_ssp_state ao_lpc_ssp_state[LPC_NUM_SPI];
-
 static struct lpc_ssp * const ao_lpc_ssp[LPC_NUM_SPI] = { &lpc_ssp0, &lpc_ssp1 };
 
-static inline void
-ao_lpc_ssp_recv(struct lpc_ssp *lpc_ssp, struct ao_lpc_ssp_state *state)
-{
-       while ((lpc_ssp->sr & (1 << LPC_SSP_SR_RNE)) &&
-              state->rx_count)
-       {
-               /* RX ready, read a byte */
-               *state->rx = lpc_ssp->dr;
-               state->rx += state->rx_inc;
-               state->rx_count--;
-       }
-}
-
-static void
-ao_lpc_ssp_isr(struct lpc_ssp *lpc_ssp, struct ao_lpc_ssp_state *state)
-{
-       ao_lpc_ssp_recv(lpc_ssp, state);
-       while ((lpc_ssp->sr & (1 << LPC_SSP_SR_TNF)) &&
-              state->tx_count)
-       {
-               /* TX ready, write a byte */
-               lpc_ssp->dr = *state->tx;
-               state->tx += state->tx_inc;
-               state->tx_count--;
-               ao_lpc_ssp_recv(lpc_ssp, state);
-       }
-       if (!state->rx_count) {
-               lpc_ssp->imsc &= ~(1 << LPC_SSP_IMSC_TXIM);
-               ao_wakeup(state);
-       }
-}
-
-void
-lpc_ssp0_isr(void)
-{
-       ao_lpc_ssp_isr(&lpc_ssp0, &ao_lpc_ssp_state[0]);
-}
-
-void
-lpc_ssp1_isr(void)
-{
-       ao_lpc_ssp_isr(&lpc_ssp1, &ao_lpc_ssp_state[1]);
-}
-
-static void
-ao_spi_run(struct lpc_ssp *lpc_ssp, struct ao_lpc_ssp_state *state)
-{
-       ao_arch_block_interrupts();
-       lpc_ssp->imsc = (1 << LPC_SSP_IMSC_TXIM);
-       while (state->rx_count)
-               ao_sleep(state);
-       ao_arch_release_interrupts();
-}
-
-static uint8_t ao_spi_tx_dummy = 0xff;
-static uint8_t ao_spi_rx_dummy;
+#define spi_loop(len, put, get) do {                                   \
+               while (len--) {                                         \
+                       /* send a byte */                               \
+                       lpc_ssp->dr = put;                              \
+                       /* wait for the received byte to appear */      \
+                       while ((lpc_ssp->sr & (1 << LPC_SSP_SR_RNE)) == 0) \
+                               ;                                       \
+                       /* receive a byte */                            \
+                       get lpc_ssp->dr;                                \
+               }                                                       \
+               /* Wait for the SSP to go idle (it already should be) */ \
+               while (lpc_ssp->sr & (1 << LPC_SSP_SR_BSY));            \
+       } while (0)
 
 void
 ao_spi_send(const void *block, uint16_t len, uint8_t id)
 {
        struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
-       struct ao_lpc_ssp_state *state = &ao_lpc_ssp_state[id];
-
-       state->tx_count = state->rx_count = len;
-       state->tx = block;
-       state->tx_inc = 1;
-       state->rx = &ao_spi_rx_dummy;
-       state->rx_inc = 0;
-       ao_spi_run(lpc_ssp, state);
+       const uint8_t   *o = block;
+
+       spi_loop(len, *o++, (void));
 }
 
 void
 ao_spi_send_fixed(uint8_t value, uint16_t len, uint8_t id)
 {
        struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
-       struct ao_lpc_ssp_state *state = &ao_lpc_ssp_state[id];
-
-       state->tx_count = state->rx_count = len;
-       state->tx = &value;
-       state->tx_inc = 0;
-       state->rx = &ao_spi_rx_dummy;
-       state->rx_inc = 0;
-       ao_spi_run(lpc_ssp, state);
+
+       spi_loop(len, value, (void));
 }
 
 void
 ao_spi_recv(void *block, uint16_t len, uint8_t id)
 {
        struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
-       struct ao_lpc_ssp_state *state = &ao_lpc_ssp_state[id];
-
-       state->tx_count = state->rx_count = len;
-       state->tx = &ao_spi_tx_dummy;
-       state->tx_inc = 0;
-       state->rx = block;
-       state->rx_inc = 1;
-       ao_spi_run(lpc_ssp, state);
+       uint8_t *i = block;
+
+       spi_loop(len, 0xff, *i++ =);
 }
 
 void
 ao_spi_duplex(const void *out, void *in, uint16_t len, uint8_t id)
 {
        struct lpc_ssp *lpc_ssp = ao_lpc_ssp[id];
-       struct ao_lpc_ssp_state *state = &ao_lpc_ssp_state[id];
-
-       state->tx_count = state->rx_count = len;
-       state->tx = out;
-       state->tx_inc = 1;
-       state->rx = in;
-       state->rx_inc = 1;
-       ao_spi_run(lpc_ssp, state);
+       const uint8_t *o = out;
+       uint8_t *i = in;
+
+       spi_loop(len, *o++, *i++ =);
 }
 
 void
@@ -223,10 +149,6 @@ ao_spi_init(void)
        lpc_scb.presetctrl &= ~(1 << LPC_SCB_PRESETCTRL_SSP0_RST_N);
        lpc_scb.presetctrl |= (1 << LPC_SCB_PRESETCTRL_SSP0_RST_N);
        ao_spi_channel_init(0);
-
-       /* Configure NVIC */
-       lpc_nvic_set_enable(LPC_ISR_SSP0_POS);
-       lpc_nvic_set_priority(LPC_ISR_SSP0_POS, 0);
 #endif
 
 #if HAS_SPI_1
@@ -277,10 +199,5 @@ ao_spi_init(void)
        lpc_scb.presetctrl &= ~(1 << LPC_SCB_PRESETCTRL_SSP1_RST_N);
        lpc_scb.presetctrl |= (1 << LPC_SCB_PRESETCTRL_SSP1_RST_N);
        ao_spi_channel_init(1);
-
-       /* Configure NVIC */
-       lpc_nvic_set_enable(LPC_ISR_SSP1_POS);
-       lpc_nvic_set_priority(LPC_ISR_SSP1_POS, 0);
-
 #endif /* HAS_SPI_1 */
 }