altos/stmf0: Add ADC and DMA APIs

The ADC api is what USBtrng wants; a way to repeatedly read a single
ADC input as fast as possible.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 141 insertions, 0 deletions

diff --git a/src/stmf0/ao_dma_stm.c b/src/stmf0/ao_dma_stm.c
new file mode 100644
index 00000000..78fabe18
--- /dev/null
+++ b/src/stmf0/ao_dma_stm.c
@@ -0,0 +1,141 @@
+/*
+ * Copyright © 2012 Keith Packard <keithp@keithp.com>
+ *
+ * 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; version 2 of the License.
+ *
+ * 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, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
+ */
+
+#include "ao.h"
+
+struct ao_dma_config {
+	void		(*isr)(int index);
+};
+
+uint8_t ao_dma_done[STM_NUM_DMA];
+
+static struct ao_dma_config ao_dma_config[STM_NUM_DMA];
+static uint8_t ao_dma_allocated[STM_NUM_DMA];
+static uint8_t ao_dma_mutex[STM_NUM_DMA];
+static uint8_t ao_dma_active;
+
+#define id(ch)		STM_DMA_INDEX(ch)
+#define id_mask(id)	(STM_DMA_ISR_MASK << (id))
+#define ch_mask(ch)	id_mask(id(ch))
+
+static void
+ao_dma_isr(uint8_t low_index, uint8_t high_index, uint32_t mask) {
+	/* Get channel interrupt bits */
+	uint32_t	isr = stm_dma.isr & mask;
+	uint8_t		index;
+
+	/* Ack them */
+	stm_dma.ifcr = isr;
+	for (index = low_index; index <= high_index; index++) {
+		if (isr & id_mask(index)) {
+			if (ao_dma_config[index].isr)
+				(*ao_dma_config[index].isr)(index);
+			else {
+				ao_dma_done[index] = 1;
+				ao_wakeup(&ao_dma_done[index]);
+			}
+		}
+	}
+}
+
+void stm_dma_ch1_isr(void) { ao_dma_isr(id(1), id(1), ch_mask(1)); }
+void stm_dma_ch2_3_isr(void) { ao_dma_isr(id(2), id(3), ch_mask(2) | ch_mask(3)); }
+void stm_dma1_ch4_5_6_isr(void) { ao_dma_isr(id(4), id(6), ch_mask(4) | ch_mask(5) | ch_mask(6)); }
+
+void
+ao_dma_set_transfer(uint8_t 		index,
+		    volatile void	*peripheral,
+		    void		*memory,
+		    uint16_t		count,
+		    uint32_t		ccr)
+{
+	if (ao_dma_allocated[index]) {
+		if (ao_dma_mutex[index])
+			ao_panic(AO_PANIC_DMA);
+		ao_dma_mutex[index] = 1;
+	} else
+		ao_mutex_get(&ao_dma_mutex[index]);
+	ao_arch_critical(
+		if (ao_dma_active++ == 0)
+			stm_rcc.ahbenr |= (1 << STM_RCC_AHBENR_DMAEN);
+		);
+	stm_dma.channel[index].ccr = ccr | (1 << STM_DMA_CCR_TCIE);
+	stm_dma.channel[index].cndtr = count;
+	stm_dma.channel[index].cpar = peripheral;
+	stm_dma.channel[index].cmar = memory;
+	ao_dma_config[index].isr = NULL;
+}
+
+void
+ao_dma_set_isr(uint8_t index, void (*isr)(int))
+{
+	ao_dma_config[index].isr = isr;
+}
+
+void
+ao_dma_start(uint8_t index)
+{
+	ao_dma_done[index] = 0;
+	stm_dma.channel[index].ccr |= (1 << STM_DMA_CCR_EN);
+}
+
+void
+ao_dma_done_transfer(uint8_t index)
+{
+	stm_dma.channel[index].ccr &= ~(1 << STM_DMA_CCR_EN);
+	ao_arch_critical(
+		if (--ao_dma_active == 0)
+			stm_rcc.ahbenr &= ~(1 << STM_RCC_AHBENR_DMAEN);
+		);
+	if (ao_dma_allocated[index])
+		ao_dma_mutex[index] = 0;
+	else
+		ao_mutex_put(&ao_dma_mutex[index]);
+}
+
+void
+ao_dma_abort(uint8_t index)
+{
+	stm_dma.channel[index].ccr &= ~(1 << STM_DMA_CCR_EN);
+	ao_wakeup(&ao_dma_done[index]);
+}
+
+void
+ao_dma_alloc(uint8_t index)
+{
+	if (ao_dma_allocated[index])
+		ao_panic(AO_PANIC_DMA);
+	ao_dma_allocated[index] = 1;
+}
+
+#define STM_NUM_DMA_ISR	3
+
+void
+ao_dma_init(void)
+{
+	int	isr_id;
+	int	index;
+
+	for (isr_id = 0; isr_id < STM_NUM_DMA_ISR; isr_id++) {
+		stm_nvic_set_enable(STM_ISR_DMA_CH1_POS + isr_id);
+		stm_nvic_set_priority(STM_ISR_DMA_CH1_POS + isr_id, 4);
+	}
+	for (index = 0; index < STM_NUM_DMA; index++) {
+		ao_dma_allocated[index] = 0;
+		ao_dma_mutex[index] = 0;
+	}
+}