--- /dev/null
+/*
+ * Copyright © 2019 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, either version 2 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, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <ao.h>
+#include <ao_dma-samd21.h>
+
+static struct samd21_dmac_desc samd21_dmac_desc[SAMD21_DMAC_NCHAN] __attribute__((aligned(16)));
+static struct samd21_dmac_desc samd21_dmac_wrb[SAMD21_DMAC_NCHAN] __attribute__((aligned(16)));
+
+static volatile uint16_t saved_intpend;
+static volatile int interrupts;
+
+static struct {
+ void (*callback)(uint8_t id, void *closure);
+ void *closure;
+} dmac_callback[SAMD21_DMAC_NCHAN];
+
+void
+samd21_dmac_isr(void)
+{
+ uint16_t intpend = samd21_dmac.intpend;
+
+ ++interrupts;
+ saved_intpend = intpend;
+ if (intpend & 0xff00) {
+ uint8_t id = (intpend >> SAMD21_DMAC_INTPEND_ID) & SAMD21_DMAC_INTPEND_ID_MASK;
+ samd21_dmac.intpend = intpend;
+ if (intpend & (1 << SAMD21_DMAC_INTPEND_TCMPL)) {
+ if (dmac_callback[id].callback)
+ (*dmac_callback[id].callback)(id, dmac_callback[id].closure);
+ }
+ }
+}
+
+void
+ao_dma_dump(char *where)
+{
+ printf("DMA %s ctrl %04x intpend %04x intstatus %04x\n",
+ where,
+ samd21_dmac.ctrl,
+ samd21_dmac.intpend,
+ samd21_dmac.intstatus);
+ fflush(stdout);
+ printf(" busych %04x pendch %04x active %08x chctrla %02x\n",
+ samd21_dmac.busych,
+ samd21_dmac.pendch,
+ samd21_dmac.active,
+ samd21_dmac.chctrla);
+ fflush(stdout);
+ printf(" chctrlb %08x chintflag %02x chstatus %02x\n",
+ samd21_dmac.chctrlb,
+ samd21_dmac.chintflag,
+ samd21_dmac.chstatus);
+ fflush(stdout);
+ printf(" btctrl %04x btcnt %04x srcaddr %08x dstaddr %08x descaddr %08x\n",
+ samd21_dmac_desc[0].btctrl,
+ samd21_dmac_desc[0].btcnt,
+ samd21_dmac_desc[0].srcaddr,
+ samd21_dmac_desc[0].dstaddr,
+ samd21_dmac_desc[0].descaddr);
+ fflush(stdout);
+ printf("intpend %04x interrupts %d\n", saved_intpend, interrupts);
+}
+
+void
+_ao_dma_start_transfer(uint8_t id,
+ void *src,
+ void *dst,
+ uint16_t count,
+ uint32_t chctrlb,
+ uint16_t btctrl,
+ void (*callback)(uint8_t id, void *closure),
+ void *closure)
+{
+ /* Set up the callback */
+ dmac_callback[id].closure = closure;
+ dmac_callback[id].callback = callback;
+
+ /* Set up the descriptor */
+ samd21_dmac_desc[id].btctrl = btctrl;
+ samd21_dmac_desc[id].btcnt = count;
+ samd21_dmac_desc[id].srcaddr = (uint32_t) src;
+ samd21_dmac_desc[id].dstaddr = (uint32_t) dst;
+ samd21_dmac_desc[id].descaddr = 0;
+
+ /* Configure the channel and enable it */
+ samd21_dmac.chid = id;
+ samd21_dmac.chctrlb = chctrlb;
+ samd21_dmac.chctrla = (1 << SAMD21_DMAC_CHCTRLA_ENABLE);
+}
+
+void
+_ao_dma_done_transfer(uint8_t id)
+{
+ /* Disable channel */
+ samd21_dmac.chid = id;
+ samd21_dmac.chctrla = 0;
+}
+
+void
+ao_dma_init(void)
+{
+ uint8_t ch;
+
+ /* Enable DMAC clocks */
+ samd21_pm.ahbmask |= (1 << SAMD21_PM_AHBMASK_DMAC);
+ samd21_pm.apbbmask |= (1 << SAMD21_PM_APBBMASK_DMAC);
+
+#if 0
+ /* Enable HPB clocks so we can talk to peripherals */
+ samd21_pm.ahbmask |= ((1 << SAMD21_PM_AHBMASK_HPB0) |
+ (1 << SAMD21_PM_AHBMASK_HPB1) |
+ (1 << SAMD21_PM_AHBMASK_HPB2));
+#endif
+
+ samd21_pm.apbamask |= (1 << SAMD21_PM_APBAMASK_PAC0);
+ samd21_pm.apbbmask |= (1 << SAMD21_PM_APBBMASK_PAC1);
+ samd21_pm.apbcmask |= (1 << SAMD21_PM_APBCMASK_PAC2);
+
+ /* Reset DMAC device */
+ samd21_dmac.ctrl = 0;
+ samd21_dmac.ctrl = (1 << SAMD21_DMAC_CTRL_SWRST);
+ while (samd21_dmac.ctrl & (1 << SAMD21_DMAC_CTRL_SWRST))
+ ;
+
+ samd21_dmac.baseaddr = (uint32_t) &samd21_dmac_desc[0];
+ samd21_dmac.wrbaddr = (uint32_t) &samd21_dmac_wrb[0];
+
+ samd21_dmac.swtrigctrl = 0;
+
+ /* Set QoS to highest value */
+ samd21_dmac.qosctrl = ((SAMD21_DMAC_QOSCTRL_HIGH << SAMD21_DMAC_QOSCTRL_DQOS) |
+ (SAMD21_DMAC_QOSCTRL_HIGH << SAMD21_DMAC_QOSCTRL_FQOS) |
+ (SAMD21_DMAC_QOSCTRL_HIGH << SAMD21_DMAC_QOSCTRL_WRBQOS));
+
+ /* Enable DMAC controller with all priority levels */
+ samd21_dmac.ctrl = ((1 << SAMD21_DMAC_CTRL_DMAENABLE) |
+ (1 << SAMD21_DMAC_CTRL_LVLEN(0)) |
+ (1 << SAMD21_DMAC_CTRL_LVLEN(1)) |
+ (1 << SAMD21_DMAC_CTRL_LVLEN(2)) |
+ (1 << SAMD21_DMAC_CTRL_LVLEN(3)));
+
+ /* Reset all DMAC channels */
+ for (ch = 0; ch < SAMD21_DMAC_NCHAN; ch++) {
+ samd21_dmac.chid = ch;
+ samd21_dmac.chctrla = (1 << SAMD21_DMAC_CHCTRLA_SWRST);
+ while (samd21_dmac.chctrla & (1 << SAMD21_DMAC_CHCTRLA_SWRST))
+ ;
+ samd21_dmac.chintenset = (1 << SAMD21_DMAC_CHINTFLAG_TCMPL);
+ }
+
+ /* configure interrupts */
+ samd21_nvic_set_enable(SAMD21_NVIC_ISR_DMAC_POS);
+ samd21_nvic_set_priority(SAMD21_NVIC_ISR_DMAC_POS, 3);
+}