altos/lpc: Get USART running

Adds a simple demo thread that spews data to the serial port

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

5 files changed, 283 insertions, 33 deletions

diff --git a/src/lpc/ao_serial_lpc.c b/src/lpc/ao_serial_lpc.c
index e47f743e..4ecaa175 100644
--- a/src/lpc/ao_serial_lpc.c
+++ b/src/lpc/ao_serial_lpc.c
@@ -27,10 +27,9 @@ ao_debug_out(char c)
 {
 	if (c == '\n')
 		ao_debug_out('\r');
-#if 0
-	while (!(stm_usart1.sr & (1 << STM_USART_SR_TXE)));
-	stm_usart1.dr = c;
-#endif
+	while (!(lpc_usart.lsr & (1 << LPC_USART_LSR_TEMT)))
+		;
+	lpc_usart.rbr_thr = c;
 }
 
 static void
@@ -39,35 +38,28 @@ _ao_serial_tx_start(void)
 	if (!ao_fifo_empty(ao_usart_tx_fifo) & !ao_usart_tx_started)
 	{
 		ao_usart_tx_started = 1;
-#if 0
-		ao_fifo_remove(ao_usart_tx_fifo, usart->reg->dr);
-#endif
+		ao_fifo_remove(ao_usart_tx_fifo, lpc_usart.rbr_thr);
 	}
 }
 
 void
 lpc_usart_isr(void)
 {
-#if 0
-	uint32_t	sr;
-
-	sr = usart->reg->sr;
-	usart->reg->sr = 0;
+	(void) lpc_usart.iir_fcr;
 
-	if (sr & (1 << STM_USART_SR_RXNE)) {
-		char c = usart->reg->dr;
+	while (lpc_usart.lsr & (1 << LPC_USART_LSR_RDR)) {
+		char c = lpc_usart.rbr_thr;
 		if (!ao_fifo_full(ao_usart_rx_fifo))
 			ao_fifo_insert(ao_usart_rx_fifo, c);
-		ao_wakeup(ao_usart_rx_fifo);
+		ao_wakeup(&ao_usart_rx_fifo);
 		if (stdin)
 			ao_wakeup(&ao_stdin_ready);
 	}
-	if (sr & (1 << STM_USART_SR_TC)) {
+	if (lpc_usart.lsr & (1 << LPC_USART_LSR_THRE)) {
 		ao_usart_tx_started = 0;
-		_ao_usart_tx_start(usart);
-		ao_wakeup(ao_usart_tx_fifo);
+		_ao_serial_tx_start();
+		ao_wakeup(&ao_usart_tx_fifo);
 	}
-#endif
 }
 
 int
@@ -116,24 +108,33 @@ ao_serial_drain(void)
 	ao_arch_release_interrupts();
 }
 
+#include "ao_serial_lpc.h"
+
 void
 ao_serial_set_speed(uint8_t speed)
 {
 	if (speed > AO_SERIAL_SPEED_115200)
 		return;
-#if 0
-	usart->reg->brr = ao_usart_speeds[speed].brr;
-#endif
-}
 
-#include "ao_serial_lpc.h"
+	/* Flip to allow access to divisor latches */
+	lpc_usart.lcr |= (1 << LPC_USART_LCR_DLAB);
+
+	/* DL LSB */
+	lpc_usart.rbr_thr = ao_usart_speeds[speed].dl & 0xff;
+	
+	/* DL MSB */
+	lpc_usart.ier = (ao_usart_speeds[speed].dl >> 8) & 0xff;
+
+	lpc_usart.fdr = ((ao_usart_speeds[speed].divaddval << LPC_USART_FDR_DIVADDVAL) |
+			 (ao_usart_speeds[speed].mulval << LPC_USART_FDR_MULVAL));
+
+	/* Turn access to divisor latches back off */
+	lpc_usart.lcr &= ~(1 << LPC_USART_LCR_DLAB);
+}
 
 void
 ao_serial_init(void)
 {
-	/* Turn on the USART clock */
-	lpc_scb.uartclkdiv = 1;
-
 #if SERIAL_0_18_19
 	lpc_ioconf.pio0_18 = ((LPC_IOCONF_FUNC_PIO0_18_RXD << LPC_IOCONF_FUNC) |
 			      (LPC_IOCONF_MODE_INACTIVE << LPC_IOCONF_MODE) |
@@ -149,6 +150,53 @@ ao_serial_init(void)
 
 	/* Turn on the USART */
 	lpc_scb.sysahbclkctrl |= (1 << LPC_SCB_SYSAHBCLKCTRL_USART);
-}
-
 
+	/* Turn on the USART clock */
+	lpc_scb.uartclkdiv = AO_LPC_CLKOUT / AO_LPC_USARTCLK;
+
+	/* Configure USART */
+
+	/* Enable FIFOs, reset fifo contents, interrupt on 1 received char */
+	lpc_usart.iir_fcr = ((1 << LPC_USART_FCR_FIFOEN) |
+			 (1 << LPC_USART_FCR_RXFIFORES) |
+			 (1 << LPC_USART_FCR_TXFIFORES) |
+			 (LPC_USART_FCR_RXTL_1 << LPC_USART_FCR_RXTL));
+
+	/* 8 n 1 */
+	lpc_usart.lcr = ((LPC_USART_LCR_WLS_8 << LPC_USART_LCR_WLS) |
+			 (LPC_USART_LCR_SBS_1 << LPC_USART_LCR_SBS) |
+			 (0 << LPC_USART_LCR_PE) |
+			 (LPC_USART_LCR_PS_ODD << LPC_USART_LCR_PS) |
+			 (0 << LPC_USART_LCR_BC) |
+			 (0 << LPC_USART_LCR_DLAB));
+
+	/* Disable flow control */
+	lpc_usart.mcr = ((0 << LPC_USART_MCR_DTRCTRL) |
+			 (0 << LPC_USART_MCR_RTSCTRL) |
+			 (0 << LPC_USART_MCR_LMS) |
+			 (0 << LPC_USART_MCR_RTSEN) |
+			 (0 << LPC_USART_MCR_CTSEN));
+
+	/* 16x oversampling */
+	lpc_usart.osr = ((0 << LPC_USART_OSR_OSFRAC) |
+			 ((16 - 1) << LPC_USART_OSR_OSINT) |
+			 (0 << LPC_USART_OSR_FDINT));
+
+	/* Full duplex */
+	lpc_usart.hden = ((0 << LPC_USART_HDEN_HDEN));
+
+	/* Set baud rate */
+	ao_serial_set_speed(AO_SERIAL_SPEED_9600);
+
+	/* Enable interrupts */
+	lpc_usart.ier = ((1 << LPC_USART_IER_RBRINTEN) |
+			 (1 << LPC_USART_IER_THREINTEN));
+
+	lpc_nvic_set_enable(LPC_ISR_USART_POS);
+	lpc_nvic_set_priority(LPC_ISR_USART_POS, 0);
+#if USE_SERIAL_0_STDIN
+	ao_add_stdio(_ao_serial_pollchar,
+		     ao_serial_putchar,
+		     NULL);
+#endif
+}
diff --git a/src/lpc/lpc.h b/src/lpc/lpc.h
index 87af494a..81cd0cc8 100644
--- a/src/lpc/lpc.h
+++ b/src/lpc/lpc.h
@@ -720,4 +720,193 @@ struct lpc_usart {
 
 extern struct lpc_usart lpc_usart;
 
+#define LPC_USART_IER_RBRINTEN	0
+#define LPC_USART_IER_THREINTEN	1
+#define LPC_USART_IER_RSLINTEN	2
+#define LPC_USART_IER_MSINTEN	3
+#define LPC_USART_IER_ABEOINTEN	8
+#define LPC_USART_IER_ABTOINTEN	9
+
+#define LPC_USART_IIR_INTSTATUS		0
+#define LPC_USART_IIR_INTID		1
+#define LPC_USART_IIR_INTID_RLS			3
+#define LPC_USART_IIR_INTID_RDA			2
+#define LPC_USART_IIR_INTID_CTI			6
+#define LPC_USART_IIR_INTID_THRE		1
+#define LPC_USART_IIR_INTID_MS			0
+#define LPC_USART_IIR_INTID_MASK		7
+#define LPC_USART_IIR_FIFOEN		6
+#define LPC_USART_IIR_ABEOINT		8
+#define LPC_USART_IIR_ABTOINT		9
+
+#define LPC_USART_FCR_FIFOEN		0
+#define LPC_USART_FCR_RXFIFORES		1
+#define LPC_USART_FCR_TXFIFORES		2
+#define LPC_USART_FCR_RXTL		6
+#define LPC_USART_FCR_RXTL_1			0
+#define LPC_USART_FCR_RXTL_4			1
+#define LPC_USART_FCR_RXTL_8			2
+#define LPC_USART_FCR_RXTL_14			3
+
+#define LPC_USART_LCR_WLS	0
+#define LPC_USART_LCR_WLS_5		0
+#define LPC_USART_LCR_WLS_6		1
+#define LPC_USART_LCR_WLS_7		2
+#define LPC_USART_LCR_WLS_8		3
+#define LPC_USART_LCR_WLS_MASK		3
+#define LPC_USART_LCR_SBS	2
+#define LPC_USART_LCR_SBS_1		0
+#define LPC_USART_LCR_SBS_2		1
+#define LPC_USART_LCR_SBS_MASK		1
+#define LPC_USART_LCR_PE	3
+#define LPC_USART_LCR_PS	4
+#define LPC_USART_LCR_PS_ODD		0
+#define LPC_USART_LCR_PS_EVEN		1
+#define LPC_USART_LCR_PS_ONE		2
+#define LPC_USART_LCR_PS_ZERO		3
+#define LPC_USART_LCR_PS_MASK		3
+#define LPC_USART_LCR_BC	6
+#define LPC_USART_LCR_DLAB	7
+
+#define LPC_USART_MCR_DTRCTRL	0
+#define LPC_USART_MCR_RTSCTRL	1
+#define LPC_USART_MCR_LMS	4
+#define LPC_USART_MCR_RTSEN	6
+#define LPC_USART_MCR_CTSEN	7
+
+#define LPC_USART_LSR_RDR	0
+#define LPC_USART_LSR_OE	1
+#define LPC_USART_LSR_PE	2
+#define LPC_USART_LSR_FE	3
+#define LPC_USART_LSR_BI	4
+#define LPC_USART_LSR_THRE	5
+#define LPC_USART_LSR_TEMT	6
+#define LPC_USART_LSR_RXFE	7
+#define LPC_USART_LSR_TXERR	8
+
+#define LPC_USART_MSR_DCTS	0
+#define LPC_USART_MSR_DDSR	1
+#define LPC_USART_MSR_TERI	2
+#define LPC_USART_MSR_DDCD	3
+#define LPC_USART_MSR_CTS	4
+#define LPC_USART_MSR_DSR	5
+#define LPC_USART_MSR_RI	6
+#define LPC_USART_MSR_DCD	7
+
+#define LPC_USART_ACR_START	0
+#define LPC_USART_ACR_MODE	1
+#define LPC_USART_ACR_AUTORESTART	2
+#define LPC_USART_ACR_ABEOINTCLR	8
+#define LPC_USART_ACR_ABTOINTCLR	9
+
+#define LPC_USART_FDR_DIVADDVAL	0
+#define LPC_USART_FDR_MULVAL	4
+
+#define LPC_USART_OSR_OSFRAC	1
+#define LPC_USART_OSR_OSINT	4
+#define LPC_USART_OSR_FDINT	8
+
+#define LPC_USART_TER_TXEN	7
+
+#define LPC_USART_HDEN_HDEN	0
+
+#define LPC_ISR_PIN_INT0_POS	0
+#define LPC_ISR_PIN_INT1_POS	1
+#define LPC_ISR_PIN_INT2_POS	2
+#define LPC_ISR_PIN_INT3_POS	3
+#define LPC_ISR_PIN_INT4_POS	4
+#define LPC_ISR_PIN_INT5_POS	5
+#define LPC_ISR_PIN_INT6_POS	6
+#define LPC_ISR_PIN_INT7_POS	7
+#define LPC_ISR_GINT0_POS	8
+#define LPC_ISR_GINT1_POS	9
+#define LPC_ISR_SSP1_POS	14
+#define LPC_ISR_I2C_POS		15
+#define LPC_ISR_CT16B0_POS	16
+#define LPC_ISR_CT16B1_POS	17
+#define LPC_ISR_CT32B0_POS	18
+#define LPC_ISR_CT32B1_POS	19
+#define LPC_ISR_SSP0_POS	20
+#define LPC_ISR_USART_POS	21
+#define LPC_ISR_USB_IRQ_POS	22
+#define LPC_ISR_USB_FIQ_POS	23
+#define LPC_ISR_ADC_POS		24
+#define LPC_ISR_WWDT_POS	25
+#define LPC_ISR_BOD_POS		26
+#define LPC_ISR_FLASH_POS	27
+#define LPC_ISR_USB_WAKEUP_POS	30
+
+struct lpc_nvic {
+	vuint32_t	iser;		/* 0x000 0xe000e100 Set Enable Register */
+
+	uint8_t		_unused020[0x080 - 0x004];
+
+	vuint32_t	icer;		/* 0x080 0xe000e180 Clear Enable Register */
+
+	uint8_t		_unused0a0[0x100 - 0x084];
+
+	vuint32_t	ispr;		/* 0x100 0xe000e200 Set Pending Register */
+
+	uint8_t		_unused120[0x180 - 0x104];
+
+	vuint32_t	icpr;		/* 0x180 0xe000e280 Clear Pending Register */
+
+	uint8_t		_unused1a0[0x300 - 0x184];
+
+	vuint32_t	ipr[8];		/* 0x300 0xe000e400 Priority Register */
+};
+
+extern struct lpc_nvic lpc_nvic;
+
+static inline void
+lpc_nvic_set_enable(int irq) {
+	lpc_nvic.iser |= (1 << irq);
+}
+
+static inline void
+lpc_nvic_clear_enable(int irq) {
+	lpc_nvic.icer |= (1 << irq);
+}
+
+static inline int
+lpc_nvic_enabled(int irq) {
+	return (lpc_nvic.iser >> irq) & 1;
+}
+
+	
+static inline void
+lpc_nvic_set_pending(int irq) {
+	lpc_nvic.ispr = (1 << irq);
+}
+
+static inline void
+lpc_nvic_clear_pending(int irq) {
+	lpc_nvic.icpr = (1 << irq);
+}
+
+static inline int
+lpc_nvic_pending(int irq) {
+	return (lpc_nvic.ispr >> irq) & 1;
+}
+
+#define IRQ_PRIO_REG(irq)	((irq) >> 2)
+#define IRQ_PRIO_BIT(irq)	(((irq) & 3) << 3)
+#define IRQ_PRIO_MASK(irq)	(0xff << IRQ_PRIO_BIT(irq))
+
+static inline void
+lpc_nvic_set_priority(int irq, uint8_t prio) {
+	int		n = IRQ_PRIO_REG(irq);
+	uint32_t	v;
+
+	v = lpc_nvic.ipr[n];
+	v &= ~IRQ_PRIO_MASK(irq);
+	v |= (prio) << IRQ_PRIO_BIT(irq);
+	lpc_nvic.ipr[n] = v;
+}
+
+static inline uint8_t
+lpc_nvic_get_priority(int irq) {
+	return (lpc_nvic.ipr[IRQ_PRIO_REG(irq)] >> IRQ_PRIO_BIT(irq)) & IRQ_PRIO_MASK(0);
+}
+
 #endif /* _LPC_H_ */
diff --git a/src/lpc/registers.ld b/src/lpc/registers.ld
index cd6ac5f5..e444d832 100644
--- a/src/lpc/registers.ld
+++ b/src/lpc/registers.ld
@@ -7,3 +7,4 @@ lpc_gpio_group0 = 0x4005c000;
 lpc_gpio_group1 = 0x40060000;
 lpc_gpio	= 0x50000000;
 lpc_systick	= 0xe000e000;
+lpc_nvic	= 0xe000e100;
diff --git a/src/lpcxpresso/ao_demo.c b/src/lpcxpresso/ao_demo.c
index 56fef706..eae9503e 100644
--- a/src/lpcxpresso/ao_demo.c
+++ b/src/lpcxpresso/ao_demo.c
@@ -26,6 +26,14 @@ static void demo(void) {
 	}
 }
 
+static struct ao_task serial_task;
+
+static void serial(void) {
+	for (;;) {
+		printf ("hello, world\n");
+	}
+}
+
 int
 main(void)
 {
@@ -35,9 +43,12 @@ main(void)
 	ao_clock_init();
 	ao_timer_init();
 	
+	ao_serial_init();
+
 	ao_task_init();
 
 	ao_add_task(&demo_task, demo, "demo");
+	ao_add_task(&serial_task, serial, "serial");
 
 	ao_start_scheduler();
 
diff --git a/src/lpcxpresso/ao_pins.h b/src/lpcxpresso/ao_pins.h
index 56391c2b..7748f73c 100644
--- a/src/lpcxpresso/ao_pins.h
+++ b/src/lpcxpresso/ao_pins.h
@@ -40,8 +40,9 @@
 
 /* USART */
 
-#define HAS_SERIAL	1
+#define HAS_SERIAL		1
+#define USE_SERIAL_0_STDIN	1
 #define SERIAL_0_18_19		1
-#define SERIAL_1_14_15		0
-#define SERIAL_1_17_18		0
-#define SERIAL_1_26_27		0
+#define SERIAL_0_14_15		0
+#define SERIAL_0_17_18		0
+#define SERIAL_0_26_27		0