Try #91:

CHANGELOG.md

@@ -2,7 +2,87 @@
 
 ## Unreleased
 
-- Add `teensy4_bsp::usb::Filter` type alias to simplify USB filter definitions
+This release lets users combine the USB logging system with RTIC. The new
+feature required a few breaking changes. The rest of this section notes
+the breaking changes, migration tips, and other minor features in this
+release.
+
+De-couple the USB logging and SysTick modules. You no longer need the SysTick
+timer to use the USB logging system. The BSP features are now independent,
+though they're both enabled by default. This change means that you can use
+RTIC with USB logging. See the RTIC examples for a demonstration.
+
+Users may now check USB poll status in their own USB interrupt handler. This
+may support more responsive reading from a USB host.
+
+**BREAKING** The `"usb-logging"` feature will not implicitly enable the
+`"systick"` feature. To fix your build, explicitly add the `"systick"` feature:
+
+```toml
+[dependencies.teensy4-bsp]
+# features = ["usb-logging"]  # Before
+features = ["usb-logging", "systick"]  # After
+default-features = false
+```
+
+This only affects users who specify `default-features = false`.
+
+**BREAKING** Since USB logging does not need SysTick, the setup functions
+do not accept a `&SysTick` reference. The change applies to these two
+functions:
+
+- `usb::init`
+- `usb::split`
+
+Instead, the functions require the `imxrt_ral`'s `USB1` instance. The example
+below shows one way to migrate your code:
+
+```rust
+use teensy4_bsp as bsp;
+
+// Before
+let systick = bsp::SysTick::new(cortex_m::Peripherals::take().unwrap().SYST);
+bsp::usb::init(&systick, Default::default()).unwrap();
+
+// Now
+use bsp::hal::ral::usb::USB1;
+bsp::usb::init(USB1::take().unwrap(), Default::default()).unwrap();
+```
+
+**BREAKING** The USB `Reader` and `Writer` methods are fallible. Instead of
+returning `usize`s, the methods now return `Result<usize, Error>`. See the
+documentation to understand the `Error` type, and to learn about the new
+method guarantees.
+
+**BREAKING** Users must `poll()` the USB driver to coordinate USB I/O. The BSP
+does not implement the `USB_OTG1` interrupt handler. If you do not 
+repeatedly call `poll()`, or you do not call it fast enough, the USB device may
+now work.
+
+Consider calling `poll()` in your own `USB_OTG1` interrupt handler to maintain
+compatibility. If using an interrupt handler, make sure to unmask the `USB_OTG1`
+interrupt.
+
+The snippet below should be sufficient to maintain compatibility in your
+system:
+
+```rust
+use teensy4_bsp as bsp;
+use bsp::interrupt;
+
+#[cortex_m_rt::interrupt]
+unsafe fn USB_OTG1() {
+    bsp::usb::poll();
+}
+
+// Unmask the interrupt after calling the `usb::init`
+// or `usb::setup` functions.
+unsafe { cortex_m::peripheral::NVIC::unmask(interrupt::USB_OTG1) };
+```
+
+Add a `flush` method to the `usb::Writer` type.
+
+Add `teensy4_bsp::usb::Filter` type alias to simplify USB filter definitions.
 
 ## [0.1.0] - 2020-10-16
 

Cargo.toml

@@ -79,11 +79,7 @@ members = [
 # Default features established for prototype development
 default = ["usb-logging", "systick"]
 # Enables the USB logging stack
-#
-# This will introduce the teensy4-usb-sys bindings into the build
-# graph. It also requires systick, since the USB stack depends on
-# the systick counter for timekeeping.
-usb-logging = ["systick", "log"]
+usb-logging = ["log"]
 # Include a definition of the SysTick exception handler. This enables
 # a simple delay() spinloop that waits for the timer to elapse.
 #

bin/usb.c

@@ -5,8 +5,6 @@
 #include <string.h>
 #include "debug/printf.h"
 
-void delay(uint32_t);
-
 //#define LOG_SIZE  20
 //uint32_t transfer_log_head=0;
 //uint32_t transfer_log_count=0;
@@ -97,6 +95,9 @@ static void endpoint0_complete(void);
 
 static void run_callbacks(endpoint_t *ep);
 
+int32_t usb_device_is_configured(void) {
+	return !!usb_configuration;
+}
 
 FLASHMEM void usb_init(void)
 {
@@ -143,14 +144,12 @@ FLASHMEM void usb_init(void)
 		USBPHY1_CTRL_CLR = USBPHY_CTRL_SFTRST; // reset PHY
 		//USB1_USBSTS = USB1_USBSTS; // TODO: is this needed?
 		printf("USB reset took %d loops\n", count);
-		//delay(10);
 		//printf("\n");
 		//printf("USBPHY1_PWD=%08lX\n", USBPHY1_PWD);
 		//printf("USBPHY1_TX=%08lX\n", USBPHY1_TX);
 		//printf("USBPHY1_RX=%08lX\n", USBPHY1_RX);
 		//printf("USBPHY1_CTRL=%08lX\n", USBPHY1_CTRL);
 		//printf("USB1_USBMODE=%08lX\n", USB1_USBMODE);
-		delay(25);
 	}
 #endif
 	// Device Controller Initialization, page 3161
@@ -197,15 +196,28 @@ FLASHMEM void usb_init(void)
 	//transfer_log_count = 0;
 }
 
+#define POLL_RX_ENDPOINT_MASK(ep) (1 << ep)
+#define POLL_TX_ENDPOINT_MASK(ep) (1 << (ep + 16))
+
+//
+// Keep these in sync with the constants
+// in bindings.rs.
+//
+
+typedef enum {
+	POLL_CDC_RX_COMPLETE = 1,
+	POLL_CDC_TX_COMPLETE = 2,
+} poll_flag_t;
 
-void isr(void)
+uint32_t poll(void)
 {
 	//printf("*");
 
 	//  Port control in device mode is only used for
 	//  status port reset, suspend, and current connect status.
 	uint32_t status = USB1_USBSTS;
 	USB1_USBSTS = status;
+	uint32_t poll_flags = 0;
 
 	// USB_USBSTS_SLI - set to 1 when enters a suspend state from an active state
 	// USB_USBSTS_SRI - set at start of frame
@@ -232,6 +244,10 @@ void isr(void)
 			setupstatus = USB1_ENDPTSETUPSTAT; // page 3175
 		}
 		uint32_t completestatus = USB1_ENDPTCOMPLETE;
+
+		poll_flags |= (POLL_RX_ENDPOINT_MASK(CDC_RX_ENDPOINT) & completestatus) ? POLL_CDC_RX_COMPLETE : 0;
+		poll_flags |= (POLL_TX_ENDPOINT_MASK(CDC_TX_ENDPOINT) & completestatus) ? POLL_CDC_TX_COMPLETE : 0;
+
 		if (completestatus) {
 			USB1_ENDPTCOMPLETE = completestatus;
 			//printf("USB1_ENDPTCOMPLETE=%lX\n", completestatus);
@@ -308,6 +324,8 @@ void isr(void)
 			USB1_USBINTR &= ~USB_USBINTR_SRE;
 		}
 	}
+
+	return poll_flags;
 }
 
 
@@ -450,7 +468,6 @@ static void endpoint0_setup(uint64_t setupdata)
 		break;
 #if defined(CDC_STATUS_INTERFACE)
 	  case 0x2221: // CDC_SET_CONTROL_LINE_STATE
-		usb_cdc_line_rtsdtr_millis = systick_millis_count;
 		usb_cdc_line_rtsdtr = setup.wValue;
 		__attribute__((fallthrough));
 	  case 0x2321: // CDC_SEND_BREAK

bin/usb_serial.c

@@ -42,7 +42,6 @@ void yield(void);
 //#if F_CPU >= 20000000
 
 uint32_t usb_cdc_line_coding[2];
-volatile uint32_t usb_cdc_line_rtsdtr_millis;
 volatile uint8_t usb_cdc_line_rtsdtr=0;
 volatile uint8_t usb_cdc_transmit_flush_timer=0;
 
@@ -99,7 +98,7 @@ void usb_serial_configure(void)
 	}
 	memset(tx_transfer, 0, sizeof(tx_transfer));
 	tx_head = 0;
-	tx_available = 0;
+	tx_available = TX_SIZE;
 	memset(rx_transfer, 0, sizeof(rx_transfer));
 	memset(rx_count, 0, sizeof(rx_count));
 	memset(rx_index, 0, sizeof(rx_index));
@@ -267,21 +266,12 @@ int usb_serial_getchar(void)
 #define TX_TIMEOUT_MSEC 120
 
 
-// When we've suffered the transmit timeout, don't wait again until the computer
-// begins accepting data.  If no software is running to receive, we'll just discard
-// data as rapidly as Serial.print() can generate it, until there's something to
-// actually receive it.
-static uint8_t transmit_previous_timeout=0;
-
-
 // transmit a character.  0 returned on success, -1 on error
 int usb_serial_putchar(uint8_t c)
 {
 	return usb_serial_write(&c, 1);
 }
 
-extern volatile uint32_t systick_millis_count;
-
 static void timer_config(void (*callback)(void), uint32_t microseconds);
 static void timer_start_oneshot();
 static void timer_stop();
@@ -305,50 +295,20 @@ static void timer_stop(void)
 	USB1_GPTIMER0CTRL = 0;
 }
 
+// Keep this in sync with the error constants
+// in bindings.rs.
+typedef enum {
+	SERIAL_NOT_CONFIGURED = -1,
+} serial_err_t;
 
 int usb_serial_write(const void *buffer, uint32_t size)
 {
 	uint32_t sent=0;
 	const uint8_t *data = (const uint8_t *)buffer;
 
-	if (!usb_configuration) return 0;
+	if (!usb_configuration) return SERIAL_NOT_CONFIGURED;
 	while (size > 0) {
 		transfer_t *xfer = tx_transfer + tx_head;
-		int waiting=0;
-		uint32_t wait_begin_at=0;
-		while (!tx_available) {
-			//digitalWriteFast(3, HIGH);
-			uint32_t status = usb_transfer_status(xfer);
-			if (!(status & 0x80)) {
-				if (status & 0x68) {
-					// TODO: what if status has errors???
-					printf("ERROR status = %x, i=%d, ms=%u\n",
-						status, tx_head, systick_millis_count);
-				}
-				tx_available = TX_SIZE;
-				transmit_previous_timeout = 0;
-				break;
-			}
-			if (!waiting) {
-				wait_begin_at = systick_millis_count;
-				waiting = 1;
-			}
-			if (transmit_previous_timeout) return sent;
-			if (systick_millis_count - wait_begin_at > TX_TIMEOUT_MSEC) {
-				// waited too long, assume the USB host isn't listening
-				transmit_previous_timeout = 1;
-				return sent;
-				//printf("\nstop, waited too long\n");
-				//printf("status = %x\n", status);
-				//printf("tx head=%d\n", tx_head);
-				//printf("TXFILLTUNING=%08lX\n", USB1_TXFILLTUNING);
-				//usb_print_transfer_log();
-				//while (1) ;
-			}
-			if (!usb_configuration) return sent;
-			yield();
-		}
-		//digitalWriteFast(3, LOW);
 		uint8_t *txdata = txbuffer + (tx_head * TX_SIZE) + (TX_SIZE - tx_available);
 		if (size >= tx_available) {
 			memcpy(txdata, data, tx_available);
@@ -362,7 +322,7 @@ int usb_serial_write(const void *buffer, uint32_t size)
 			size -= tx_available;
 			sent += tx_available;
 			data += tx_available;
-			tx_available = 0;
+			tx_available = TX_SIZE;
 			timer_stop();
 		} else {
 			memcpy(txdata, data, size);
@@ -391,7 +351,6 @@ void usb_serial_flush_output(void)
 {
 
 	if (!usb_configuration) return;
-	if (tx_available == 0) return;
 	tx_noautoflush = 1;
 	transfer_t *xfer = tx_transfer + tx_head;
 	uint8_t *txbuf = txbuffer + (tx_head * TX_SIZE);
@@ -400,15 +359,14 @@ void usb_serial_flush_output(void)
 	arm_dcache_flush_delete(txbuf, txnum);
 	usb_transmit(CDC_TX_ENDPOINT, xfer);
 	if (++tx_head >= TX_NUM) tx_head = 0;
-	tx_available = 0;
+	tx_available = TX_SIZE;
 	tx_noautoflush = 0;
 }
 
 static void usb_serial_flush_callback(void)
 {
 	if (tx_noautoflush) return;
 	if (!usb_configuration) return;
-	if (tx_available == 0) return;
 	//printf("flush callback, %d bytes\n", TX_SIZE - tx_available);
 	transfer_t *xfer = tx_transfer + tx_head;
 	uint8_t *txbuf = txbuffer + (tx_head * TX_SIZE);
@@ -417,7 +375,7 @@ static void usb_serial_flush_callback(void)
 	arm_dcache_flush_delete(txbuf, txnum);
 	usb_transmit(CDC_TX_ENDPOINT, xfer);
 	if (++tx_head >= TX_NUM) tx_head = 0;
-	tx_available = 0;
+	tx_available = TX_SIZE;
 }