usb: ehci: Support interrupt transfers via periodic list

Interrupt transfers aren't meant to be used from the async list
(the EHCI spec indicates trouble with low/full-speed intr on async).

Build a periodic list instead, and provide an API to make use of it.
Then, use that API from the existing interrupt transfer API.

This provides support for USB keyboards using EHCI.

Use timeouts to ensure we cannot get stuck in the keyboard scanning
if something wrong happens (USB device unplugged or fatal I/O error)

Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
Signed-off-by: Julius Werner <jwerner@chromium.org>

Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/usb/host/ehci-hcd.c

@@ -21,12 +21,14 @@
  * MA 02111-1307 USA
  */
 #include <common.h>
+#include <errno.h>
 #include <asm/byteorder.h>
 #include <asm/unaligned.h>
 #include <usb.h>
 #include <asm/io.h>
 #include <malloc.h>
 #include <watchdog.h>
+#include <linux/compiler.h>
 
 #include "ehci.h"
 
@@ -39,7 +41,10 @@ static struct ehci_ctrl {
 	struct ehci_hcor *hcor;
 	int rootdev;
 	uint16_t portreset;
-	struct QH qh_list __attribute__((aligned(USB_DMA_MINALIGN)));
+	struct QH qh_list __aligned(USB_DMA_MINALIGN);
+	struct QH periodic_queue __aligned(USB_DMA_MINALIGN);
+	uint32_t *periodic_list;
+	int ntds;
 } ehcic[CONFIG_USB_MAX_CONTROLLER_COUNT];
 
 #define ALIGN_END_ADDR(type, ptr, size)			\
@@ -858,6 +863,8 @@ int usb_lowlevel_init(int index, void **controller)
 	uint32_t reg;
 	uint32_t cmd;
 	struct QH *qh_list;
+	struct QH *periodic;
+	int i;
 
 	if (ehci_hcd_init(index, &ehcic[index].hccr, &ehcic[index].hcor))
 		return -1;
@@ -887,6 +894,40 @@ int usb_lowlevel_init(int index, void **controller)
 	qh_list->qh_overlay.qt_token =
 			cpu_to_hc32(QT_TOKEN_STATUS(QT_TOKEN_STATUS_HALTED));
 
+	/* Set async. queue head pointer. */
+	ehci_writel(&ehcic[index].hcor->or_asynclistaddr, (uint32_t)qh_list);
+
+	/*
+	 * Set up periodic list
+	 * Step 1: Parent QH for all periodic transfers.
+	 */
+	periodic = &ehcic[index].periodic_queue;
+	memset(periodic, 0, sizeof(*periodic));
+	periodic->qh_link = cpu_to_hc32(QH_LINK_TERMINATE);
+	periodic->qh_overlay.qt_next = cpu_to_hc32(QT_NEXT_TERMINATE);
+	periodic->qh_overlay.qt_altnext = cpu_to_hc32(QT_NEXT_TERMINATE);
+
+	/*
+	 * Step 2: Setup frame-list: Every microframe, USB tries the same list.
+	 *         In particular, device specifications on polling frequency
+	 *         are disregarded. Keyboards seem to send NAK/NYet reliably
+	 *         when polled with an empty buffer.
+	 *
+	 *         Split Transactions will be spread across microframes using
+	 *         S-mask and C-mask.
+	 */
+	ehcic[index].periodic_list = memalign(4096, 1024*4);
+	if (!ehcic[index].periodic_list)
+		return -ENOMEM;
+	for (i = 0; i < 1024; i++) {
+		ehcic[index].periodic_list[i] = (uint32_t)periodic
+						| QH_LINK_TYPE_QH;
+	}
+
+	/* Set periodic list base address */
+	ehci_writel(&ehcic[index].hcor->or_periodiclistbase,
+		(uint32_t)ehcic[index].periodic_list);
+
 	reg = ehci_readl(&ehcic[index].hccr->cr_hcsparams);
 	descriptor.hub.bNbrPorts = HCS_N_PORTS(reg);
 	debug("Register %x NbrPorts %d\n", reg, descriptor.hub.bNbrPorts);
@@ -956,10 +997,254 @@ submit_control_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
 	return ehci_submit_async(dev, pipe, buffer, length, setup);
 }
 
+struct int_queue {
+	struct QH *first;
+	struct QH *current;
+	struct QH *last;
+	struct qTD *tds;
+};
+
+#define NEXT_QH(qh) (struct QH *)((qh)->qh_link & ~0x1f)
+
+static int
+enable_periodic(struct ehci_ctrl *ctrl)
+{
+	uint32_t cmd;
+	struct ehci_hcor *hcor = ctrl->hcor;
+	int ret;
+
+	cmd = ehci_readl(&hcor->or_usbcmd);
+	cmd |= CMD_PSE;
+	ehci_writel(&hcor->or_usbcmd, cmd);
+
+	ret = handshake((uint32_t *)&hcor->or_usbsts,
+			STS_PSS, STS_PSS, 100 * 1000);
+	if (ret < 0) {
+		printf("EHCI failed: timeout when enabling periodic list\n");
+		return -ETIMEDOUT;
+	}
+	udelay(1000);
+	return 0;
+}
+
+static int
+disable_periodic(struct ehci_ctrl *ctrl)
+{
+	uint32_t cmd;
+	struct ehci_hcor *hcor = ctrl->hcor;
+	int ret;
+
+	cmd = ehci_readl(&hcor->or_usbcmd);
+	cmd &= ~CMD_PSE;
+	ehci_writel(&hcor->or_usbcmd, cmd);
+
+	ret = handshake((uint32_t *)&hcor->or_usbsts,
+			STS_PSS, 0, 100 * 1000);
+	if (ret < 0) {
+		printf("EHCI failed: timeout when disabling periodic list\n");
+		return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static int periodic_schedules;
+
+struct int_queue *
+create_int_queue(struct usb_device *dev, unsigned long pipe, int queuesize,
+		 int elementsize, void *buffer)
+{
+	struct ehci_ctrl *ctrl = dev->controller;
+	struct int_queue *result = NULL;
+	int i;
+
+	debug("Enter create_int_queue\n");
+	if (usb_pipetype(pipe) != PIPE_INTERRUPT) {
+		debug("non-interrupt pipe (type=%lu)", usb_pipetype(pipe));
+		return NULL;
+	}
+
+	/* limit to 4 full pages worth of data -
+	 * we can safely fit them in a single TD,
+	 * no matter the alignment
+	 */
+	if (elementsize >= 16384) {
+		debug("too large elements for interrupt transfers\n");
+		return NULL;
+	}
+
+	result = malloc(sizeof(*result));
+	if (!result) {
+		debug("ehci intr queue: out of memory\n");
+		goto fail1;
+	}
+	result->first = memalign(32, sizeof(struct QH) * queuesize);
+	if (!result->first) {
+		debug("ehci intr queue: out of memory\n");
+		goto fail2;
+	}
+	result->current = result->first;
+	result->last = result->first + queuesize - 1;
+	result->tds = memalign(32, sizeof(struct qTD) * queuesize);
+	if (!result->tds) {
+		debug("ehci intr queue: out of memory\n");
+		goto fail3;
+	}
+	memset(result->first, 0, sizeof(struct QH) * queuesize);
+	memset(result->tds, 0, sizeof(struct qTD) * queuesize);
+
+	for (i = 0; i < queuesize; i++) {
+		struct QH *qh = result->first + i;
+		struct qTD *td = result->tds + i;
+		void **buf = &qh->buffer;
+
+		qh->qh_link = (uint32_t)(qh+1) | QH_LINK_TYPE_QH;
+		if (i == queuesize - 1)
+			qh->qh_link = QH_LINK_TERMINATE;
+
+		qh->qh_overlay.qt_next = (uint32_t)td;
+		qh->qh_endpt1 = (0 << 28) | /* No NAK reload (ehci 4.9) */
+			(usb_maxpacket(dev, pipe) << 16) | /* MPS */
+			(1 << 14) |
+			QH_ENDPT1_EPS(ehci_encode_speed(dev->speed)) |
+			(usb_pipeendpoint(pipe) << 8) | /* Endpoint Number */
+			(usb_pipedevice(pipe) << 0);
+		qh->qh_endpt2 = (1 << 30) | /* 1 Tx per mframe */
+			(1 << 0); /* S-mask: microframe 0 */
+		if (dev->speed == USB_SPEED_LOW ||
+				dev->speed == USB_SPEED_FULL) {
+			debug("TT: port: %d, hub address: %d\n",
+				dev->portnr, dev->parent->devnum);
+			qh->qh_endpt2 |= (dev->portnr << 23) |
+				(dev->parent->devnum << 16) |
+				(0x1c << 8); /* C-mask: microframes 2-4 */
+		}
+
+		td->qt_next = QT_NEXT_TERMINATE;
+		td->qt_altnext = QT_NEXT_TERMINATE;
+		debug("communication direction is '%s'\n",
+		      usb_pipein(pipe) ? "in" : "out");
+		td->qt_token = (elementsize << 16) |
+			((usb_pipein(pipe) ? 1 : 0) << 8) | /* IN/OUT token */
+			0x80; /* active */
+		td->qt_buffer[0] = (uint32_t)buffer + i * elementsize;
+		td->qt_buffer[1] = (td->qt_buffer[0] + 0x1000) & ~0xfff;
+		td->qt_buffer[2] = (td->qt_buffer[0] + 0x2000) & ~0xfff;
+		td->qt_buffer[3] = (td->qt_buffer[0] + 0x3000) & ~0xfff;
+		td->qt_buffer[4] = (td->qt_buffer[0] + 0x4000) & ~0xfff;
+
+		*buf = buffer + i * elementsize;
+	}
+
+	if (disable_periodic(ctrl) < 0) {
+		debug("FATAL: periodic should never fail, but did");
+		goto fail3;
+	}
+
+	/* hook up to periodic list */
+	struct QH *list = &ctrl->periodic_queue;
+	result->last->qh_link = list->qh_link;
+	list->qh_link = (uint32_t)result->first | QH_LINK_TYPE_QH;
+
+	if (enable_periodic(ctrl) < 0) {
+		debug("FATAL: periodic should never fail, but did");
+		goto fail3;
+	}
+	periodic_schedules++;
+
+	debug("Exit create_int_queue\n");
+	return result;
+fail3:
+	if (result->tds)
+		free(result->tds);
+fail2:
+	if (result->first)
+		free(result->first);
+	if (result)
+		free(result);
+fail1:
+	return NULL;
+}
+
+void *poll_int_queue(struct usb_device *dev, struct int_queue *queue)
+{
+	struct QH *cur = queue->current;
+
+	/* depleted queue */
+	if (cur == NULL) {
+		debug("Exit poll_int_queue with completed queue\n");
+		return NULL;
+	}
+	/* still active */
+	if (cur->qh_overlay.qt_token & 0x80) {
+		debug("Exit poll_int_queue with no completed intr transfer. "
+		      "token is %x\n", cur->qh_overlay.qt_token);
+		return NULL;
+	}
+	if (!(cur->qh_link & QH_LINK_TERMINATE))
+		queue->current++;
+	else
+		queue->current = NULL;
+	debug("Exit poll_int_queue with completed intr transfer. "
+	      "token is %x at %p (first at %p)\n", cur->qh_overlay.qt_token,
+	      &cur->qh_overlay.qt_token, queue->first);
+	return cur->buffer;
+}
+
+/* Do not free buffers associated with QHs, they're owned by someone else */
+int
+destroy_int_queue(struct usb_device *dev, struct int_queue *queue)
+{
+	struct ehci_ctrl *ctrl = dev->controller;
+	int result = -1;
+	unsigned long timeout;
+
+	if (disable_periodic(ctrl) < 0) {
+		debug("FATAL: periodic should never fail, but did");
+		goto out;
+	}
+	periodic_schedules--;
+
+	struct QH *cur = &ctrl->periodic_queue;
+	timeout = get_timer(0) + 500; /* abort after 500ms */
+	while (!(cur->qh_link & QH_LINK_TERMINATE)) {
+		debug("considering %p, with qh_link %x\n", cur, cur->qh_link);
+		if (NEXT_QH(cur) == queue->first) {
+			debug("found candidate. removing from chain\n");
+			cur->qh_link = queue->last->qh_link;
+			result = 0;
+			break;
+		}
+		cur = NEXT_QH(cur);
+		if (get_timer(0) > timeout) {
+			printf("Timeout destroying interrupt endpoint queue\n");
+			result = -1;
+			goto out;
+		}
+	}
+
+	if (periodic_schedules > 0) {
+		result = enable_periodic(ctrl);
+		if (result < 0)
+			debug("FATAL: periodic should never fail, but did");
+	}
+
+out:
+	free(queue->tds);
+	free(queue->first);
+	free(queue);
+
+	return result;
+}
+
 int
 submit_int_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
 	       int length, int interval)
 {
+	void *backbuffer;
+	struct int_queue *queue;
+	unsigned long timeout;
+	int result = 0, ret;
+
 	debug("dev=%p, pipe=%lu, buffer=%p, length=%d, interval=%d",
 	      dev, pipe, buffer, length, interval);
 
@@ -975,9 +1260,31 @@ submit_int_msg(struct usb_device *dev, unsigned long pipe, void *buffer,
 	 * not require more than a single qTD.
 	 */
 	if (length > usb_maxpacket(dev, pipe)) {
-		printf("%s: Interrupt transfers requiring several transactions "
-			"are not supported.\n", __func__);
+		printf("%s: Interrupt transfers requiring several "
+			"transactions are not supported.\n", __func__);
 		return -1;
 	}
-	return ehci_submit_async(dev, pipe, buffer, length, NULL);
+
+	queue = create_int_queue(dev, pipe, 1, length, buffer);
+
+	timeout = get_timer(0) + USB_TIMEOUT_MS(pipe);
+	while ((backbuffer = poll_int_queue(dev, queue)) == NULL)
+		if (get_timer(0) > timeout) {
+			printf("Timeout poll on interrupt endpoint\n");
+			result = -ETIMEDOUT;
+			break;
+		}
+
+	if (backbuffer != buffer) {
+		debug("got wrong buffer back (%x instead of %x)\n",
+		      (uint32_t)backbuffer, (uint32_t)buffer);
+		return -EINVAL;
+	}
+
+	ret = destroy_int_queue(dev, queue);
+	if (ret < 0)
+		return ret;
+
+	/* everything worked out fine */
+	return result;
 }

drivers/usb/host/ehci.h

@@ -69,6 +69,7 @@ struct ehci_hcor {
 #define CMD_RUN		(1 << 0)		/* start/stop HC */
 	uint32_t or_usbsts;
 #define STS_ASS		(1 << 15)
+#define	STS_PSS		(1 << 14)
 #define STS_HALT	(1 << 12)
 	uint32_t or_usbintr;
 #define INTR_UE         (1 << 0)                /* USB interrupt enable */
@@ -245,7 +246,10 @@ struct QH {
 	 * Add dummy fill value to make the size of this struct
 	 * aligned to 32 bytes
 	 */
-	uint8_t fill[16];
+	union {
+		uint8_t fill[16];
+		void *buffer;
+	};
 };
 
 /* Low level init functions */