staging: ozwpan: High resolution timers

Current implementation assumes HZ = 1000 for calculating
all internal timer intervals, which creates problem on
platforms where HZ != 1000.

As well we need resolution of less than 10 mSec for heartbeat
calculation, this creates problem on some platforms where HZ is
configured as HZ = 100, or around, which restricts us to timer interval
of 10 mSec. This is particularly found on embedded devices.

This patch moves on to use high resolution timers to calculate
all timer intervals as it allows us to have very small resolution
of timer interval, removing dependency on HZ.

Signed-off-by: Rupesh Gujare <rupesh.gujare@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 46 insertions, 45 deletions

diff --git a/drivers/staging/ozwpan/ozhcd.c b/drivers/staging/ozwpan/ozhcd.c
index 6b16bfc4cdd8..f81a0c53b39b 100644
--- a/drivers/staging/ozwpan/ozhcd.c
+++ b/drivers/staging/ozwpan/ozhcd.c
@@ -26,7 +26,6 @@
  */
 #include <linux/platform_device.h>
 #include <linux/usb.h>
-#include <linux/jiffies.h>
 #include <linux/slab.h>
 #include <linux/export.h>
 #include "linux/usb/hcd.h"
@@ -49,6 +48,9 @@
 /* Get endpoint object from the containing link.
  */
 #define ep_from_link(__e) container_of((__e), struct oz_endpoint, link)
+/*EP0 timeout before ep0 request is again added to TX queue. (13*8 = 98mSec)
+ */
+#define EP0_TIMEOUT_COUNTER 13
 /*------------------------------------------------------------------------------
  * Used to link urbs together and also store some status information for each
  * urb.
@@ -60,7 +62,7 @@ struct oz_urb_link {
 	struct oz_port *port;
 	u8 req_id;
 	u8 ep_num;
-	unsigned long submit_jiffies;
+	unsigned submit_counter;
 };
 
 /* Holds state information about a USB endpoint.
@@ -69,7 +71,7 @@ struct oz_endpoint {
 	struct list_head urb_list;	/* List of oz_urb_link items. */
 	struct list_head link;		/* For isoc ep, links in to isoc
 					   lists of oz_port. */
-	unsigned long last_jiffies;
+	struct timespec timestamp;
 	int credit;
 	int credit_ceiling;
 	u8 ep_num;
@@ -187,6 +189,7 @@ static DEFINE_SPINLOCK(g_tasklet_lock);
 static struct tasklet_struct g_urb_process_tasklet;
 static struct tasklet_struct g_urb_cancel_tasklet;
 static atomic_t g_pending_urbs = ATOMIC_INIT(0);
+static atomic_t g_usb_frame_number = ATOMIC_INIT(0);
 static const struct hc_driver g_oz_hc_drv = {
 	.description =		g_hcd_name,
 	.product_desc =		"Ozmo Devices WPAN",
@@ -344,7 +347,7 @@ static struct oz_urb_link *oz_uncancel_urb(struct oz_hcd *ozhcd, struct urb *urb
  * Context: softirq or process
  */
 static void oz_complete_urb(struct usb_hcd *hcd, struct urb *urb,
-		int status, unsigned long submit_jiffies)
+		int status)
 {
 	struct oz_hcd *ozhcd = oz_hcd_private(hcd);
 	unsigned long irq_state;
@@ -372,12 +375,7 @@ static void oz_complete_urb(struct usb_hcd *hcd, struct urb *urb,
 	if (oz_forget_urb(urb)) {
 		oz_dbg(ON, "ERROR Unknown URB %p\n", urb);
 	} else {
-		static unsigned long last_time;
 		atomic_dec(&g_pending_urbs);
-		oz_dbg(URB, "%lu: giveback_urb(%p,%x) %lu %lu pending:%d\n",
-		       jiffies, urb, status, jiffies-submit_jiffies,
-		       jiffies-last_time, atomic_read(&g_pending_urbs));
-		last_time = jiffies;
 		usb_hcd_giveback_urb(hcd, urb, status);
 	}
 	spin_lock(&g_tasklet_lock);
@@ -445,7 +443,7 @@ static void oz_complete_buffered_urb(struct oz_port *port,
 	ep->buffered_units--;
 	oz_dbg(ON, "Trying to give back buffered frame of size=%d\n",
 	       available_space);
-	oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+	oz_complete_urb(port->ozhcd->hcd, urb, 0);
 }
 
 /*------------------------------------------------------------------------------
@@ -464,7 +462,7 @@ static int oz_enqueue_ep_urb(struct oz_port *port, u8 ep_addr, int in_dir,
 	urbl = oz_alloc_urb_link();
 	if (!urbl)
 		return -ENOMEM;
-	urbl->submit_jiffies = jiffies;
+	urbl->submit_counter = 0;
 	urbl->urb = urb;
 	urbl->req_id = req_id;
 	urbl->ep_num = ep_addr;
@@ -478,7 +476,7 @@ static int oz_enqueue_ep_urb(struct oz_port *port, u8 ep_addr, int in_dir,
 	if (urb->unlinked) {
 		spin_unlock_bh(&port->ozhcd->hcd_lock);
 		oz_dbg(ON, "urb %p unlinked so complete immediately\n", urb);
-		oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+		oz_complete_urb(port->ozhcd->hcd, urb, 0);
 		oz_free_urb_link(urbl);
 		return 0;
 	}
@@ -501,7 +499,7 @@ static int oz_enqueue_ep_urb(struct oz_port *port, u8 ep_addr, int in_dir,
 	if (ep && port->hpd) {
 		list_add_tail(&urbl->link, &ep->urb_list);
 		if (!in_dir && ep_addr && (ep->credit < 0)) {
-			ep->last_jiffies = jiffies;
+			getrawmonotonic(&ep->timestamp);
 			ep->credit = 0;
 		}
 	} else {
@@ -790,7 +788,7 @@ void oz_hcd_get_desc_cnf(void *hport, u8 req_id, int status, const u8 *desc,
 		}
 	}
 	urb->actual_length = total_size;
-	oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+	oz_complete_urb(port->ozhcd->hcd, urb, 0);
 }
 /*------------------------------------------------------------------------------
  * Context: softirq
@@ -852,7 +850,7 @@ static void oz_hcd_complete_set_config(struct oz_port *port, struct urb *urb,
 	} else {
 		rc = -ENOMEM;
 	}
-	oz_complete_urb(hcd, urb, rc, 0);
+	oz_complete_urb(hcd, urb, rc);
 }
 /*------------------------------------------------------------------------------
  * Context: softirq
@@ -877,7 +875,7 @@ static void oz_hcd_complete_set_interface(struct oz_port *port, struct urb *urb,
 	} else {
 		rc = -ENOMEM;
 	}
-	oz_complete_urb(hcd, urb, rc, 0);
+	oz_complete_urb(hcd, urb, rc);
 }
 /*------------------------------------------------------------------------------
  * Context: softirq
@@ -914,7 +912,7 @@ void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode, const u8 *data,
 				(u8)windex, (u8)wvalue);
 			break;
 		default:
-			oz_complete_urb(hcd, urb, 0, 0);
+			oz_complete_urb(hcd, urb, 0);
 		}
 
 	} else {
@@ -928,7 +926,7 @@ void oz_hcd_control_cnf(void *hport, u8 req_id, u8 rcode, const u8 *data,
 			memcpy(urb->transfer_buffer, data, copy_len);
 			urb->actual_length = copy_len;
 		}
-		oz_complete_urb(hcd, urb, 0, 0);
+		oz_complete_urb(hcd, urb, 0);
 	}
 }
 /*------------------------------------------------------------------------------
@@ -998,7 +996,7 @@ void oz_hcd_data_ind(void *hport, u8 endpoint, const u8 *data, int data_len)
 				copy_len = urb->transfer_buffer_length;
 			memcpy(urb->transfer_buffer, data, copy_len);
 			urb->actual_length = copy_len;
-			oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+			oz_complete_urb(port->ozhcd->hcd, urb, 0);
 			return;
 		} else {
 			oz_dbg(ON, "buffering frame as URB is not available\n");
@@ -1017,7 +1015,7 @@ done:
  */
 static inline int oz_usb_get_frame_number(void)
 {
-	return jiffies_to_msecs(get_jiffies_64());
+	return atomic_inc_return(&g_usb_frame_number);
 }
 /*------------------------------------------------------------------------------
  * Context: softirq
@@ -1033,7 +1031,8 @@ int oz_hcd_heartbeat(void *hport)
 	struct list_head *n;
 	struct urb *urb;
 	struct oz_endpoint *ep;
-	unsigned long now = jiffies;
+	struct timespec ts, delta;
+	getrawmonotonic(&ts);
 	INIT_LIST_HEAD(&xfr_list);
 	/* Check the OUT isoc endpoints to see if any URB data can be sent.
 	 */
@@ -1042,10 +1041,11 @@ int oz_hcd_heartbeat(void *hport)
 		ep = ep_from_link(e);
 		if (ep->credit < 0)
 			continue;
-		ep->credit += jiffies_to_msecs(now - ep->last_jiffies);
+		delta = timespec_sub(ts, ep->timestamp);
+		ep->credit += timespec_to_ns(&delta) / NSEC_PER_MSEC;
 		if (ep->credit > ep->credit_ceiling)
 			ep->credit = ep->credit_ceiling;
-		ep->last_jiffies = now;
+		ep->timestamp = ts;
 		while (ep->credit && !list_empty(&ep->urb_list)) {
 			urbl = list_first_entry(&ep->urb_list,
 				struct oz_urb_link, link);
@@ -1053,6 +1053,8 @@ int oz_hcd_heartbeat(void *hport)
 			if ((ep->credit + 1) < urb->number_of_packets)
 				break;
 			ep->credit -= urb->number_of_packets;
+			if (ep->credit < 0)
+				ep->credit = 0;
 			list_move_tail(&urbl->link, &xfr_list);
 		}
 	}
@@ -1060,16 +1062,14 @@ int oz_hcd_heartbeat(void *hport)
 	/* Send to PD and complete URBs.
 	 */
 	list_for_each_safe(e, n, &xfr_list) {
-		unsigned long t;
 		urbl = container_of(e, struct oz_urb_link, link);
 		urb = urbl->urb;
-		t = urbl->submit_jiffies;
 		list_del_init(e);
 		urb->error_count = 0;
 		urb->start_frame = oz_usb_get_frame_number();
 		oz_usb_send_isoc(port->hpd, urbl->ep_num, urb);
 		oz_free_urb_link(urbl);
-		oz_complete_urb(port->ozhcd->hcd, urb, 0, t);
+		oz_complete_urb(port->ozhcd->hcd, urb, 0);
 	}
 	/* Check the IN isoc endpoints to see if any URBs can be completed.
 	 */
@@ -1080,13 +1080,14 @@ int oz_hcd_heartbeat(void *hport)
 			if (ep->buffered_units >= OZ_IN_BUFFERING_UNITS) {
 				ep->flags &= ~OZ_F_EP_BUFFERING;
 				ep->credit = 0;
-				ep->last_jiffies = now;
+				ep->timestamp = ts;
 				ep->start_frame = 0;
 			}
 			continue;
 		}
-		ep->credit += jiffies_to_msecs(now - ep->last_jiffies);
-		ep->last_jiffies = now;
+		delta = timespec_sub(ts, ep->timestamp);
+		ep->credit += timespec_to_ns(&delta) / NSEC_PER_MSEC;
+		ep->timestamp = ts;
 		while (!list_empty(&ep->urb_list)) {
 			struct oz_urb_link *urbl =
 				list_first_entry(&ep->urb_list,
@@ -1095,7 +1096,7 @@ int oz_hcd_heartbeat(void *hport)
 			int len = 0;
 			int copy_len;
 			int i;
-			if ((ep->credit + 1) < urb->number_of_packets)
+			if (ep->credit  < urb->number_of_packets)
 				break;
 			if (ep->buffered_units < urb->number_of_packets)
 				break;
@@ -1141,7 +1142,7 @@ int oz_hcd_heartbeat(void *hport)
 		urb = urbl->urb;
 		list_del_init(e);
 		oz_free_urb_link(urbl);
-		oz_complete_urb(port->ozhcd->hcd, urb, 0, 0);
+		oz_complete_urb(port->ozhcd->hcd, urb, 0);
 	}
 	/* Check if there are any ep0 requests that have timed out.
 	 * If so resent to PD.
@@ -1153,11 +1154,12 @@ int oz_hcd_heartbeat(void *hport)
 		spin_lock_bh(&ozhcd->hcd_lock);
 		list_for_each_safe(e, n, &ep->urb_list) {
 			urbl = container_of(e, struct oz_urb_link, link);
-			if (time_after(now, urbl->submit_jiffies+HZ/2)) {
-				oz_dbg(ON, "%ld: Request 0x%p timeout\n",
-				       now, urbl->urb);
-				urbl->submit_jiffies = now;
+			if (urbl->submit_counter > EP0_TIMEOUT_COUNTER) {
+				oz_dbg(ON, "Request 0x%p timeout\n", urbl->urb);
 				list_move_tail(e, &xfr_list);
+				urbl->submit_counter = 0;
+			} else {
+				urbl->submit_counter++;
 			}
 		}
 		if (!list_empty(&ep->urb_list))
@@ -1382,7 +1384,7 @@ static void oz_process_ep0_urb(struct oz_hcd *ozhcd, struct urb *urb,
 	int port_ix = -1;
 	struct oz_port *port = NULL;
 
-	oz_dbg(URB, "%lu: %s: (%p)\n", jiffies, __func__, urb);
+	oz_dbg(URB, "[%s]:(%p)\n", __func__, urb);
 	port_ix = oz_get_port_from_addr(ozhcd, urb->dev->devnum);
 	if (port_ix < 0) {
 		rc = -EPIPE;
@@ -1505,7 +1507,7 @@ static void oz_process_ep0_urb(struct oz_hcd *ozhcd, struct urb *urb,
 out:
 	if (rc || complete) {
 		oz_dbg(ON, "Completing request locally\n");
-		oz_complete_urb(ozhcd->hcd, urb, rc, 0);
+		oz_complete_urb(ozhcd->hcd, urb, rc);
 	} else {
 		oz_usb_request_heartbeat(port->hpd);
 	}
@@ -1569,7 +1571,7 @@ static void oz_urb_process_tasklet(unsigned long unused)
 		oz_free_urb_link(urbl);
 		rc = oz_urb_process(ozhcd, urb);
 		if (rc)
-			oz_complete_urb(ozhcd->hcd, urb, rc, 0);
+			oz_complete_urb(ozhcd->hcd, urb, rc);
 		spin_lock_irqsave(&g_tasklet_lock, irq_state);
 	}
 	spin_unlock_irqrestore(&g_tasklet_lock, irq_state);
@@ -1638,7 +1640,7 @@ out2:
 	if (urbl) {
 		urb->actual_length = 0;
 		oz_free_urb_link(urbl);
-		oz_complete_urb(ozhcd->hcd, urb, -EPIPE, 0);
+		oz_complete_urb(ozhcd->hcd, urb, -EPIPE);
 	}
 }
 /*------------------------------------------------------------------------------
@@ -1678,7 +1680,7 @@ static void oz_hcd_clear_orphanage(struct oz_hcd *ozhcd, int status)
 			urbl = list_first_entry(&ozhcd->orphanage,
 				struct oz_urb_link, link);
 			list_del(&urbl->link);
-			oz_complete_urb(ozhcd->hcd, urbl->urb, status, 0);
+			oz_complete_urb(ozhcd->hcd, urbl->urb, status);
 			oz_free_urb_link(urbl);
 		}
 	}
@@ -1720,14 +1722,13 @@ static int oz_hcd_urb_enqueue(struct usb_hcd *hcd, struct urb *urb,
 	struct oz_port *port;
 	unsigned long irq_state;
 	struct oz_urb_link *urbl;
-	oz_dbg(URB, "%lu: %s: (%p)\n", jiffies, __func__, urb);
+	oz_dbg(URB, "%s: (%p)\n",  __func__, urb);
 	if (unlikely(ozhcd == NULL)) {
-		oz_dbg(URB, "%lu: Refused urb(%p) not ozhcd\n", jiffies, urb);
+		oz_dbg(URB, "Refused urb(%p) not ozhcd\n", urb);
 		return -EPIPE;
 	}
 	if (unlikely(hcd->state != HC_STATE_RUNNING)) {
-		oz_dbg(URB, "%lu: Refused urb(%p) not running\n",
-		       jiffies, urb);
+		oz_dbg(URB, "Refused urb(%p) not running\n", urb);
 		return -EPIPE;
 	}
 	port_ix = oz_get_port_from_addr(ozhcd, urb->dev->devnum);
@@ -1795,7 +1796,7 @@ static int oz_hcd_urb_dequeue(struct usb_hcd *hcd, struct urb *urb, int status)
 	struct oz_urb_link *urbl = NULL;
 	int rc;
 	unsigned long irq_state;
-	oz_dbg(URB, "%lu: %s: (%p)\n", jiffies, __func__, urb);
+	oz_dbg(URB, "%s: (%p)\n",  __func__, urb);
 	urbl = oz_alloc_urb_link();
 	if (unlikely(urbl == NULL))
 		return -ENOMEM;