[PATCH] ohci-hcd endpoint scheduling, driverfs

This patch cleans up some messy parts of this driver, and
was pleasantly painless.

      - gets rid of ED dma hashtables
         * less memory needed
         * also less (+faster) code
         * ... rewrites all ED scheduling ops, they now use
           cpu addresses, like EHCI and UHCI do already

      - simplifies ED scheduling (no dma hashtables)
         * control and bulk lists are now doubly linked
         * periodic tree still singly linked; driver uses a
           new CPU view "shadow" of the hardware framelist
         * previous periodic code was cryptic, almost read-only
         * simpler tree code for EDs with {branch,period}

      - bugfixes periodic scheduling
         * when CONFIG_USB_BANDWIDTH, checks per-frame load
           against the limit; no more dodgey accounting
         * handles iso period != 1; interrupt and iso schedule
           EDs with the same routine (HW sees special TDs)
         * credit usbfs with bandwidth for endpoints, not URBs

      - adds driverfs output (when CONFIG_USB_DEBUG)
         * resembles EHCI:  'async' (control+bulk) and
           'periodic' (interrupt+iso) files show schedules
         * shows only queue heads (EDs) just now (*)

      - has minor text and code cleanups, etc

Now that this logic has morphed into more comprehensible
form, I know what to borrow into the EHCI code!


     (*) It shows TDs on the td_list, but this patch won't
         put them there.  A queue fault handling update will.

drivers/usb/host/ohci-dbg.c

@@ -72,37 +72,6 @@ static void urb_print (struct urb * urb, char * str, int small)
 #endif
 }
 
-static inline struct ed *
-dma_to_ed (struct ohci_hcd *hc, dma_addr_t ed_dma);
-
-/* print non-empty branches of the periodic ed tree */
-static void __attribute__ ((unused))
-ohci_dump_periodic (struct ohci_hcd *ohci, char *label)
-{
-	int i, j;
-	u32 *ed_p;
-	int printed = 0;
-
-	for (i= 0; i < 32; i++) {
-		j = 5;
-		ed_p = &(ohci->hcca->int_table [i]);
-		if (*ed_p == 0)
-			continue;
-		printed = 1;
-		printk (KERN_DEBUG "%s, ohci %s frame %2d:",
-				label, ohci->hcd.self.bus_name, i);
-		while (*ed_p != 0 && j--) {
-			struct ed *ed = dma_to_ed (ohci, le32_to_cpup(ed_p));
-			printk (" %p/%08x;", ed, ed->hwINFO);
-			ed_p = &ed->hwNextED;
-		}
-		printk ("\n");
-	}
-	if (!printed)
-		printk (KERN_DEBUG "%s, ohci %s, empty periodic schedule\n",
-				label, ohci->hcd.self.bus_name);
-}
-
 static void ohci_dump_intr_mask (char *label, __u32 mask)
 {
 	dbg ("%s: 0x%08x%s%s%s%s%s%s%s%s%s",
@@ -316,8 +285,9 @@ ohci_dump_ed (struct ohci_hcd *ohci, char *label, struct ed *ed, int verbose)
 	case ED_IN: type = "-IN"; break;
 	/* else from TDs ... control */
 	}
-	dbg ("  info %08x MAX=%d%s%s%s EP=%d%s DEV=%d", le32_to_cpu (tmp),
-		0x0fff & (le32_to_cpu (tmp) >> 16),
+	dbg ("  info %08x MAX=%d%s%s%s%s EP=%d%s DEV=%d", le32_to_cpu (tmp),
+		0x03ff & (le32_to_cpu (tmp) >> 16),
+		(tmp & ED_DEQUEUE) ? " DQ" : "",
 		(tmp & ED_ISO) ? " ISO" : "",
 		(tmp & ED_SKIP) ? " SKIP" : "",
 		(tmp & ED_LOWSPEED) ? " LOW" : "",
@@ -344,5 +314,222 @@ ohci_dump_ed (struct ohci_hcd *ohci, char *label, struct ed *ed, int verbose)
 	}
 }
 
+#if LINUX_VERSION_CODE > KERNEL_VERSION(2,5,32)
+#	define DRIVERFS_DEBUG_FILES
 #endif
 
+#endif /* DEBUG */
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef DRIVERFS_DEBUG_FILES
+
+static ssize_t
+show_list (struct ohci_hcd *ohci, char *buf, size_t count, struct ed *ed)
+{
+	unsigned		temp, size = count;
+
+	if (!ed)
+		return 0;
+
+	/* print first --> last */
+	while (ed->ed_prev)
+		ed = ed->ed_prev;
+
+	/* dump a snapshot of the bulk or control schedule */
+	while (ed) {
+		u32			info = ed->hwINFO;
+		u32			scratch = cpu_to_le32p (&ed->hwINFO);
+		struct list_head	*entry;
+		struct td		*td;
+
+		temp = snprintf (buf, size,
+			"ed/%p %cs dev%d ep%d-%s max %d %08x%s%s %s",
+			ed,
+			(info & ED_LOWSPEED) ? 'l' : 'f',
+			scratch & 0x7f,
+			(scratch >> 7) & 0xf,
+			(info & ED_IN) ? "in" : "out",
+			0x03ff & (scratch >> 16),
+			scratch,
+			(info & ED_SKIP) ? " s" : "",
+			(ed->hwHeadP & ED_H) ? " H" : "",
+			(ed->hwHeadP & ED_C) ? data1 : data0);
+		size -= temp;
+		buf += temp;
+
+		list_for_each (entry, &ed->td_list) {
+			u32		cbp, be;
+
+			td = list_entry (entry, struct td, td_list);
+			scratch = cpu_to_le32p (&td->hwINFO);
+			cbp = le32_to_cpup (&td->hwCBP);
+			be = le32_to_cpup (&td->hwBE);
+			temp = snprintf (buf, size,
+					"\n\ttd %p %s %d cc=%x urb %p (%08x)",
+					td,
+					({ char *pid;
+					switch (scratch & TD_DP) {
+					case TD_DP_SETUP: pid = "setup"; break;
+					case TD_DP_IN: pid = "in"; break;
+					case TD_DP_OUT: pid = "out"; break;
+					default: pid = "(?)"; break;
+					 } pid;}),
+					cbp ? (be + 1 - cbp) : 0,
+					TD_CC_GET (scratch), td->urb, scratch);
+			size -= temp;
+			buf += temp;
+		}
+
+		temp = snprintf (buf, size, "\n");
+		size -= temp;
+		buf += temp;
+
+		ed = ed->ed_next;
+	}
+	return count - size;
+}
+
+static ssize_t
+show_async (struct device *dev, char *buf, size_t count, loff_t off)
+{
+	struct pci_dev		*pdev;
+	struct ohci_hcd		*ohci;
+	size_t			temp;
+	unsigned long		flags;
+
+	if (off != 0)
+		return 0;
+	pdev = container_of (dev, struct pci_dev, dev);
+	ohci = container_of (pci_get_drvdata (pdev), struct ohci_hcd, hcd);
+
+	/* display control and bulk lists together, for simplicity */
+	spin_lock_irqsave (&ohci->lock, flags);
+	temp = show_list (ohci, buf, count, ohci->ed_controltail);
+	count = show_list (ohci, buf + temp, count - temp, ohci->ed_bulktail);
+	spin_unlock_irqrestore (&ohci->lock, flags);
+
+	return temp + count;
+}
+static DEVICE_ATTR (async, S_IRUGO, show_async, NULL);
+
+
+#define DBG_SCHED_LIMIT 64
+
+static ssize_t
+show_periodic (struct device *dev, char *buf, size_t count, loff_t off)
+{
+	struct pci_dev		*pdev;
+	struct ohci_hcd		*ohci;
+	struct ed		**seen, *ed;
+	unsigned long		flags;
+	unsigned		temp, size, seen_count;
+	char			*next;
+	unsigned		i;
+
+	if (off != 0)
+		return 0;
+	if (!(seen = kmalloc (DBG_SCHED_LIMIT * sizeof *seen, SLAB_ATOMIC)))
+		return 0;
+	seen_count = 0;
+
+	pdev = container_of (dev, struct pci_dev, dev);
+	ohci = container_of (pci_get_drvdata (pdev), struct ohci_hcd, hcd);
+	next = buf;
+	size = count;
+
+	temp = snprintf (next, size, "size = %d\n", NUM_INTS);
+	size -= temp;
+	next += temp;
+
+	/* dump a snapshot of the periodic schedule (and load) */
+	spin_lock_irqsave (&ohci->lock, flags);
+	for (i = 0; i < NUM_INTS; i++) {
+		if (!(ed = ohci->periodic [i]))
+			continue;
+
+		temp = snprintf (next, size, "%2d [%3d]:", i, ohci->load [i]);
+		size -= temp;
+		next += temp;
+
+		do {
+			temp = snprintf (next, size, " ed%d/%p",
+				ed->interval, ed);
+			size -= temp;
+			next += temp;
+			for (temp = 0; temp < seen_count; temp++) {
+				if (seen [temp] == ed)
+					break;
+			}
+
+			/* show more info the first time around */
+			if (temp == seen_count) {
+				u32	info = ed->hwINFO;
+				u32	scratch = cpu_to_le32p (&ed->hwINFO);
+
+				temp = snprintf (next, size,
+					" (%cs dev%d%s ep%d-%s"
+					" max %d %08x%s%s)",
+					(info & ED_LOWSPEED) ? 'l' : 'f',
+					scratch & 0x7f,
+					(info & ED_ISO) ? " iso" : "",
+					(scratch >> 7) & 0xf,
+					(info & ED_IN) ? "in" : "out",
+					0x03ff & (scratch >> 16),
+					scratch,
+					(info & ED_SKIP) ? " s" : "",
+					(ed->hwHeadP & ED_H) ? " H" : "");
+				size -= temp;
+				next += temp;
+
+				// FIXME some TD info too
+
+				if (seen_count < DBG_SCHED_LIMIT)
+					seen [seen_count++] = ed;
+
+				ed = ed->ed_next;
+
+			} else {
+				/* we've seen it and what's after */
+				temp = 0;
+				ed = 0;
+			}
+
+		} while (ed);
+
+		temp = snprintf (next, size, "\n");
+		size -= temp;
+		next += temp;
+	}
+	spin_unlock_irqrestore (&ohci->lock, flags);
+	kfree (seen);
+
+	return count - size;
+}
+static DEVICE_ATTR (periodic, S_IRUGO, show_periodic, NULL);
+
+#undef DBG_SCHED_LIMIT
+
+static inline void create_debug_files (struct ohci_hcd *bus)
+{
+	device_create_file (&bus->hcd.pdev->dev, &dev_attr_async);
+	device_create_file (&bus->hcd.pdev->dev, &dev_attr_periodic);
+	// registers
+	dbg ("%s: created debug files", bus->hcd.self.bus_name);
+}
+
+static inline void remove_debug_files (struct ohci_hcd *bus)
+{
+	device_remove_file (&bus->hcd.pdev->dev, &dev_attr_async);
+	device_remove_file (&bus->hcd.pdev->dev, &dev_attr_periodic);
+}
+
+#else /* empty stubs for creating those files */
+
+static inline void create_debug_files (struct ohci_hcd *bus) { }
+static inline void remove_debug_files (struct ohci_hcd *bus) { }
+
+#endif /* DRIVERFS_DEBUG_FILES */
+
+/*-------------------------------------------------------------------------*/
+

drivers/usb/host/ohci-hcd.c

@@ -17,6 +17,8 @@
  *
  * History:
  * 
+ * 2002/09/03 get rid of ed hashtables, rework periodic scheduling and
+ * 	bandwidth accounting; if debugging, show schedules in driverfs
  * 2002/07/19 fixes to management of ED and schedule state.
  * 2002/06/09 SA-1111 support (Christopher Hoover)
  * 2002/06/01 remember frame when HC won't see EDs any more; use that info
@@ -66,7 +68,6 @@
  * v1.0 1999/04/27 initial release
  *
  * This file is licenced under the GPL.
- * $Id: ohci-hcd.c,v 1.9 2002/03/27 20:41:57 dbrownell Exp $
  */
  
 #include <linux/config.h>
@@ -107,8 +108,8 @@
  *	- lots more testing!!
  */
 
-#define DRIVER_VERSION "2002-Jul-19"
-#define DRIVER_AUTHOR "Roman Weissgaerber <weissg@vienna.at>, David Brownell"
+#define DRIVER_VERSION "2002-Sep-03"
+#define DRIVER_AUTHOR "Roman Weissgaerber, David Brownell"
 #define DRIVER_DESC "USB 1.1 'Open' Host Controller (OHCI) Driver"
 
 /*-------------------------------------------------------------------------*/
@@ -152,7 +153,6 @@ static int ohci_urb_enqueue (
 	unsigned int	pipe = urb->pipe;
 	int		i, size = 0;
 	unsigned long	flags;
-	int		bustime = 0;
 	int		retval = 0;
 	
 #ifdef OHCI_VERBOSE_DEBUG
@@ -230,43 +230,32 @@ static int ohci_urb_enqueue (
 		}
 	}	
 
-// FIXME:  much of this switch should be generic, move to hcd code ...
-// ... and what's not generic can't really be handled this way.
-// need to consider periodicity for both types!
-
-	/* allocate and claim bandwidth if needed; ISO
-	 * needs start frame index if it was't provided.
-	 */
-	switch (usb_pipetype (pipe)) {
-		case PIPE_ISOCHRONOUS:
-			if (urb->transfer_flags & USB_ISO_ASAP) { 
-				urb->start_frame = ((ed->state != ED_IDLE)
-					? (ed->intriso.last_iso + 1)
-					: (le16_to_cpu (ohci->hcca->frame_no)
-						+ 10)) & 0xffff;
-			}
-			/* FALLTHROUGH */
-		case PIPE_INTERRUPT:
-			if (urb->bandwidth == 0) {
-				bustime = usb_check_bandwidth (urb->dev, urb);
-			}
-			if (bustime < 0) {
-				retval = bustime;
-				goto fail;
-			}
-			usb_claim_bandwidth (urb->dev, urb,
-				bustime, usb_pipeisoc (urb->pipe));
-	}
+	/* schedule the ed if needed */
+	if (ed->state == ED_IDLE) {
+		retval = ed_schedule (ohci, ed);
+		if (retval < 0)
+			goto fail;
+		if (ed->type == PIPE_ISOCHRONOUS) {
+			u16	frame = le16_to_cpu (ohci->hcca->frame_no);
 
-	urb->hcpriv = urb_priv;
+			/* delay a few frames before the first TD */
+			frame += max_t (u16, 8, ed->interval);
+			frame &= ~(ed->interval - 1);
+			frame |= ed->branch;
+			urb->start_frame = frame;
 
-	/* schedule the ed if needed */
-	if (ed->state == ED_IDLE)
-		ed_schedule (ohci, ed);
+			/* yes, only USB_ISO_ASAP is supported, and
+			 * urb->start_frame is never used as input.
+			 */
+		}
+	} else if (ed->type == PIPE_ISOCHRONOUS)
+		urb->start_frame = ed->last_iso + ed->interval;
 
 	/* fill the TDs and link them to the ed; and
 	 * enable that part of the schedule, if needed
+	 * and update count of queued periodic urbs
 	 */
+	urb->hcpriv = urb_priv;
 	td_submit_urb (ohci, urb);
 
 fail:
@@ -537,6 +526,7 @@ static int hc_start (struct ohci_hcd *ohci)
 		return -ENODEV;
 	}
 
+	create_debug_files (ohci);
 	return 0;
 }
 
@@ -571,7 +561,8 @@ static void ohci_irq (struct usb_hcd *hcd)
 
 	if (ints & OHCI_INTR_UE) {
 		disable (ohci);
-		err ("OHCI Unrecoverable Error, %s disabled", hcd->self.bus_name);
+		err ("OHCI Unrecoverable Error, %s disabled",
+				hcd->self.bus_name);
 		// e.g. due to PCI Master/Target Abort
 
 #ifdef	DEBUG
@@ -620,6 +611,7 @@ static void ohci_stop (struct usb_hcd *hcd)
 	if (!ohci->disabled)
 		hc_reset (ohci);
 	
+	remove_debug_files (ohci);
 	ohci_mem_cleanup (ohci);
 	if (ohci->hcca) {
 		pci_free_consistent (ohci->hcd.pdev, sizeof *ohci->hcca,
@@ -649,14 +641,13 @@ static int hc_restart (struct ohci_hcd *ohci)
 		usb_disconnect (&ohci->hcd.self.root_hub);
 	
 	/* empty the interrupt branches */
-	for (i = 0; i < NUM_INTS; i++) ohci->ohci_int_load [i] = 0;
+	for (i = 0; i < NUM_INTS; i++) ohci->load [i] = 0;
 	for (i = 0; i < NUM_INTS; i++) ohci->hcca->int_table [i] = 0;
 	
 	/* no EDs to remove */
 	ohci->ed_rm_list = NULL;
 
 	/* empty control and bulk lists */	 
-	ohci->ed_isotail     = NULL;
 	ohci->ed_controltail = NULL;
 	ohci->ed_bulktail    = NULL;
 

drivers/usb/host/ohci-mem.c

@@ -5,7 +5,6 @@
  * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
  * 
  * This file is licenced under the GPL.
- * $Id: ohci-mem.c,v 1.3 2002/03/22 16:04:54 dbrownell Exp $
  */
 
 /*-------------------------------------------------------------------------*/
@@ -52,13 +51,6 @@ dma_to_ed_td (struct hash_list_t * entry, dma_addr_t dma)
 	return scan->virt;
 }
 
-static struct ed *
-dma_to_ed (struct ohci_hcd *hc, dma_addr_t ed_dma)
-{
-	return (struct ed *) dma_to_ed_td(&(hc->ed_hash [ED_HASH_FUNC(ed_dma)]),
-				      ed_dma);
-}
-
 static struct td *
 dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
 {
@@ -97,13 +89,6 @@ hash_add_ed_td (
 	return 1;
 }
 
-static inline int
-hash_add_ed (struct ohci_hcd *hc, struct ed *ed, int mem_flags)
-{
-	return hash_add_ed_td (&(hc->ed_hash [ED_HASH_FUNC (ed->dma)]),
-			ed, ed->dma, mem_flags);
-}
-
 static inline int
 hash_add_td (struct ohci_hcd *hc, struct td *td, int mem_flags)
 {
@@ -138,12 +123,6 @@ hash_free_ed_td (struct hash_list_t *entry, void *virt)
 	}
 }
 
-static inline void
-hash_free_ed (struct ohci_hcd *hc, struct ed * ed)
-{
-	hash_free_ed_td (&(hc->ed_hash[ED_HASH_FUNC(ed->dma)]), ed);
-}
-
 static inline void
 hash_free_td (struct ohci_hcd *hc, struct td * td)
 {
@@ -223,11 +202,6 @@ ed_alloc (struct ohci_hcd *hc, int mem_flags)
 		memset (ed, 0, sizeof (*ed));
 		INIT_LIST_HEAD (&ed->td_list);
 		ed->dma = dma;
-		/* hash it for later reverse mapping */
-		if (!hash_add_ed (hc, ed, mem_flags)) {
-			pci_pool_free (hc->ed_cache, ed, dma);
-			return NULL;
-		}
 	}
 	return ed;
 }
@@ -235,7 +209,6 @@ ed_alloc (struct ohci_hcd *hc, int mem_flags)
 static void
 ed_free (struct ohci_hcd *hc, struct ed *ed)
 {
-	hash_free_ed (hc, ed);
 	pci_pool_free (hc->ed_cache, ed, ed->dma);
 }
 

drivers/usb/host/ohci.h

@@ -5,7 +5,6 @@
  * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
  * 
  * This file is licenced under the GPL.
- * $Id: ohci.h,v 1.6 2002/03/22 16:04:54 dbrownell Exp $
  */
  
 /*
@@ -18,13 +17,16 @@
 struct ed {
 	/* first fields are hardware-specified, le32 */
 	__u32			hwINFO;       	/* endpoint config bitmap */
+	/* info bits defined by hcd */
+#define ED_DEQUEUE	__constant_cpu_to_le32(1 << 27)
+	/* info bits defined by the hardware */
 #define ED_ISO		__constant_cpu_to_le32(1 << 15)
 #define ED_SKIP		__constant_cpu_to_le32(1 << 14)
 #define ED_LOWSPEED	__constant_cpu_to_le32(1 << 13)
 #define ED_OUT		__constant_cpu_to_le32(0x01 << 11)
 #define ED_IN		__constant_cpu_to_le32(0x02 << 11)
 	__u32			hwTailP;	/* tail of TD list */
-	__u32			hwHeadP;	/* head of TD list */
+	__u32			hwHeadP;	/* head of TD list (hc r/w) */
 #define ED_C		__constant_cpu_to_le32(0x02)	/* toggle carry */
 #define ED_H		__constant_cpu_to_le32(0x01)	/* halted */
 	__u32			hwNextED;	/* next ED in list */
@@ -48,14 +50,12 @@ struct ed {
 #define ED_OPER		0x02		/* IS linked to hc */
 
 	u8			type; 		/* PIPE_{BULK,...} */
-	u16			interval;	/* interrupt, isochronous */
-	union {
-		struct intr_info {		/* interrupt */
-			u8	int_branch;
-			u8	int_load; 
-		} intr_info;
-		u16		last_iso;	/* isochronous */
-	} intriso;
+
+	/* periodic scheduling params (for intr and iso) */
+	u8			branch;
+	u16			interval;
+	u16			load;
+	u16			last_iso;	/* iso only */
 
 	/* HC may see EDs on rm_list until next frame (frame_no == tick) */
 	u16			tick;
@@ -335,10 +335,8 @@ struct hash_list_t {
 };
 
 #define TD_HASH_SIZE    64    /* power'o'two */
-#define ED_HASH_SIZE    64    /* power'o'two */
 
 #define TD_HASH_FUNC(td_dma) ((td_dma ^ (td_dma >> 5)) % TD_HASH_SIZE)
-#define ED_HASH_FUNC(ed_dma) ((ed_dma ^ (ed_dma >> 5)) % ED_HASH_SIZE)
 
 
 /*
@@ -373,7 +371,7 @@ struct ohci_hcd {
 
 	struct ed		*ed_bulktail;		/* last in bulk list */
 	struct ed		*ed_controltail;	/* last in ctrl list */
- 	struct ed		*ed_isotail;		/* last in iso list */
+ 	struct ed		*periodic [NUM_INTS];	/* shadow int_table */
 
 	/*
 	 * memory management for queue data structures
@@ -381,14 +379,13 @@ struct ohci_hcd {
 	struct pci_pool		*td_cache;
 	struct pci_pool		*ed_cache;
 	struct hash_list_t	td_hash [TD_HASH_SIZE];
-	struct hash_list_t	ed_hash [ED_HASH_SIZE];
 
 	/*
 	 * driver state
 	 */
 	int			disabled;	/* e.g. got a UE, we're hung */
 	int			sleeping;
-	int			ohci_int_load [NUM_INTS];
+	int			load [NUM_INTS];
 	u32 			hc_control;	/* copy of hc control reg */
 
 	unsigned long		flags;		/* for HC bugs */