[PATCH] USB: ehci-hcd: short reads, chip workaround, cleanup

This is a minor update to the patch I posted the other day:

  - Updates processing for completed QTDs, fixing a regression
    I've been chasing for a while.

  - Works around a bug seen in some EHCI silicon (like NEC),
    which the previous problem was covering up.

  - Cleanup: updates the debug support a bit, removes a
    now-fixed FIXME comment, etc; and a version ID change.

drivers/usb/host/ehci-dbg.c

@@ -114,20 +114,29 @@ static inline void dbg_hcc_params (struct ehci_hcd *ehci, char *label) {}
 
 #ifdef	DEBUG
 
+static void __attribute__((__unused__))
+dbg_qtd (char *label, struct ehci_hcd *ehci, struct ehci_qtd *qtd)
+{
+	ehci_dbg (ehci, "%s td %p n%08x %08x t%08x p0=%08x\n", label, qtd,
+		cpu_to_le32p (&qtd->hw_next),
+		cpu_to_le32p (&qtd->hw_alt_next),
+		cpu_to_le32p (&qtd->hw_token),
+		cpu_to_le32p (&qtd->hw_buf [0]));
+	if (qtd->hw_buf [1])
+		ehci_dbg (ehci, "  p1=%08x p2=%08x p3=%08x p4=%08x\n",
+			cpu_to_le32p (&qtd->hw_buf [1]),
+			cpu_to_le32p (&qtd->hw_buf [2]),
+			cpu_to_le32p (&qtd->hw_buf [3]),
+			cpu_to_le32p (&qtd->hw_buf [4]));
+}
+
 static void __attribute__((__unused__))
 dbg_qh (char *label, struct ehci_hcd *ehci, struct ehci_qh *qh)
 {
-	dbg ("%s %p n%08x info1 %x info2 %x hw_curr %x qtd_next %x", label,
+	ehci_dbg (ehci, "%s qh %p n%08x info %x %x qtd %x\n", label,
 		qh, qh->hw_next, qh->hw_info1, qh->hw_info2,
-		qh->hw_current, qh->hw_qtd_next);
-	dbg ("  alt+nak+t= %x, token= %x, page0= %x, page1= %x",
-		qh->hw_alt_next, qh->hw_token,
-		qh->hw_buf [0], qh->hw_buf [1]);
-	if (qh->hw_buf [2]) {
-		dbg ("  page2= %x, page3= %x, page4= %x",
-			qh->hw_buf [2], qh->hw_buf [3],
-			qh->hw_buf [4]);
-	}
+		qh->hw_current);
+	dbg_qtd ("overlay", ehci, (struct ehci_qtd *) &qh->hw_qtd_next);
 }
 
 static int __attribute__((__unused__))
@@ -284,8 +293,7 @@ static inline char token_mark (u32 token)
 		return '*';
 	if (token & QTD_STS_HALT)
 		return '-';
-	if (QTD_PID (token) != 1 /* not IN: OUT or SETUP */
-			|| QTD_LENGTH (token) == 0)
+	if (!IS_SHORT_READ (token))
 		return ' ';
 	/* tries to advance through hw_alt_next */
 	return '/';
@@ -307,11 +315,14 @@ static void qh_lines (
 	char			*next = *nextp;
 	char			mark;
 
+	if (qh->hw_qtd_next == EHCI_LIST_END)	/* NEC does this */
+		mark = '@';
+	else
 		mark = token_mark (qh->hw_token);
 	if (mark == '/') {	/* qh_alt_next controls qh advance? */
 		if ((qh->hw_alt_next & QTD_MASK) == ehci->async->hw_alt_next)
 			mark = '#';	/* blocked */
-		else if (qh->hw_alt_next & cpu_to_le32 (0x01))
+		else if (qh->hw_alt_next == EHCI_LIST_END)
 			mark = '.';	/* use hw_qtd_next */
 		/* else alt_next points to some other qtd */
 	}
@@ -324,7 +335,7 @@ static void qh_lines (
 			(scratch >> 8) & 0x000f,
 			scratch, cpu_to_le32p (&qh->hw_info2),
 			cpu_to_le32p (&qh->hw_token), mark,
-			(cpu_to_le32 (0x8000000) & qh->hw_token)
+			(__constant_cpu_to_le32 (QTD_TOGGLE) & qh->hw_token)
 				? "data0" : "data1",
 			(cpu_to_le32p (&qh->hw_alt_next) >> 1) & 0x0f);
 	size -= temp;
@@ -390,6 +401,8 @@ show_async (struct device *dev, char *buf)
 	char			*next;
 	struct ehci_qh		*qh;
 
+	*buf = 0;
+
 	pdev = container_of (dev, struct pci_dev, dev);
 	ehci = container_of (pci_get_drvdata (pdev), struct ehci_hcd, hcd);
 	next = buf;
@@ -412,7 +425,7 @@ show_async (struct device *dev, char *buf)
 	}
 	spin_unlock_irqrestore (&ehci->lock, flags);
 
-	return PAGE_SIZE - size;
+	return strlen (buf);
 }
 static DEVICE_ATTR (async, S_IRUGO, show_async, NULL);
 
@@ -548,7 +561,8 @@ show_registers (struct device *dev, char *buf)
 	/* Capability Registers */
 	i = readw (&ehci->caps->hci_version);
 	temp = snprintf (next, size,
-		"EHCI %x.%02x, hcd state %d (version " DRIVER_VERSION ")\n",
+		"%s\nEHCI %x.%02x, hcd state %d (driver " DRIVER_VERSION ")\n",
+		pdev->dev.name,
 		i >> 8, i & 0x0ff, ehci->hcd.state);
 	size -= temp;
 	next += temp;

drivers/usb/host/ehci-hcd.c

@@ -39,13 +39,10 @@
 #include <linux/interrupt.h>
 #include <linux/reboot.h>
 #include <linux/usb.h>
+#include <linux/moduleparam.h>
 
 #include <linux/version.h>
-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,5,32)
-#include "../hcd.h"
-#else
 #include "../core/hcd.h"
-#endif
 
 #include <asm/byteorder.h>
 #include <asm/io.h>
@@ -94,11 +91,11 @@
  * 2001-June	Works with usb-storage and NEC EHCI on 2.4
  */
 
-#define DRIVER_VERSION "2003-Jan-22"
+#define DRIVER_VERSION "2003-Jun-12"
 #define DRIVER_AUTHOR "David Brownell"
 #define DRIVER_DESC "USB 2.0 'Enhanced' Host Controller (EHCI) Driver"
 
-static const char	hcd_name [] = "ehci-hcd";
+static const char	hcd_name [] = "ehci_hcd";
 
 
 // #define EHCI_VERBOSE_DEBUG
@@ -123,7 +120,7 @@ static const char	hcd_name [] = "ehci-hcd";
 
 /* Initial IRQ latency:  lower than default */
 static int log2_irq_thresh = 0;		// 0 to 6
-MODULE_PARM (log2_irq_thresh, "i");
+module_param (log2_irq_thresh, int, S_IRUGO);
 MODULE_PARM_DESC (log2_irq_thresh, "log2 IRQ latency, 1-64 microframes");
 
 #define	INTR_MASK (STS_IAA | STS_FATAL | STS_ERR | STS_INT)
@@ -1020,7 +1017,8 @@ static int __init init (void)
 	if (usb_disabled())
 		return -ENODEV;
 
-	dbg ("block sizes: qh %Zd qtd %Zd itd %Zd sitd %Zd",
+	pr_debug ("%s: block sizes: qh %Zd qtd %Zd itd %Zd sitd %Zd\n",
+		hcd_name,
 		sizeof (struct ehci_qh), sizeof (struct ehci_qtd),
 		sizeof (struct ehci_itd), sizeof (struct ehci_sitd));
 

drivers/usb/host/ehci-q.c

@@ -88,7 +88,6 @@ qtd_fill (struct ehci_qtd *qtd, dma_addr_t buf, size_t len,
 static inline void
 qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
 {
-	qh->hw_current = 0;
 	qh->hw_qtd_next = QTD_NEXT (qtd->qtd_dma);
 	qh->hw_alt_next = EHCI_LIST_END;
 
@@ -99,8 +98,6 @@ qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd)
 
 /*-------------------------------------------------------------------------*/
 
-#define IS_SHORT_READ(token) (QTD_LENGTH (token) != 0 && QTD_PID (token) == 1)
-
 static void qtd_copy_status (
 	struct ehci_hcd *ehci,
 	struct urb *urb,
@@ -279,16 +276,15 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh, struct pt_regs *regs)
 		/* hardware copies qtd out of qh overlay */
 		rmb ();
 		token = le32_to_cpu (qtd->hw_token);
-		stopped = stopped
-			|| (HALT_BIT & qh->hw_token) != 0
-			|| (ehci->hcd.state == USB_STATE_HALT);
 
 		/* always clean up qtds the hc de-activated */
 		if ((token & QTD_STS_ACTIVE) == 0) {
 
-			/* magic dummy for short reads; won't advance */
-			if (IS_SHORT_READ (token)
-					&& !(token & QTD_STS_HALT)
+			if ((token & QTD_STS_HALT) != 0) {
+				stopped = 1;
+
+			/* magic dummy for some short reads; qh won't advance */
+			} else if (IS_SHORT_READ (token)
 					&& (qh->hw_alt_next & QTD_MASK)
 						== ehci->async->hw_alt_next) {
 				stopped = 1;
@@ -296,10 +292,13 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh, struct pt_regs *regs)
 			}
 
 		/* stop scanning when we reach qtds the hc is using */
-		} else if (likely (!stopped)) {
+		} else if (likely (!stopped
+				|| HCD_IS_RUNNING (ehci->hcd.state))) {
 			break;
 
 		} else {
+			stopped = 1;
+
 			/* ignore active urbs unless some previous qtd
 			 * for the urb faulted (including short read) or
 			 * its urb was canceled.  we may patch qh or qtds.
@@ -358,7 +357,9 @@ qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh, struct pt_regs *regs)
 	qh->qh_state = state;
 
 	/* update qh after fault cleanup */
-	if (unlikely ((HALT_BIT & qh->hw_token) != 0)) {
+	if (unlikely (stopped != 0)
+			/* some EHCI 0.95 impls will overlay dummy qtds */ 
+			|| qh->hw_qtd_next == EHCI_LIST_END) {
 		qh_update (ehci, qh,
 			list_empty (&qh->qtd_list)
 				? qh->dummy
@@ -788,11 +789,6 @@ static struct ehci_qh *qh_append_tds (
 			}
 		}
 
-		/* FIXME:  changing config or interface setting is not
-		 * supported yet.  preferred fix is for usbcore to tell
-		 * us to clear out each endpoint's state, but...
-		 */
-
 		/* usb_clear_halt() means qh data toggle gets reset */
 		if (unlikely (!usb_gettoggle (urb->dev,
 					(epnum & 0x0f), !(epnum & 0x10)))

drivers/usb/host/ehci.h

@@ -290,7 +290,10 @@ struct ehci_qtd {
 	size_t			length;			/* length of buffer */
 } __attribute__ ((aligned (32)));
 
-#define QTD_MASK cpu_to_le32 (~0x1f)	/* mask NakCnt+T in qh->hw_alt_next */
+/* mask NakCnt+T in qh->hw_alt_next */
+#define QTD_MASK __constant_cpu_to_le32 (~0x1f)
+
+#define IS_SHORT_READ(token) (QTD_LENGTH (token) != 0 && QTD_PID (token) == 1)
 
 /*-------------------------------------------------------------------------*/