From: Alan Stern Date: Fri, 19 May 2006 20:34:57 +0000 (-0400) Subject: [PATCH] UHCI: use integer-sized frame numbers X-Git-Tag: v2.6.18-rc1~858^2~76 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c433472658b4df11bd3590a59be79194a1ff43ae;p=linux-2.6 [PATCH] UHCI: use integer-sized frame numbers This patch (as687) changes uhci-hcd to keep track of frame numbers as full-sized integers rather than 11-bit values. This makes them a lot easier to handle and makes it possible to schedule beyond a 2-second window, should anyone ever want to do so. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c index 081c592fe8..ecef5880cf 100644 --- a/drivers/usb/host/uhci-debug.c +++ b/drivers/usb/host/uhci-debug.c @@ -289,7 +289,7 @@ static int uhci_show_status(struct uhci_hcd *uhci, char *buf, int len) unsigned short portsc1, portsc2; /* Try to make sure there's enough memory */ - if (len < 80 * 6) + if (len < 80 * 9) return 0; usbcmd = inw(io_addr + 0); @@ -328,6 +328,8 @@ static int uhci_show_status(struct uhci_hcd *uhci, char *buf, int len) out += sprintf(out, " sof = %02x\n", sof); out += uhci_show_sc(1, portsc1, out, len - (out - buf)); out += uhci_show_sc(2, portsc2, out, len - (out - buf)); + out += sprintf(out, "Most recent frame: %x\n", + uhci->frame_number); return out - buf; } diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c index 395402eec5..5e75ad6dc2 100644 --- a/drivers/usb/host/uhci-hcd.c +++ b/drivers/usb/host/uhci-hcd.c @@ -13,7 +13,7 @@ * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface * support from usb-ohci.c by Adam Richter, adam@yggdrasil.com). * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c) - * (C) Copyright 2004-2005 Alan Stern, stern@rowland.harvard.edu + * (C) Copyright 2004-2006 Alan Stern, stern@rowland.harvard.edu * * Intel documents this fairly well, and as far as I know there * are no royalties or anything like that, but even so there are @@ -31,7 +31,6 @@ #include #include #include -#include #include #include #include @@ -146,7 +145,8 @@ static void configure_hc(struct uhci_hcd *uhci) outl(uhci->frame_dma_handle, uhci->io_addr + USBFLBASEADD); /* Set the current frame number */ - outw(uhci->frame_number, uhci->io_addr + USBFRNUM); + outw(uhci->frame_number & UHCI_MAX_SOF_NUMBER, + uhci->io_addr + USBFRNUM); /* Mark controller as not halted before we enable interrupts */ uhci_to_hcd(uhci)->state = HC_STATE_SUSPENDED; @@ -239,7 +239,6 @@ __acquires(uhci->lock) dev_warn(uhci_dev(uhci), "Controller not stopped yet!\n"); uhci_get_current_frame_number(uhci); - smp_wmb(); uhci->rh_state = new_state; uhci->is_stopped = UHCI_IS_STOPPED; @@ -253,7 +252,6 @@ static void start_rh(struct uhci_hcd *uhci) { uhci_to_hcd(uhci)->state = HC_STATE_RUNNING; uhci->is_stopped = 0; - smp_wmb(); /* Mark it configured and running with a 64-byte max packet. * All interrupts are enabled, even though RESUME won't do anything. @@ -360,12 +358,21 @@ static irqreturn_t uhci_irq(struct usb_hcd *hcd, struct pt_regs *regs) /* * Store the current frame number in uhci->frame_number if the controller - * is runnning + * is runnning. Expand from 11 bits (of which we use only 10) to a + * full-sized integer. + * + * Like many other parts of the driver, this code relies on being polled + * more than once per second as long as the controller is running. */ static void uhci_get_current_frame_number(struct uhci_hcd *uhci) { - if (!uhci->is_stopped) - uhci->frame_number = inw(uhci->io_addr + USBFRNUM); + if (!uhci->is_stopped) { + unsigned delta; + + delta = (inw(uhci->io_addr + USBFRNUM) - uhci->frame_number) & + (UHCI_NUMFRAMES - 1); + uhci->frame_number += delta; + } } /* @@ -798,18 +805,15 @@ done: static int uhci_hcd_get_frame_number(struct usb_hcd *hcd) { struct uhci_hcd *uhci = hcd_to_uhci(hcd); - unsigned long flags; - int is_stopped; - int frame_number; + unsigned frame_number; + unsigned delta; /* Minimize latency by avoiding the spinlock */ - local_irq_save(flags); - is_stopped = uhci->is_stopped; - smp_rmb(); - frame_number = (is_stopped ? uhci->frame_number : - inw(uhci->io_addr + USBFRNUM)); - local_irq_restore(flags); - return frame_number; + frame_number = uhci->frame_number; + barrier(); + delta = (inw(uhci->io_addr + USBFRNUM) - frame_number) & + (UHCI_NUMFRAMES - 1); + return frame_number + delta; } static const char hcd_name[] = "uhci_hcd"; diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h index 04938e6479..c87ceaa178 100644 --- a/drivers/usb/host/uhci-hcd.h +++ b/drivers/usb/host/uhci-hcd.h @@ -448,6 +448,9 @@ static inline struct usb_hcd *uhci_to_hcd(struct uhci_hcd *uhci) #define uhci_dev(u) (uhci_to_hcd(u)->self.controller) +/* Utility macro for comparing frame numbers */ +#define uhci_frame_before_eq(f1, f2) (0 <= (int) ((f2) - (f1))) + /* * Private per-URB data