From patchwork Tue Aug 25 20:44:45 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Laurent Vivier X-Patchwork-Id: 510620 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 6894B14010F for ; Wed, 26 Aug 2015 06:47:47 +1000 (AEST) Received: from localhost ([::1]:34508 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUL8D-0000GV-I1 for incoming@patchwork.ozlabs.org; Tue, 25 Aug 2015 16:47:45 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:32977) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUL5X-0004KB-Hs for qemu-devel@nongnu.org; Tue, 25 Aug 2015 16:45:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZUL5U-0000FL-Qu for qemu-devel@nongnu.org; Tue, 25 Aug 2015 16:44:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34483) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZUL5U-0000Ez-Iz for qemu-devel@nongnu.org; Tue, 25 Aug 2015 16:44:56 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 497A5461C2 for ; Tue, 25 Aug 2015 20:44:56 +0000 (UTC) Received: from thinkpad.redhat.com (vpn1-5-196.ams2.redhat.com [10.36.5.196]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t7PKipFm030113; Tue, 25 Aug 2015 16:44:55 -0400 From: Laurent Vivier To: qemu-devel@nongnu.org, Stefan Hajnoczi , "Michael S . Tsirkin" , Paolo Bonzini Date: Tue, 25 Aug 2015 22:44:45 +0200 Message-Id: <1440535491-4511-2-git-send-email-lvivier@redhat.com> In-Reply-To: <1440535491-4511-1-git-send-email-lvivier@redhat.com> References: <1440535491-4511-1-git-send-email-lvivier@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.26 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 1/7] PCI: remove muldiv64() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Originally, timers were ticks based, and it made sense to add ticks to current time to know when to trigger an alarm. But since commit: 7447545 change all other clock references to use nanosecond resolution accessors All timers use nanoseconds and we need to convert ticks to nanoseconds, by doing something like: y = muldiv64(x, get_ticks_per_sec(), PCI_FREQUENCY) where x is the number of device ticks and y the number of system ticks. y is used as nanoseconds in timer functions, it works because 1 tick is 1 nanosecond. (get_ticks_per_sec() is 10^9) But as PCI frequency is 33 MHz, we can also do: y = x * 30; /* 33 MHz PCI period is 30 ns */ Which is much more simple. This implies a 33.333333 MHz PCI frequency, but this is correct. Signed-off-by: Laurent Vivier --- hw/net/pcnet.c | 3 +-- hw/net/rtl8139.c | 14 ++++++-------- hw/watchdog/wdt_i6300esb.c | 11 +++-------- tests/rtl8139-test.c | 2 +- 4 files changed, 11 insertions(+), 19 deletions(-) diff --git a/hw/net/pcnet.c b/hw/net/pcnet.c index 3437376..0eb3cc4 100644 --- a/hw/net/pcnet.c +++ b/hw/net/pcnet.c @@ -670,8 +670,7 @@ static inline hwaddr pcnet_rdra_addr(PCNetState *s, int idx) static inline int64_t pcnet_get_next_poll_time(PCNetState *s, int64_t current_time) { int64_t next_time = current_time + - muldiv64(65536 - (CSR_SPND(s) ? 0 : CSR_POLL(s)), - get_ticks_per_sec(), 33000000L); + (65536 - (CSR_SPND(s) ? 0 : CSR_POLL(s))) * 30; if (next_time <= current_time) next_time = current_time + 1; return next_time; diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index edbb61c..1e119e6 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -63,7 +63,7 @@ /* debug RTL8139 card */ //#define DEBUG_RTL8139 1 -#define PCI_FREQUENCY 33000000L +#define PCI_PERIOD 30 /* 30 ns period = 33.333333 Mhz frequency */ #define SET_MASKED(input, mask, curr) \ ( ( (input) & ~(mask) ) | ( (curr) & (mask) ) ) @@ -2881,8 +2881,7 @@ static void rtl8139_io_writew(void *opaque, uint8_t addr, uint32_t val) static void rtl8139_set_next_tctr_time(RTL8139State *s) { - const uint64_t ns_per_period = - muldiv64(0x100000000LL, get_ticks_per_sec(), PCI_FREQUENCY); + const uint64_t ns_per_period = (uint64_t)PCI_PERIOD << 32; DPRINTF("entered rtl8139_set_next_tctr_time\n"); @@ -2900,7 +2899,7 @@ static void rtl8139_set_next_tctr_time(RTL8139State *s) if (!s->TimerInt) { timer_del(s->timer); } else { - uint64_t delta = muldiv64(s->TimerInt, get_ticks_per_sec(), PCI_FREQUENCY); + uint64_t delta = (uint64_t)s->TimerInt * PCI_PERIOD; if (s->TCTR_base + delta <= qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)) { delta += ns_per_period; } @@ -3174,8 +3173,8 @@ static uint32_t rtl8139_io_readl(void *opaque, uint8_t addr) break; case Timer: - ret = muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - s->TCTR_base, - PCI_FREQUENCY, get_ticks_per_sec()); + ret = (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) - s->TCTR_base) / + PCI_PERIOD; DPRINTF("TCTR Timer read val=0x%08x\n", ret); break; @@ -3269,8 +3268,7 @@ static void rtl8139_pre_save(void *opaque) int64_t current_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); /* for migration to older versions */ - s->TCTR = muldiv64(current_time - s->TCTR_base, PCI_FREQUENCY, - get_ticks_per_sec()); + s->TCTR = (current_time - s->TCTR_base) / PCI_PERIOD; s->rtl8139_mmio_io_addr_dummy = 0; } diff --git a/hw/watchdog/wdt_i6300esb.c b/hw/watchdog/wdt_i6300esb.c index cfa2b1b..a91c8fd 100644 --- a/hw/watchdog/wdt_i6300esb.c +++ b/hw/watchdog/wdt_i6300esb.c @@ -129,14 +129,9 @@ static void i6300esb_restart_timer(I6300State *d, int stage) else timeout <<= 5; - /* Get the timeout in units of ticks_per_sec. - * - * ticks_per_sec is typically 10^9 == 0x3B9ACA00 (30 bits), with - * 20 bits of user supplied preload, and 15 bits of scale, the - * multiply here can exceed 64-bits, before we divide by 33MHz, so - * we use a higher-precision intermediate result. - */ - timeout = muldiv64(get_ticks_per_sec(), timeout, 33000000); + /* Get the timeout in nanoseconds. */ + + timeout = timeout * 30; /* on a PCI bus, 1 tick is 30 ns*/ i6300esb_debug("stage %d, timeout %" PRIi64 "\n", d->stage, timeout); diff --git a/tests/rtl8139-test.c b/tests/rtl8139-test.c index e749be3..ba62851 100644 --- a/tests/rtl8139-test.c +++ b/tests/rtl8139-test.c @@ -20,7 +20,7 @@ static void nop(void) { } -#define CLK 33000000 +#define CLK 33333333 static QPCIBus *pcibus; static QPCIDevice *dev;