From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.69 #1 (Red Hat Linux)) id 1NUdrz-0007Gq-69 for barebox@lists.infradead.org; Tue, 12 Jan 2010 10:21:04 +0000 Received: from octopus.hi.pengutronix.de ([2001:6f8:1178:2:215:17ff:fe12:23b0]) by metis.ext.pengutronix.de with esmtp (Exim 4.69) (envelope-from ) id 1NUdrr-0006W8-D4 for barebox@lists.infradead.org; Tue, 12 Jan 2010 11:20:55 +0100 Received: from jbe by octopus.hi.pengutronix.de with local (Exim 4.69) (envelope-from ) id 1NUdrr-000718-B0 for barebox@lists.infradead.org; Tue, 12 Jan 2010 11:20:55 +0100 Message-Id: <20100112102055.221848267@pengutronix.de> References: <20100112101534.868276907@pengutronix.de> Date: Tue, 12 Jan 2010 11:15:43 +0100 From: Juergen Beisert Content-Disposition: inline; filename=add_timer.diff List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCHv2 09/14] Bring in the time reference for the x86 platforms To: barebox@lists.infradead.org This code uses the always (hopefully) existing PIT device to get the time reference for barebox. Signed-off-by: Juergen Beisert --- arch/x86/mach-i386/Makefile | 3 + arch/x86/mach-i386/pit_timer.c | 71 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 74 insertions(+) Index: u-boot-2.0.0-rc10/arch/x86/mach-i386/pit_timer.c =================================================================== --- /dev/null +++ u-boot-2.0.0-rc10/arch/x86/mach-i386/pit_timer.c @@ -0,0 +1,71 @@ +/* + * Copyright (C) 2009 Juergen Beisert, Pengutronix + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, + * MA 02111-1307 USA + * + */ + +/** + * @file + * @brief Clocksource based on the 'Programmable Interval Timer' PIT (8253) + * + * This timer should be available on almost all PCs. It also should be run + * at a fixed frequency (1193181.8181 Hz) and not modified to use another + * reload value than 0xFFFF. So, it always counts from 0xffff down to 0. + * + * @note: We can't reprogram the PIT, it will be still used by the BIOS. This + * clocksource driver does not touch any PIT settings. + */ + +#include +#include +#include + +/** base address of the PIT in a standard PC */ +#define PIT 0x40 + +static uint64_t pit_clocksource_read(void) +{ + uint16_t val1, val2; + + outb(0x00, PIT + 3); /* latch counter 0 */ + outb(0x00, 0x80); + + val1 = inb(PIT); + outb(0x00, 0x80); + + val2 = inb(PIT); + val2 <<= 8; + + /* note: its a down counter */ + return 0xFFFFU - (val1 | val2); +} + +static struct clocksource cs = { + .read = pit_clocksource_read, + .mask = 0x0000ffff, + .shift = 10, +}; + +static int clocksource_init (void) +{ + cs.mult = clocksource_hz2mult(1193182, cs.shift); + init_clock(&cs); + + return 0; +} + +core_initcall(clocksource_init); Index: u-boot-2.0.0-rc10/arch/x86/mach-i386/Makefile =================================================================== --- u-boot-2.0.0-rc10.orig/arch/x86/mach-i386/Makefile +++ u-boot-2.0.0-rc10/arch/x86/mach-i386/Makefile @@ -1,2 +1,5 @@ obj-y += generic.o obj-y += reset.o + +# reference clocksource +obj-y += pit_timer.o -- _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox