linux/arch/mips/bcm47xx/time.c
Hauke Mehrtens 8eae19ccae MIPS: BCM47XX: Fix detected clock on Asus WL520GC and WL520GU
The Asus WL520GC and WL520GU are based on the BCM5354 and clocked at
200MHz, but they do not have a clkfreq nvram variable set to the
correct value. This adds a workaround for these devices.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5843/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2013-10-29 21:24:09 +01:00

84 lines
2.5 KiB
C

/*
* Copyright (C) 2004 Florian Schirmer <jolt@tuxbox.org>
*
* 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 SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* 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.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/init.h>
#include <linux/ssb/ssb.h>
#include <asm/time.h>
#include <bcm47xx.h>
#include <bcm47xx_nvram.h>
#include <bcm47xx_board.h>
void __init plat_time_init(void)
{
unsigned long hz = 0;
u16 chip_id = 0;
char buf[10];
int len;
enum bcm47xx_board board = bcm47xx_board_get();
/*
* Use deterministic values for initial counter interrupt
* so that calibrate delay avoids encountering a counter wrap.
*/
write_c0_count(0);
write_c0_compare(0xffff);
switch (bcm47xx_bus_type) {
#ifdef CONFIG_BCM47XX_SSB
case BCM47XX_BUS_TYPE_SSB:
hz = ssb_cpu_clock(&bcm47xx_bus.ssb.mipscore) / 2;
chip_id = bcm47xx_bus.ssb.chip_id;
break;
#endif
#ifdef CONFIG_BCM47XX_BCMA
case BCM47XX_BUS_TYPE_BCMA:
hz = bcma_cpu_clock(&bcm47xx_bus.bcma.bus.drv_mips) / 2;
chip_id = bcm47xx_bus.bcma.bus.chipinfo.id;
break;
#endif
}
if (chip_id == 0x5354) {
len = bcm47xx_nvram_getenv("clkfreq", buf, sizeof(buf));
if (len >= 0 && !strncmp(buf, "200", 4))
hz = 100000000;
}
switch (board) {
case BCM47XX_BOARD_ASUS_WL520GC:
case BCM47XX_BOARD_ASUS_WL520GU:
hz = 100000000;
break;
default:
break;
}
if (!hz)
hz = 100000000;
/* Set MIPS counter frequency for fixed_rate_gettimeoffset() */
mips_hpt_frequency = hz;
}