mirror of https://gitee.com/openkylin/linux.git
92 lines
2.3 KiB
C
92 lines
2.3 KiB
C
/*
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* R-Car Generation 2 support
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*
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* Copyright (C) 2013 Renesas Solutions Corp.
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* Copyright (C) 2013 Magnus Damm
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <linux/clocksource.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <mach/common.h>
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#include <mach/rcar-gen2.h>
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#include <asm/mach/arch.h>
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#define MODEMR 0xe6160060
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u32 __init rcar_gen2_read_mode_pins(void)
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{
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void __iomem *modemr = ioremap_nocache(MODEMR, 4);
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u32 mode;
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BUG_ON(!modemr);
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mode = ioread32(modemr);
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iounmap(modemr);
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return mode;
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}
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#define CNTCR 0
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#define CNTFID0 0x20
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void __init rcar_gen2_timer_init(void)
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{
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#ifdef CONFIG_ARM_ARCH_TIMER
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u32 mode = rcar_gen2_read_mode_pins();
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void __iomem *base;
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int extal_mhz = 0;
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u32 freq;
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/* At Linux boot time the r8a7790 arch timer comes up
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* with the counter disabled. Moreover, it may also report
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* a potentially incorrect fixed 13 MHz frequency. To be
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* correct these registers need to be updated to use the
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* frequency EXTAL / 2 which can be determined by the MD pins.
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*/
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switch (mode & (MD(14) | MD(13))) {
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case 0:
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extal_mhz = 15;
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break;
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case MD(13):
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extal_mhz = 20;
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break;
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case MD(14):
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extal_mhz = 26;
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break;
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case MD(13) | MD(14):
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extal_mhz = 30;
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break;
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}
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/* The arch timer frequency equals EXTAL / 2 */
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freq = extal_mhz * (1000000 / 2);
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/* Remap "armgcnt address map" space */
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base = ioremap(0xe6080000, PAGE_SIZE);
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/* Update registers with correct frequency */
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iowrite32(freq, base + CNTFID0);
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asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));
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/* make sure arch timer is started by setting bit 0 of CNTCR */
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iowrite32(1, base + CNTCR);
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iounmap(base);
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#endif /* CONFIG_ARM_ARCH_TIMER */
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clocksource_of_init();
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}
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