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2c11b57a8a
The current comment in the code does not make it clear why the double writes on SRC bit is needed. Let's quote the errata to get it clear. Also, to ensure there are at least 2 writes happen in the same one 32kHz period, we actually need 3 writes. Let's add the third one. Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
150 lines
3.9 KiB
C
150 lines
3.9 KiB
C
/*
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* Copyright (C) 1999 ARM Limited
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* Copyright (C) 2000 Deep Blue Solutions Ltd
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* Copyright 2006-2007 Freescale Semiconductor, Inc. All Rights Reserved.
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* Copyright 2008 Juergen Beisert, kernel@pengutronix.de
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* Copyright 2009 Ilya Yanok, Emcraft Systems Ltd, yanok@emcraft.com
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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; either version 2 of the License, or
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* (at your option) any later version.
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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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#include <linux/kernel.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <asm/system_misc.h>
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#include <asm/proc-fns.h>
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#include <asm/mach-types.h>
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#include <asm/hardware/cache-l2x0.h>
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#include "common.h"
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#include "hardware.h"
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static void __iomem *wdog_base;
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static struct clk *wdog_clk;
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/*
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* Reset the system. It is called by machine_restart().
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*/
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void mxc_restart(enum reboot_mode mode, const char *cmd)
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{
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unsigned int wcr_enable;
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if (wdog_clk)
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clk_enable(wdog_clk);
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if (cpu_is_mx1())
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wcr_enable = (1 << 0);
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else
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wcr_enable = (1 << 2);
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/* Assert SRS signal */
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__raw_writew(wcr_enable, wdog_base);
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/*
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* Due to imx6q errata ERR004346 (WDOG: WDOG SRS bit requires to be
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* written twice), we add another two writes to ensure there must be at
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* least two writes happen in the same one 32kHz clock period. We save
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* the target check here, since the writes shouldn't be a huge burden
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* for other platforms.
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*/
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__raw_writew(wcr_enable, wdog_base);
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__raw_writew(wcr_enable, wdog_base);
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/* wait for reset to assert... */
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mdelay(500);
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pr_err("%s: Watchdog reset failed to assert reset\n", __func__);
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/* delay to allow the serial port to show the message */
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mdelay(50);
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/* we'll take a jump through zero as a poor second */
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soft_restart(0);
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}
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void __init mxc_arch_reset_init(void __iomem *base)
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{
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wdog_base = base;
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wdog_clk = clk_get_sys("imx2-wdt.0", NULL);
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if (IS_ERR(wdog_clk)) {
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pr_warn("%s: failed to get wdog clock\n", __func__);
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wdog_clk = NULL;
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return;
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}
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clk_prepare(wdog_clk);
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}
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void __init mxc_arch_reset_init_dt(void)
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{
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struct device_node *np;
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np = of_find_compatible_node(NULL, NULL, "fsl,imx21-wdt");
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wdog_base = of_iomap(np, 0);
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WARN_ON(!wdog_base);
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wdog_clk = of_clk_get(np, 0);
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if (IS_ERR(wdog_clk)) {
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pr_warn("%s: failed to get wdog clock\n", __func__);
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wdog_clk = NULL;
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return;
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}
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clk_prepare(wdog_clk);
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}
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#ifdef CONFIG_CACHE_L2X0
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void __init imx_init_l2cache(void)
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{
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void __iomem *l2x0_base;
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struct device_node *np;
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unsigned int val;
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np = of_find_compatible_node(NULL, NULL, "arm,pl310-cache");
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if (!np)
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goto out;
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l2x0_base = of_iomap(np, 0);
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if (!l2x0_base) {
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of_node_put(np);
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goto out;
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}
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/* Configure the L2 PREFETCH and POWER registers */
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val = readl_relaxed(l2x0_base + L2X0_PREFETCH_CTRL);
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val |= 0x70800000;
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/*
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* The L2 cache controller(PL310) version on the i.MX6D/Q is r3p1-50rel0
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* The L2 cache controller(PL310) version on the i.MX6DL/SOLO/SL is r3p2
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* But according to ARM PL310 errata: 752271
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* ID: 752271: Double linefill feature can cause data corruption
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* Fault Status: Present in: r3p0, r3p1, r3p1-50rel0. Fixed in r3p2
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* Workaround: The only workaround to this erratum is to disable the
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* double linefill feature. This is the default behavior.
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*/
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if (cpu_is_imx6q())
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val &= ~(1 << 30 | 1 << 23);
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writel_relaxed(val, l2x0_base + L2X0_PREFETCH_CTRL);
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val = L2X0_DYNAMIC_CLK_GATING_EN | L2X0_STNDBY_MODE_EN;
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writel_relaxed(val, l2x0_base + L2X0_POWER_CTRL);
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iounmap(l2x0_base);
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of_node_put(np);
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out:
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l2x0_of_init(0, ~0UL);
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}
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#endif
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