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https://github.com/brain-hackers/u-boot-brain
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0b1b60c779
Warm reset on OMAP5 freezes when USB cable is connected. Fix requires PRM_RSTTIME.RSTTIME1 to be programmed with the time for which reset should be held low for the voltages and the oscillator to reach stable state. There are 3 parameters to be considered for calculating the time, which are mostly board and PMIC dependent. -1- Time taken by the Oscillator to shut + restart -2- PMIC OTP times -3- Voltage rail ramp times, which inturn depends on the PMIC slew rate and value of the voltage ramp needed. In order to keep the code in u-boot simple, have a way for boards to specify a pre computed time directly using the 'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC' option. If boards fail to specify the time, use a default as specified by 'CONFIG_DEFAULT_OMAP_RESET_TIME_MAX_USEC' instead. Using the default value translates into some ~22ms and should work in all cases. However in order to avoid this large delay hiding other bugs, its recommended that all boards look at their respective data sheets and specify a pre computed and optimal value using 'CONFIG_OMAP_PLATFORM_RESET_TIME_MAX_USEC' In order to help future board additions to compute this config option value, add a README at doc/README.omap-reset-time which explains how to compute the value. Also update the toplevel README with the additional option and pointers to doc/README.omap-reset-time. Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com> [rnayak@ti.com: Updated changelog and added the README] Signed-off-by: Rajendra Nayak <rnayak@ti.com>
46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
/*
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*
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* Common layer for reset related functionality of OMAP based socs.
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*
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* (C) Copyright 2012
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* Texas Instruments, <www.ti.com>
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*
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* Sricharan R <r.sricharan@ti.com>
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (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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* 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., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <config.h>
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#include <asm/io.h>
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#include <asm/arch/cpu.h>
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#include <linux/compiler.h>
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void __weak reset_cpu(unsigned long ignored)
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{
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writel(PRM_RSTCTRL_RESET, PRM_RSTCTRL);
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}
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u32 __weak warm_reset(void)
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{
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return (readl(PRM_RSTST) & PRM_RSTST_WARM_RESET_MASK);
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}
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void __weak setup_warmreset_time(void)
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{
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}
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