mirror of https://gitee.com/openkylin/linux.git
84 lines
2.2 KiB
C
84 lines
2.2 KiB
C
/*
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* Zynq power management
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*
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* Copyright (C) 2012 - 2014 Xilinx
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*
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* Sören Brinkmann <soren.brinkmann@xilinx.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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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/io.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#include "common.h"
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/* register offsets */
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#define DDRC_CTRL_REG1_OFFS 0x60
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#define DDRC_DRAM_PARAM_REG3_OFFS 0x20
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/* bitfields */
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#define DDRC_CLOCKSTOP_MASK BIT(23)
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#define DDRC_SELFREFRESH_MASK BIT(12)
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static void __iomem *ddrc_base;
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/**
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* zynq_pm_ioremap() - Create IO mappings
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* @comp: DT compatible string
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* Return: Pointer to the mapped memory or NULL.
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*
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* Remap the memory region for a compatible DT node.
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*/
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static void __iomem *zynq_pm_ioremap(const char *comp)
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{
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struct device_node *np;
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void __iomem *base = NULL;
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np = of_find_compatible_node(NULL, NULL, comp);
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if (np) {
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base = of_iomap(np, 0);
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of_node_put(np);
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} else {
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pr_warn("%s: no compatible node found for '%s'\n", __func__,
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comp);
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}
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return base;
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}
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/**
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* zynq_pm_late_init() - Power management init
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*
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* Initialization of power management related featurs and infrastructure.
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*/
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void __init zynq_pm_late_init(void)
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{
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u32 reg;
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ddrc_base = zynq_pm_ioremap("xlnx,zynq-ddrc-a05");
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if (!ddrc_base) {
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pr_warn("%s: Unable to map DDRC IO memory.\n", __func__);
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} else {
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/*
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* Enable DDRC clock stop feature. The HW takes care of
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* entering/exiting the correct mode depending
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* on activity state.
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*/
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reg = readl(ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS);
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reg |= DDRC_CLOCKSTOP_MASK;
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writel(reg, ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS);
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}
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}
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