89 lines
1.9 KiB
C
89 lines
1.9 KiB
C
/*
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* Copyright 2011 Freescale Semiconductor, Inc.
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* Copyright 2011 Linaro Ltd.
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*
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* The code contained herein is licensed under the GNU General Public
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* License. You may obtain a copy of the GNU General Public License
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* Version 2 or later at the following locations:
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*
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* http://www.opensource.org/licenses/gpl-license.html
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* http://www.gnu.org/copyleft/gpl.html
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*/
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/module.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_device.h>
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#define MMDC_MAPSR 0x404
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#define BP_MMDC_MAPSR_PSD 0
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#define BP_MMDC_MAPSR_PSS 4
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#define MMDC_MDMISC 0x18
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#define BM_MMDC_MDMISC_DDR_TYPE 0x18
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#define BP_MMDC_MDMISC_DDR_TYPE 0x3
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static int ddr_type;
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static int imx_mmdc_probe(struct platform_device *pdev)
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{
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struct device_node *np = pdev->dev.of_node;
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void __iomem *mmdc_base, *reg;
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u32 val;
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int timeout = 0x400;
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mmdc_base = of_iomap(np, 0);
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WARN_ON(!mmdc_base);
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reg = mmdc_base + MMDC_MDMISC;
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/* Get ddr type */
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val = readl_relaxed(reg);
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ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >>
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BP_MMDC_MDMISC_DDR_TYPE;
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reg = mmdc_base + MMDC_MAPSR;
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/* Enable automatic power saving */
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val = readl_relaxed(reg);
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val &= ~(1 << BP_MMDC_MAPSR_PSD);
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writel_relaxed(val, reg);
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/* Ensure it's successfully enabled */
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while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout)
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cpu_relax();
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if (unlikely(!timeout)) {
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pr_warn("%s: failed to enable automatic power saving\n",
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__func__);
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return -EBUSY;
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}
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return 0;
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}
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int imx_mmdc_get_ddr_type(void)
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{
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return ddr_type;
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}
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static const struct of_device_id imx_mmdc_dt_ids[] = {
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{ .compatible = "fsl,imx6q-mmdc", },
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{ /* sentinel */ }
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};
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static struct platform_driver imx_mmdc_driver = {
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.driver = {
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.name = "imx-mmdc",
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.of_match_table = imx_mmdc_dt_ids,
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},
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.probe = imx_mmdc_probe,
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};
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static int __init imx_mmdc_init(void)
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{
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return platform_driver_register(&imx_mmdc_driver);
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}
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postcore_initcall(imx_mmdc_init);
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