1 /* 2 * Copyright 2011 Freescale Semiconductor, Inc. 3 * Copyright 2011 Linaro Ltd. 4 * 5 * The code contained herein is licensed under the GNU General Public 6 * License. You may obtain a copy of the GNU General Public License 7 * Version 2 or later at the following locations: 8 * 9 * http://www.opensource.org/licenses/gpl-license.html 10 * http://www.gnu.org/copyleft/gpl.html 11 */ 12 13 #include <linux/init.h> 14 #include <linux/io.h> 15 #include <linux/module.h> 16 #include <linux/of.h> 17 #include <linux/of_address.h> 18 #include <linux/of_device.h> 19 20 #include "common.h" 21 22 #define MMDC_MAPSR 0x404 23 #define BP_MMDC_MAPSR_PSD 0 24 #define BP_MMDC_MAPSR_PSS 4 25 26 #define MMDC_MDMISC 0x18 27 #define BM_MMDC_MDMISC_DDR_TYPE 0x18 28 #define BP_MMDC_MDMISC_DDR_TYPE 0x3 29 30 static int ddr_type; 31 32 static int imx_mmdc_probe(struct platform_device *pdev) 33 { 34 struct device_node *np = pdev->dev.of_node; 35 void __iomem *mmdc_base, *reg; 36 u32 val; 37 int timeout = 0x400; 38 39 mmdc_base = of_iomap(np, 0); 40 WARN_ON(!mmdc_base); 41 42 reg = mmdc_base + MMDC_MDMISC; 43 /* Get ddr type */ 44 val = readl_relaxed(reg); 45 ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >> 46 BP_MMDC_MDMISC_DDR_TYPE; 47 48 reg = mmdc_base + MMDC_MAPSR; 49 50 /* Enable automatic power saving */ 51 val = readl_relaxed(reg); 52 val &= ~(1 << BP_MMDC_MAPSR_PSD); 53 writel_relaxed(val, reg); 54 55 /* Ensure it's successfully enabled */ 56 while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout) 57 cpu_relax(); 58 59 if (unlikely(!timeout)) { 60 pr_warn("%s: failed to enable automatic power saving\n", 61 __func__); 62 return -EBUSY; 63 } 64 65 return 0; 66 } 67 68 int imx_mmdc_get_ddr_type(void) 69 { 70 return ddr_type; 71 } 72 73 static const struct of_device_id imx_mmdc_dt_ids[] = { 74 { .compatible = "fsl,imx6q-mmdc", }, 75 { /* sentinel */ } 76 }; 77 78 static struct platform_driver imx_mmdc_driver = { 79 .driver = { 80 .name = "imx-mmdc", 81 .of_match_table = imx_mmdc_dt_ids, 82 }, 83 .probe = imx_mmdc_probe, 84 }; 85 86 static int __init imx_mmdc_init(void) 87 { 88 return platform_driver_register(&imx_mmdc_driver); 89 } 90 postcore_initcall(imx_mmdc_init); 91