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 #define MMDC_MAPSR 0x404 21 #define BP_MMDC_MAPSR_PSD 0 22 #define BP_MMDC_MAPSR_PSS 4 23 24 #define MMDC_MDMISC 0x18 25 #define BM_MMDC_MDMISC_DDR_TYPE 0x18 26 #define BP_MMDC_MDMISC_DDR_TYPE 0x3 27 28 static int ddr_type; 29 30 static int imx_mmdc_probe(struct platform_device *pdev) 31 { 32 struct device_node *np = pdev->dev.of_node; 33 void __iomem *mmdc_base, *reg; 34 u32 val; 35 int timeout = 0x400; 36 37 mmdc_base = of_iomap(np, 0); 38 WARN_ON(!mmdc_base); 39 40 reg = mmdc_base + MMDC_MDMISC; 41 /* Get ddr type */ 42 val = readl_relaxed(reg); 43 ddr_type = (val & BM_MMDC_MDMISC_DDR_TYPE) >> 44 BP_MMDC_MDMISC_DDR_TYPE; 45 46 reg = mmdc_base + MMDC_MAPSR; 47 48 /* Enable automatic power saving */ 49 val = readl_relaxed(reg); 50 val &= ~(1 << BP_MMDC_MAPSR_PSD); 51 writel_relaxed(val, reg); 52 53 /* Ensure it's successfully enabled */ 54 while (!(readl_relaxed(reg) & 1 << BP_MMDC_MAPSR_PSS) && --timeout) 55 cpu_relax(); 56 57 if (unlikely(!timeout)) { 58 pr_warn("%s: failed to enable automatic power saving\n", 59 __func__); 60 return -EBUSY; 61 } 62 63 return 0; 64 } 65 66 int imx_mmdc_get_ddr_type(void) 67 { 68 return ddr_type; 69 } 70 71 static struct of_device_id imx_mmdc_dt_ids[] = { 72 { .compatible = "fsl,imx6q-mmdc", }, 73 { /* sentinel */ } 74 }; 75 76 static struct platform_driver imx_mmdc_driver = { 77 .driver = { 78 .name = "imx-mmdc", 79 .of_match_table = imx_mmdc_dt_ids, 80 }, 81 .probe = imx_mmdc_probe, 82 }; 83 84 static int __init imx_mmdc_init(void) 85 { 86 return platform_driver_register(&imx_mmdc_driver); 87 } 88 postcore_initcall(imx_mmdc_init); 89