| Soren Brinkmann | 0beb2bd | 2014-09-02 14:19:09 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Zynq power management |
| 3 | * |
| 4 | * Copyright (C) 2012 - 2014 Xilinx |
| 5 | * |
| 6 | * Sören Brinkmann <soren.brinkmann@xilinx.com> |
| 7 | * |
| 8 | * This program is free software: you can redistribute it and/or modify |
| 9 | * it under the terms of the GNU General Public License as published by |
| 10 | * the Free Software Foundation, either version 2 of the License, or |
| 11 | * (at your option) any later version. |
| 12 | * |
| 13 | * This program is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | * GNU General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU General Public License |
| 19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 20 | */ |
| 21 | |
| 22 | #include <linux/io.h> |
| 23 | #include <linux/of_address.h> |
| 24 | #include <linux/of_device.h> |
| 25 | #include "common.h" |
| 26 | |
| 27 | /* register offsets */ |
| 28 | #define DDRC_CTRL_REG1_OFFS 0x60 |
| 29 | #define DDRC_DRAM_PARAM_REG3_OFFS 0x20 |
| 30 | |
| 31 | /* bitfields */ |
| 32 | #define DDRC_CLOCKSTOP_MASK BIT(23) |
| 33 | #define DDRC_SELFREFRESH_MASK BIT(12) |
| 34 | |
| 35 | static void __iomem *ddrc_base; |
| 36 | |
| 37 | /** |
| 38 | * zynq_pm_ioremap() - Create IO mappings |
| 39 | * @comp: DT compatible string |
| 40 | * Return: Pointer to the mapped memory or NULL. |
| 41 | * |
| 42 | * Remap the memory region for a compatible DT node. |
| 43 | */ |
| 44 | static void __iomem *zynq_pm_ioremap(const char *comp) |
| 45 | { |
| 46 | struct device_node *np; |
| 47 | void __iomem *base = NULL; |
| 48 | |
| 49 | np = of_find_compatible_node(NULL, NULL, comp); |
| 50 | if (np) { |
| 51 | base = of_iomap(np, 0); |
| 52 | of_node_put(np); |
| 53 | } else { |
| 54 | pr_warn("%s: no compatible node found for '%s'\n", __func__, |
| 55 | comp); |
| 56 | } |
| 57 | |
| 58 | return base; |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * zynq_pm_late_init() - Power management init |
| 63 | * |
| 64 | * Initialization of power management related featurs and infrastructure. |
| 65 | */ |
| 66 | void __init zynq_pm_late_init(void) |
| 67 | { |
| 68 | u32 reg; |
| 69 | |
| 70 | ddrc_base = zynq_pm_ioremap("xlnx,zynq-ddrc-a05"); |
| 71 | if (!ddrc_base) { |
| 72 | pr_warn("%s: Unable to map DDRC IO memory.\n", __func__); |
| 73 | } else { |
| 74 | /* |
| 75 | * Enable DDRC clock stop feature. The HW takes care of |
| 76 | * entering/exiting the correct mode depending |
| 77 | * on activity state. |
| 78 | */ |
| 79 | reg = readl(ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS); |
| 80 | reg |= DDRC_CLOCKSTOP_MASK; |
| 81 | writel(reg, ddrc_base + DDRC_DRAM_PARAM_REG3_OFFS); |
| 82 | } |
| 83 | } |