4 * Copyright (c) 2011-2013 Xilinx Inc.
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 * You should have received a copy of the GNU General Public
12 * License along with this program; if not, write to the Free
13 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
18 #include <linux/mfd/syscon.h>
19 #include <linux/of_address.h>
20 #include <linux/regmap.h>
21 #include <linux/clk/zynq.h>
24 /* register offsets */
25 #define SLCR_UNLOCK_OFFSET 0x8 /* SCLR unlock register */
26 #define SLCR_PS_RST_CTRL_OFFSET 0x200 /* PS Software Reset Control */
27 #define SLCR_A9_CPU_RST_CTRL_OFFSET 0x244 /* CPU Software Reset Control */
28 #define SLCR_REBOOT_STATUS_OFFSET 0x258 /* PS Reboot Status */
30 #define SLCR_UNLOCK_MAGIC 0xDF0D
31 #define SLCR_A9_CPU_CLKSTOP 0x10
32 #define SLCR_A9_CPU_RST 0x1
34 static void __iomem *zynq_slcr_base;
35 static struct regmap *zynq_slcr_regmap;
38 * zynq_slcr_write - Write to a register in SLCR block
40 * @val: Value to write to the register
41 * @offset: Register offset in SLCR block
43 * Return: a negative value on error, 0 on success
45 static int zynq_slcr_write(u32 val, u32 offset)
47 if (!zynq_slcr_regmap) {
48 writel(val, zynq_slcr_base + offset);
52 return regmap_write(zynq_slcr_regmap, offset, val);
56 * zynq_slcr_read - Read a register in SLCR block
58 * @val: Pointer to value to be read from SLCR
59 * @offset: Register offset in SLCR block
61 * Return: a negative value on error, 0 on success
63 static int zynq_slcr_read(u32 *val, u32 offset)
66 return regmap_read(zynq_slcr_regmap, offset, val);
68 *val = readl(zynq_slcr_base + offset);
74 * zynq_slcr_unlock - Unlock SLCR registers
76 * Return: a negative value on error, 0 on success
78 static inline int zynq_slcr_unlock(void)
80 zynq_slcr_write(SLCR_UNLOCK_MAGIC, SLCR_UNLOCK_OFFSET);
86 * zynq_slcr_system_reset - Reset the entire system.
88 void zynq_slcr_system_reset(void)
93 * Unlock the SLCR then reset the system.
94 * Note that this seems to require raw i/o
95 * functions or there's a lockup?
100 * Clear 0x0F000000 bits of reboot status register to workaround
101 * the FSBL not loading the bitstream after soft-reboot
102 * This is a temporary solution until we know more.
104 zynq_slcr_read(&reboot, SLCR_REBOOT_STATUS_OFFSET);
105 zynq_slcr_write(reboot & 0xF0FFFFFF, SLCR_REBOOT_STATUS_OFFSET);
106 zynq_slcr_write(1, SLCR_PS_RST_CTRL_OFFSET);
110 * zynq_slcr_cpu_start - Start cpu
113 void zynq_slcr_cpu_start(int cpu)
117 zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET);
118 reg &= ~(SLCR_A9_CPU_RST << cpu);
119 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
120 reg &= ~(SLCR_A9_CPU_CLKSTOP << cpu);
121 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
125 * zynq_slcr_cpu_stop - Stop cpu
128 void zynq_slcr_cpu_stop(int cpu)
132 zynq_slcr_read(®, SLCR_A9_CPU_RST_CTRL_OFFSET);
133 reg |= (SLCR_A9_CPU_CLKSTOP | SLCR_A9_CPU_RST) << cpu;
134 zynq_slcr_write(reg, SLCR_A9_CPU_RST_CTRL_OFFSET);
138 * zynq_slcr_init - Regular slcr driver init
140 * Return: 0 on success, negative errno otherwise.
142 * Called early during boot from platform code to remap SLCR area.
144 int __init zynq_slcr_init(void)
146 zynq_slcr_regmap = syscon_regmap_lookup_by_compatible("xlnx,zynq-slcr");
147 if (IS_ERR(zynq_slcr_regmap)) {
148 pr_err("%s: failed to find zynq-slcr\n", __func__);
156 * zynq_early_slcr_init - Early slcr init function
158 * Return: 0 on success, negative errno otherwise.
160 * Called very early during boot from platform code to unlock SLCR.
162 int __init zynq_early_slcr_init(void)
164 struct device_node *np;
166 np = of_find_compatible_node(NULL, NULL, "xlnx,zynq-slcr");
168 pr_err("%s: no slcr node found\n", __func__);
172 zynq_slcr_base = of_iomap(np, 0);
173 if (!zynq_slcr_base) {
174 pr_err("%s: Unable to map I/O memory\n", __func__);
178 np->data = (__force void *)zynq_slcr_base;
180 /* unlock the SLCR so that registers can be changed */
183 pr_info("%s mapped to %p\n", np->name, zynq_slcr_base);