1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Broadcom BCM63138 PMB initialization for secondary CPU(s)
4 *
5 * Copyright (C) 2015 Broadcom Corporation
6 * Author: Florian Fainelli <f.fainelli@gmail.com>
7 */
8 #include <linux/kernel.h>
9 #include <linux/io.h>
10 #include <linux/spinlock.h>
11 #include <linux/reset/bcm63xx_pmb.h>
12 #include <linux/of.h>
13 #include <linux/of_address.h>
14
15 #include "bcm63xx_smp.h"
16
17 /* ARM Control register definitions */
18 #define CORE_PWR_CTRL_SHIFT 0
19 #define CORE_PWR_CTRL_MASK 0x3
20 #define PLL_PWR_ON BIT(8)
21 #define PLL_LDO_PWR_ON BIT(9)
22 #define PLL_CLAMP_ON BIT(10)
23 #define CPU_RESET_N(x) BIT(13 + (x))
24 #define NEON_RESET_N BIT(15)
25 #define PWR_CTRL_STATUS_SHIFT 28
26 #define PWR_CTRL_STATUS_MASK 0x3
27 #define PWR_DOWN_SHIFT 30
28 #define PWR_DOWN_MASK 0x3
29
30 /* CPU Power control register definitions */
31 #define MEM_PWR_OK BIT(0)
32 #define MEM_PWR_ON BIT(1)
33 #define MEM_CLAMP_ON BIT(2)
34 #define MEM_PWR_OK_STATUS BIT(4)
35 #define MEM_PWR_ON_STATUS BIT(5)
36 #define MEM_PDA_SHIFT 8
37 #define MEM_PDA_MASK 0xf
38 #define MEM_PDA_CPU_MASK 0x1
39 #define MEM_PDA_NEON_MASK 0xf
40 #define CLAMP_ON BIT(15)
41 #define PWR_OK_SHIFT 16
42 #define PWR_OK_MASK 0xf
43 #define PWR_ON_SHIFT 20
44 #define PWR_CPU_MASK 0x03
45 #define PWR_NEON_MASK 0x01
46 #define PWR_ON_MASK 0xf
47 #define PWR_OK_STATUS_SHIFT 24
48 #define PWR_OK_STATUS_MASK 0xf
49 #define PWR_ON_STATUS_SHIFT 28
50 #define PWR_ON_STATUS_MASK 0xf
51
52 #define ARM_CONTROL 0x30
53 #define ARM_PWR_CONTROL_BASE 0x34
54 #define ARM_PWR_CONTROL(x) (ARM_PWR_CONTROL_BASE + (x) * 0x4)
55 #define ARM_NEON_L2 0x3c
56
57 /* Perform a value write, then spin until the value shifted by
58 * shift is seen, masked with mask and is different from cond.
59 */
bpcm_wr_rd_mask(void __iomem * master,unsigned int addr,u32 off,u32 * val,u32 shift,u32 mask,u32 cond)60 static int bpcm_wr_rd_mask(void __iomem *master,
61 unsigned int addr, u32 off, u32 *val,
62 u32 shift, u32 mask, u32 cond)
63 {
64 int ret;
65
66 ret = bpcm_wr(master, addr, off, *val);
67 if (ret)
68 return ret;
69
70 do {
71 ret = bpcm_rd(master, addr, off, val);
72 if (ret)
73 return ret;
74
75 cpu_relax();
76 } while (((*val >> shift) & mask) != cond);
77
78 return ret;
79 }
80
81 /* Global lock to serialize accesses to the PMB registers while we
82 * are bringing up the secondary CPU
83 */
84 static DEFINE_SPINLOCK(pmb_lock);
85
bcm63xx_pmb_get_resources(struct device_node * dn,void __iomem ** base,unsigned int * cpu,unsigned int * addr)86 static int bcm63xx_pmb_get_resources(struct device_node *dn,
87 void __iomem **base,
88 unsigned int *cpu,
89 unsigned int *addr)
90 {
91 struct of_phandle_args args;
92 int ret;
93
94 *cpu = of_get_cpu_hwid(dn, 0);
95 if (*cpu == ~0U) {
96 pr_err("CPU is missing a reg node\n");
97 return -ENODEV;
98 }
99
100 ret = of_parse_phandle_with_args(dn, "resets", "#reset-cells",
101 0, &args);
102 if (ret) {
103 pr_err("CPU is missing a resets phandle\n");
104 return ret;
105 }
106
107 if (args.args_count != 2) {
108 pr_err("reset-controller does not conform to reset-cells\n");
109 return -EINVAL;
110 }
111
112 *base = of_iomap(args.np, 0);
113 if (!*base) {
114 pr_err("failed remapping PMB register\n");
115 return -ENOMEM;
116 }
117
118 /* We do not need the number of zones */
119 *addr = args.args[0];
120
121 return 0;
122 }
123
bcm63xx_pmb_power_on_cpu(struct device_node * dn)124 int bcm63xx_pmb_power_on_cpu(struct device_node *dn)
125 {
126 void __iomem *base;
127 unsigned int cpu, addr;
128 unsigned long flags;
129 u32 val, ctrl;
130 int ret;
131
132 ret = bcm63xx_pmb_get_resources(dn, &base, &cpu, &addr);
133 if (ret)
134 return ret;
135
136 /* We would not know how to enable a third and greater CPU */
137 WARN_ON(cpu > 1);
138
139 spin_lock_irqsave(&pmb_lock, flags);
140
141 /* Check if the CPU is already on and save the ARM_CONTROL register
142 * value since we will use it later for CPU de-assert once done with
143 * the CPU-specific power sequence
144 */
145 ret = bpcm_rd(base, addr, ARM_CONTROL, &ctrl);
146 if (ret)
147 goto out;
148
149 if (ctrl & CPU_RESET_N(cpu)) {
150 pr_info("PMB: CPU%d is already powered on\n", cpu);
151 ret = 0;
152 goto out;
153 }
154
155 /* Power on PLL */
156 ret = bpcm_rd(base, addr, ARM_PWR_CONTROL(cpu), &val);
157 if (ret)
158 goto out;
159
160 val |= (PWR_CPU_MASK << PWR_ON_SHIFT);
161
162 ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
163 PWR_ON_STATUS_SHIFT, PWR_CPU_MASK, PWR_CPU_MASK);
164 if (ret)
165 goto out;
166
167 val |= (PWR_CPU_MASK << PWR_OK_SHIFT);
168
169 ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
170 PWR_OK_STATUS_SHIFT, PWR_CPU_MASK, PWR_CPU_MASK);
171 if (ret)
172 goto out;
173
174 val &= ~CLAMP_ON;
175
176 ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
177 if (ret)
178 goto out;
179
180 /* Power on CPU<N> RAM */
181 val &= ~(MEM_PDA_MASK << MEM_PDA_SHIFT);
182
183 ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
184 if (ret)
185 goto out;
186
187 val |= MEM_PWR_ON;
188
189 ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
190 0, MEM_PWR_ON_STATUS, MEM_PWR_ON_STATUS);
191 if (ret)
192 goto out;
193
194 val |= MEM_PWR_OK;
195
196 ret = bpcm_wr_rd_mask(base, addr, ARM_PWR_CONTROL(cpu), &val,
197 0, MEM_PWR_OK_STATUS, MEM_PWR_OK_STATUS);
198 if (ret)
199 goto out;
200
201 val &= ~MEM_CLAMP_ON;
202
203 ret = bpcm_wr(base, addr, ARM_PWR_CONTROL(cpu), val);
204 if (ret)
205 goto out;
206
207 /* De-assert CPU reset */
208 ctrl |= CPU_RESET_N(cpu);
209
210 ret = bpcm_wr(base, addr, ARM_CONTROL, ctrl);
211 out:
212 spin_unlock_irqrestore(&pmb_lock, flags);
213 iounmap(base);
214 return ret;
215 }
216