xref: /openbmc/linux/drivers/soc/tegra/flowctrl.c (revision 42c67aa2)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * drivers/soc/tegra/flowctrl.c
4  *
5  * Functions and macros to control the flowcontroller
6  *
7  * Copyright (c) 2010-2012, NVIDIA Corporation. All rights reserved.
8  */
9 
10 #include <linux/cpumask.h>
11 #include <linux/init.h>
12 #include <linux/io.h>
13 #include <linux/kernel.h>
14 #include <linux/of.h>
15 #include <linux/of_address.h>
16 #include <linux/platform_device.h>
17 
18 #include <soc/tegra/common.h>
19 #include <soc/tegra/flowctrl.h>
20 #include <soc/tegra/fuse.h>
21 
22 static u8 flowctrl_offset_halt_cpu[] = {
23 	FLOW_CTRL_HALT_CPU0_EVENTS,
24 	FLOW_CTRL_HALT_CPU1_EVENTS,
25 	FLOW_CTRL_HALT_CPU1_EVENTS + 8,
26 	FLOW_CTRL_HALT_CPU1_EVENTS + 16,
27 };
28 
29 static u8 flowctrl_offset_cpu_csr[] = {
30 	FLOW_CTRL_CPU0_CSR,
31 	FLOW_CTRL_CPU1_CSR,
32 	FLOW_CTRL_CPU1_CSR + 8,
33 	FLOW_CTRL_CPU1_CSR + 16,
34 };
35 
36 static void __iomem *tegra_flowctrl_base;
37 
flowctrl_update(u8 offset,u32 value)38 static void flowctrl_update(u8 offset, u32 value)
39 {
40 	if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base),
41 		      "Tegra flowctrl not initialised!\n"))
42 		return;
43 
44 	writel(value, tegra_flowctrl_base + offset);
45 
46 	/* ensure the update has reached the flow controller */
47 	wmb();
48 	readl_relaxed(tegra_flowctrl_base + offset);
49 }
50 
flowctrl_read_cpu_csr(unsigned int cpuid)51 u32 flowctrl_read_cpu_csr(unsigned int cpuid)
52 {
53 	u8 offset = flowctrl_offset_cpu_csr[cpuid];
54 
55 	if (WARN_ONCE(IS_ERR_OR_NULL(tegra_flowctrl_base),
56 		      "Tegra flowctrl not initialised!\n"))
57 		return 0;
58 
59 	return readl(tegra_flowctrl_base + offset);
60 }
61 
flowctrl_write_cpu_csr(unsigned int cpuid,u32 value)62 void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
63 {
64 	return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value);
65 }
66 
flowctrl_write_cpu_halt(unsigned int cpuid,u32 value)67 void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value)
68 {
69 	return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value);
70 }
71 
flowctrl_cpu_suspend_enter(unsigned int cpuid)72 void flowctrl_cpu_suspend_enter(unsigned int cpuid)
73 {
74 	unsigned int reg;
75 	int i;
76 
77 	reg = flowctrl_read_cpu_csr(cpuid);
78 	switch (tegra_get_chip_id()) {
79 	case TEGRA20:
80 		/* clear wfe bitmap */
81 		reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
82 		/* clear wfi bitmap */
83 		reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
84 		/* pwr gating on wfe */
85 		reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid;
86 		break;
87 	case TEGRA30:
88 	case TEGRA114:
89 	case TEGRA124:
90 		/* clear wfe bitmap */
91 		reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
92 		/* clear wfi bitmap */
93 		reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;
94 
95 		if (tegra_get_chip_id() == TEGRA30) {
96 			/*
97 			 * The wfi doesn't work well on Tegra30 because
98 			 * CPU hangs under some odd circumstances after
99 			 * power-gating (like memory running off PLLP),
100 			 * hence use wfe that is working perfectly fine.
101 			 * Note that Tegra30 TRM doc clearly stands that
102 			 * wfi should be used for the "Cluster Switching",
103 			 * while wfe for the power-gating, just like it
104 			 * is done on Tegra20.
105 			 */
106 			reg |= TEGRA20_FLOW_CTRL_CSR_WFE_CPU0 << cpuid;
107 		} else {
108 			/* pwr gating on wfi */
109 			reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid;
110 		}
111 		break;
112 	}
113 	reg |= FLOW_CTRL_CSR_INTR_FLAG;			/* clear intr flag */
114 	reg |= FLOW_CTRL_CSR_EVENT_FLAG;		/* clear event flag */
115 	reg |= FLOW_CTRL_CSR_ENABLE;			/* pwr gating */
116 	flowctrl_write_cpu_csr(cpuid, reg);
117 
118 	for (i = 0; i < num_possible_cpus(); i++) {
119 		if (i == cpuid)
120 			continue;
121 		reg = flowctrl_read_cpu_csr(i);
122 		reg |= FLOW_CTRL_CSR_EVENT_FLAG;
123 		reg |= FLOW_CTRL_CSR_INTR_FLAG;
124 		flowctrl_write_cpu_csr(i, reg);
125 	}
126 }
127 
flowctrl_cpu_suspend_exit(unsigned int cpuid)128 void flowctrl_cpu_suspend_exit(unsigned int cpuid)
129 {
130 	unsigned int reg;
131 
132 	/* Disable powergating via flow controller for CPU0 */
133 	reg = flowctrl_read_cpu_csr(cpuid);
134 	switch (tegra_get_chip_id()) {
135 	case TEGRA20:
136 		/* clear wfe bitmap */
137 		reg &= ~TEGRA20_FLOW_CTRL_CSR_WFE_BITMAP;
138 		/* clear wfi bitmap */
139 		reg &= ~TEGRA20_FLOW_CTRL_CSR_WFI_BITMAP;
140 		break;
141 	case TEGRA30:
142 	case TEGRA114:
143 	case TEGRA124:
144 		/* clear wfe bitmap */
145 		reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;
146 		/* clear wfi bitmap */
147 		reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;
148 		break;
149 	}
150 	reg &= ~FLOW_CTRL_CSR_ENABLE;			/* clear enable */
151 	reg |= FLOW_CTRL_CSR_INTR_FLAG;			/* clear intr */
152 	reg |= FLOW_CTRL_CSR_EVENT_FLAG;		/* clear event */
153 	flowctrl_write_cpu_csr(cpuid, reg);
154 }
155 
tegra_flowctrl_probe(struct platform_device * pdev)156 static int tegra_flowctrl_probe(struct platform_device *pdev)
157 {
158 	void __iomem *base = tegra_flowctrl_base;
159 
160 	tegra_flowctrl_base = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
161 	if (IS_ERR(tegra_flowctrl_base))
162 		return PTR_ERR(tegra_flowctrl_base);
163 
164 	iounmap(base);
165 
166 	return 0;
167 }
168 
169 static const struct of_device_id tegra_flowctrl_match[] = {
170 	{ .compatible = "nvidia,tegra210-flowctrl" },
171 	{ .compatible = "nvidia,tegra124-flowctrl" },
172 	{ .compatible = "nvidia,tegra114-flowctrl" },
173 	{ .compatible = "nvidia,tegra30-flowctrl" },
174 	{ .compatible = "nvidia,tegra20-flowctrl" },
175 	{ }
176 };
177 
178 static struct platform_driver tegra_flowctrl_driver = {
179 	.driver = {
180 		.name = "tegra-flowctrl",
181 		.suppress_bind_attrs = true,
182 		.of_match_table = tegra_flowctrl_match,
183 	},
184 	.probe = tegra_flowctrl_probe,
185 };
186 builtin_platform_driver(tegra_flowctrl_driver);
187 
tegra_flowctrl_init(void)188 static int __init tegra_flowctrl_init(void)
189 {
190 	struct resource res;
191 	struct device_node *np;
192 
193 	if (!soc_is_tegra())
194 		return 0;
195 
196 	np = of_find_matching_node(NULL, tegra_flowctrl_match);
197 	if (np) {
198 		if (of_address_to_resource(np, 0, &res) < 0) {
199 			pr_err("failed to get flowctrl register\n");
200 			return -ENXIO;
201 		}
202 		of_node_put(np);
203 	} else if (IS_ENABLED(CONFIG_ARM)) {
204 		/*
205 		 * Hardcoded fallback for 32-bit Tegra
206 		 * devices if device tree node is missing.
207 		 */
208 		res.start = 0x60007000;
209 		res.end = 0x60007fff;
210 		res.flags = IORESOURCE_MEM;
211 	} else {
212 		/*
213 		 * At this point we're running on a Tegra,
214 		 * that doesn't support the flow controller
215 		 * (eg. Tegra186), so just return.
216 		 */
217 		return 0;
218 	}
219 
220 	tegra_flowctrl_base = ioremap(res.start, resource_size(&res));
221 	if (!tegra_flowctrl_base)
222 		return -ENXIO;
223 
224 	return 0;
225 }
226 early_initcall(tegra_flowctrl_init);
227