xref: /openbmc/linux/drivers/mfd/altera-sysmgr.c (revision e0d07278)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 2018-2019, Intel Corporation.
4  *  Copyright (C) 2012 Freescale Semiconductor, Inc.
5  *  Copyright (C) 2012 Linaro Ltd.
6  *
7  *  Based on syscon driver.
8  */
9 
10 #include <linux/arm-smccc.h>
11 #include <linux/err.h>
12 #include <linux/io.h>
13 #include <linux/mfd/altera-sysmgr.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/module.h>
16 #include <linux/of.h>
17 #include <linux/of_address.h>
18 #include <linux/of_platform.h>
19 #include <linux/regmap.h>
20 #include <linux/slab.h>
21 
22 /**
23  * struct altr_sysmgr - Altera SOCFPGA System Manager
24  * @regmap: the regmap used for System Manager accesses.
25  */
26 struct altr_sysmgr {
27 	struct regmap   *regmap;
28 };
29 
30 static struct platform_driver altr_sysmgr_driver;
31 
32 /**
33  * s10_protected_reg_write
34  * Write to a protected SMC register.
35  * @base: Base address of System Manager
36  * @reg:  Address offset of register
37  * @val:  Value to write
38  * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
39  *	   INTEL_SIP_SMC_REG_ERROR on error
40  *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
41  */
42 static int s10_protected_reg_write(void *base,
43 				   unsigned int reg, unsigned int val)
44 {
45 	struct arm_smccc_res result;
46 	unsigned long sysmgr_base = (unsigned long)base;
47 
48 	arm_smccc_smc(INTEL_SIP_SMC_REG_WRITE, sysmgr_base + reg,
49 		      val, 0, 0, 0, 0, 0, &result);
50 
51 	return (int)result.a0;
52 }
53 
54 /**
55  * s10_protected_reg_read
56  * Read the status of a protected SMC register
57  * @base: Base address of System Manager.
58  * @reg:  Address of register
59  * @val:  Value read.
60  * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
61  *	   INTEL_SIP_SMC_REG_ERROR on error
62  *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
63  */
64 static int s10_protected_reg_read(void *base,
65 				  unsigned int reg, unsigned int *val)
66 {
67 	struct arm_smccc_res result;
68 	unsigned long sysmgr_base = (unsigned long)base;
69 
70 	arm_smccc_smc(INTEL_SIP_SMC_REG_READ, sysmgr_base + reg,
71 		      0, 0, 0, 0, 0, 0, &result);
72 
73 	*val = (unsigned int)result.a1;
74 
75 	return (int)result.a0;
76 }
77 
78 static struct regmap_config altr_sysmgr_regmap_cfg = {
79 	.name = "altr_sysmgr",
80 	.reg_bits = 32,
81 	.reg_stride = 4,
82 	.val_bits = 32,
83 	.fast_io = true,
84 	.use_single_read = true,
85 	.use_single_write = true,
86 };
87 
88 /**
89  * altr_sysmgr_regmap_lookup_by_phandle
90  * Find the sysmgr previous configured in probe() and return regmap property.
91  * Return: regmap if found or error if not found.
92  *
93  * @np: Pointer to device's Device Tree node
94  * @property: Device Tree property name which references the sysmgr
95  */
96 struct regmap *altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
97 						    const char *property)
98 {
99 	struct device *dev;
100 	struct altr_sysmgr *sysmgr;
101 	struct device_node *sysmgr_np;
102 
103 	if (property)
104 		sysmgr_np = of_parse_phandle(np, property, 0);
105 	else
106 		sysmgr_np = np;
107 
108 	if (!sysmgr_np)
109 		return ERR_PTR(-ENODEV);
110 
111 	dev = driver_find_device_by_of_node(&altr_sysmgr_driver.driver,
112 					    (void *)sysmgr_np);
113 	of_node_put(sysmgr_np);
114 	if (!dev)
115 		return ERR_PTR(-EPROBE_DEFER);
116 
117 	sysmgr = dev_get_drvdata(dev);
118 
119 	return sysmgr->regmap;
120 }
121 EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_phandle);
122 
123 static int sysmgr_probe(struct platform_device *pdev)
124 {
125 	struct altr_sysmgr *sysmgr;
126 	struct regmap *regmap;
127 	struct resource *res;
128 	struct regmap_config sysmgr_config = altr_sysmgr_regmap_cfg;
129 	struct device *dev = &pdev->dev;
130 	struct device_node *np = dev->of_node;
131 	void __iomem *base;
132 
133 	sysmgr = devm_kzalloc(dev, sizeof(*sysmgr), GFP_KERNEL);
134 	if (!sysmgr)
135 		return -ENOMEM;
136 
137 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
138 	if (!res)
139 		return -ENOENT;
140 
141 	sysmgr_config.max_register = resource_size(res) -
142 				     sysmgr_config.reg_stride;
143 	if (of_device_is_compatible(np, "altr,sys-mgr-s10")) {
144 		sysmgr_config.reg_read = s10_protected_reg_read;
145 		sysmgr_config.reg_write = s10_protected_reg_write;
146 
147 		/* Need physical address for SMCC call */
148 		regmap = devm_regmap_init(dev, NULL, (void *)res->start,
149 					  &sysmgr_config);
150 	} else {
151 		base = devm_ioremap(dev, res->start, resource_size(res));
152 		if (!base)
153 			return -ENOMEM;
154 
155 		sysmgr_config.max_register = res->end - res->start - 3;
156 		regmap = devm_regmap_init_mmio(dev, base, &sysmgr_config);
157 	}
158 
159 	if (IS_ERR(regmap)) {
160 		pr_err("regmap init failed\n");
161 		return PTR_ERR(regmap);
162 	}
163 
164 	sysmgr->regmap = regmap;
165 
166 	platform_set_drvdata(pdev, sysmgr);
167 
168 	return 0;
169 }
170 
171 static const struct of_device_id altr_sysmgr_of_match[] = {
172 	{ .compatible = "altr,sys-mgr" },
173 	{ .compatible = "altr,sys-mgr-s10" },
174 	{},
175 };
176 MODULE_DEVICE_TABLE(of, altr_sysmgr_of_match);
177 
178 static struct platform_driver altr_sysmgr_driver = {
179 	.probe =  sysmgr_probe,
180 	.driver = {
181 		.name = "altr,system_manager",
182 		.of_match_table = altr_sysmgr_of_match,
183 	},
184 };
185 
186 static int __init altr_sysmgr_init(void)
187 {
188 	return platform_driver_register(&altr_sysmgr_driver);
189 }
190 core_initcall(altr_sysmgr_init);
191 
192 static void __exit altr_sysmgr_exit(void)
193 {
194 	platform_driver_unregister(&altr_sysmgr_driver);
195 }
196 module_exit(altr_sysmgr_exit);
197 
198 MODULE_AUTHOR("Thor Thayer <>");
199 MODULE_DESCRIPTION("SOCFPGA System Manager driver");
200 MODULE_LICENSE("GPL v2");
201