xref: /openbmc/linux/drivers/mfd/altera-sysmgr.c (revision 74be2d3b)
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  * @base  : the base address for the System Manager
26  */
27 struct altr_sysmgr {
28 	struct regmap   *regmap;
29 	resource_size_t *base;
30 };
31 
32 static struct platform_driver altr_sysmgr_driver;
33 
34 /**
35  * s10_protected_reg_write
36  * Write to a protected SMC register.
37  * @base: Base address of System Manager
38  * @reg:  Address offset of register
39  * @val:  Value to write
40  * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
41  *	   INTEL_SIP_SMC_REG_ERROR on error
42  *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
43  */
44 static int s10_protected_reg_write(void *base,
45 				   unsigned int reg, unsigned int val)
46 {
47 	struct arm_smccc_res result;
48 	unsigned long sysmgr_base = (unsigned long)base;
49 
50 	arm_smccc_smc(INTEL_SIP_SMC_REG_WRITE, sysmgr_base + reg,
51 		      val, 0, 0, 0, 0, 0, &result);
52 
53 	return (int)result.a0;
54 }
55 
56 /**
57  * s10_protected_reg_read
58  * Read the status of a protected SMC register
59  * @base: Base address of System Manager.
60  * @reg:  Address of register
61  * @val:  Value read.
62  * Return: INTEL_SIP_SMC_STATUS_OK (0) on success
63  *	   INTEL_SIP_SMC_REG_ERROR on error
64  *	   INTEL_SIP_SMC_RETURN_UNKNOWN_FUNCTION if not supported
65  */
66 static int s10_protected_reg_read(void *base,
67 				  unsigned int reg, unsigned int *val)
68 {
69 	struct arm_smccc_res result;
70 	unsigned long sysmgr_base = (unsigned long)base;
71 
72 	arm_smccc_smc(INTEL_SIP_SMC_REG_READ, sysmgr_base + reg,
73 		      0, 0, 0, 0, 0, 0, &result);
74 
75 	*val = (unsigned int)result.a1;
76 
77 	return (int)result.a0;
78 }
79 
80 static struct regmap_config altr_sysmgr_regmap_cfg = {
81 	.name = "altr_sysmgr",
82 	.reg_bits = 32,
83 	.reg_stride = 4,
84 	.val_bits = 32,
85 	.fast_io = true,
86 	.use_single_read = true,
87 	.use_single_write = true,
88 };
89 
90 /**
91  * altr_sysmgr_regmap_lookup_by_phandle
92  * Find the sysmgr previous configured in probe() and return regmap property.
93  * Return: regmap if found or error if not found.
94  */
95 struct regmap *altr_sysmgr_regmap_lookup_by_phandle(struct device_node *np,
96 						    const char *property)
97 {
98 	struct device *dev;
99 	struct altr_sysmgr *sysmgr;
100 	struct device_node *sysmgr_np;
101 
102 	if (property)
103 		sysmgr_np = of_parse_phandle(np, property, 0);
104 	else
105 		sysmgr_np = np;
106 
107 	if (!sysmgr_np)
108 		return ERR_PTR(-ENODEV);
109 
110 	dev = driver_find_device_by_of_node(&altr_sysmgr_driver.driver,
111 					    (void *)sysmgr_np);
112 	of_node_put(sysmgr_np);
113 	if (!dev)
114 		return ERR_PTR(-EPROBE_DEFER);
115 
116 	sysmgr = dev_get_drvdata(dev);
117 
118 	return sysmgr->regmap;
119 }
120 EXPORT_SYMBOL_GPL(altr_sysmgr_regmap_lookup_by_phandle);
121 
122 static int sysmgr_probe(struct platform_device *pdev)
123 {
124 	struct altr_sysmgr *sysmgr;
125 	struct regmap *regmap;
126 	struct resource *res;
127 	struct regmap_config sysmgr_config = altr_sysmgr_regmap_cfg;
128 	struct device *dev = &pdev->dev;
129 	struct device_node *np = dev->of_node;
130 
131 	sysmgr = devm_kzalloc(dev, sizeof(*sysmgr), GFP_KERNEL);
132 	if (!sysmgr)
133 		return -ENOMEM;
134 
135 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
136 	if (!res)
137 		return -ENOENT;
138 
139 	sysmgr_config.max_register = resource_size(res) -
140 				     sysmgr_config.reg_stride;
141 	if (of_device_is_compatible(np, "altr,sys-mgr-s10")) {
142 		/* Need physical address for SMCC call */
143 		sysmgr->base = (resource_size_t *)res->start;
144 		sysmgr_config.reg_read = s10_protected_reg_read;
145 		sysmgr_config.reg_write = s10_protected_reg_write;
146 
147 		regmap = devm_regmap_init(dev, NULL, sysmgr->base,
148 					  &sysmgr_config);
149 	} else {
150 		sysmgr->base = devm_ioremap(dev, res->start,
151 					    resource_size(res));
152 		if (!sysmgr->base)
153 			return -ENOMEM;
154 
155 		sysmgr_config.max_register = res->end - res->start - 3;
156 		regmap = devm_regmap_init_mmio(dev, sysmgr->base,
157 					       &sysmgr_config);
158 	}
159 
160 	if (IS_ERR(regmap)) {
161 		pr_err("regmap init failed\n");
162 		return PTR_ERR(regmap);
163 	}
164 
165 	sysmgr->regmap = regmap;
166 
167 	platform_set_drvdata(pdev, sysmgr);
168 
169 	return 0;
170 }
171 
172 static const struct of_device_id altr_sysmgr_of_match[] = {
173 	{ .compatible = "altr,sys-mgr" },
174 	{ .compatible = "altr,sys-mgr-s10" },
175 	{},
176 };
177 MODULE_DEVICE_TABLE(of, altr_sysmgr_of_match);
178 
179 static struct platform_driver altr_sysmgr_driver = {
180 	.probe =  sysmgr_probe,
181 	.driver = {
182 		.name = "altr,system_manager",
183 		.of_match_table = altr_sysmgr_of_match,
184 	},
185 };
186 
187 static int __init altr_sysmgr_init(void)
188 {
189 	return platform_driver_register(&altr_sysmgr_driver);
190 }
191 core_initcall(altr_sysmgr_init);
192 
193 static void __exit altr_sysmgr_exit(void)
194 {
195 	platform_driver_unregister(&altr_sysmgr_driver);
196 }
197 module_exit(altr_sysmgr_exit);
198 
199 MODULE_AUTHOR("Thor Thayer <>");
200 MODULE_DESCRIPTION("SOCFPGA System Manager driver");
201 MODULE_LICENSE("GPL v2");
202