xref: /linux/drivers/bus/uniphier-system-bus.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Masahiro Yamada <yamada.masahiro@socionext.com>
4  */
5 
6 #include <linux/io.h>
7 #include <linux/log2.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/of_address.h>
11 #include <linux/of_platform.h>
12 #include <linux/platform_device.h>
13 
14 /* System Bus Controller registers */
15 #define UNIPHIER_SBC_BASE	0x100	/* base address of bank0 space */
16 #define    UNIPHIER_SBC_BASE_BE		BIT(0)	/* bank_enable */
17 #define UNIPHIER_SBC_CTRL0	0x200	/* timing parameter 0 of bank0 */
18 #define UNIPHIER_SBC_CTRL1	0x204	/* timing parameter 1 of bank0 */
19 #define UNIPHIER_SBC_CTRL2	0x208	/* timing parameter 2 of bank0 */
20 #define UNIPHIER_SBC_CTRL3	0x20c	/* timing parameter 3 of bank0 */
21 #define UNIPHIER_SBC_CTRL4	0x300	/* timing parameter 4 of bank0 */
22 
23 #define UNIPHIER_SBC_STRIDE	0x10	/* register stride to next bank */
24 #define UNIPHIER_SBC_NR_BANKS	8	/* number of banks (chip select) */
25 #define UNIPHIER_SBC_BASE_DUMMY	0xffffffff	/* data to squash bank 0, 1 */
26 
27 struct uniphier_system_bus_bank {
28 	u32 base;
29 	u32 end;
30 };
31 
32 struct uniphier_system_bus_priv {
33 	struct device *dev;
34 	void __iomem *membase;
35 	struct uniphier_system_bus_bank bank[UNIPHIER_SBC_NR_BANKS];
36 };
37 
38 static int uniphier_system_bus_add_bank(struct uniphier_system_bus_priv *priv,
39 					int bank, u32 addr, u64 paddr, u32 size)
40 {
41 	u64 end, mask;
42 
43 	dev_dbg(priv->dev,
44 		"range found: bank = %d, addr = %08x, paddr = %08llx, size = %08x\n",
45 		bank, addr, paddr, size);
46 
47 	if (bank >= ARRAY_SIZE(priv->bank)) {
48 		dev_err(priv->dev, "unsupported bank number %d\n", bank);
49 		return -EINVAL;
50 	}
51 
52 	if (priv->bank[bank].base || priv->bank[bank].end) {
53 		dev_err(priv->dev,
54 			"range for bank %d has already been specified\n", bank);
55 		return -EINVAL;
56 	}
57 
58 	if (paddr > U32_MAX) {
59 		dev_err(priv->dev, "base address %llx is too high\n", paddr);
60 		return -EINVAL;
61 	}
62 
63 	end = paddr + size;
64 
65 	if (addr > paddr) {
66 		dev_err(priv->dev,
67 			"base %08x cannot be mapped to %08llx of parent\n",
68 			addr, paddr);
69 		return -EINVAL;
70 	}
71 	paddr -= addr;
72 
73 	paddr = round_down(paddr, 0x00020000);
74 	end = round_up(end, 0x00020000);
75 
76 	if (end > U32_MAX) {
77 		dev_err(priv->dev, "end address %08llx is too high\n", end);
78 		return -EINVAL;
79 	}
80 	mask = paddr ^ (end - 1);
81 	mask = roundup_pow_of_two(mask);
82 
83 	paddr = round_down(paddr, mask);
84 	end = round_up(end, mask);
85 
86 	priv->bank[bank].base = paddr;
87 	priv->bank[bank].end = end;
88 
89 	dev_dbg(priv->dev, "range added: bank = %d, addr = %08x, end = %08x\n",
90 		bank, priv->bank[bank].base, priv->bank[bank].end);
91 
92 	return 0;
93 }
94 
95 static int uniphier_system_bus_check_overlap(
96 				const struct uniphier_system_bus_priv *priv)
97 {
98 	int i, j;
99 
100 	for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
101 		for (j = i + 1; j < ARRAY_SIZE(priv->bank); j++) {
102 			if (priv->bank[i].end > priv->bank[j].base &&
103 			    priv->bank[i].base < priv->bank[j].end) {
104 				dev_err(priv->dev,
105 					"region overlap between bank%d and bank%d\n",
106 					i, j);
107 				return -EINVAL;
108 			}
109 		}
110 	}
111 
112 	return 0;
113 }
114 
115 static void uniphier_system_bus_check_boot_swap(
116 					struct uniphier_system_bus_priv *priv)
117 {
118 	void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
119 	int is_swapped;
120 
121 	is_swapped = !(readl(base_reg) & UNIPHIER_SBC_BASE_BE);
122 
123 	dev_dbg(priv->dev, "Boot Swap: %s\n", is_swapped ? "on" : "off");
124 
125 	/*
126 	 * If BOOT_SWAP was asserted on power-on-reset, the CS0 and CS1 are
127 	 * swapped.  In this case, bank0 and bank1 should be swapped as well.
128 	 */
129 	if (is_swapped)
130 		swap(priv->bank[0], priv->bank[1]);
131 }
132 
133 static void uniphier_system_bus_set_reg(
134 				const struct uniphier_system_bus_priv *priv)
135 {
136 	void __iomem *base_reg = priv->membase + UNIPHIER_SBC_BASE;
137 	u32 base, end, mask, val;
138 	int i;
139 
140 	for (i = 0; i < ARRAY_SIZE(priv->bank); i++) {
141 		base = priv->bank[i].base;
142 		end = priv->bank[i].end;
143 
144 		if (base == end) {
145 			/*
146 			 * If SBC_BASE0 or SBC_BASE1 is set to zero, the access
147 			 * to anywhere in the system bus space is routed to
148 			 * bank 0 (if boot swap if off) or bank 1 (if boot swap
149 			 * if on).  It means that CPUs cannot get access to
150 			 * bank 2 or later.  In other words, bank 0/1 cannot
151 			 * be disabled even if its bank_enable bits is cleared.
152 			 * This seems odd, but it is how this hardware goes.
153 			 * As a workaround, dummy data (0xffffffff) should be
154 			 * set when the bank 0/1 is unused.  As for bank 2 and
155 			 * later, they can be simply disable by clearing the
156 			 * bank_enable bit.
157 			 */
158 			if (i < 2)
159 				val = UNIPHIER_SBC_BASE_DUMMY;
160 			else
161 				val = 0;
162 		} else {
163 			mask = base ^ (end - 1);
164 
165 			val = base & 0xfffe0000;
166 			val |= (~mask >> 16) & 0xfffe;
167 			val |= UNIPHIER_SBC_BASE_BE;
168 		}
169 		dev_dbg(priv->dev, "SBC_BASE[%d] = 0x%08x\n", i, val);
170 
171 		writel(val, base_reg + UNIPHIER_SBC_STRIDE * i);
172 	}
173 }
174 
175 static int uniphier_system_bus_probe(struct platform_device *pdev)
176 {
177 	struct device *dev = &pdev->dev;
178 	struct uniphier_system_bus_priv *priv;
179 	struct of_range_parser parser;
180 	struct of_range range;
181 	int ret;
182 
183 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
184 	if (!priv)
185 		return -ENOMEM;
186 
187 	priv->membase = devm_platform_ioremap_resource(pdev, 0);
188 	if (IS_ERR(priv->membase))
189 		return PTR_ERR(priv->membase);
190 
191 	priv->dev = dev;
192 
193 	ret = of_range_parser_init(&parser, dev->of_node);
194 	if (ret)
195 		return ret;
196 
197 	for_each_of_range(&parser, &range) {
198 		if (range.cpu_addr == OF_BAD_ADDR)
199 			return -EINVAL;
200 		ret = uniphier_system_bus_add_bank(priv,
201 						   upper_32_bits(range.bus_addr),
202 						   lower_32_bits(range.bus_addr),
203 						   range.cpu_addr, range.size);
204 		if (ret)
205 			return ret;
206 	}
207 
208 	ret = uniphier_system_bus_check_overlap(priv);
209 	if (ret)
210 		return ret;
211 
212 	uniphier_system_bus_check_boot_swap(priv);
213 
214 	uniphier_system_bus_set_reg(priv);
215 
216 	platform_set_drvdata(pdev, priv);
217 
218 	/* Now, the bus is configured.  Populate platform_devices below it */
219 	return of_platform_default_populate(dev->of_node, NULL, dev);
220 }
221 
222 static int __maybe_unused uniphier_system_bus_resume(struct device *dev)
223 {
224 	uniphier_system_bus_set_reg(dev_get_drvdata(dev));
225 
226 	return 0;
227 }
228 
229 static const struct dev_pm_ops uniphier_system_bus_pm_ops = {
230 	SET_SYSTEM_SLEEP_PM_OPS(NULL, uniphier_system_bus_resume)
231 };
232 
233 static const struct of_device_id uniphier_system_bus_match[] = {
234 	{ .compatible = "socionext,uniphier-system-bus" },
235 	{ /* sentinel */ }
236 };
237 MODULE_DEVICE_TABLE(of, uniphier_system_bus_match);
238 
239 static struct platform_driver uniphier_system_bus_driver = {
240 	.probe		= uniphier_system_bus_probe,
241 	.driver = {
242 		.name	= "uniphier-system-bus",
243 		.of_match_table = uniphier_system_bus_match,
244 		.pm = &uniphier_system_bus_pm_ops,
245 	},
246 };
247 module_platform_driver(uniphier_system_bus_driver);
248 
249 MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
250 MODULE_DESCRIPTION("UniPhier System Bus driver");
251 MODULE_LICENSE("GPL");
252