1// SPDX-License-Identifier: GPL-2.0+
  2/*
  3 * Allwinner sunXi SoCs Security ID support.
  4 *
  5 * Copyright (c) 2013 Oliver Schinagl <oliver@schinagl.nl>
  6 * Copyright (C) 2014 Maxime Ripard <maxime.ripard@free-electrons.com>
  7 */
  8
  9#include <linux/device.h>
 10#include <linux/io.h>
 11#include <linux/iopoll.h>
 12#include <linux/module.h>
 13#include <linux/nvmem-provider.h>
 14#include <linux/of.h>
 15#include <linux/of_device.h>
 16#include <linux/platform_device.h>
 17#include <linux/slab.h>
 18#include <linux/random.h>
 19
 20/* Registers and special values for doing register-based SID readout on H3 */
 21#define SUN8I_SID_PRCTL		0x40
 22#define SUN8I_SID_RDKEY		0x60
 23
 24#define SUN8I_SID_OFFSET_MASK	0x1FF
 25#define SUN8I_SID_OFFSET_SHIFT	16
 26#define SUN8I_SID_OP_LOCK	(0xAC << 8)
 27#define SUN8I_SID_READ		BIT(1)
 28
 29struct sunxi_sid_cfg {
 30	u32	value_offset;
 31	u32	size;
 32	bool	need_register_readout;
 33};
 34
 35struct sunxi_sid {
 36	void __iomem		*base;
 37	u32			value_offset;
 38};
 39
 40static int sunxi_sid_read(void *context, unsigned int offset,
 41			  void *val, size_t bytes)
 42{
 43	struct sunxi_sid *sid = context;
 44	u32 word;
 45
 46	/* .stride = 4 so offset is guaranteed to be aligned */
 47	__ioread32_copy(val, sid->base + sid->value_offset + offset, bytes / 4);
 48
 49	val += round_down(bytes, 4);
 50	offset += round_down(bytes, 4);
 51	bytes = bytes % 4;
 52
 53	if (!bytes)
 54		return 0;
 55
 56	/* Handle any trailing bytes */
 57	word = readl_relaxed(sid->base + sid->value_offset + offset);
 58	memcpy(val, &word, bytes);
 59
 60	return 0;
 61}
 62
 63static int sun8i_sid_register_readout(const struct sunxi_sid *sid,
 64				      const unsigned int offset,
 65				      u32 *out)
 66{
 67	u32 reg_val;
 68	int ret;
 69
 70	/* Set word, lock access, and set read command */
 71	reg_val = (offset & SUN8I_SID_OFFSET_MASK)
 72		  << SUN8I_SID_OFFSET_SHIFT;
 73	reg_val |= SUN8I_SID_OP_LOCK | SUN8I_SID_READ;
 74	writel(reg_val, sid->base + SUN8I_SID_PRCTL);
 75
 76	ret = readl_poll_timeout(sid->base + SUN8I_SID_PRCTL, reg_val,
 77				 !(reg_val & SUN8I_SID_READ), 100, 250000);
 78	if (ret)
 79		return ret;
 80
 81	if (out)
 82		*out = readl(sid->base + SUN8I_SID_RDKEY);
 83
 84	writel(0, sid->base + SUN8I_SID_PRCTL);
 85
 86	return 0;
 87}
 88
 89/*
 90 * On Allwinner H3, the value on the 0x200 offset of the SID controller seems
 91 * to be not reliable at all.
 92 * Read by the registers instead.
 93 */
 94static int sun8i_sid_read_by_reg(void *context, unsigned int offset,
 95				 void *val, size_t bytes)
 96{
 97	struct sunxi_sid *sid = context;
 98	u32 word;
 99	int ret;
100
101	/* .stride = 4 so offset is guaranteed to be aligned */
102	while (bytes >= 4) {
103		ret = sun8i_sid_register_readout(sid, offset, val);
104		if (ret)
105			return ret;
106
107		val += 4;
108		offset += 4;
109		bytes -= 4;
110	}
111
112	if (!bytes)
113		return 0;
114
115	/* Handle any trailing bytes */
116	ret = sun8i_sid_register_readout(sid, offset, &word);
117	if (ret)
118		return ret;
119
120	memcpy(val, &word, bytes);
121
122	return 0;
123}
124
125static int sunxi_sid_probe(struct platform_device *pdev)
126{
127	struct device *dev = &pdev->dev;
128	struct resource *res;
129	struct nvmem_config *nvmem_cfg;
130	struct nvmem_device *nvmem;
131	struct sunxi_sid *sid;
132	int size;
133	char *randomness;
134	const struct sunxi_sid_cfg *cfg;
135
136	sid = devm_kzalloc(dev, sizeof(*sid), GFP_KERNEL);
137	if (!sid)
138		return -ENOMEM;
139
140	cfg = of_device_get_match_data(dev);
141	if (!cfg)
142		return -EINVAL;
143	sid->value_offset = cfg->value_offset;
144
145	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
146	sid->base = devm_ioremap_resource(dev, res);
147	if (IS_ERR(sid->base))
148		return PTR_ERR(sid->base);
149
150	size = cfg->size;
151
152	nvmem_cfg = devm_kzalloc(dev, sizeof(*nvmem_cfg), GFP_KERNEL);
153	if (!nvmem_cfg)
154		return -ENOMEM;
155
156	nvmem_cfg->dev = dev;
157	nvmem_cfg->name = "sunxi-sid";
158	nvmem_cfg->type = NVMEM_TYPE_OTP;
159	nvmem_cfg->read_only = true;
160	nvmem_cfg->size = cfg->size;
161	nvmem_cfg->word_size = 1;
162	nvmem_cfg->stride = 4;
163	nvmem_cfg->priv = sid;
164	if (cfg->need_register_readout)
165		nvmem_cfg->reg_read = sun8i_sid_read_by_reg;
166	else
167		nvmem_cfg->reg_read = sunxi_sid_read;
168
169	nvmem = devm_nvmem_register(dev, nvmem_cfg);
170	if (IS_ERR(nvmem))
171		return PTR_ERR(nvmem);
172
173	randomness = kzalloc(size, GFP_KERNEL);
174	if (!randomness)
175		return -ENOMEM;
176
177	nvmem_cfg->reg_read(sid, 0, randomness, size);
178	add_device_randomness(randomness, size);
179	kfree(randomness);
180
181	platform_set_drvdata(pdev, nvmem);
182
183	return 0;
184}
185
186static const struct sunxi_sid_cfg sun4i_a10_cfg = {
187	.size = 0x10,
188};
189
190static const struct sunxi_sid_cfg sun7i_a20_cfg = {
191	.size = 0x200,
192};
193
194static const struct sunxi_sid_cfg sun8i_h3_cfg = {
195	.value_offset = 0x200,
196	.size = 0x100,
197	.need_register_readout = true,
198};
199
200static const struct sunxi_sid_cfg sun20i_d1_cfg = {
201	.value_offset = 0x200,
202	.size = 0x100,
203};
204
205static const struct sunxi_sid_cfg sun50i_a64_cfg = {
206	.value_offset = 0x200,
207	.size = 0x100,
208	.need_register_readout = true,
209};
210
211static const struct sunxi_sid_cfg sun50i_h6_cfg = {
212	.value_offset = 0x200,
213	.size = 0x200,
214};
215
216static const struct of_device_id sunxi_sid_of_match[] = {
217	{ .compatible = "allwinner,sun4i-a10-sid", .data = &sun4i_a10_cfg },
218	{ .compatible = "allwinner,sun7i-a20-sid", .data = &sun7i_a20_cfg },
219	{ .compatible = "allwinner,sun8i-a83t-sid", .data = &sun50i_a64_cfg },
220	{ .compatible = "allwinner,sun8i-h3-sid", .data = &sun8i_h3_cfg },
221	{ .compatible = "allwinner,sun20i-d1-sid", .data = &sun20i_d1_cfg },
222	{ .compatible = "allwinner,sun50i-a64-sid", .data = &sun50i_a64_cfg },
223	{ .compatible = "allwinner,sun50i-h5-sid", .data = &sun50i_a64_cfg },
224	{ .compatible = "allwinner,sun50i-h6-sid", .data = &sun50i_h6_cfg },
225	{/* sentinel */},
226};
227MODULE_DEVICE_TABLE(of, sunxi_sid_of_match);
228
229static struct platform_driver sunxi_sid_driver = {
230	.probe = sunxi_sid_probe,
231	.driver = {
232		.name = "eeprom-sunxi-sid",
233		.of_match_table = sunxi_sid_of_match,
234	},
235};
236module_platform_driver(sunxi_sid_driver);
237
238MODULE_AUTHOR("Oliver Schinagl <oliver@schinagl.nl>");
239MODULE_DESCRIPTION("Allwinner sunxi security id driver");
240MODULE_LICENSE("GPL");