1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Nuvoton Technology corporation
3 
4 #include <linux/bitfield.h>
5 #include <linux/clk.h>
6 #include <linux/interrupt.h>
7 #include <linux/jiffies.h>
8 #include <linux/module.h>
9 #include <linux/of.h>
10 #include <linux/peci.h>
11 #include <linux/platform_device.h>
12 #include <linux/regmap.h>
13 #include <linux/reset.h>
14 
15 /* NPCM GCR module */
16 #define NPCM_INTCR3_OFFSET	0x9C
17 #define NPCM_INTCR3_PECIVSEL	BIT(19)
18 
19 /* NPCM PECI Registers */
20 #define NPCM_PECI_CTL_STS	0x00
21 #define NPCM_PECI_RD_LENGTH	0x04
22 #define NPCM_PECI_ADDR		0x08
23 #define NPCM_PECI_CMD		0x0C
24 #define NPCM_PECI_CTL2		0x10
25 #define NPCM_PECI_WR_LENGTH	0x1C
26 #define NPCM_PECI_PDDR		0x2C
27 #define NPCM_PECI_DAT_INOUT(n)	(0x100 + ((n) * 4))
28 
29 #define NPCM_PECI_MAX_REG	0x200
30 
31 /* NPCM_PECI_CTL_STS - 0x00 : Control Register */
32 #define NPCM_PECI_CTRL_DONE_INT_EN	BIT(6)
33 #define NPCM_PECI_CTRL_ABRT_ERR		BIT(4)
34 #define NPCM_PECI_CTRL_CRC_ERR		BIT(3)
35 #define NPCM_PECI_CTRL_DONE		BIT(1)
36 #define NPCM_PECI_CTRL_START_BUSY	BIT(0)
37 
38 /* NPCM_PECI_RD_LENGTH - 0x04 : Command Register */
39 #define NPCM_PECI_RD_LEN_MASK		GENMASK(6, 0)
40 
41 /* NPCM_PECI_CMD - 0x10 : Command Register */
42 #define NPCM_PECI_CTL2_MASK		GENMASK(7, 6)
43 
44 /* NPCM_PECI_WR_LENGTH - 0x1C : Command Register */
45 #define NPCM_PECI_WR_LEN_MASK		GENMASK(6, 0)
46 
47 /* NPCM_PECI_PDDR - 0x2C : Command Register */
48 #define NPCM_PECI_PDDR_MASK		GENMASK(4, 0)
49 
50 #define NPCM_PECI_INT_MASK		(NPCM_PECI_CTRL_ABRT_ERR | \
51 					 NPCM_PECI_CTRL_CRC_ERR  | \
52 					 NPCM_PECI_CTRL_DONE)
53 
54 #define NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC	(50 * USEC_PER_MSEC)
55 #define NPCM_PECI_IDLE_CHECK_INTERVAL_USEC	(10 * USEC_PER_MSEC)
56 #define NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT	1000
57 #define NPCM_PECI_CMD_TIMEOUT_MS_MAX		60000
58 #define NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT	15
59 #define NPCM_PECI_PULL_DOWN_DEFAULT		0
60 
61 struct npcm_peci {
62 	u32			cmd_timeout_ms;
63 	struct completion	xfer_complete;
64 	struct regmap		*regmap;
65 	u32			status;
66 	spinlock_t		lock; /* to sync completion status handling */
67 	struct peci_controller *controller;
68 	struct device		*dev;
69 	struct clk		*clk;
70 	int			irq;
71 };
72 
73 static int npcm_peci_xfer(struct peci_controller *controller, u8 addr, struct peci_request *req)
74 {
75 	struct npcm_peci *priv = dev_get_drvdata(controller->dev.parent);
76 	unsigned long timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
77 	unsigned int msg_rd;
78 	u32 cmd_sts;
79 	int i, ret;
80 
81 	/* Check command sts and bus idle state */
82 	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
83 				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
84 				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
85 				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
86 	if (ret)
87 		return ret; /* -ETIMEDOUT */
88 
89 	spin_lock_irq(&priv->lock);
90 	reinit_completion(&priv->xfer_complete);
91 
92 	regmap_write(priv->regmap, NPCM_PECI_ADDR, addr);
93 	regmap_write(priv->regmap, NPCM_PECI_RD_LENGTH, NPCM_PECI_WR_LEN_MASK & req->rx.len);
94 	regmap_write(priv->regmap, NPCM_PECI_WR_LENGTH, NPCM_PECI_WR_LEN_MASK & req->tx.len);
95 
96 	if (req->tx.len) {
97 		regmap_write(priv->regmap, NPCM_PECI_CMD, req->tx.buf[0]);
98 
99 		for (i = 0; i < (req->tx.len - 1); i++)
100 			regmap_write(priv->regmap, NPCM_PECI_DAT_INOUT(i), req->tx.buf[i + 1]);
101 	}
102 
103 #if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
104 	dev_dbg(priv->dev, "addr : %#02x, tx.len : %#02x, rx.len : %#02x\n",
105 		addr, req->tx.len, req->rx.len);
106 	print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req->tx.len);
107 #endif
108 
109 	priv->status = 0;
110 	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_START_BUSY,
111 			   NPCM_PECI_CTRL_START_BUSY);
112 
113 	spin_unlock_irq(&priv->lock);
114 
115 	ret = wait_for_completion_interruptible_timeout(&priv->xfer_complete, timeout);
116 	if (ret < 0)
117 		return ret;
118 
119 	if (ret == 0) {
120 		dev_dbg(priv->dev, "timeout waiting for a response\n");
121 		return -ETIMEDOUT;
122 	}
123 
124 	spin_lock_irq(&priv->lock);
125 
126 	if (priv->status != NPCM_PECI_CTRL_DONE) {
127 		spin_unlock_irq(&priv->lock);
128 		dev_dbg(priv->dev, "no valid response, status: %#02x\n", priv->status);
129 		return -EIO;
130 	}
131 
132 	regmap_write(priv->regmap, NPCM_PECI_CMD, 0);
133 
134 	for (i = 0; i < req->rx.len; i++) {
135 		regmap_read(priv->regmap, NPCM_PECI_DAT_INOUT(i), &msg_rd);
136 		req->rx.buf[i] = (u8)msg_rd;
137 	}
138 
139 	spin_unlock_irq(&priv->lock);
140 
141 #if IS_ENABLED(CONFIG_DYNAMIC_DEBUG)
142 	print_hex_dump_bytes("RX : ", DUMP_PREFIX_NONE, req->rx.buf, req->rx.len);
143 #endif
144 	return 0;
145 }
146 
147 static irqreturn_t npcm_peci_irq_handler(int irq, void *arg)
148 {
149 	struct npcm_peci *priv = arg;
150 	u32 status_ack = 0;
151 	u32 status;
152 
153 	spin_lock(&priv->lock);
154 	regmap_read(priv->regmap, NPCM_PECI_CTL_STS, &status);
155 	priv->status |= (status & NPCM_PECI_INT_MASK);
156 
157 	if (status & NPCM_PECI_CTRL_CRC_ERR)
158 		status_ack |= NPCM_PECI_CTRL_CRC_ERR;
159 
160 	if (status & NPCM_PECI_CTRL_ABRT_ERR)
161 		status_ack |= NPCM_PECI_CTRL_ABRT_ERR;
162 
163 	/*
164 	 * All commands should be ended up with a NPCM_PECI_CTRL_DONE
165 	 * bit set even in an error case.
166 	 */
167 	if (status & NPCM_PECI_CTRL_DONE) {
168 		status_ack |= NPCM_PECI_CTRL_DONE;
169 		complete(&priv->xfer_complete);
170 	}
171 
172 	regmap_write_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_INT_MASK, status_ack);
173 
174 	spin_unlock(&priv->lock);
175 	return IRQ_HANDLED;
176 }
177 
178 static int npcm_peci_init_ctrl(struct npcm_peci *priv)
179 {
180 	u32 cmd_sts;
181 	int ret;
182 
183 	priv->clk = devm_clk_get_enabled(priv->dev, NULL);
184 	if (IS_ERR(priv->clk)) {
185 		dev_err(priv->dev, "failed to get ref clock\n");
186 		return PTR_ERR(priv->clk);
187 	}
188 
189 	ret = device_property_read_u32(priv->dev, "cmd-timeout-ms", &priv->cmd_timeout_ms);
190 	if (ret) {
191 		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
192 	} else if (priv->cmd_timeout_ms > NPCM_PECI_CMD_TIMEOUT_MS_MAX ||
193 		   priv->cmd_timeout_ms == 0) {
194 		dev_warn(priv->dev, "invalid cmd-timeout-ms: %u, falling back to: %u\n",
195 			 priv->cmd_timeout_ms, NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT);
196 
197 		priv->cmd_timeout_ms = NPCM_PECI_CMD_TIMEOUT_MS_DEFAULT;
198 	}
199 
200 	regmap_update_bits(priv->regmap, NPCM_PECI_CTL2, NPCM_PECI_CTL2_MASK,
201 			   NPCM_PECI_PULL_DOWN_DEFAULT << 6);
202 
203 	regmap_update_bits(priv->regmap, NPCM_PECI_PDDR, NPCM_PECI_PDDR_MASK,
204 			   NPCM_PECI_HOST_NEG_BIT_RATE_DEFAULT);
205 
206 	ret = regmap_read_poll_timeout(priv->regmap, NPCM_PECI_CTL_STS, cmd_sts,
207 				       !(cmd_sts & NPCM_PECI_CTRL_START_BUSY),
208 				       NPCM_PECI_IDLE_CHECK_INTERVAL_USEC,
209 				       NPCM_PECI_IDLE_CHECK_TIMEOUT_USEC);
210 	if (ret)
211 		return ret; /* -ETIMEDOUT */
212 
213 	/* PECI interrupt enable */
214 	regmap_update_bits(priv->regmap, NPCM_PECI_CTL_STS, NPCM_PECI_CTRL_DONE_INT_EN,
215 			   NPCM_PECI_CTRL_DONE_INT_EN);
216 
217 	return 0;
218 }
219 
220 static const struct regmap_config npcm_peci_regmap_config = {
221 	.reg_bits = 8,
222 	.val_bits = 8,
223 	.max_register = NPCM_PECI_MAX_REG,
224 	.fast_io = true,
225 };
226 
227 static struct peci_controller_ops npcm_ops = {
228 	.xfer = npcm_peci_xfer,
229 };
230 
231 static int npcm_peci_probe(struct platform_device *pdev)
232 {
233 	struct peci_controller *controller;
234 	struct npcm_peci *priv;
235 	void __iomem *base;
236 	int ret;
237 
238 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
239 	if (!priv)
240 		return -ENOMEM;
241 
242 	priv->dev = &pdev->dev;
243 	dev_set_drvdata(&pdev->dev, priv);
244 
245 	base = devm_platform_ioremap_resource(pdev, 0);
246 	if (IS_ERR(base))
247 		return PTR_ERR(base);
248 
249 	priv->regmap = devm_regmap_init_mmio(&pdev->dev, base, &npcm_peci_regmap_config);
250 	if (IS_ERR(priv->regmap))
251 		return PTR_ERR(priv->regmap);
252 
253 	priv->irq = platform_get_irq(pdev, 0);
254 	if (priv->irq < 0)
255 		return priv->irq;
256 
257 	ret = devm_request_irq(&pdev->dev, priv->irq, npcm_peci_irq_handler,
258 			       0, "peci-npcm-irq", priv);
259 	if (ret)
260 		return ret;
261 
262 	init_completion(&priv->xfer_complete);
263 	spin_lock_init(&priv->lock);
264 
265 	ret = npcm_peci_init_ctrl(priv);
266 	if (ret)
267 		return ret;
268 
269 	controller = devm_peci_controller_add(priv->dev, &npcm_ops);
270 	if (IS_ERR(controller))
271 		return dev_err_probe(priv->dev, PTR_ERR(controller),
272 				     "failed to add npcm peci controller\n");
273 
274 	priv->controller = controller;
275 
276 	return 0;
277 }
278 
279 static const struct of_device_id npcm_peci_of_table[] = {
280 	{ .compatible = "nuvoton,npcm750-peci", },
281 	{ .compatible = "nuvoton,npcm845-peci", },
282 	{ }
283 };
284 MODULE_DEVICE_TABLE(of, npcm_peci_of_table);
285 
286 static struct platform_driver npcm_peci_driver = {
287 	.probe  = npcm_peci_probe,
288 	.driver = {
289 		.name           = KBUILD_MODNAME,
290 		.of_match_table = npcm_peci_of_table,
291 	},
292 };
293 module_platform_driver(npcm_peci_driver);
294 
295 MODULE_AUTHOR("Tomer Maimon <tomer.maimon@nuvoton.com>");
296 MODULE_DESCRIPTION("NPCM PECI driver");
297 MODULE_LICENSE("GPL");
298 MODULE_IMPORT_NS(PECI);
299