xref: /openbmc/linux/drivers/mailbox/stm32-ipcc.c (revision 6c33a6f4) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
4  * Authors: Ludovic Barre <ludovic.barre@st.com> for STMicroelectronics.
5  *          Fabien Dessenne <fabien.dessenne@st.com> for STMicroelectronics.
6  */
7 
8 #include <linux/bitfield.h>
9 #include <linux/clk.h>
10 #include <linux/interrupt.h>
11 #include <linux/io.h>
12 #include <linux/mailbox_controller.h>
13 #include <linux/module.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm_wakeirq.h>
16 
17 #define IPCC_XCR		0x000
18 #define XCR_RXOIE		BIT(0)
19 #define XCR_TXOIE		BIT(16)
20 
21 #define IPCC_XMR		0x004
22 #define IPCC_XSCR		0x008
23 #define IPCC_XTOYSR		0x00c
24 
25 #define IPCC_PROC_OFFST		0x010
26 
27 #define IPCC_HWCFGR		0x3f0
28 #define IPCFGR_CHAN_MASK	GENMASK(7, 0)
29 
30 #define IPCC_VER		0x3f4
31 #define VER_MINREV_MASK		GENMASK(3, 0)
32 #define VER_MAJREV_MASK		GENMASK(7, 4)
33 
34 #define RX_BIT_MASK		GENMASK(15, 0)
35 #define RX_BIT_CHAN(chan)	BIT(chan)
36 #define TX_BIT_SHIFT		16
37 #define TX_BIT_MASK		GENMASK(31, 16)
38 #define TX_BIT_CHAN(chan)	BIT(TX_BIT_SHIFT + (chan))
39 
40 #define STM32_MAX_PROCS		2
41 
42 enum {
43 	IPCC_IRQ_RX,
44 	IPCC_IRQ_TX,
45 	IPCC_IRQ_NUM,
46 };
47 
48 struct stm32_ipcc {
49 	struct mbox_controller controller;
50 	void __iomem *reg_base;
51 	void __iomem *reg_proc;
52 	struct clk *clk;
53 	spinlock_t lock; /* protect access to IPCC registers */
54 	int irqs[IPCC_IRQ_NUM];
55 	u32 proc_id;
56 	u32 n_chans;
57 	u32 xcr;
58 	u32 xmr;
59 };
60 
61 static inline void stm32_ipcc_set_bits(spinlock_t *lock, void __iomem *reg,
62 				       u32 mask)
63 {
64 	unsigned long flags;
65 
66 	spin_lock_irqsave(lock, flags);
67 	writel_relaxed(readl_relaxed(reg) | mask, reg);
68 	spin_unlock_irqrestore(lock, flags);
69 }
70 
71 static inline void stm32_ipcc_clr_bits(spinlock_t *lock, void __iomem *reg,
72 				       u32 mask)
73 {
74 	unsigned long flags;
75 
76 	spin_lock_irqsave(lock, flags);
77 	writel_relaxed(readl_relaxed(reg) & ~mask, reg);
78 	spin_unlock_irqrestore(lock, flags);
79 }
80 
81 static irqreturn_t stm32_ipcc_rx_irq(int irq, void *data)
82 {
83 	struct stm32_ipcc *ipcc = data;
84 	struct device *dev = ipcc->controller.dev;
85 	u32 status, mr, tosr, chan;
86 	irqreturn_t ret = IRQ_NONE;
87 	int proc_offset;
88 
89 	/* read 'channel occupied' status from other proc */
90 	proc_offset = ipcc->proc_id ? -IPCC_PROC_OFFST : IPCC_PROC_OFFST;
91 	tosr = readl_relaxed(ipcc->reg_proc + proc_offset + IPCC_XTOYSR);
92 	mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
93 
94 	/* search for unmasked 'channel occupied' */
95 	status = tosr & FIELD_GET(RX_BIT_MASK, ~mr);
96 
97 	for (chan = 0; chan < ipcc->n_chans; chan++) {
98 		if (!(status & (1 << chan)))
99 			continue;
100 
101 		dev_dbg(dev, "%s: chan:%d rx\n", __func__, chan);
102 
103 		mbox_chan_received_data(&ipcc->controller.chans[chan], NULL);
104 
105 		stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
106 				    RX_BIT_CHAN(chan));
107 
108 		ret = IRQ_HANDLED;
109 	}
110 
111 	return ret;
112 }
113 
114 static irqreturn_t stm32_ipcc_tx_irq(int irq, void *data)
115 {
116 	struct stm32_ipcc *ipcc = data;
117 	struct device *dev = ipcc->controller.dev;
118 	u32 status, mr, tosr, chan;
119 	irqreturn_t ret = IRQ_NONE;
120 
121 	tosr = readl_relaxed(ipcc->reg_proc + IPCC_XTOYSR);
122 	mr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
123 
124 	/* search for unmasked 'channel free' */
125 	status = ~tosr & FIELD_GET(TX_BIT_MASK, ~mr);
126 
127 	for (chan = 0; chan < ipcc->n_chans ; chan++) {
128 		if (!(status & (1 << chan)))
129 			continue;
130 
131 		dev_dbg(dev, "%s: chan:%d tx\n", __func__, chan);
132 
133 		/* mask 'tx channel free' interrupt */
134 		stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
135 				    TX_BIT_CHAN(chan));
136 
137 		mbox_chan_txdone(&ipcc->controller.chans[chan], 0);
138 
139 		ret = IRQ_HANDLED;
140 	}
141 
142 	return ret;
143 }
144 
145 static int stm32_ipcc_send_data(struct mbox_chan *link, void *data)
146 {
147 	unsigned int chan = (unsigned int)link->con_priv;
148 	struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
149 					       controller);
150 
151 	dev_dbg(ipcc->controller.dev, "%s: chan:%d\n", __func__, chan);
152 
153 	/* set channel n occupied */
154 	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XSCR,
155 			    TX_BIT_CHAN(chan));
156 
157 	/* unmask 'tx channel free' interrupt */
158 	stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
159 			    TX_BIT_CHAN(chan));
160 
161 	return 0;
162 }
163 
164 static int stm32_ipcc_startup(struct mbox_chan *link)
165 {
166 	unsigned int chan = (unsigned int)link->con_priv;
167 	struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
168 					       controller);
169 	int ret;
170 
171 	ret = clk_prepare_enable(ipcc->clk);
172 	if (ret) {
173 		dev_err(ipcc->controller.dev, "can not enable the clock\n");
174 		return ret;
175 	}
176 
177 	/* unmask 'rx channel occupied' interrupt */
178 	stm32_ipcc_clr_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
179 			    RX_BIT_CHAN(chan));
180 
181 	return 0;
182 }
183 
184 static void stm32_ipcc_shutdown(struct mbox_chan *link)
185 {
186 	unsigned int chan = (unsigned int)link->con_priv;
187 	struct stm32_ipcc *ipcc = container_of(link->mbox, struct stm32_ipcc,
188 					       controller);
189 
190 	/* mask rx/tx interrupt */
191 	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
192 			    RX_BIT_CHAN(chan) | TX_BIT_CHAN(chan));
193 
194 	clk_disable_unprepare(ipcc->clk);
195 }
196 
197 static const struct mbox_chan_ops stm32_ipcc_ops = {
198 	.send_data	= stm32_ipcc_send_data,
199 	.startup	= stm32_ipcc_startup,
200 	.shutdown	= stm32_ipcc_shutdown,
201 };
202 
203 static int stm32_ipcc_probe(struct platform_device *pdev)
204 {
205 	struct device *dev = &pdev->dev;
206 	struct device_node *np = dev->of_node;
207 	struct stm32_ipcc *ipcc;
208 	struct resource *res;
209 	unsigned int i;
210 	int ret;
211 	u32 ip_ver;
212 	static const char * const irq_name[] = {"rx", "tx"};
213 	irq_handler_t irq_thread[] = {stm32_ipcc_rx_irq, stm32_ipcc_tx_irq};
214 
215 	if (!np) {
216 		dev_err(dev, "No DT found\n");
217 		return -ENODEV;
218 	}
219 
220 	ipcc = devm_kzalloc(dev, sizeof(*ipcc), GFP_KERNEL);
221 	if (!ipcc)
222 		return -ENOMEM;
223 
224 	spin_lock_init(&ipcc->lock);
225 
226 	/* proc_id */
227 	if (of_property_read_u32(np, "st,proc-id", &ipcc->proc_id)) {
228 		dev_err(dev, "Missing st,proc-id\n");
229 		return -ENODEV;
230 	}
231 
232 	if (ipcc->proc_id >= STM32_MAX_PROCS) {
233 		dev_err(dev, "Invalid proc_id (%d)\n", ipcc->proc_id);
234 		return -EINVAL;
235 	}
236 
237 	/* regs */
238 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
239 	ipcc->reg_base = devm_ioremap_resource(dev, res);
240 	if (IS_ERR(ipcc->reg_base))
241 		return PTR_ERR(ipcc->reg_base);
242 
243 	ipcc->reg_proc = ipcc->reg_base + ipcc->proc_id * IPCC_PROC_OFFST;
244 
245 	/* clock */
246 	ipcc->clk = devm_clk_get(dev, NULL);
247 	if (IS_ERR(ipcc->clk))
248 		return PTR_ERR(ipcc->clk);
249 
250 	ret = clk_prepare_enable(ipcc->clk);
251 	if (ret) {
252 		dev_err(dev, "can not enable the clock\n");
253 		return ret;
254 	}
255 
256 	/* irq */
257 	for (i = 0; i < IPCC_IRQ_NUM; i++) {
258 		ipcc->irqs[i] = platform_get_irq_byname(pdev, irq_name[i]);
259 		if (ipcc->irqs[i] < 0) {
260 			if (ipcc->irqs[i] != -EPROBE_DEFER)
261 				dev_err(dev, "no IRQ specified %s\n",
262 					irq_name[i]);
263 			ret = ipcc->irqs[i];
264 			goto err_clk;
265 		}
266 
267 		ret = devm_request_threaded_irq(dev, ipcc->irqs[i], NULL,
268 						irq_thread[i], IRQF_ONESHOT,
269 						dev_name(dev), ipcc);
270 		if (ret) {
271 			dev_err(dev, "failed to request irq %d (%d)\n", i, ret);
272 			goto err_clk;
273 		}
274 	}
275 
276 	/* mask and enable rx/tx irq */
277 	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XMR,
278 			    RX_BIT_MASK | TX_BIT_MASK);
279 	stm32_ipcc_set_bits(&ipcc->lock, ipcc->reg_proc + IPCC_XCR,
280 			    XCR_RXOIE | XCR_TXOIE);
281 
282 	/* wakeup */
283 	if (of_property_read_bool(np, "wakeup-source")) {
284 		device_set_wakeup_capable(dev, true);
285 
286 		ret = dev_pm_set_wake_irq(dev, ipcc->irqs[IPCC_IRQ_RX]);
287 		if (ret) {
288 			dev_err(dev, "Failed to set wake up irq\n");
289 			goto err_init_wkp;
290 		}
291 	}
292 
293 	/* mailbox controller */
294 	ipcc->n_chans = readl_relaxed(ipcc->reg_base + IPCC_HWCFGR);
295 	ipcc->n_chans &= IPCFGR_CHAN_MASK;
296 
297 	ipcc->controller.dev = dev;
298 	ipcc->controller.txdone_irq = true;
299 	ipcc->controller.ops = &stm32_ipcc_ops;
300 	ipcc->controller.num_chans = ipcc->n_chans;
301 	ipcc->controller.chans = devm_kcalloc(dev, ipcc->controller.num_chans,
302 					      sizeof(*ipcc->controller.chans),
303 					      GFP_KERNEL);
304 	if (!ipcc->controller.chans) {
305 		ret = -ENOMEM;
306 		goto err_irq_wkp;
307 	}
308 
309 	for (i = 0; i < ipcc->controller.num_chans; i++)
310 		ipcc->controller.chans[i].con_priv = (void *)i;
311 
312 	ret = devm_mbox_controller_register(dev, &ipcc->controller);
313 	if (ret)
314 		goto err_irq_wkp;
315 
316 	platform_set_drvdata(pdev, ipcc);
317 
318 	ip_ver = readl_relaxed(ipcc->reg_base + IPCC_VER);
319 
320 	dev_info(dev, "ipcc rev:%ld.%ld enabled, %d chans, proc %d\n",
321 		 FIELD_GET(VER_MAJREV_MASK, ip_ver),
322 		 FIELD_GET(VER_MINREV_MASK, ip_ver),
323 		 ipcc->controller.num_chans, ipcc->proc_id);
324 
325 	clk_disable_unprepare(ipcc->clk);
326 	return 0;
327 
328 err_irq_wkp:
329 	if (of_property_read_bool(np, "wakeup-source"))
330 		dev_pm_clear_wake_irq(dev);
331 err_init_wkp:
332 	device_set_wakeup_capable(dev, false);
333 err_clk:
334 	clk_disable_unprepare(ipcc->clk);
335 	return ret;
336 }
337 
338 static int stm32_ipcc_remove(struct platform_device *pdev)
339 {
340 	struct device *dev = &pdev->dev;
341 
342 	if (of_property_read_bool(dev->of_node, "wakeup-source"))
343 		dev_pm_clear_wake_irq(&pdev->dev);
344 
345 	device_set_wakeup_capable(dev, false);
346 
347 	return 0;
348 }
349 
350 #ifdef CONFIG_PM_SLEEP
351 static int stm32_ipcc_suspend(struct device *dev)
352 {
353 	struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
354 
355 	ipcc->xmr = readl_relaxed(ipcc->reg_proc + IPCC_XMR);
356 	ipcc->xcr = readl_relaxed(ipcc->reg_proc + IPCC_XCR);
357 
358 	return 0;
359 }
360 
361 static int stm32_ipcc_resume(struct device *dev)
362 {
363 	struct stm32_ipcc *ipcc = dev_get_drvdata(dev);
364 
365 	writel_relaxed(ipcc->xmr, ipcc->reg_proc + IPCC_XMR);
366 	writel_relaxed(ipcc->xcr, ipcc->reg_proc + IPCC_XCR);
367 
368 	return 0;
369 }
370 #endif
371 
372 static SIMPLE_DEV_PM_OPS(stm32_ipcc_pm_ops,
373 			 stm32_ipcc_suspend, stm32_ipcc_resume);
374 
375 static const struct of_device_id stm32_ipcc_of_match[] = {
376 	{ .compatible = "st,stm32mp1-ipcc" },
377 	{},
378 };
379 MODULE_DEVICE_TABLE(of, stm32_ipcc_of_match);
380 
381 static struct platform_driver stm32_ipcc_driver = {
382 	.driver = {
383 		.name = "stm32-ipcc",
384 		.pm = &stm32_ipcc_pm_ops,
385 		.of_match_table = stm32_ipcc_of_match,
386 	},
387 	.probe		= stm32_ipcc_probe,
388 	.remove		= stm32_ipcc_remove,
389 };
390 
391 module_platform_driver(stm32_ipcc_driver);
392 
393 MODULE_AUTHOR("Ludovic Barre <ludovic.barre@st.com>");
394 MODULE_AUTHOR("Fabien Dessenne <fabien.dessenne@st.com>");
395 MODULE_DESCRIPTION("STM32 IPCC driver");
396 MODULE_LICENSE("GPL v2");
397