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  1// SPDX-License-Identifier: GPL-2.0
  2// Copyright (c) 2017-2018 Hisilicon Limited.
  3// Copyright (c) 2017-2018 Linaro Limited.
  4
  5#include <linux/bitops.h>
  6#include <linux/delay.h>
  7#include <linux/device.h>
  8#include <linux/err.h>
  9#include <linux/interrupt.h>
 10#include <linux/io.h>
 11#include <linux/iopoll.h>
 12#include <linux/mailbox_controller.h>
 13#include <linux/module.h>
 14#include <linux/platform_device.h>
 15#include <linux/slab.h>
 16
 17#include "mailbox.h"
 18
 19#define MBOX_CHAN_MAX			32
 20
 21#define MBOX_RX				0x0
 22#define MBOX_TX				0x1
 23
 24#define MBOX_BASE(mbox, ch)		((mbox)->base + ((ch) * 0x40))
 25#define MBOX_SRC_REG			0x00
 26#define MBOX_DST_REG			0x04
 27#define MBOX_DCLR_REG			0x08
 28#define MBOX_DSTAT_REG			0x0c
 29#define MBOX_MODE_REG			0x10
 30#define MBOX_IMASK_REG			0x14
 31#define MBOX_ICLR_REG			0x18
 32#define MBOX_SEND_REG			0x1c
 33#define MBOX_DATA_REG			0x20
 34
 35#define MBOX_IPC_LOCK_REG		0xa00
 36#define MBOX_IPC_UNLOCK			0x1acce551
 37
 38#define MBOX_AUTOMATIC_ACK		1
 39
 40#define MBOX_STATE_IDLE			BIT(4)
 41#define MBOX_STATE_ACK			BIT(7)
 42
 43#define MBOX_MSG_LEN			8
 44
 45/**
 46 * Hi3660 mailbox channel information
 47 *
 48 * A channel can be used for TX or RX, it can trigger remote
 49 * processor interrupt to notify remote processor and can receive
 50 * interrupt if has incoming message.
 51 *
 52 * @dst_irq:	Interrupt vector for remote processor
 53 * @ack_irq:	Interrupt vector for local processor
 54 */
 55struct hi3660_chan_info {
 56	unsigned int dst_irq;
 57	unsigned int ack_irq;
 58};
 59
 60/**
 61 * Hi3660 mailbox controller data
 62 *
 63 * Mailbox controller includes 32 channels and can allocate
 64 * channel for message transferring.
 65 *
 66 * @dev:	Device to which it is attached
 67 * @base:	Base address of the register mapping region
 68 * @chan:	Representation of channels in mailbox controller
 69 * @mchan:	Representation of channel info
 70 * @controller:	Representation of a communication channel controller
 71 */
 72struct hi3660_mbox {
 73	struct device *dev;
 74	void __iomem *base;
 75	struct mbox_chan chan[MBOX_CHAN_MAX];
 76	struct hi3660_chan_info mchan[MBOX_CHAN_MAX];
 77	struct mbox_controller controller;
 78};
 79
 80static struct hi3660_mbox *to_hi3660_mbox(struct mbox_controller *mbox)
 81{
 82	return container_of(mbox, struct hi3660_mbox, controller);
 83}
 84
 85static int hi3660_mbox_check_state(struct mbox_chan *chan)
 86{
 87	unsigned long ch = (unsigned long)chan->con_priv;
 88	struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
 89	struct hi3660_chan_info *mchan = &mbox->mchan[ch];
 90	void __iomem *base = MBOX_BASE(mbox, ch);
 91	unsigned long val;
 92	unsigned int ret;
 93
 94	/* Mailbox is idle so directly bail out */
 95	if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE)
 96		return 0;
 97
 98	/* Wait for acknowledge from remote */
 99	ret = readx_poll_timeout_atomic(readl, base + MBOX_MODE_REG,
100			val, (val & MBOX_STATE_ACK), 1000, 300000);
101	if (ret) {
102		dev_err(mbox->dev, "%s: timeout for receiving ack\n", __func__);
103		return ret;
104	}
105
106	/* Ensure channel is released */
107	writel(0xffffffff, base + MBOX_IMASK_REG);
108	writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
109	return 0;
110}
111
112static int hi3660_mbox_unlock(struct mbox_chan *chan)
113{
114	struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
115	unsigned int val, retry = 3;
116
117	do {
118		writel(MBOX_IPC_UNLOCK, mbox->base + MBOX_IPC_LOCK_REG);
119
120		val = readl(mbox->base + MBOX_IPC_LOCK_REG);
121		if (!val)
122			break;
123
124		udelay(10);
125	} while (retry--);
126
127	if (val)
128		dev_err(mbox->dev, "%s: failed to unlock mailbox\n", __func__);
129
130	return (!val) ? 0 : -ETIMEDOUT;
131}
132
133static int hi3660_mbox_acquire_channel(struct mbox_chan *chan)
134{
135	unsigned long ch = (unsigned long)chan->con_priv;
136	struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
137	struct hi3660_chan_info *mchan = &mbox->mchan[ch];
138	void __iomem *base = MBOX_BASE(mbox, ch);
139	unsigned int val, retry;
140
141	for (retry = 10; retry; retry--) {
142		/* Check if channel is in idle state */
143		if (readl(base + MBOX_MODE_REG) & MBOX_STATE_IDLE) {
144			writel(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
145
146			/* Check ack bit has been set successfully */
147			val = readl(base + MBOX_SRC_REG);
148			if (val & BIT(mchan->ack_irq))
149				break;
150		}
151	}
152
153	if (!retry)
154		dev_err(mbox->dev, "%s: failed to acquire channel\n", __func__);
155
156	return retry ? 0 : -ETIMEDOUT;
157}
158
159static int hi3660_mbox_startup(struct mbox_chan *chan)
160{
161	int ret;
162
163	ret = hi3660_mbox_check_state(chan);
164	if (ret)
165		return ret;
166
167	ret = hi3660_mbox_unlock(chan);
168	if (ret)
169		return ret;
170
171	ret = hi3660_mbox_acquire_channel(chan);
172	if (ret)
173		return ret;
174
175	return 0;
176}
177
178static int hi3660_mbox_send_data(struct mbox_chan *chan, void *msg)
179{
180	unsigned long ch = (unsigned long)chan->con_priv;
181	struct hi3660_mbox *mbox = to_hi3660_mbox(chan->mbox);
182	struct hi3660_chan_info *mchan = &mbox->mchan[ch];
183	void __iomem *base = MBOX_BASE(mbox, ch);
184	u32 *buf = msg;
185	unsigned int i;
186
187	/* Ensure channel is released */
188	writel_relaxed(0xffffffff, base + MBOX_IMASK_REG);
189	writel_relaxed(BIT(mchan->ack_irq), base + MBOX_SRC_REG);
190
191	/* Clear mask for destination interrupt */
192	writel_relaxed(~BIT(mchan->dst_irq), base + MBOX_IMASK_REG);
193
194	/* Config destination for interrupt vector */
195	writel_relaxed(BIT(mchan->dst_irq), base + MBOX_DST_REG);
196
197	/* Automatic acknowledge mode */
198	writel_relaxed(MBOX_AUTOMATIC_ACK, base + MBOX_MODE_REG);
199
200	/* Fill message data */
201	for (i = 0; i < MBOX_MSG_LEN; i++)
202		writel_relaxed(buf[i], base + MBOX_DATA_REG + i * 4);
203
204	/* Trigger data transferring */
205	writel(BIT(mchan->ack_irq), base + MBOX_SEND_REG);
206	return 0;
207}
208
209static struct mbox_chan_ops hi3660_mbox_ops = {
210	.startup	= hi3660_mbox_startup,
211	.send_data	= hi3660_mbox_send_data,
212};
213
214static struct mbox_chan *hi3660_mbox_xlate(struct mbox_controller *controller,
215					   const struct of_phandle_args *spec)
216{
217	struct hi3660_mbox *mbox = to_hi3660_mbox(controller);
218	struct hi3660_chan_info *mchan;
219	unsigned int ch = spec->args[0];
220
221	if (ch >= MBOX_CHAN_MAX) {
222		dev_err(mbox->dev, "Invalid channel idx %d\n", ch);
223		return ERR_PTR(-EINVAL);
224	}
225
226	mchan = &mbox->mchan[ch];
227	mchan->dst_irq = spec->args[1];
228	mchan->ack_irq = spec->args[2];
229
230	return &mbox->chan[ch];
231}
232
233static const struct of_device_id hi3660_mbox_of_match[] = {
234	{ .compatible = "hisilicon,hi3660-mbox", },
235	{},
236};
237
238MODULE_DEVICE_TABLE(of, hi3660_mbox_of_match);
239
240static int hi3660_mbox_probe(struct platform_device *pdev)
241{
242	struct device *dev = &pdev->dev;
243	struct hi3660_mbox *mbox;
244	struct mbox_chan *chan;
245	struct resource *res;
246	unsigned long ch;
247	int err;
248
249	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
250	if (!mbox)
251		return -ENOMEM;
252
253	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
254	mbox->base = devm_ioremap_resource(dev, res);
255	if (IS_ERR(mbox->base))
256		return PTR_ERR(mbox->base);
257
258	mbox->dev = dev;
259	mbox->controller.dev = dev;
260	mbox->controller.chans = mbox->chan;
261	mbox->controller.num_chans = MBOX_CHAN_MAX;
262	mbox->controller.ops = &hi3660_mbox_ops;
263	mbox->controller.of_xlate = hi3660_mbox_xlate;
264
265	/* Initialize mailbox channel data */
266	chan = mbox->chan;
267	for (ch = 0; ch < MBOX_CHAN_MAX; ch++)
268		chan[ch].con_priv = (void *)ch;
269
270	err = mbox_controller_register(&mbox->controller);
271	if (err) {
272		dev_err(dev, "Failed to register mailbox %d\n", err);
273		return err;
274	}
275
276	platform_set_drvdata(pdev, mbox);
277	dev_info(dev, "Mailbox enabled\n");
278	return 0;
279}
280
281static int hi3660_mbox_remove(struct platform_device *pdev)
282{
283	struct hi3660_mbox *mbox = platform_get_drvdata(pdev);
284
285	mbox_controller_unregister(&mbox->controller);
286	return 0;
287}
288
289static struct platform_driver hi3660_mbox_driver = {
290	.probe  = hi3660_mbox_probe,
291	.remove = hi3660_mbox_remove,
292	.driver = {
293		.name = "hi3660-mbox",
294		.of_match_table = hi3660_mbox_of_match,
295	},
296};
297
298static int __init hi3660_mbox_init(void)
299{
300	return platform_driver_register(&hi3660_mbox_driver);
301}
302core_initcall(hi3660_mbox_init);
303
304static void __exit hi3660_mbox_exit(void)
305{
306	platform_driver_unregister(&hi3660_mbox_driver);
307}
308module_exit(hi3660_mbox_exit);
309
310MODULE_LICENSE("GPL");
311MODULE_DESCRIPTION("Hisilicon Hi3660 Mailbox Controller");
312MODULE_AUTHOR("Leo Yan <leo.yan@linaro.org>");