1/*
  2 * Copyright (c) 2015, Fuzhou Rockchip Electronics Co., Ltd
  3 *
  4 * This program is free software; you can redistribute it and/or modify it
  5 * under the terms and conditions of the GNU General Public License,
  6 * version 2, as published by the Free Software Foundation.
  7 *
  8 * This program is distributed in the hope it will be useful, but WITHOUT
  9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 11 * more details.
 12 */
 13
 14#include <linux/clk.h>
 15#include <linux/interrupt.h>
 16#include <linux/io.h>
 17#include <linux/kernel.h>
 18#include <linux/mailbox_controller.h>
 19#include <linux/module.h>
 20#include <linux/of_device.h>
 21#include <linux/platform_device.h>
 22
 23#define MAILBOX_A2B_INTEN		0x00
 24#define MAILBOX_A2B_STATUS		0x04
 25#define MAILBOX_A2B_CMD(x)		(0x08 + (x) * 8)
 26#define MAILBOX_A2B_DAT(x)		(0x0c + (x) * 8)
 27
 28#define MAILBOX_B2A_INTEN		0x28
 29#define MAILBOX_B2A_STATUS		0x2C
 30#define MAILBOX_B2A_CMD(x)		(0x30 + (x) * 8)
 31#define MAILBOX_B2A_DAT(x)		(0x34 + (x) * 8)
 32
 33struct rockchip_mbox_msg {
 34	u32 cmd;
 35	int rx_size;
 36};
 37
 38struct rockchip_mbox_data {
 39	int num_chans;
 40};
 41
 42struct rockchip_mbox_chan {
 43	int idx;
 44	int irq;
 45	struct rockchip_mbox_msg *msg;
 46	struct rockchip_mbox *mb;
 47};
 48
 49struct rockchip_mbox {
 50	struct mbox_controller mbox;
 51	struct clk *pclk;
 52	void __iomem *mbox_base;
 53
 54	/* The maximum size of buf for each channel */
 55	u32 buf_size;
 56
 57	struct rockchip_mbox_chan *chans;
 58};
 59
 60static int rockchip_mbox_send_data(struct mbox_chan *chan, void *data)
 61{
 62	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
 63	struct rockchip_mbox_msg *msg = data;
 64	struct rockchip_mbox_chan *chans = mb->chans;
 65
 66	if (!msg)
 67		return -EINVAL;
 68
 69	if (msg->rx_size > mb->buf_size) {
 70		dev_err(mb->mbox.dev, "Transmit size over buf size(%d)\n",
 71			mb->buf_size);
 72		return -EINVAL;
 73	}
 74
 75	dev_dbg(mb->mbox.dev, "Chan[%d]: A2B message, cmd 0x%08x\n",
 76		chans->idx, msg->cmd);
 77
 78	mb->chans[chans->idx].msg = msg;
 79
 80	writel_relaxed(msg->cmd, mb->mbox_base + MAILBOX_A2B_CMD(chans->idx));
 81	writel_relaxed(msg->rx_size, mb->mbox_base +
 82		       MAILBOX_A2B_DAT(chans->idx));
 83
 84	return 0;
 85}
 86
 87static int rockchip_mbox_startup(struct mbox_chan *chan)
 88{
 89	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
 90
 91	/* Enable all B2A interrupts */
 92	writel_relaxed((1 << mb->mbox.num_chans) - 1,
 93		       mb->mbox_base + MAILBOX_B2A_INTEN);
 94
 95	return 0;
 96}
 97
 98static void rockchip_mbox_shutdown(struct mbox_chan *chan)
 99{
100	struct rockchip_mbox *mb = dev_get_drvdata(chan->mbox->dev);
101	struct rockchip_mbox_chan *chans = mb->chans;
102
103	/* Disable all B2A interrupts */
104	writel_relaxed(0, mb->mbox_base + MAILBOX_B2A_INTEN);
105
106	mb->chans[chans->idx].msg = NULL;
107}
108
109static const struct mbox_chan_ops rockchip_mbox_chan_ops = {
110	.send_data	= rockchip_mbox_send_data,
111	.startup	= rockchip_mbox_startup,
112	.shutdown	= rockchip_mbox_shutdown,
113};
114
115static irqreturn_t rockchip_mbox_irq(int irq, void *dev_id)
116{
117	int idx;
118	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
119	u32 status = readl_relaxed(mb->mbox_base + MAILBOX_B2A_STATUS);
120
121	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
122		if ((status & (1 << idx)) && (irq == mb->chans[idx].irq)) {
123			/* Clear mbox interrupt */
124			writel_relaxed(1 << idx,
125				       mb->mbox_base + MAILBOX_B2A_STATUS);
126			return IRQ_WAKE_THREAD;
127		}
128	}
129
130	return IRQ_NONE;
131}
132
133static irqreturn_t rockchip_mbox_isr(int irq, void *dev_id)
134{
135	int idx;
136	struct rockchip_mbox_msg *msg = NULL;
137	struct rockchip_mbox *mb = (struct rockchip_mbox *)dev_id;
138
139	for (idx = 0; idx < mb->mbox.num_chans; idx++) {
140		if (irq != mb->chans[idx].irq)
141			continue;
142
143		msg = mb->chans[idx].msg;
144		if (!msg) {
145			dev_err(mb->mbox.dev,
146				"Chan[%d]: B2A message is NULL\n", idx);
147			break; /* spurious */
148		}
149
150		mbox_chan_received_data(&mb->mbox.chans[idx], msg);
151		mb->chans[idx].msg = NULL;
152
153		dev_dbg(mb->mbox.dev, "Chan[%d]: B2A message, cmd 0x%08x\n",
154			idx, msg->cmd);
155
156		break;
157	}
158
159	return IRQ_HANDLED;
160}
161
162static const struct rockchip_mbox_data rk3368_drv_data = {
163	.num_chans = 4,
164};
165
166static const struct of_device_id rockchip_mbox_of_match[] = {
167	{ .compatible = "rockchip,rk3368-mailbox", .data = &rk3368_drv_data},
168	{ },
169};
170MODULE_DEVICE_TABLE(of, rockchp_mbox_of_match);
171
172static int rockchip_mbox_probe(struct platform_device *pdev)
173{
174	struct rockchip_mbox *mb;
175	const struct of_device_id *match;
176	const struct rockchip_mbox_data *drv_data;
177	struct resource *res;
178	int ret, irq, i;
179
180	if (!pdev->dev.of_node)
181		return -ENODEV;
182
183	match = of_match_node(rockchip_mbox_of_match, pdev->dev.of_node);
184	drv_data = (const struct rockchip_mbox_data *)match->data;
185
186	mb = devm_kzalloc(&pdev->dev, sizeof(*mb), GFP_KERNEL);
187	if (!mb)
188		return -ENOMEM;
189
190	mb->chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
191				 sizeof(*mb->chans), GFP_KERNEL);
192	if (!mb->chans)
193		return -ENOMEM;
194
195	mb->mbox.chans = devm_kcalloc(&pdev->dev, drv_data->num_chans,
196				      sizeof(*mb->mbox.chans), GFP_KERNEL);
197	if (!mb->mbox.chans)
198		return -ENOMEM;
199
200	platform_set_drvdata(pdev, mb);
201
202	mb->mbox.dev = &pdev->dev;
203	mb->mbox.num_chans = drv_data->num_chans;
204	mb->mbox.ops = &rockchip_mbox_chan_ops;
205	mb->mbox.txdone_irq = true;
206
207	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
208	if (!res)
209		return -ENODEV;
210
211	mb->mbox_base = devm_ioremap_resource(&pdev->dev, res);
212	if (IS_ERR(mb->mbox_base))
213		return PTR_ERR(mb->mbox_base);
214
215	/* Each channel has two buffers for A2B and B2A */
216	mb->buf_size = (size_t)resource_size(res) / (drv_data->num_chans * 2);
217
218	mb->pclk = devm_clk_get(&pdev->dev, "pclk_mailbox");
219	if (IS_ERR(mb->pclk)) {
220		ret = PTR_ERR(mb->pclk);
221		dev_err(&pdev->dev, "failed to get pclk_mailbox clock: %d\n",
222			ret);
223		return ret;
224	}
225
226	ret = clk_prepare_enable(mb->pclk);
227	if (ret) {
228		dev_err(&pdev->dev, "failed to enable pclk: %d\n", ret);
229		return ret;
230	}
231
232	for (i = 0; i < mb->mbox.num_chans; i++) {
233		irq = platform_get_irq(pdev, i);
234		if (irq < 0)
235			return irq;
236
237		ret = devm_request_threaded_irq(&pdev->dev, irq,
238						rockchip_mbox_irq,
239						rockchip_mbox_isr, IRQF_ONESHOT,
240						dev_name(&pdev->dev), mb);
241		if (ret < 0)
242			return ret;
243
244		mb->chans[i].idx = i;
245		mb->chans[i].irq = irq;
246		mb->chans[i].mb = mb;
247		mb->chans[i].msg = NULL;
248	}
249
250	ret = mbox_controller_register(&mb->mbox);
251	if (ret < 0)
252		dev_err(&pdev->dev, "Failed to register mailbox: %d\n", ret);
253
254	return ret;
255}
256
257static int rockchip_mbox_remove(struct platform_device *pdev)
258{
259	struct rockchip_mbox *mb = platform_get_drvdata(pdev);
260
261	if (!mb)
262		return -EINVAL;
263
264	mbox_controller_unregister(&mb->mbox);
265
266	return 0;
267}
268
269static struct platform_driver rockchip_mbox_driver = {
270	.probe	= rockchip_mbox_probe,
271	.remove	= rockchip_mbox_remove,
272	.driver = {
273		.name = "rockchip-mailbox",
274		.of_match_table = of_match_ptr(rockchip_mbox_of_match),
275	},
276};
277
278module_platform_driver(rockchip_mbox_driver);
279
280MODULE_LICENSE("GPL v2");
281MODULE_DESCRIPTION("Rockchip mailbox: communicate between CPU cores and MCU");
282MODULE_AUTHOR("Addy Ke <addy.ke@rock-chips.com>");
283MODULE_AUTHOR("Caesar Wang <wxt@rock-chips.com>");