1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * APM X-Gene SLIMpro MailBox Driver
4 *
5 * Copyright (c) 2015, Applied Micro Circuits Corporation
6 * Author: Feng Kan fkan@apm.com
7 */
8#include <linux/acpi.h>
9#include <linux/delay.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/of.h>
15#include <linux/platform_device.h>
16#include <linux/spinlock.h>
17
18#define MBOX_CON_NAME			"slimpro-mbox"
19#define MBOX_REG_SET_OFFSET		0x1000
20#define MBOX_CNT			8
21#define MBOX_STATUS_AVAIL_MASK		BIT(16)
22#define MBOX_STATUS_ACK_MASK		BIT(0)
23
24/* Configuration and Status Registers */
25#define REG_DB_IN		0x00
26#define REG_DB_DIN0		0x04
27#define REG_DB_DIN1		0x08
28#define REG_DB_OUT		0x10
29#define REG_DB_DOUT0		0x14
30#define REG_DB_DOUT1		0x18
31#define REG_DB_STAT		0x20
32#define REG_DB_STATMASK		0x24
33
34/**
35 * X-Gene SlimPRO mailbox channel information
36 *
37 * @dev:	Device to which it is attached
38 * @chan:	Pointer to mailbox communication channel
39 * @reg:	Base address to access channel registers
40 * @irq:	Interrupt number of the channel
41 * @rx_msg:	Received message storage
42 */
43struct slimpro_mbox_chan {
44	struct device		*dev;
45	struct mbox_chan	*chan;
46	void __iomem		*reg;
47	int			irq;
48	u32			rx_msg[3];
49};
50
51/**
52 * X-Gene SlimPRO Mailbox controller data
53 *
54 * X-Gene SlimPRO Mailbox controller has 8 communication channels.
55 * Each channel has a separate IRQ number assigned to it.
56 *
57 * @mb_ctrl:	Representation of the communication channel controller
58 * @mc:		Array of SlimPRO mailbox channels of the controller
59 * @chans:	Array of mailbox communication channels
60 *
61 */
62struct slimpro_mbox {
63	struct mbox_controller		mb_ctrl;
64	struct slimpro_mbox_chan	mc[MBOX_CNT];
65	struct mbox_chan		chans[MBOX_CNT];
66};
67
68static void mb_chan_send_msg(struct slimpro_mbox_chan *mb_chan, u32 *msg)
69{
70	writel(msg[1], mb_chan->reg + REG_DB_DOUT0);
71	writel(msg[2], mb_chan->reg + REG_DB_DOUT1);
72	writel(msg[0], mb_chan->reg + REG_DB_OUT);
73}
74
75static void mb_chan_recv_msg(struct slimpro_mbox_chan *mb_chan)
76{
77	mb_chan->rx_msg[1] = readl(mb_chan->reg + REG_DB_DIN0);
78	mb_chan->rx_msg[2] = readl(mb_chan->reg + REG_DB_DIN1);
79	mb_chan->rx_msg[0] = readl(mb_chan->reg + REG_DB_IN);
80}
81
82static int mb_chan_status_ack(struct slimpro_mbox_chan *mb_chan)
83{
84	u32 val = readl(mb_chan->reg + REG_DB_STAT);
85
86	if (val & MBOX_STATUS_ACK_MASK) {
87		writel(MBOX_STATUS_ACK_MASK, mb_chan->reg + REG_DB_STAT);
88		return 1;
89	}
90	return 0;
91}
92
93static int mb_chan_status_avail(struct slimpro_mbox_chan *mb_chan)
94{
95	u32 val = readl(mb_chan->reg + REG_DB_STAT);
96
97	if (val & MBOX_STATUS_AVAIL_MASK) {
98		mb_chan_recv_msg(mb_chan);
99		writel(MBOX_STATUS_AVAIL_MASK, mb_chan->reg + REG_DB_STAT);
100		return 1;
101	}
102	return 0;
103}
104
105static irqreturn_t slimpro_mbox_irq(int irq, void *id)
106{
107	struct slimpro_mbox_chan *mb_chan = id;
108
109	if (mb_chan_status_ack(mb_chan))
110		mbox_chan_txdone(mb_chan->chan, 0);
111
112	if (mb_chan_status_avail(mb_chan))
113		mbox_chan_received_data(mb_chan->chan, mb_chan->rx_msg);
114
115	return IRQ_HANDLED;
116}
117
118static int slimpro_mbox_send_data(struct mbox_chan *chan, void *msg)
119{
120	struct slimpro_mbox_chan *mb_chan = chan->con_priv;
121
122	mb_chan_send_msg(mb_chan, msg);
123	return 0;
124}
125
126static int slimpro_mbox_startup(struct mbox_chan *chan)
127{
128	struct slimpro_mbox_chan *mb_chan = chan->con_priv;
129	int rc;
130	u32 val;
131
132	rc = devm_request_irq(mb_chan->dev, mb_chan->irq, slimpro_mbox_irq, 0,
133			      MBOX_CON_NAME, mb_chan);
134	if (unlikely(rc)) {
135		dev_err(mb_chan->dev, "failed to register mailbox interrupt %d\n",
136			mb_chan->irq);
137		return rc;
138	}
139
140	/* Enable HW interrupt */
141	writel(MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK,
142	       mb_chan->reg + REG_DB_STAT);
143	/* Unmask doorbell status interrupt */
144	val = readl(mb_chan->reg + REG_DB_STATMASK);
145	val &= ~(MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK);
146	writel(val, mb_chan->reg + REG_DB_STATMASK);
147
148	return 0;
149}
150
151static void slimpro_mbox_shutdown(struct mbox_chan *chan)
152{
153	struct slimpro_mbox_chan *mb_chan = chan->con_priv;
154	u32 val;
155
156	/* Mask doorbell status interrupt */
157	val = readl(mb_chan->reg + REG_DB_STATMASK);
158	val |= (MBOX_STATUS_ACK_MASK | MBOX_STATUS_AVAIL_MASK);
159	writel(val, mb_chan->reg + REG_DB_STATMASK);
160
161	devm_free_irq(mb_chan->dev, mb_chan->irq, mb_chan);
162}
163
164static const struct mbox_chan_ops slimpro_mbox_ops = {
165	.send_data = slimpro_mbox_send_data,
166	.startup = slimpro_mbox_startup,
167	.shutdown = slimpro_mbox_shutdown,
168};
169
170static int slimpro_mbox_probe(struct platform_device *pdev)
171{
172	struct slimpro_mbox *ctx;
173	void __iomem *mb_base;
174	int rc;
175	int i;
176
177	ctx = devm_kzalloc(&pdev->dev, sizeof(struct slimpro_mbox), GFP_KERNEL);
178	if (!ctx)
179		return -ENOMEM;
180
181	platform_set_drvdata(pdev, ctx);
182
183	mb_base = devm_platform_ioremap_resource(pdev, 0);
184	if (IS_ERR(mb_base))
185		return PTR_ERR(mb_base);
186
187	/* Setup mailbox links */
188	for (i = 0; i < MBOX_CNT; i++) {
189		ctx->mc[i].irq = platform_get_irq(pdev, i);
190		if (ctx->mc[i].irq < 0) {
191			if (i == 0) {
192				dev_err(&pdev->dev, "no available IRQ\n");
193				return -EINVAL;
194			}
195			dev_info(&pdev->dev, "no IRQ for channel %d\n", i);
196			break;
197		}
198
199		ctx->mc[i].dev = &pdev->dev;
200		ctx->mc[i].reg = mb_base + i * MBOX_REG_SET_OFFSET;
201		ctx->mc[i].chan = &ctx->chans[i];
202		ctx->chans[i].con_priv = &ctx->mc[i];
203	}
204
205	/* Setup mailbox controller */
206	ctx->mb_ctrl.dev = &pdev->dev;
207	ctx->mb_ctrl.chans = ctx->chans;
208	ctx->mb_ctrl.txdone_irq = true;
209	ctx->mb_ctrl.ops = &slimpro_mbox_ops;
210	ctx->mb_ctrl.num_chans = i;
211
212	rc = devm_mbox_controller_register(&pdev->dev, &ctx->mb_ctrl);
213	if (rc) {
214		dev_err(&pdev->dev,
215			"APM X-Gene SLIMpro MailBox register failed:%d\n", rc);
216		return rc;
217	}
218
219	dev_info(&pdev->dev, "APM X-Gene SLIMpro MailBox registered\n");
220	return 0;
221}
222
223static const struct of_device_id slimpro_of_match[] = {
224	{.compatible = "apm,xgene-slimpro-mbox" },
225	{ },
226};
227MODULE_DEVICE_TABLE(of, slimpro_of_match);
228
229#ifdef CONFIG_ACPI
230static const struct acpi_device_id slimpro_acpi_ids[] = {
231	{"APMC0D01", 0},
232	{}
233};
234MODULE_DEVICE_TABLE(acpi, slimpro_acpi_ids);
235#endif
236
237static struct platform_driver slimpro_mbox_driver = {
238	.probe	= slimpro_mbox_probe,
239	.driver	= {
240		.name = "xgene-slimpro-mbox",
241		.of_match_table = of_match_ptr(slimpro_of_match),
242		.acpi_match_table = ACPI_PTR(slimpro_acpi_ids)
243	},
244};
245
246static int __init slimpro_mbox_init(void)
247{
248	return platform_driver_register(&slimpro_mbox_driver);
249}
250
251static void __exit slimpro_mbox_exit(void)
252{
253	platform_driver_unregister(&slimpro_mbox_driver);
254}
255
256subsys_initcall(slimpro_mbox_init);
257module_exit(slimpro_mbox_exit);
258
259MODULE_DESCRIPTION("APM X-Gene SLIMpro Mailbox Driver");
260MODULE_LICENSE("GPL");
261