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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Microchip PolarFire SoC (MPFS) system controller/mailbox controller driver
4 *
5 * Copyright (c) 2020-2022 Microchip Corporation. All rights reserved.
6 *
7 * Author: Conor Dooley <conor.dooley@microchip.com>
8 *
9 */
10
11#include <linux/io.h>
12#include <linux/err.h>
13#include <linux/init.h>
14#include <linux/module.h>
15#include <linux/kernel.h>
16#include <linux/interrupt.h>
17#include <linux/platform_device.h>
18#include <linux/mailbox_controller.h>
19#include <soc/microchip/mpfs.h>
20
21#define SERVICES_CR_OFFSET 0x50u
22#define SERVICES_SR_OFFSET 0x54u
23#define MAILBOX_REG_OFFSET 0x800u
24#define MSS_SYS_MAILBOX_DATA_OFFSET 0u
25#define SCB_MASK_WIDTH 16u
26
27/* SCBCTRL service control register */
28
29#define SCB_CTRL_REQ (0)
30#define SCB_CTRL_REQ_MASK BIT(SCB_CTRL_REQ)
31
32#define SCB_CTRL_BUSY (1)
33#define SCB_CTRL_BUSY_MASK BIT(SCB_CTRL_BUSY)
34
35#define SCB_CTRL_ABORT (2)
36#define SCB_CTRL_ABORT_MASK BIT(SCB_CTRL_ABORT)
37
38#define SCB_CTRL_NOTIFY (3)
39#define SCB_CTRL_NOTIFY_MASK BIT(SCB_CTRL_NOTIFY)
40
41#define SCB_CTRL_POS (16)
42#define SCB_CTRL_MASK GENMASK_ULL(SCB_CTRL_POS + SCB_MASK_WIDTH, SCB_CTRL_POS)
43
44/* SCBCTRL service status register */
45
46#define SCB_STATUS_REQ (0)
47#define SCB_STATUS_REQ_MASK BIT(SCB_STATUS_REQ)
48
49#define SCB_STATUS_BUSY (1)
50#define SCB_STATUS_BUSY_MASK BIT(SCB_STATUS_BUSY)
51
52#define SCB_STATUS_ABORT (2)
53#define SCB_STATUS_ABORT_MASK BIT(SCB_STATUS_ABORT)
54
55#define SCB_STATUS_NOTIFY (3)
56#define SCB_STATUS_NOTIFY_MASK BIT(SCB_STATUS_NOTIFY)
57
58#define SCB_STATUS_POS (16)
59#define SCB_STATUS_MASK GENMASK(SCB_STATUS_POS + SCB_MASK_WIDTH - 1, SCB_STATUS_POS)
60
61struct mpfs_mbox {
62 struct mbox_controller controller;
63 struct device *dev;
64 int irq;
65 void __iomem *ctrl_base;
66 void __iomem *mbox_base;
67 void __iomem *int_reg;
68 struct mbox_chan chans[1];
69 struct mpfs_mss_response *response;
70 u16 resp_offset;
71};
72
73static bool mpfs_mbox_busy(struct mpfs_mbox *mbox)
74{
75 u32 status;
76
77 status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
78
79 return status & SCB_STATUS_BUSY_MASK;
80}
81
82static int mpfs_mbox_send_data(struct mbox_chan *chan, void *data)
83{
84 struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
85 struct mpfs_mss_msg *msg = data;
86 u32 tx_trigger;
87 u16 opt_sel;
88 u32 val = 0u;
89
90 mbox->response = msg->response;
91 mbox->resp_offset = msg->resp_offset;
92
93 if (mpfs_mbox_busy(mbox))
94 return -EBUSY;
95
96 if (msg->cmd_data_size) {
97 u32 index;
98 u8 extra_bits = msg->cmd_data_size & 3;
99 u32 *word_buf = (u32 *)msg->cmd_data;
100
101 for (index = 0; index < (msg->cmd_data_size / 4); index++)
102 writel_relaxed(word_buf[index],
103 mbox->mbox_base + msg->mbox_offset + index * 0x4);
104 if (extra_bits) {
105 u8 i;
106 u8 byte_off = ALIGN_DOWN(msg->cmd_data_size, 4);
107 u8 *byte_buf = msg->cmd_data + byte_off;
108
109 val = readl_relaxed(mbox->mbox_base + msg->mbox_offset + index * 0x4);
110
111 for (i = 0u; i < extra_bits; i++) {
112 val &= ~(0xffu << (i * 8u));
113 val |= (byte_buf[i] << (i * 8u));
114 }
115
116 writel_relaxed(val, mbox->mbox_base + msg->mbox_offset + index * 0x4);
117 }
118 }
119
120 opt_sel = ((msg->mbox_offset << 7u) | (msg->cmd_opcode & 0x7fu));
121 tx_trigger = (opt_sel << SCB_CTRL_POS) & SCB_CTRL_MASK;
122 tx_trigger |= SCB_CTRL_REQ_MASK | SCB_STATUS_NOTIFY_MASK;
123 writel_relaxed(tx_trigger, mbox->ctrl_base + SERVICES_CR_OFFSET);
124
125 return 0;
126}
127
128static void mpfs_mbox_rx_data(struct mbox_chan *chan)
129{
130 struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
131 struct mpfs_mss_response *response = mbox->response;
132 u16 num_words = ALIGN((response->resp_size), (4)) / 4U;
133 u32 i, status;
134
135 if (!response->resp_msg) {
136 dev_err(mbox->dev, "failed to assign memory for response %d\n", -ENOMEM);
137 return;
138 }
139
140 /*
141 * The status is stored in bits 31:16 of the SERVICES_SR register.
142 * It is only valid when BUSY == 0.
143 * We should *never* get an interrupt while the controller is
144 * still in the busy state. If we do, something has gone badly
145 * wrong & the content of the mailbox would not be valid.
146 */
147 if (mpfs_mbox_busy(mbox)) {
148 dev_err(mbox->dev, "got an interrupt but system controller is busy\n");
149 response->resp_status = 0xDEAD;
150 return;
151 }
152
153 status = readl_relaxed(mbox->ctrl_base + SERVICES_SR_OFFSET);
154
155 /*
156 * If the status of the individual servers is non-zero, the service has
157 * failed. The contents of the mailbox at this point are not be valid,
158 * so don't bother reading them. Set the status so that the driver
159 * implementing the service can handle the result.
160 */
161 response->resp_status = (status & SCB_STATUS_MASK) >> SCB_STATUS_POS;
162 if (response->resp_status)
163 return;
164
165 if (!mpfs_mbox_busy(mbox)) {
166 for (i = 0; i < num_words; i++) {
167 response->resp_msg[i] =
168 readl_relaxed(mbox->mbox_base
169 + mbox->resp_offset + i * 0x4);
170 }
171 }
172
173 mbox_chan_received_data(chan, response);
174}
175
176static irqreturn_t mpfs_mbox_inbox_isr(int irq, void *data)
177{
178 struct mbox_chan *chan = data;
179 struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
180
181 writel_relaxed(0, mbox->int_reg);
182
183 mpfs_mbox_rx_data(chan);
184
185 mbox_chan_txdone(chan, 0);
186 return IRQ_HANDLED;
187}
188
189static int mpfs_mbox_startup(struct mbox_chan *chan)
190{
191 struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
192 int ret = 0;
193
194 if (!mbox)
195 return -EINVAL;
196
197 ret = devm_request_irq(mbox->dev, mbox->irq, mpfs_mbox_inbox_isr, 0, "mpfs-mailbox", chan);
198 if (ret)
199 dev_err(mbox->dev, "failed to register mailbox interrupt:%d\n", ret);
200
201 return ret;
202}
203
204static void mpfs_mbox_shutdown(struct mbox_chan *chan)
205{
206 struct mpfs_mbox *mbox = (struct mpfs_mbox *)chan->con_priv;
207
208 devm_free_irq(mbox->dev, mbox->irq, chan);
209}
210
211static const struct mbox_chan_ops mpfs_mbox_ops = {
212 .send_data = mpfs_mbox_send_data,
213 .startup = mpfs_mbox_startup,
214 .shutdown = mpfs_mbox_shutdown,
215};
216
217static int mpfs_mbox_probe(struct platform_device *pdev)
218{
219 struct mpfs_mbox *mbox;
220 struct resource *regs;
221 int ret;
222
223 mbox = devm_kzalloc(&pdev->dev, sizeof(*mbox), GFP_KERNEL);
224 if (!mbox)
225 return -ENOMEM;
226
227 mbox->ctrl_base = devm_platform_get_and_ioremap_resource(pdev, 0, ®s);
228 if (IS_ERR(mbox->ctrl_base))
229 return PTR_ERR(mbox->ctrl_base);
230
231 mbox->int_reg = devm_platform_get_and_ioremap_resource(pdev, 1, ®s);
232 if (IS_ERR(mbox->int_reg))
233 return PTR_ERR(mbox->int_reg);
234
235 mbox->mbox_base = devm_platform_get_and_ioremap_resource(pdev, 2, ®s);
236 if (IS_ERR(mbox->mbox_base)) // account for the old dt-binding w/ 2 regs
237 mbox->mbox_base = mbox->ctrl_base + MAILBOX_REG_OFFSET;
238
239 mbox->irq = platform_get_irq(pdev, 0);
240 if (mbox->irq < 0)
241 return mbox->irq;
242
243 mbox->dev = &pdev->dev;
244
245 mbox->chans[0].con_priv = mbox;
246 mbox->controller.dev = mbox->dev;
247 mbox->controller.num_chans = 1;
248 mbox->controller.chans = mbox->chans;
249 mbox->controller.ops = &mpfs_mbox_ops;
250 mbox->controller.txdone_irq = true;
251
252 ret = devm_mbox_controller_register(&pdev->dev, &mbox->controller);
253 if (ret) {
254 dev_err(&pdev->dev, "Registering MPFS mailbox controller failed\n");
255 return ret;
256 }
257 dev_info(&pdev->dev, "Registered MPFS mailbox controller driver\n");
258
259 return 0;
260}
261
262static const struct of_device_id mpfs_mbox_of_match[] = {
263 {.compatible = "microchip,mpfs-mailbox", },
264 {},
265};
266MODULE_DEVICE_TABLE(of, mpfs_mbox_of_match);
267
268static struct platform_driver mpfs_mbox_driver = {
269 .driver = {
270 .name = "mpfs-mailbox",
271 .of_match_table = mpfs_mbox_of_match,
272 },
273 .probe = mpfs_mbox_probe,
274};
275module_platform_driver(mpfs_mbox_driver);
276
277MODULE_LICENSE("GPL v2");
278MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
279MODULE_DESCRIPTION("MPFS mailbox controller driver");