1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (c) 2019 MediaTek Inc.
4 
5 #include <asm/barrier.h>
6 #include <linux/clk.h>
7 #include <linux/err.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/platform_device.h>
12 #include <linux/remoteproc/mtk_scp.h>
13 
14 #include "mtk_common.h"
15 
16 /**
17  * scp_ipi_register() - register an ipi function
18  *
19  * @scp:	mtk_scp structure
20  * @id:		IPI ID
21  * @handler:	IPI handler
22  * @priv:	private data for IPI handler
23  *
24  * Register an ipi function to receive ipi interrupt from SCP.
25  *
26  * Returns 0 if ipi registers successfully, -error on error.
27  */
28 int scp_ipi_register(struct mtk_scp *scp,
29 		     u32 id,
30 		     scp_ipi_handler_t handler,
31 		     void *priv)
32 {
33 	if (!scp) {
34 		dev_err(scp->dev, "scp device is not ready\n");
35 		return -EPROBE_DEFER;
36 	}
37 
38 	if (WARN_ON(id >= SCP_IPI_MAX) || WARN_ON(handler == NULL))
39 		return -EINVAL;
40 
41 	scp_ipi_lock(scp, id);
42 	scp->ipi_desc[id].handler = handler;
43 	scp->ipi_desc[id].priv = priv;
44 	scp_ipi_unlock(scp, id);
45 
46 	return 0;
47 }
48 EXPORT_SYMBOL_GPL(scp_ipi_register);
49 
50 /**
51  * scp_ipi_unregister() - unregister an ipi function
52  *
53  * @scp:	mtk_scp structure
54  * @id:		IPI ID
55  *
56  * Unregister an ipi function to receive ipi interrupt from SCP.
57  */
58 void scp_ipi_unregister(struct mtk_scp *scp, u32 id)
59 {
60 	if (!scp)
61 		return;
62 
63 	if (WARN_ON(id >= SCP_IPI_MAX))
64 		return;
65 
66 	scp_ipi_lock(scp, id);
67 	scp->ipi_desc[id].handler = NULL;
68 	scp->ipi_desc[id].priv = NULL;
69 	scp_ipi_unlock(scp, id);
70 }
71 EXPORT_SYMBOL_GPL(scp_ipi_unregister);
72 
73 /*
74  * scp_memcpy_aligned() - Copy src to dst, where dst is in SCP SRAM region.
75  *
76  * @dst:	Pointer to the destination buffer, should be in SCP SRAM region.
77  * @src:	Pointer to the source buffer.
78  * @len:	Length of the source buffer to be copied.
79  *
80  * Since AP access of SCP SRAM don't support byte write, this always write a
81  * full word at a time, and may cause some extra bytes to be written at the
82  * beginning & ending of dst.
83  */
84 void scp_memcpy_aligned(void __iomem *dst, const void *src, unsigned int len)
85 {
86 	void __iomem *ptr;
87 	u32 val;
88 	unsigned int i = 0, remain;
89 
90 	if (!IS_ALIGNED((unsigned long)dst, 4)) {
91 		ptr = (void __iomem *)ALIGN_DOWN((unsigned long)dst, 4);
92 		i = 4 - (dst - ptr);
93 		val = readl_relaxed(ptr);
94 		memcpy((u8 *)&val + (4 - i), src, i);
95 		writel_relaxed(val, ptr);
96 	}
97 
98 	__iowrite32_copy(dst + i, src + i, (len - i) / 4);
99 	remain = (len - i) % 4;
100 
101 	if (remain > 0) {
102 		val = readl_relaxed(dst + len - remain);
103 		memcpy(&val, src + len - remain, remain);
104 		writel_relaxed(val, dst + len - remain);
105 	}
106 }
107 EXPORT_SYMBOL_GPL(scp_memcpy_aligned);
108 
109 /**
110  * scp_ipi_lock() - Lock before operations of an IPI ID
111  *
112  * @scp:	mtk_scp structure
113  * @id:		IPI ID
114  *
115  * Note: This should not be used by drivers other than mtk_scp.
116  */
117 void scp_ipi_lock(struct mtk_scp *scp, u32 id)
118 {
119 	if (WARN_ON(id >= SCP_IPI_MAX))
120 		return;
121 	mutex_lock(&scp->ipi_desc[id].lock);
122 }
123 EXPORT_SYMBOL_GPL(scp_ipi_lock);
124 
125 /**
126  * scp_ipi_lock() - Unlock after operations of an IPI ID
127  *
128  * @scp:	mtk_scp structure
129  * @id:		IPI ID
130  *
131  * Note: This should not be used by drivers other than mtk_scp.
132  */
133 void scp_ipi_unlock(struct mtk_scp *scp, u32 id)
134 {
135 	if (WARN_ON(id >= SCP_IPI_MAX))
136 		return;
137 	mutex_unlock(&scp->ipi_desc[id].lock);
138 }
139 EXPORT_SYMBOL_GPL(scp_ipi_unlock);
140 
141 /**
142  * scp_ipi_send() - send data from AP to scp.
143  *
144  * @scp:	mtk_scp structure
145  * @id:		IPI ID
146  * @buf:	the data buffer
147  * @len:	the data buffer length
148  * @wait:	number of msecs to wait for ack. 0 to skip waiting.
149  *
150  * This function is thread-safe. When this function returns,
151  * SCP has received the data and starts the processing.
152  * When the processing completes, IPI handler registered
153  * by scp_ipi_register will be called in interrupt context.
154  *
155  * Returns 0 if sending data successfully, -error on error.
156  **/
157 int scp_ipi_send(struct mtk_scp *scp, u32 id, void *buf, unsigned int len,
158 		 unsigned int wait)
159 {
160 	struct mtk_share_obj __iomem *send_obj = scp->send_buf;
161 	unsigned long timeout;
162 	int ret;
163 
164 	if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
165 	    WARN_ON(id == SCP_IPI_NS_SERVICE) ||
166 	    WARN_ON(len > sizeof(send_obj->share_buf)) || WARN_ON(!buf))
167 		return -EINVAL;
168 
169 	mutex_lock(&scp->send_lock);
170 
171 	ret = clk_prepare_enable(scp->clk);
172 	if (ret) {
173 		dev_err(scp->dev, "failed to enable clock\n");
174 		goto unlock_mutex;
175 	}
176 
177 	 /* Wait until SCP receives the last command */
178 	timeout = jiffies + msecs_to_jiffies(2000);
179 	do {
180 		if (time_after(jiffies, timeout)) {
181 			dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
182 			ret = -ETIMEDOUT;
183 			goto clock_disable;
184 		}
185 	} while (readl(scp->reg_base + MT8183_HOST_TO_SCP));
186 
187 	scp_memcpy_aligned(send_obj->share_buf, buf, len);
188 
189 	writel(len, &send_obj->len);
190 	writel(id, &send_obj->id);
191 
192 	scp->ipi_id_ack[id] = false;
193 	/* send the command to SCP */
194 	writel(MT8183_HOST_IPC_INT_BIT, scp->reg_base + MT8183_HOST_TO_SCP);
195 
196 	if (wait) {
197 		/* wait for SCP's ACK */
198 		timeout = msecs_to_jiffies(wait);
199 		ret = wait_event_timeout(scp->ack_wq,
200 					 scp->ipi_id_ack[id],
201 					 timeout);
202 		scp->ipi_id_ack[id] = false;
203 		if (WARN(!ret, "scp ipi %d ack time out !", id))
204 			ret = -EIO;
205 		else
206 			ret = 0;
207 	}
208 
209 clock_disable:
210 	clk_disable_unprepare(scp->clk);
211 unlock_mutex:
212 	mutex_unlock(&scp->send_lock);
213 
214 	return ret;
215 }
216 EXPORT_SYMBOL_GPL(scp_ipi_send);
217 
218 MODULE_LICENSE("GPL v2");
219 MODULE_DESCRIPTION("MediaTek scp IPI interface");
220