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