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/iopoll.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/platform_device.h>
13 #include <linux/time64.h>
14 #include <linux/remoteproc/mtk_scp.h>
15 
16 #include "mtk_common.h"
17 
18 #define SCP_TIMEOUT_US		(2000 * USEC_PER_MSEC)
19 
20 /**
21  * scp_ipi_register() - register an ipi function
22  *
23  * @scp:	mtk_scp structure
24  * @id:		IPI ID
25  * @handler:	IPI handler
26  * @priv:	private data for IPI handler
27  *
28  * Register an ipi function to receive ipi interrupt from SCP.
29  *
30  * Return: 0 if ipi registers successfully, -error on error.
31  */
scp_ipi_register(struct mtk_scp * scp,u32 id,scp_ipi_handler_t handler,void * priv)32 int scp_ipi_register(struct mtk_scp *scp,
33 		     u32 id,
34 		     scp_ipi_handler_t handler,
35 		     void *priv)
36 {
37 	if (!scp)
38 		return -EPROBE_DEFER;
39 
40 	if (WARN_ON(id >= SCP_IPI_MAX) || WARN_ON(handler == NULL))
41 		return -EINVAL;
42 
43 	scp_ipi_lock(scp, id);
44 	scp->ipi_desc[id].handler = handler;
45 	scp->ipi_desc[id].priv = priv;
46 	scp_ipi_unlock(scp, id);
47 
48 	return 0;
49 }
50 EXPORT_SYMBOL_GPL(scp_ipi_register);
51 
52 /**
53  * scp_ipi_unregister() - unregister an ipi function
54  *
55  * @scp:	mtk_scp structure
56  * @id:		IPI ID
57  *
58  * Unregister an ipi function to receive ipi interrupt from SCP.
59  */
scp_ipi_unregister(struct mtk_scp * scp,u32 id)60 void scp_ipi_unregister(struct mtk_scp *scp, u32 id)
61 {
62 	if (!scp)
63 		return;
64 
65 	if (WARN_ON(id >= SCP_IPI_MAX))
66 		return;
67 
68 	scp_ipi_lock(scp, id);
69 	scp->ipi_desc[id].handler = NULL;
70 	scp->ipi_desc[id].priv = NULL;
71 	scp_ipi_unlock(scp, id);
72 }
73 EXPORT_SYMBOL_GPL(scp_ipi_unregister);
74 
75 /*
76  * scp_memcpy_aligned() - Copy src to dst, where dst is in SCP SRAM region.
77  *
78  * @dst:	Pointer to the destination buffer, should be in SCP SRAM region.
79  * @src:	Pointer to the source buffer.
80  * @len:	Length of the source buffer to be copied.
81  *
82  * Since AP access of SCP SRAM don't support byte write, this always write a
83  * full word at a time, and may cause some extra bytes to be written at the
84  * beginning & ending of dst.
85  */
scp_memcpy_aligned(void __iomem * dst,const void * src,unsigned int len)86 void scp_memcpy_aligned(void __iomem *dst, const void *src, unsigned int len)
87 {
88 	void __iomem *ptr;
89 	u32 val;
90 	unsigned int i = 0, remain;
91 
92 	if (!IS_ALIGNED((unsigned long)dst, 4)) {
93 		ptr = (void __iomem *)ALIGN_DOWN((unsigned long)dst, 4);
94 		i = 4 - (dst - ptr);
95 		val = readl_relaxed(ptr);
96 		memcpy((u8 *)&val + (4 - i), src, i);
97 		writel_relaxed(val, ptr);
98 	}
99 
100 	__iowrite32_copy(dst + i, src + i, (len - i) / 4);
101 	remain = (len - i) % 4;
102 
103 	if (remain > 0) {
104 		val = readl_relaxed(dst + len - remain);
105 		memcpy(&val, src + len - remain, remain);
106 		writel_relaxed(val, dst + len - remain);
107 	}
108 }
109 EXPORT_SYMBOL_GPL(scp_memcpy_aligned);
110 
111 /**
112  * scp_ipi_lock() - Lock before operations of an IPI ID
113  *
114  * @scp:	mtk_scp structure
115  * @id:		IPI ID
116  *
117  * Note: This should not be used by drivers other than mtk_scp.
118  */
scp_ipi_lock(struct mtk_scp * scp,u32 id)119 void scp_ipi_lock(struct mtk_scp *scp, u32 id)
120 {
121 	if (WARN_ON(id >= SCP_IPI_MAX))
122 		return;
123 	mutex_lock(&scp->ipi_desc[id].lock);
124 }
125 EXPORT_SYMBOL_GPL(scp_ipi_lock);
126 
127 /**
128  * scp_ipi_unlock() - Unlock after operations of an IPI ID
129  *
130  * @scp:	mtk_scp structure
131  * @id:		IPI ID
132  *
133  * Note: This should not be used by drivers other than mtk_scp.
134  */
scp_ipi_unlock(struct mtk_scp * scp,u32 id)135 void scp_ipi_unlock(struct mtk_scp *scp, u32 id)
136 {
137 	if (WARN_ON(id >= SCP_IPI_MAX))
138 		return;
139 	mutex_unlock(&scp->ipi_desc[id].lock);
140 }
141 EXPORT_SYMBOL_GPL(scp_ipi_unlock);
142 
143 /**
144  * scp_ipi_send() - send data from AP to scp.
145  *
146  * @scp:	mtk_scp structure
147  * @id:		IPI ID
148  * @buf:	the data buffer
149  * @len:	the data buffer length
150  * @wait:	number of msecs to wait for ack. 0 to skip waiting.
151  *
152  * This function is thread-safe. When this function returns,
153  * SCP has received the data and starts the processing.
154  * When the processing completes, IPI handler registered
155  * by scp_ipi_register will be called in interrupt context.
156  *
157  * Return: 0 if sending data successfully, -error on error.
158  **/
scp_ipi_send(struct mtk_scp * scp,u32 id,void * buf,unsigned int len,unsigned int wait)159 int scp_ipi_send(struct mtk_scp *scp, u32 id, void *buf, unsigned int len,
160 		 unsigned int wait)
161 {
162 	struct mtk_share_obj __iomem *send_obj = scp->send_buf;
163 	u32 val;
164 	int ret;
165 
166 	if (WARN_ON(id <= SCP_IPI_INIT) || WARN_ON(id >= SCP_IPI_MAX) ||
167 	    WARN_ON(id == SCP_IPI_NS_SERVICE) ||
168 	    WARN_ON(len > sizeof(send_obj->share_buf)) || WARN_ON(!buf))
169 		return -EINVAL;
170 
171 	ret = clk_prepare_enable(scp->clk);
172 	if (ret) {
173 		dev_err(scp->dev, "failed to enable clock\n");
174 		return ret;
175 	}
176 
177 	mutex_lock(&scp->send_lock);
178 
179 	 /* Wait until SCP receives the last command */
180 	ret = readl_poll_timeout_atomic(scp->reg_base + scp->data->host_to_scp_reg,
181 					val, !val, 0, SCP_TIMEOUT_US);
182 	if (ret) {
183 		dev_err(scp->dev, "%s: IPI timeout!\n", __func__);
184 		goto unlock_mutex;
185 	}
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(scp->data->host_to_scp_int_bit,
195 	       scp->reg_base + scp->data->host_to_scp_reg);
196 
197 	if (wait) {
198 		/* wait for SCP's ACK */
199 		ret = wait_event_timeout(scp->ack_wq,
200 					 scp->ipi_id_ack[id],
201 					 msecs_to_jiffies(wait));
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 unlock_mutex:
210 	mutex_unlock(&scp->send_lock);
211 	clk_disable_unprepare(scp->clk);
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