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 */
28int 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}
46EXPORT_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 */
56void 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}
69EXPORT_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 */
82void 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}
105EXPORT_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 */
115void 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}
121EXPORT_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 */
131void 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}
137EXPORT_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 **/
155int 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	ret = clk_prepare_enable(scp->clk);
168	if (ret) {
169		dev_err(scp->dev, "failed to enable clock\n");
170		return ret;
171	}
172
173	mutex_lock(&scp->send_lock);
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 unlock_mutex;
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
208unlock_mutex:
209	mutex_unlock(&scp->send_lock);
210	clk_disable_unprepare(scp->clk);
211
212	return ret;
213}
214EXPORT_SYMBOL_GPL(scp_ipi_send);
215
216MODULE_LICENSE("GPL v2");
217MODULE_DESCRIPTION("MediaTek scp IPI interface");
218