1/*
2 * Copyright 2012 Calxeda, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify it
5 * under the terms and conditions of the GNU General Public License,
6 * version 2, as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program.  If not, see <http://www.gnu.org/licenses/>.
15 */
16#include <linux/types.h>
17#include <linux/err.h>
18#include <linux/delay.h>
19#include <linux/export.h>
20#include <linux/io.h>
21#include <linux/interrupt.h>
22#include <linux/completion.h>
23#include <linux/mutex.h>
24#include <linux/notifier.h>
25#include <linux/spinlock.h>
26#include <linux/device.h>
27#include <linux/amba/bus.h>
28
29#include <linux/pl320-ipc.h>
30
31#define IPCMxSOURCE(m)		((m) * 0x40)
32#define IPCMxDSET(m)		(((m) * 0x40) + 0x004)
33#define IPCMxDCLEAR(m)		(((m) * 0x40) + 0x008)
34#define IPCMxDSTATUS(m)		(((m) * 0x40) + 0x00C)
35#define IPCMxMODE(m)		(((m) * 0x40) + 0x010)
36#define IPCMxMSET(m)		(((m) * 0x40) + 0x014)
37#define IPCMxMCLEAR(m)		(((m) * 0x40) + 0x018)
38#define IPCMxMSTATUS(m)		(((m) * 0x40) + 0x01C)
39#define IPCMxSEND(m)		(((m) * 0x40) + 0x020)
40#define IPCMxDR(m, dr)		(((m) * 0x40) + ((dr) * 4) + 0x024)
41
42#define IPCMMIS(irq)		(((irq) * 8) + 0x800)
43#define IPCMRIS(irq)		(((irq) * 8) + 0x804)
44
45#define MBOX_MASK(n)		(1 << (n))
46#define IPC_TX_MBOX		1
47#define IPC_RX_MBOX		2
48
49#define CHAN_MASK(n)		(1 << (n))
50#define A9_SOURCE		1
51#define M3_SOURCE		0
52
53static void __iomem *ipc_base;
54static int ipc_irq;
55static DEFINE_MUTEX(ipc_m1_lock);
56static DECLARE_COMPLETION(ipc_completion);
57static ATOMIC_NOTIFIER_HEAD(ipc_notifier);
58
59static inline void set_destination(int source, int mbox)
60{
61	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxDSET(mbox));
62	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxMSET(mbox));
63}
64
65static inline void clear_destination(int source, int mbox)
66{
67	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxDCLEAR(mbox));
68	__raw_writel(CHAN_MASK(source), ipc_base + IPCMxMCLEAR(mbox));
69}
70
71static void __ipc_send(int mbox, u32 *data)
72{
73	int i;
74	for (i = 0; i < 7; i++)
75		__raw_writel(data[i], ipc_base + IPCMxDR(mbox, i));
76	__raw_writel(0x1, ipc_base + IPCMxSEND(mbox));
77}
78
79static u32 __ipc_rcv(int mbox, u32 *data)
80{
81	int i;
82	for (i = 0; i < 7; i++)
83		data[i] = __raw_readl(ipc_base + IPCMxDR(mbox, i));
84	return data[1];
85}
86
87/* blocking implmentation from the A9 side, not usuable in interrupts! */
88int pl320_ipc_transmit(u32 *data)
89{
90	int ret;
91
92	mutex_lock(&ipc_m1_lock);
93
94	init_completion(&ipc_completion);
95	__ipc_send(IPC_TX_MBOX, data);
96	ret = wait_for_completion_timeout(&ipc_completion,
97					  msecs_to_jiffies(1000));
98	if (ret == 0) {
99		ret = -ETIMEDOUT;
100		goto out;
101	}
102
103	ret = __ipc_rcv(IPC_TX_MBOX, data);
104out:
105	mutex_unlock(&ipc_m1_lock);
106	return ret;
107}
108EXPORT_SYMBOL_GPL(pl320_ipc_transmit);
109
110static irqreturn_t ipc_handler(int irq, void *dev)
111{
112	u32 irq_stat;
113	u32 data[7];
114
115	irq_stat = __raw_readl(ipc_base + IPCMMIS(1));
116	if (irq_stat & MBOX_MASK(IPC_TX_MBOX)) {
117		__raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
118		complete(&ipc_completion);
119	}
120	if (irq_stat & MBOX_MASK(IPC_RX_MBOX)) {
121		__ipc_rcv(IPC_RX_MBOX, data);
122		atomic_notifier_call_chain(&ipc_notifier, data[0], data + 1);
123		__raw_writel(2, ipc_base + IPCMxSEND(IPC_RX_MBOX));
124	}
125
126	return IRQ_HANDLED;
127}
128
129int pl320_ipc_register_notifier(struct notifier_block *nb)
130{
131	return atomic_notifier_chain_register(&ipc_notifier, nb);
132}
133EXPORT_SYMBOL_GPL(pl320_ipc_register_notifier);
134
135int pl320_ipc_unregister_notifier(struct notifier_block *nb)
136{
137	return atomic_notifier_chain_unregister(&ipc_notifier, nb);
138}
139EXPORT_SYMBOL_GPL(pl320_ipc_unregister_notifier);
140
141static int pl320_probe(struct amba_device *adev, const struct amba_id *id)
142{
143	int ret;
144
145	ipc_base = ioremap(adev->res.start, resource_size(&adev->res));
146	if (ipc_base == NULL)
147		return -ENOMEM;
148
149	__raw_writel(0, ipc_base + IPCMxSEND(IPC_TX_MBOX));
150
151	ipc_irq = adev->irq[0];
152	ret = request_irq(ipc_irq, ipc_handler, 0, dev_name(&adev->dev), NULL);
153	if (ret < 0)
154		goto err;
155
156	/* Init slow mailbox */
157	__raw_writel(CHAN_MASK(A9_SOURCE),
158			ipc_base + IPCMxSOURCE(IPC_TX_MBOX));
159	__raw_writel(CHAN_MASK(M3_SOURCE),
160			ipc_base + IPCMxDSET(IPC_TX_MBOX));
161	__raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
162		     ipc_base + IPCMxMSET(IPC_TX_MBOX));
163
164	/* Init receive mailbox */
165	__raw_writel(CHAN_MASK(M3_SOURCE),
166			ipc_base + IPCMxSOURCE(IPC_RX_MBOX));
167	__raw_writel(CHAN_MASK(A9_SOURCE),
168			ipc_base + IPCMxDSET(IPC_RX_MBOX));
169	__raw_writel(CHAN_MASK(M3_SOURCE) | CHAN_MASK(A9_SOURCE),
170		     ipc_base + IPCMxMSET(IPC_RX_MBOX));
171
172	return 0;
173err:
174	iounmap(ipc_base);
175	return ret;
176}
177
178static struct amba_id pl320_ids[] = {
179	{
180		.id	= 0x00041320,
181		.mask	= 0x000fffff,
182	},
183	{ 0, 0 },
184};
185
186static struct amba_driver pl320_driver = {
187	.drv = {
188		.name	= "pl320",
189	},
190	.id_table	= pl320_ids,
191	.probe		= pl320_probe,
192};
193
194static int __init ipc_init(void)
195{
196	return amba_driver_register(&pl320_driver);
197}
198module_init(ipc_init);
199