1/*
2 * Copyright 2011 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 * Authors: Alex Deucher
23 *
24 */
25#include <drm/drmP.h>
26#include <drm/radeon_drm.h>
27#include "radeon.h"
28#include "atom.h"
29
30#define TARGET_HW_I2C_CLOCK 50
31
32/* these are a limitation of ProcessI2cChannelTransaction not the hw */
33#define ATOM_MAX_HW_I2C_WRITE 3
34#define ATOM_MAX_HW_I2C_READ  255
35
36static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
37				 u8 slave_addr, u8 flags,
38				 u8 *buf, u8 num)
39{
40	struct drm_device *dev = chan->dev;
41	struct radeon_device *rdev = dev->dev_private;
42	PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
43	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
44	unsigned char *base;
45	u16 out = cpu_to_le16(0);
46	int r = 0;
47
48	memset(&args, 0, sizeof(args));
49
50	mutex_lock(&chan->mutex);
51	mutex_lock(&rdev->mode_info.atom_context->scratch_mutex);
52
53	base = (unsigned char *)rdev->mode_info.atom_context->scratch;
54
55	if (flags & HW_I2C_WRITE) {
56		if (num > ATOM_MAX_HW_I2C_WRITE) {
57			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
58			r = -EINVAL;
59			goto done;
60		}
61		if (buf == NULL)
62			args.ucRegIndex = 0;
63		else
64			args.ucRegIndex = buf[0];
65		if (num)
66			num--;
67		if (num)
68			memcpy(&out, &buf[1], num);
69		args.lpI2CDataOut = cpu_to_le16(out);
70	} else {
71		if (num > ATOM_MAX_HW_I2C_READ) {
72			DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
73			r = -EINVAL;
74			goto done;
75		}
76		args.ucRegIndex = 0;
77		args.lpI2CDataOut = 0;
78	}
79
80	args.ucFlag = flags;
81	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
82	args.ucTransBytes = num;
83	args.ucSlaveAddr = slave_addr << 1;
84	args.ucLineNumber = chan->rec.i2c_id;
85
86	atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
87
88	/* error */
89	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
90		DRM_DEBUG_KMS("hw_i2c error\n");
91		r = -EIO;
92		goto done;
93	}
94
95	if (!(flags & HW_I2C_WRITE))
96		radeon_atom_copy_swap(buf, base, num, false);
97
98done:
99	mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
100	mutex_unlock(&chan->mutex);
101
102	return r;
103}
104
105int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
106			    struct i2c_msg *msgs, int num)
107{
108	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
109	struct i2c_msg *p;
110	int i, remaining, current_count, buffer_offset, max_bytes, ret;
111	u8 flags;
112
113	/* check for bus probe */
114	p = &msgs[0];
115	if ((num == 1) && (p->len == 0)) {
116		ret = radeon_process_i2c_ch(i2c,
117					    p->addr, HW_I2C_WRITE,
118					    NULL, 0);
119		if (ret)
120			return ret;
121		else
122			return num;
123	}
124
125	for (i = 0; i < num; i++) {
126		p = &msgs[i];
127		remaining = p->len;
128		buffer_offset = 0;
129		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
130		if (p->flags & I2C_M_RD) {
131			max_bytes = ATOM_MAX_HW_I2C_READ;
132			flags = HW_I2C_READ;
133		} else {
134			max_bytes = ATOM_MAX_HW_I2C_WRITE;
135			flags = HW_I2C_WRITE;
136		}
137		while (remaining) {
138			if (remaining > max_bytes)
139				current_count = max_bytes;
140			else
141				current_count = remaining;
142			ret = radeon_process_i2c_ch(i2c,
143						    p->addr, flags,
144						    &p->buf[buffer_offset], current_count);
145			if (ret)
146				return ret;
147			remaining -= current_count;
148			buffer_offset += current_count;
149		}
150	}
151
152	return num;
153}
154
155u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
156{
157	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
158}
159
160