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 
36 static 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 
47 	memset(&args, 0, sizeof(args));
48 
49 	base = (unsigned char *)rdev->mode_info.atom_context->scratch;
50 
51 	if (flags & HW_I2C_WRITE) {
52 		if (num > ATOM_MAX_HW_I2C_WRITE) {
53 			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 3)\n", num);
54 			return -EINVAL;
55 		}
56 		if (buf == NULL)
57 			args.ucRegIndex = 0;
58 		else
59 			args.ucRegIndex = buf[0];
60 		if (num)
61 			num--;
62 		if (num)
63 			memcpy(&out, &buf[1], num);
64 		args.lpI2CDataOut = cpu_to_le16(out);
65 	} else {
66 		if (num > ATOM_MAX_HW_I2C_READ) {
67 			DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
68 			return -EINVAL;
69 		}
70 		args.ucRegIndex = 0;
71 		args.lpI2CDataOut = 0;
72 	}
73 
74 	args.ucFlag = flags;
75 	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
76 	args.ucTransBytes = num;
77 	args.ucSlaveAddr = slave_addr << 1;
78 	args.ucLineNumber = chan->rec.i2c_id;
79 
80 	atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
81 
82 	/* error */
83 	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
84 		DRM_DEBUG_KMS("hw_i2c error\n");
85 		return -EIO;
86 	}
87 
88 	if (!(flags & HW_I2C_WRITE))
89 		radeon_atom_copy_swap(buf, base, num, false);
90 
91 	return 0;
92 }
93 
94 int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
95 			    struct i2c_msg *msgs, int num)
96 {
97 	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
98 	struct i2c_msg *p;
99 	int i, remaining, current_count, buffer_offset, max_bytes, ret;
100 	u8 flags;
101 
102 	/* check for bus probe */
103 	p = &msgs[0];
104 	if ((num == 1) && (p->len == 0)) {
105 		ret = radeon_process_i2c_ch(i2c,
106 					    p->addr, HW_I2C_WRITE,
107 					    NULL, 0);
108 		if (ret)
109 			return ret;
110 		else
111 			return num;
112 	}
113 
114 	for (i = 0; i < num; i++) {
115 		p = &msgs[i];
116 		remaining = p->len;
117 		buffer_offset = 0;
118 		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
119 		if (p->flags & I2C_M_RD) {
120 			max_bytes = ATOM_MAX_HW_I2C_READ;
121 			flags = HW_I2C_READ;
122 		} else {
123 			max_bytes = ATOM_MAX_HW_I2C_WRITE;
124 			flags = HW_I2C_WRITE;
125 		}
126 		while (remaining) {
127 			if (remaining > max_bytes)
128 				current_count = max_bytes;
129 			else
130 				current_count = remaining;
131 			ret = radeon_process_i2c_ch(i2c,
132 						    p->addr, flags,
133 						    &p->buf[buffer_offset], current_count);
134 			if (ret)
135 				return ret;
136 			remaining -= current_count;
137 			buffer_offset += current_count;
138 		}
139 	}
140 
141 	return num;
142 }
143 
144 u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
145 {
146 	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
147 }
148 
149