atombios_i2c.c revision 1.9 
1/*	$OpenBSD: atombios_i2c.c,v 1.9 2018/04/20 16:09:36 deraadt Exp $	*/
2/*
3 * Copyright 2011 Advanced Micro Devices, Inc.
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be included in
13 * all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
21 * OTHER DEALINGS IN THE SOFTWARE.
22 *
23 * Authors: Alex Deucher
24 *
25 */
26#include <dev/pci/drm/drmP.h>
27#include <dev/pci/drm/radeon_drm.h>
28#include "radeon.h"
29#include "atom.h"
30
31extern void radeon_atom_copy_swap(u8 *dst, u8 *src, u8 num_bytes, bool to_le);
32
33#define TARGET_HW_I2C_CLOCK 50
34
35/* these are a limitation of ProcessI2cChannelTransaction not the hw */
36#define ATOM_MAX_HW_I2C_WRITE 2
37#define ATOM_MAX_HW_I2C_READ  255
38
39static int radeon_process_i2c_ch(struct radeon_i2c_chan *chan,
40				 u8 slave_addr, u8 flags,
41				 u8 *buf, u8 num)
42{
43	struct drm_device *dev = chan->dev;
44	struct radeon_device *rdev = dev->dev_private;
45	PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
46	int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
47	unsigned char *base;
48	u16 out = cpu_to_le16(0);
49
50	memset(&args, 0, sizeof(args));
51
52	base = (unsigned char *)rdev->mode_info.atom_context->scratch;
53
54	if (flags & HW_I2C_WRITE) {
55		if (num > ATOM_MAX_HW_I2C_WRITE) {
56			DRM_ERROR("hw i2c: tried to write too many bytes (%d vs 2)\n", num);
57			return -EINVAL;
58		}
59		if (buf == NULL)
60			args.ucRegIndex = 0;
61		else
62			args.ucRegIndex = buf[0];
63		if (num)
64			num--;
65		if (num)
66			memcpy(&out, &buf[1], num);
67		args.lpI2CDataOut = cpu_to_le16(out);
68#if 0
69	} else {
70		if (num > ATOM_MAX_HW_I2C_READ) {
71			DRM_ERROR("hw i2c: tried to read too many bytes (%d vs 255)\n", num);
72			return -EINVAL;
73		}
74#endif
75	}
76
77	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
78	args.ucRegIndex = 0;
79	args.ucTransBytes = num;
80	args.ucSlaveAddr = slave_addr << 1;
81	args.ucLineNumber = chan->rec.i2c_id;
82
83	atom_execute_table(rdev->mode_info.atom_context, index, (uint32_t *)&args);
84
85	/* error */
86	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
87		DRM_DEBUG_KMS("hw_i2c error\n");
88		return -EIO;
89	}
90
91	if (!(flags & HW_I2C_WRITE))
92		radeon_atom_copy_swap(buf, base, num, false);
93
94	return 0;
95}
96
97int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
98			    struct i2c_msg *msgs, int num)
99{
100	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
101	struct i2c_msg *p;
102	int i, remaining, current_count, buffer_offset, max_bytes, ret;
103	u8 flags;
104
105	/* check for bus probe */
106	p = &msgs[0];
107	if ((num == 1) && (p->len == 0)) {
108		ret = radeon_process_i2c_ch(i2c,
109					    p->addr, HW_I2C_WRITE,
110					    NULL, 0);
111		if (ret)
112			return ret;
113		else
114			return num;
115	}
116
117	for (i = 0; i < num; i++) {
118		p = &msgs[i];
119		remaining = p->len;
120		buffer_offset = 0;
121		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
122		if (p->flags & I2C_M_RD) {
123			max_bytes = ATOM_MAX_HW_I2C_READ;
124			flags = HW_I2C_READ;
125		} else {
126			max_bytes = ATOM_MAX_HW_I2C_WRITE;
127			flags = HW_I2C_WRITE;
128		}
129		while (remaining) {
130			if (remaining > max_bytes)
131				current_count = max_bytes;
132			else
133				current_count = remaining;
134			ret = radeon_process_i2c_ch(i2c,
135						    p->addr, flags,
136						    &p->buf[buffer_offset], current_count);
137			if (ret)
138				return ret;
139			remaining -= current_count;
140			buffer_offset += current_count;
141		}
142	}
143
144	return num;
145}
146
147u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
148{
149	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
150}
151