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
 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, int 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		args.ucRegIndex = 0;
 72		args.lpI2CDataOut = 0;
 73	}
 74
 75	args.ucFlag = flags;
 76	args.ucI2CSpeed = TARGET_HW_I2C_CLOCK;
 77	args.ucTransBytes = num;
 78	args.ucSlaveAddr = slave_addr << 1;
 79	args.ucLineNumber = chan->rec.i2c_id;
 80
 81	atom_execute_table_scratch_unlocked(rdev->mode_info.atom_context, index, (uint32_t *)&args);
 82
 83	/* error */
 84	if (args.ucStatus != HW_ASSISTED_I2C_STATUS_SUCCESS) {
 85		DRM_DEBUG_KMS("hw_i2c error\n");
 86		r = -EIO;
 87		goto done;
 88	}
 89
 90	if (!(flags & HW_I2C_WRITE))
 91		radeon_atom_copy_swap(buf, base, num, false);
 92
 93done:
 94	mutex_unlock(&rdev->mode_info.atom_context->scratch_mutex);
 95	mutex_unlock(&chan->mutex);
 96
 97	return r;
 98}
 99
100int radeon_atom_hw_i2c_xfer(struct i2c_adapter *i2c_adap,
101			    struct i2c_msg *msgs, int num)
102{
103	struct radeon_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
104	struct i2c_msg *p;
105	int i, remaining, current_count, buffer_offset, max_bytes, ret;
106	u8 flags;
107
108	/* check for bus probe */
109	p = &msgs[0];
110	if ((num == 1) && (p->len == 0)) {
111		ret = radeon_process_i2c_ch(i2c,
112					    p->addr, HW_I2C_WRITE,
113					    NULL, 0);
114		if (ret)
115			return ret;
116		else
117			return num;
118	}
119
120	for (i = 0; i < num; i++) {
121		p = &msgs[i];
122		remaining = p->len;
123		buffer_offset = 0;
124		/* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
125		if (p->flags & I2C_M_RD) {
126			max_bytes = ATOM_MAX_HW_I2C_READ;
127			flags = HW_I2C_READ;
128		} else {
129			max_bytes = ATOM_MAX_HW_I2C_WRITE;
130			flags = HW_I2C_WRITE;
131		}
132		while (remaining) {
133			if (remaining > max_bytes)
134				current_count = max_bytes;
135			else
136				current_count = remaining;
137			ret = radeon_process_i2c_ch(i2c,
138						    p->addr, flags,
139						    &p->buf[buffer_offset], current_count);
140			if (ret)
141				return ret;
142			remaining -= current_count;
143			buffer_offset += current_count;
144		}
145	}
146
147	return num;
148}
149
150u32 radeon_atom_hw_i2c_func(struct i2c_adapter *adap)
151{
152	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
153}
154