kernel/drivers/gpu/drm/amd/amdgpu/atombios_i2c.c

   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/amdgpu_drm.h>
  27 #include "amdgpu.h"
  28 #include "atom.h"
  29 #include "amdgpu_atombios.h"
  30
  31 #define TARGET_HW_I2C_CLOCK 50
  32
  33 /* these are a limitation of ProcessI2cChannelTransaction not the hw */
  34 #define ATOM_MAX_HW_I2C_WRITE 3
  35 #define ATOM_MAX_HW_I2C_READ  255
  36
  37 static int amdgpu_atombios_i2c_process_i2c_ch(struct amdgpu_i2c_chan *chan,
  38                                        u8 slave_addr, u8 flags,
  39                                        u8 *buf, u8 num)
  40 {
  41         struct drm_device *dev = chan->dev;
  42         struct amdgpu_device *adev = dev->dev_private;
  43         PROCESS_I2C_CHANNEL_TRANSACTION_PS_ALLOCATION args;
  44         int index = GetIndexIntoMasterTable(COMMAND, ProcessI2cChannelTransaction);
  45         unsigned char *base;
  46         u16 out = cpu_to_le16(0);
  47         int r = 0;
  48
  49         memset(&args, 0, sizeof(args));
  50
  51         mutex_lock(&chan->mutex);
  52
  53         base = (unsigned char *)adev->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         amdgpu_atom_execute_table(adev->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                 amdgpu_atombios_copy_swap(buf, base, num, false);
  97
  98 done:
  99         mutex_unlock(&chan->mutex);
 100
 101         return r;
 102 }
 103
 104 int amdgpu_atombios_i2c_xfer(struct i2c_adapter *i2c_adap,
 105                       struct i2c_msg *msgs, int num)
 106 {
 107         struct amdgpu_i2c_chan *i2c = i2c_get_adapdata(i2c_adap);
 108         struct i2c_msg *p;
 109         int i, remaining, current_count, buffer_offset, max_bytes, ret;
 110         u8 flags;
 111
 112         /* check for bus probe */
 113         p = &msgs[0];
 114         if ((num == 1) && (p->len == 0)) {
 115                 ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
 116                                                   p->addr, HW_I2C_WRITE,
 117                                                   NULL, 0);
 118                 if (ret)
 119                         return ret;
 120                 else
 121                         return num;
 122         }
 123
 124         for (i = 0; i < num; i++) {
 125                 p = &msgs[i];
 126                 remaining = p->len;
 127                 buffer_offset = 0;
 128                 /* max_bytes are a limitation of ProcessI2cChannelTransaction not the hw */
 129                 if (p->flags & I2C_M_RD) {
 130                         max_bytes = ATOM_MAX_HW_I2C_READ;
 131                         flags = HW_I2C_READ;
 132                 } else {
 133                         max_bytes = ATOM_MAX_HW_I2C_WRITE;
 134                         flags = HW_I2C_WRITE;
 135                 }
 136                 while (remaining) {
 137                         if (remaining > max_bytes)
 138                                 current_count = max_bytes;
 139                         else
 140                                 current_count = remaining;
 141                         ret = amdgpu_atombios_i2c_process_i2c_ch(i2c,
 142                                                           p->addr, flags,
 143                                                           &p->buf[buffer_offset], current_count);
 144                         if (ret)
 145                                 return ret;
 146                         remaining -= current_count;
 147                         buffer_offset += current_count;
 148                 }
 149         }
 150
 151         return num;
 152 }
 153
 154 u32 amdgpu_atombios_i2c_func(struct i2c_adapter *adap)
 155 {
 156         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 157 }
 158