linux-stable/drivers/gpu/drm/amd/amdgpu/amdgpu_eeprom.h
Luben Tuikov 63d4c081a5 drm/amdgpu: Optimize EEPROM RAS table I/O
Split functionality between read and write, which
simplifies the code and exposes areas of
optimization and more or less complexity, and take
advantage of that.

Read and write the table in one go; use a separate
stage to decode or encode the data, as opposed to
on the fly, which keeps the I2C bus busy. Use a
single read/write to read/write the table or at
most two if the number of records we're
reading/writing wraps around.

Check the check-sum of a table in EEPROM on init.

Update the checksum at the same time as when
updating the table header signature, when the
threshold was increased on boot.

Take advantage of arithmetic modulo 256, that is,
use a byte!, to greatly simplify checksum
arithmetic.

Cc: Alexander Deucher <Alexander.Deucher@amd.com>
Cc: Andrey Grodzovsky <Andrey.Grodzovsky@amd.com>
Signed-off-by: Luben Tuikov <luben.tuikov@amd.com>
Acked-by: Alexander Deucher <Alexander.Deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2021-07-01 00:24:41 -04:00

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C

/*
* Copyright 2021 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
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* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
*/
#ifndef _AMDGPU_EEPROM_H
#define _AMDGPU_EEPROM_H
#include <linux/i2c.h>
int amdgpu_eeprom_read(struct i2c_adapter *i2c_adap,
u32 eeprom_addr, u8 *eeprom_buf,
u16 bytes);
int amdgpu_eeprom_write(struct i2c_adapter *i2c_adap,
u32 eeprom_addr, u8 *eeprom_buf,
u16 bytes);
#endif