cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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i2c-designware-baytrail.c (959B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Intel BayTrail PMIC I2C bus semaphore implementation
      4 * Copyright (c) 2014, Intel Corporation.
      5 */
      6#include <linux/device.h>
      7#include <linux/acpi.h>
      8#include <linux/i2c.h>
      9#include <linux/interrupt.h>
     10
     11#include <asm/iosf_mbi.h>
     12
     13#include "i2c-designware-core.h"
     14
     15int i2c_dw_baytrail_probe_lock_support(struct dw_i2c_dev *dev)
     16{
     17	acpi_status status;
     18	unsigned long long shared_host = 0;
     19	acpi_handle handle;
     20
     21	if (!dev)
     22		return -ENODEV;
     23
     24	handle = ACPI_HANDLE(dev->dev);
     25	if (!handle)
     26		return -ENODEV;
     27
     28	status = acpi_evaluate_integer(handle, "_SEM", NULL, &shared_host);
     29	if (ACPI_FAILURE(status))
     30		return -ENODEV;
     31
     32	if (!shared_host)
     33		return -ENODEV;
     34
     35	if (!iosf_mbi_available())
     36		return -EPROBE_DEFER;
     37
     38	dev_info(dev->dev, "I2C bus managed by PUNIT\n");
     39	dev->acquire_lock = iosf_mbi_block_punit_i2c_access;
     40	dev->release_lock = iosf_mbi_unblock_punit_i2c_access;
     41	dev->shared_with_punit = true;
     42
     43	return 0;
     44}