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| 1 | +// SPDX-License-Identifier: GPL-2.0-or-later |
| 2 | +/* |
| 3 | + * AMD 3D V-Cache Performance Optimizer Driver |
| 4 | + * |
| 5 | + * Copyright (c) 2024, Advanced Micro Devices, Inc. |
| 6 | + * All Rights Reserved. |
| 7 | + * |
| 8 | + * Authors: Basavaraj Natikar <Basavaraj.Natikar@amd.com> |
| 9 | + * Perry Yuan <perry.yuan@amd.com> |
| 10 | + * Mario Limonciello <mario.limonciello@amd.com> |
| 11 | + */ |
| 12 | + |
| 13 | +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 14 | + |
| 15 | +#include <linux/acpi.h> |
| 16 | +#include <linux/array_size.h> |
| 17 | +#include <linux/device.h> |
| 18 | +#include <linux/errno.h> |
| 19 | +#include <linux/module.h> |
| 20 | +#include <linux/mutex.h> |
| 21 | +#include <linux/platform_device.h> |
| 22 | +#include <linux/pm.h> |
| 23 | +#include <linux/sysfs.h> |
| 24 | +#include <linux/uuid.h> |
| 25 | + |
| 26 | +static char *x3d_mode = "frequency"; |
| 27 | +module_param(x3d_mode, charp, 0); |
| 28 | +MODULE_PARM_DESC(x3d_mode, "Initial 3D-VCache mode; 'frequency' (default) or 'cache'"); |
| 29 | + |
| 30 | +#define DSM_REVISION_ID 0 |
| 31 | +#define DSM_SET_X3D_MODE 1 |
| 32 | + |
| 33 | +static guid_t x3d_guid = GUID_INIT(0xdff8e55f, 0xbcfd, 0x46fb, 0xba, 0x0a, |
| 34 | + 0xef, 0xd0, 0x45, 0x0f, 0x34, 0xee); |
| 35 | + |
| 36 | +enum amd_x3d_mode_type { |
| 37 | + MODE_INDEX_FREQ, |
| 38 | + MODE_INDEX_CACHE, |
| 39 | +}; |
| 40 | + |
| 41 | +static const char * const amd_x3d_mode_strings[] = { |
| 42 | + [MODE_INDEX_FREQ] = "frequency", |
| 43 | + [MODE_INDEX_CACHE] = "cache", |
| 44 | +}; |
| 45 | + |
| 46 | +struct amd_x3d_dev { |
| 47 | + struct device *dev; |
| 48 | + acpi_handle ahandle; |
| 49 | + /* To protect x3d mode setting */ |
| 50 | + struct mutex lock; |
| 51 | + enum amd_x3d_mode_type curr_mode; |
| 52 | +}; |
| 53 | + |
| 54 | +static int amd_x3d_get_mode(struct amd_x3d_dev *data) |
| 55 | +{ |
| 56 | + guard(mutex)(&data->lock); |
| 57 | + |
| 58 | + return data->curr_mode; |
| 59 | +} |
| 60 | + |
| 61 | +static int amd_x3d_mode_switch(struct amd_x3d_dev *data, int new_state) |
| 62 | +{ |
| 63 | + union acpi_object *out, argv; |
| 64 | + |
| 65 | + guard(mutex)(&data->lock); |
| 66 | + argv.type = ACPI_TYPE_INTEGER; |
| 67 | + argv.integer.value = new_state; |
| 68 | + |
| 69 | + out = acpi_evaluate_dsm(data->ahandle, &x3d_guid, DSM_REVISION_ID, |
| 70 | + DSM_SET_X3D_MODE, &argv); |
| 71 | + if (!out) { |
| 72 | + dev_err(data->dev, "failed to evaluate _DSM\n"); |
| 73 | + return -EINVAL; |
| 74 | + } |
| 75 | + |
| 76 | + data->curr_mode = new_state; |
| 77 | + |
| 78 | + kfree(out); |
| 79 | + |
| 80 | + return 0; |
| 81 | +} |
| 82 | + |
| 83 | +static ssize_t amd_x3d_mode_store(struct device *dev, struct device_attribute *attr, |
| 84 | + const char *buf, size_t count) |
| 85 | +{ |
| 86 | + struct amd_x3d_dev *data = dev_get_drvdata(dev); |
| 87 | + int ret; |
| 88 | + |
| 89 | + ret = sysfs_match_string(amd_x3d_mode_strings, buf); |
| 90 | + if (ret < 0) |
| 91 | + return ret; |
| 92 | + |
| 93 | + ret = amd_x3d_mode_switch(data, ret); |
| 94 | + if (ret < 0) |
| 95 | + return ret; |
| 96 | + |
| 97 | + return count; |
| 98 | +} |
| 99 | + |
| 100 | +static ssize_t amd_x3d_mode_show(struct device *dev, struct device_attribute *attr, char *buf) |
| 101 | +{ |
| 102 | + struct amd_x3d_dev *data = dev_get_drvdata(dev); |
| 103 | + int mode = amd_x3d_get_mode(data); |
| 104 | + |
| 105 | + return sysfs_emit(buf, "%s\n", amd_x3d_mode_strings[mode]); |
| 106 | +} |
| 107 | +static DEVICE_ATTR_RW(amd_x3d_mode); |
| 108 | + |
| 109 | +static struct attribute *amd_x3d_attrs[] = { |
| 110 | + &dev_attr_amd_x3d_mode.attr, |
| 111 | + NULL |
| 112 | +}; |
| 113 | +ATTRIBUTE_GROUPS(amd_x3d); |
| 114 | + |
| 115 | +static int amd_x3d_resume_handler(struct device *dev) |
| 116 | +{ |
| 117 | + struct amd_x3d_dev *data = dev_get_drvdata(dev); |
| 118 | + int ret = amd_x3d_get_mode(data); |
| 119 | + |
| 120 | + return amd_x3d_mode_switch(data, ret); |
| 121 | +} |
| 122 | + |
| 123 | +static DEFINE_SIMPLE_DEV_PM_OPS(amd_x3d_pm, NULL, amd_x3d_resume_handler); |
| 124 | + |
| 125 | +static const struct acpi_device_id amd_x3d_acpi_ids[] = { |
| 126 | + {"AMDI0101"}, |
| 127 | + { }, |
| 128 | +}; |
| 129 | +MODULE_DEVICE_TABLE(acpi, amd_x3d_acpi_ids); |
| 130 | + |
| 131 | +static int amd_x3d_probe(struct platform_device *pdev) |
| 132 | +{ |
| 133 | + struct amd_x3d_dev *data; |
| 134 | + acpi_handle handle; |
| 135 | + int ret; |
| 136 | + |
| 137 | + handle = ACPI_HANDLE(&pdev->dev); |
| 138 | + if (!handle) |
| 139 | + return -ENODEV; |
| 140 | + |
| 141 | + if (!acpi_check_dsm(handle, &x3d_guid, DSM_REVISION_ID, BIT(DSM_SET_X3D_MODE))) |
| 142 | + return -ENODEV; |
| 143 | + |
| 144 | + data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); |
| 145 | + if (!data) |
| 146 | + return -ENOMEM; |
| 147 | + |
| 148 | + data->dev = &pdev->dev; |
| 149 | + |
| 150 | + ret = devm_mutex_init(data->dev, &data->lock); |
| 151 | + if (ret) |
| 152 | + return ret; |
| 153 | + |
| 154 | + data->ahandle = handle; |
| 155 | + platform_set_drvdata(pdev, data); |
| 156 | + |
| 157 | + ret = match_string(amd_x3d_mode_strings, ARRAY_SIZE(amd_x3d_mode_strings), x3d_mode); |
| 158 | + if (ret < 0) |
| 159 | + return dev_err_probe(&pdev->dev, -EINVAL, "invalid mode %s\n", x3d_mode); |
| 160 | + |
| 161 | + return amd_x3d_mode_switch(data, ret); |
| 162 | +} |
| 163 | + |
| 164 | +static struct platform_driver amd_3d_vcache_driver = { |
| 165 | + .driver = { |
| 166 | + .name = "amd_x3d_vcache", |
| 167 | + .dev_groups = amd_x3d_groups, |
| 168 | + .acpi_match_table = amd_x3d_acpi_ids, |
| 169 | + .pm = pm_sleep_ptr(&amd_x3d_pm), |
| 170 | + }, |
| 171 | + .probe = amd_x3d_probe, |
| 172 | +}; |
| 173 | +module_platform_driver(amd_3d_vcache_driver); |
| 174 | + |
| 175 | +MODULE_DESCRIPTION("AMD 3D V-Cache Performance Optimizer Driver"); |
| 176 | +MODULE_LICENSE("GPL"); |
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