linux-imx
Public
Source
committed c221c0b03081
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// SPDX-License-Identifier: GPL-2.02
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/* Copyright(c) 2016-2019 Intel Corporation. All rights reserved. */3
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int dev_dax_kmem_probe(struct device *dev)18
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{19
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struct dev_dax *dev_dax = to_dev_dax(dev);20
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struct resource *res = &dev_dax->region->res;21
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resource_size_t kmem_start;22
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resource_size_t kmem_size;23
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resource_size_t kmem_end;24
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struct resource *new_res;25
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int numa_node;26
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int rc;27
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/*29
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* Ensure good NUMA information for the persistent memory.30
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* Without this check, there is a risk that slow memory31
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* could be mixed in a node with faster memory, causing32
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* unavoidable performance issues.33
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*/34
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numa_node = dev_dax->target_node;35
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if (numa_node < 0) {36
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dev_warn(dev, "rejecting DAX region %pR with invalid node: %d\n",37
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res, numa_node);38
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return -EINVAL;39
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}40
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/* Hotplug starting at the beginning of the next block: */42
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kmem_start = ALIGN(res->start, memory_block_size_bytes());43
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kmem_size = resource_size(res);45
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/* Adjust the size down to compensate for moving up kmem_start: */46
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kmem_size -= kmem_start - res->start;47
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/* Align the size down to cover only complete blocks: */48
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kmem_size &= ~(memory_block_size_bytes() - 1);49
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kmem_end = kmem_start + kmem_size;50
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/* Region is permanently reserved. Hot-remove not yet implemented. */52
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new_res = request_mem_region(kmem_start, kmem_size, dev_name(dev));53
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if (!new_res) {54
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dev_warn(dev, "could not reserve region [%pa-%pa]\n",55
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&kmem_start, &kmem_end);56
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return -EBUSY;57
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}58
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/*60
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* Set flags appropriate for System RAM. Leave ..._BUSY clear61
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* so that add_memory() can add a child resource. Do not62
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* inherit flags from the parent since it may set new flags63
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* unknown to us that will break add_memory() below.64
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*/65
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new_res->flags = IORESOURCE_SYSTEM_RAM;66
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new_res->name = dev_name(dev);67
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rc = add_memory(numa_node, new_res->start, resource_size(new_res));69
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if (rc)70
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return rc;71
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return 0;73
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}74
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static int dev_dax_kmem_remove(struct device *dev)76
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{77
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/*78
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* Purposely leak the request_mem_region() for the device-dax79
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* range and return '0' to ->remove() attempts. The removal of80
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* the device from the driver always succeeds, but the region81
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* is permanently pinned as reserved by the unreleased82
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* request_mem_region().83
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*/84
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return 0;85
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}86
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static struct dax_device_driver device_dax_kmem_driver = {88
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.drv = {89
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.probe = dev_dax_kmem_probe,90
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.remove = dev_dax_kmem_remove,91
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},92
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};93
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static int __init dax_kmem_init(void)95
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{96
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return dax_driver_register(&device_dax_kmem_driver);97
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}98
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static void __exit dax_kmem_exit(void)100
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{101
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dax_driver_unregister(&device_dax_kmem_driver);102
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}103
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MODULE_AUTHOR("Intel Corporation");105
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MODULE_LICENSE("GPL v2");106
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module_init(dax_kmem_init);107
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module_exit(dax_kmem_exit);108
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MODULE_ALIAS_DAX_DEVICE(0);