1 // SPDX-License-Identifier: GPL-2.0+ 2 /* 3 * Pvpanic MMIO Device Support 4 * 5 * Copyright (C) 2013 Fujitsu. 6 * Copyright (C) 2018 ZTE. 7 * Copyright (C) 2021 Oracle. 8 */ 9 10 #include <linux/io.h> 11 #include <linux/kernel.h> 12 #include <linux/kexec.h> 13 #include <linux/mod_devicetable.h> 14 #include <linux/module.h> 15 #include <linux/platform_device.h> 16 #include <linux/types.h> 17 #include <linux/slab.h> 18 19 #include <uapi/misc/pvpanic.h> 20 21 #include "pvpanic.h" 22 23 MODULE_AUTHOR("Hu Tao <hutao@cn.fujitsu.com>"); 24 MODULE_DESCRIPTION("pvpanic-mmio device driver"); 25 MODULE_LICENSE("GPL"); 26 27 static ssize_t capability_show(struct device *dev, struct device_attribute *attr, char *buf) 28 { 29 struct pvpanic_instance *pi = dev_get_drvdata(dev); 30 31 return sysfs_emit(buf, "%x\n", pi->capability); 32 } 33 static DEVICE_ATTR_RO(capability); 34 35 static ssize_t events_show(struct device *dev, struct device_attribute *attr, char *buf) 36 { 37 struct pvpanic_instance *pi = dev_get_drvdata(dev); 38 39 return sysfs_emit(buf, "%x\n", pi->events); 40 } 41 42 static ssize_t events_store(struct device *dev, struct device_attribute *attr, 43 const char *buf, size_t count) 44 { 45 struct pvpanic_instance *pi = dev_get_drvdata(dev); 46 unsigned int tmp; 47 int err; 48 49 err = kstrtouint(buf, 16, &tmp); 50 if (err) 51 return err; 52 53 if ((tmp & pi->capability) != tmp) 54 return -EINVAL; 55 56 pi->events = tmp; 57 58 return count; 59 } 60 static DEVICE_ATTR_RW(events); 61 62 static struct attribute *pvpanic_mmio_dev_attrs[] = { 63 &dev_attr_capability.attr, 64 &dev_attr_events.attr, 65 NULL 66 }; 67 ATTRIBUTE_GROUPS(pvpanic_mmio_dev); 68 69 static int pvpanic_mmio_probe(struct platform_device *pdev) 70 { 71 struct device *dev = &pdev->dev; 72 struct pvpanic_instance *pi; 73 struct resource *res; 74 void __iomem *base; 75 76 res = platform_get_mem_or_io(pdev, 0); 77 if (!res) 78 return -EINVAL; 79 80 switch (resource_type(res)) { 81 case IORESOURCE_IO: 82 base = devm_ioport_map(dev, res->start, resource_size(res)); 83 if (!base) 84 return -ENOMEM; 85 break; 86 case IORESOURCE_MEM: 87 base = devm_ioremap_resource(dev, res); 88 if (IS_ERR(base)) 89 return PTR_ERR(base); 90 break; 91 default: 92 return -EINVAL; 93 } 94 95 pi = devm_kmalloc(dev, sizeof(*pi), GFP_KERNEL); 96 if (!pi) 97 return -ENOMEM; 98 99 pi->base = base; 100 pi->capability = PVPANIC_PANICKED | PVPANIC_CRASH_LOADED; 101 102 /* initialize capability by RDPT */ 103 pi->capability &= ioread8(base); 104 pi->events = pi->capability; 105 106 return devm_pvpanic_probe(dev, pi); 107 } 108 109 static const struct of_device_id pvpanic_mmio_match[] = { 110 { .compatible = "qemu,pvpanic-mmio", }, 111 {} 112 }; 113 MODULE_DEVICE_TABLE(of, pvpanic_mmio_match); 114 115 static const struct acpi_device_id pvpanic_device_ids[] = { 116 { "QEMU0001", 0 }, 117 { "", 0 } 118 }; 119 MODULE_DEVICE_TABLE(acpi, pvpanic_device_ids); 120 121 static struct platform_driver pvpanic_mmio_driver = { 122 .driver = { 123 .name = "pvpanic-mmio", 124 .of_match_table = pvpanic_mmio_match, 125 .acpi_match_table = pvpanic_device_ids, 126 .dev_groups = pvpanic_mmio_dev_groups, 127 }, 128 .probe = pvpanic_mmio_probe, 129 }; 130 module_platform_driver(pvpanic_mmio_driver); 131