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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 | // SPDX-License-Identifier: GPL-2.0 /* sercos3: UIO driver for the Automata Sercos III PCI card Copyright (C) 2008 Linutronix GmbH Author: John Ogness <john.ogness@linutronix.de> This is a straight-forward UIO driver, where interrupts are disabled by the interrupt handler and re-enabled via a write to the UIO device by the userspace-part. The only part that may seem odd is the use of a logical OR when storing and restoring enabled interrupts. This is done because the userspace-part could directly modify the Interrupt Enable Register at any time. To reduce possible conflicts, the kernel driver uses a logical OR to make more controlled changes (rather than blindly overwriting previous values). Race conditions exist if the userspace-part directly modifies the Interrupt Enable Register while in operation. The consequences are that certain interrupts would fail to be enabled or disabled. For this reason, the userspace-part should only directly modify the Interrupt Enable Register at the beginning (to get things going). The userspace-part can safely disable interrupts at any time using a write to the UIO device. */ #include <linux/device.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/uio_driver.h> #include <linux/io.h> #include <linux/slab.h> /* ID's for SERCOS III PCI card (PLX 9030) */ #define SERCOS_SUB_VENDOR_ID 0x1971 #define SERCOS_SUB_SYSID_3530 0x3530 #define SERCOS_SUB_SYSID_3535 0x3535 #define SERCOS_SUB_SYSID_3780 0x3780 /* Interrupt Enable Register */ #define IER0_OFFSET 0x08 /* Interrupt Status Register */ #define ISR0_OFFSET 0x18 struct sercos3_priv { u32 ier0_cache; spinlock_t ier0_cache_lock; }; /* this function assumes ier0_cache_lock is locked! */ static void sercos3_disable_interrupts(struct uio_info *info, struct sercos3_priv *priv) { void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; /* add enabled interrupts to cache */ priv->ier0_cache |= ioread32(ier0); /* disable interrupts */ iowrite32(0, ier0); } /* this function assumes ier0_cache_lock is locked! */ static void sercos3_enable_interrupts(struct uio_info *info, struct sercos3_priv *priv) { void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; /* restore previously enabled interrupts */ iowrite32(ioread32(ier0) | priv->ier0_cache, ier0); priv->ier0_cache = 0; } static irqreturn_t sercos3_handler(int irq, struct uio_info *info) { struct sercos3_priv *priv = info->priv; void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET; void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; if (!(ioread32(isr0) & ioread32(ier0))) return IRQ_NONE; spin_lock(&priv->ier0_cache_lock); sercos3_disable_interrupts(info, priv); spin_unlock(&priv->ier0_cache_lock); return IRQ_HANDLED; } static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) { struct sercos3_priv *priv = info->priv; spin_lock_irq(&priv->ier0_cache_lock); if (irq_on) sercos3_enable_interrupts(info, priv); else sercos3_disable_interrupts(info, priv); spin_unlock_irq(&priv->ier0_cache_lock); return 0; } static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info, int n, int pci_bar) { info->mem[n].addr = pci_resource_start(dev, pci_bar); if (!info->mem[n].addr) return -1; info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar), pci_resource_len(dev, pci_bar)); if (!info->mem[n].internal_addr) return -1; info->mem[n].size = pci_resource_len(dev, pci_bar); info->mem[n].memtype = UIO_MEM_PHYS; return 0; } static int sercos3_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) { struct uio_info *info; struct sercos3_priv *priv; int i; info = devm_kzalloc(&dev->dev, sizeof(struct uio_info), GFP_KERNEL); if (!info) return -ENOMEM; priv = devm_kzalloc(&dev->dev, sizeof(struct sercos3_priv), GFP_KERNEL); if (!priv) return -ENOMEM; if (pci_enable_device(dev)) return -ENODEV; if (pci_request_regions(dev, "sercos3")) goto out_disable; /* we only need PCI BAR's 0, 2, 3, 4, 5 */ if (sercos3_setup_iomem(dev, info, 0, 0)) goto out_unmap; if (sercos3_setup_iomem(dev, info, 1, 2)) goto out_unmap; if (sercos3_setup_iomem(dev, info, 2, 3)) goto out_unmap; if (sercos3_setup_iomem(dev, info, 3, 4)) goto out_unmap; if (sercos3_setup_iomem(dev, info, 4, 5)) goto out_unmap; spin_lock_init(&priv->ier0_cache_lock); info->priv = priv; info->name = "Sercos_III_PCI"; info->version = "0.0.1"; info->irq = dev->irq; info->irq_flags = IRQF_SHARED; info->handler = sercos3_handler; info->irqcontrol = sercos3_irqcontrol; pci_set_drvdata(dev, info); if (uio_register_device(&dev->dev, info)) goto out_unmap; return 0; out_unmap: for (i = 0; i < 5; i++) { if (info->mem[i].internal_addr) iounmap(info->mem[i].internal_addr); } pci_release_regions(dev); out_disable: pci_disable_device(dev); return -ENODEV; } static void sercos3_pci_remove(struct pci_dev *dev) { struct uio_info *info = pci_get_drvdata(dev); int i; uio_unregister_device(info); pci_release_regions(dev); pci_disable_device(dev); for (i = 0; i < 5; i++) { if (info->mem[i].internal_addr) iounmap(info->mem[i].internal_addr); } } static struct pci_device_id sercos3_pci_ids[] = { { .vendor = PCI_VENDOR_ID_PLX, .device = PCI_DEVICE_ID_PLX_9030, .subvendor = SERCOS_SUB_VENDOR_ID, .subdevice = SERCOS_SUB_SYSID_3530, }, { .vendor = PCI_VENDOR_ID_PLX, .device = PCI_DEVICE_ID_PLX_9030, .subvendor = SERCOS_SUB_VENDOR_ID, .subdevice = SERCOS_SUB_SYSID_3535, }, { .vendor = PCI_VENDOR_ID_PLX, .device = PCI_DEVICE_ID_PLX_9030, .subvendor = SERCOS_SUB_VENDOR_ID, .subdevice = SERCOS_SUB_SYSID_3780, }, { 0, } }; static struct pci_driver sercos3_pci_driver = { .name = "sercos3", .id_table = sercos3_pci_ids, .probe = sercos3_pci_probe, .remove = sercos3_pci_remove, }; module_pci_driver(sercos3_pci_driver); MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>"); MODULE_LICENSE("GPL v2"); |