1 /* sercos3: UIO driver for the Automata Sercos III PCI card 2 3 Copyright (C) 2008 Linutronix GmbH 4 Author: John Ogness <john.ogness@linutronix.de> 5 6 This is a straight-forward UIO driver, where interrupts are disabled 7 by the interrupt handler and re-enabled via a write to the UIO device 8 by the userspace-part. 9 10 The only part that may seem odd is the use of a logical OR when 11 storing and restoring enabled interrupts. This is done because the 12 userspace-part could directly modify the Interrupt Enable Register 13 at any time. To reduce possible conflicts, the kernel driver uses 14 a logical OR to make more controlled changes (rather than blindly 15 overwriting previous values). 16 17 Race conditions exist if the userspace-part directly modifies the 18 Interrupt Enable Register while in operation. The consequences are 19 that certain interrupts would fail to be enabled or disabled. For 20 this reason, the userspace-part should only directly modify the 21 Interrupt Enable Register at the beginning (to get things going). 22 The userspace-part can safely disable interrupts at any time using 23 a write to the UIO device. 24 */ 25 26 #include <linux/device.h> 27 #include <linux/module.h> 28 #include <linux/pci.h> 29 #include <linux/uio_driver.h> 30 #include <linux/io.h> 31 32 /* ID's for SERCOS III PCI card (PLX 9030) */ 33 #define SERCOS_SUB_VENDOR_ID 0x1971 34 #define SERCOS_SUB_SYSID_3530 0x3530 35 #define SERCOS_SUB_SYSID_3535 0x3535 36 #define SERCOS_SUB_SYSID_3780 0x3780 37 38 /* Interrupt Enable Register */ 39 #define IER0_OFFSET 0x08 40 41 /* Interrupt Status Register */ 42 #define ISR0_OFFSET 0x18 43 44 struct sercos3_priv { 45 u32 ier0_cache; 46 spinlock_t ier0_cache_lock; 47 }; 48 49 /* this function assumes ier0_cache_lock is locked! */ 50 static void sercos3_disable_interrupts(struct uio_info *info, 51 struct sercos3_priv *priv) 52 { 53 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 54 55 /* add enabled interrupts to cache */ 56 priv->ier0_cache |= ioread32(ier0); 57 58 /* disable interrupts */ 59 iowrite32(0, ier0); 60 } 61 62 /* this function assumes ier0_cache_lock is locked! */ 63 static void sercos3_enable_interrupts(struct uio_info *info, 64 struct sercos3_priv *priv) 65 { 66 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 67 68 /* restore previously enabled interrupts */ 69 iowrite32(ioread32(ier0) | priv->ier0_cache, ier0); 70 priv->ier0_cache = 0; 71 } 72 73 static irqreturn_t sercos3_handler(int irq, struct uio_info *info) 74 { 75 struct sercos3_priv *priv = info->priv; 76 void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET; 77 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 78 79 if (!(ioread32(isr0) & ioread32(ier0))) 80 return IRQ_NONE; 81 82 spin_lock(&priv->ier0_cache_lock); 83 sercos3_disable_interrupts(info, priv); 84 spin_unlock(&priv->ier0_cache_lock); 85 86 return IRQ_HANDLED; 87 } 88 89 static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) 90 { 91 struct sercos3_priv *priv = info->priv; 92 93 spin_lock_irq(&priv->ier0_cache_lock); 94 if (irq_on) 95 sercos3_enable_interrupts(info, priv); 96 else 97 sercos3_disable_interrupts(info, priv); 98 spin_unlock_irq(&priv->ier0_cache_lock); 99 100 return 0; 101 } 102 103 static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info, 104 int n, int pci_bar) 105 { 106 info->mem[n].addr = pci_resource_start(dev, pci_bar); 107 if (!info->mem[n].addr) 108 return -1; 109 info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar), 110 pci_resource_len(dev, pci_bar)); 111 if (!info->mem[n].internal_addr) 112 return -1; 113 info->mem[n].size = pci_resource_len(dev, pci_bar); 114 info->mem[n].memtype = UIO_MEM_PHYS; 115 return 0; 116 } 117 118 static int __devinit sercos3_pci_probe(struct pci_dev *dev, 119 const struct pci_device_id *id) 120 { 121 struct uio_info *info; 122 struct sercos3_priv *priv; 123 int i; 124 125 info = kzalloc(sizeof(struct uio_info), GFP_KERNEL); 126 if (!info) 127 return -ENOMEM; 128 129 priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL); 130 if (!priv) 131 goto out_free; 132 133 if (pci_enable_device(dev)) 134 goto out_free_priv; 135 136 if (pci_request_regions(dev, "sercos3")) 137 goto out_disable; 138 139 /* we only need PCI BAR's 0, 2, 3, 4, 5 */ 140 if (sercos3_setup_iomem(dev, info, 0, 0)) 141 goto out_unmap; 142 if (sercos3_setup_iomem(dev, info, 1, 2)) 143 goto out_unmap; 144 if (sercos3_setup_iomem(dev, info, 2, 3)) 145 goto out_unmap; 146 if (sercos3_setup_iomem(dev, info, 3, 4)) 147 goto out_unmap; 148 if (sercos3_setup_iomem(dev, info, 4, 5)) 149 goto out_unmap; 150 151 spin_lock_init(&priv->ier0_cache_lock); 152 info->priv = priv; 153 info->name = "Sercos_III_PCI"; 154 info->version = "0.0.1"; 155 info->irq = dev->irq; 156 info->irq_flags = IRQF_DISABLED | IRQF_SHARED; 157 info->handler = sercos3_handler; 158 info->irqcontrol = sercos3_irqcontrol; 159 160 pci_set_drvdata(dev, info); 161 162 if (uio_register_device(&dev->dev, info)) 163 goto out_unmap; 164 165 return 0; 166 167 out_unmap: 168 for (i = 0; i < 5; i++) { 169 if (info->mem[i].internal_addr) 170 iounmap(info->mem[i].internal_addr); 171 } 172 pci_release_regions(dev); 173 out_disable: 174 pci_disable_device(dev); 175 out_free_priv: 176 kfree(priv); 177 out_free: 178 kfree(info); 179 return -ENODEV; 180 } 181 182 static void sercos3_pci_remove(struct pci_dev *dev) 183 { 184 struct uio_info *info = pci_get_drvdata(dev); 185 int i; 186 187 uio_unregister_device(info); 188 pci_release_regions(dev); 189 pci_disable_device(dev); 190 pci_set_drvdata(dev, NULL); 191 for (i = 0; i < 5; i++) { 192 if (info->mem[i].internal_addr) 193 iounmap(info->mem[i].internal_addr); 194 } 195 kfree(info->priv); 196 kfree(info); 197 } 198 199 static struct pci_device_id sercos3_pci_ids[] __devinitdata = { 200 { 201 .vendor = PCI_VENDOR_ID_PLX, 202 .device = PCI_DEVICE_ID_PLX_9030, 203 .subvendor = SERCOS_SUB_VENDOR_ID, 204 .subdevice = SERCOS_SUB_SYSID_3530, 205 }, 206 { 207 .vendor = PCI_VENDOR_ID_PLX, 208 .device = PCI_DEVICE_ID_PLX_9030, 209 .subvendor = SERCOS_SUB_VENDOR_ID, 210 .subdevice = SERCOS_SUB_SYSID_3535, 211 }, 212 { 213 .vendor = PCI_VENDOR_ID_PLX, 214 .device = PCI_DEVICE_ID_PLX_9030, 215 .subvendor = SERCOS_SUB_VENDOR_ID, 216 .subdevice = SERCOS_SUB_SYSID_3780, 217 }, 218 { 0, } 219 }; 220 221 static struct pci_driver sercos3_pci_driver = { 222 .name = "sercos3", 223 .id_table = sercos3_pci_ids, 224 .probe = sercos3_pci_probe, 225 .remove = sercos3_pci_remove, 226 }; 227 228 static int __init sercos3_init_module(void) 229 { 230 return pci_register_driver(&sercos3_pci_driver); 231 } 232 233 static void __exit sercos3_exit_module(void) 234 { 235 pci_unregister_driver(&sercos3_pci_driver); 236 } 237 238 module_init(sercos3_init_module); 239 module_exit(sercos3_exit_module); 240 241 MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); 242 MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>"); 243 MODULE_LICENSE("GPL v2"); 244