| 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"); |