1// SPDX-License-Identifier: GPL-2.0 2/* sercos3: UIO driver for the Automata Sercos III PCI card 3 4 Copyright (C) 2008 Linutronix GmbH 5 Author: John Ogness <john.ogness@linutronix.de> 6 7 This is a straight-forward UIO driver, where interrupts are disabled 8 by the interrupt handler and re-enabled via a write to the UIO device 9 by the userspace-part. 10 11 The only part that may seem odd is the use of a logical OR when 12 storing and restoring enabled interrupts. This is done because the 13 userspace-part could directly modify the Interrupt Enable Register 14 at any time. To reduce possible conflicts, the kernel driver uses 15 a logical OR to make more controlled changes (rather than blindly 16 overwriting previous values). 17 18 Race conditions exist if the userspace-part directly modifies the 19 Interrupt Enable Register while in operation. The consequences are 20 that certain interrupts would fail to be enabled or disabled. For 21 this reason, the userspace-part should only directly modify the 22 Interrupt Enable Register at the beginning (to get things going). 23 The userspace-part can safely disable interrupts at any time using 24 a write to the UIO device. 25*/ 26 27#include <linux/device.h> 28#include <linux/module.h> 29#include <linux/pci.h> 30#include <linux/uio_driver.h> 31#include <linux/io.h> 32#include <linux/slab.h> 33 34/* ID's for SERCOS III PCI card (PLX 9030) */ 35#define SERCOS_SUB_VENDOR_ID 0x1971 36#define SERCOS_SUB_SYSID_3530 0x3530 37#define SERCOS_SUB_SYSID_3535 0x3535 38#define SERCOS_SUB_SYSID_3780 0x3780 39 40/* Interrupt Enable Register */ 41#define IER0_OFFSET 0x08 42 43/* Interrupt Status Register */ 44#define ISR0_OFFSET 0x18 45 46struct sercos3_priv { 47 u32 ier0_cache; 48 spinlock_t ier0_cache_lock; 49}; 50 51/* this function assumes ier0_cache_lock is locked! */ 52static void sercos3_disable_interrupts(struct uio_info *info, 53 struct sercos3_priv *priv) 54{ 55 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 56 57 /* add enabled interrupts to cache */ 58 priv->ier0_cache |= ioread32(ier0); 59 60 /* disable interrupts */ 61 iowrite32(0, ier0); 62} 63 64/* this function assumes ier0_cache_lock is locked! */ 65static void sercos3_enable_interrupts(struct uio_info *info, 66 struct sercos3_priv *priv) 67{ 68 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 69 70 /* restore previously enabled interrupts */ 71 iowrite32(ioread32(ier0) | priv->ier0_cache, ier0); 72 priv->ier0_cache = 0; 73} 74 75static irqreturn_t sercos3_handler(int irq, struct uio_info *info) 76{ 77 struct sercos3_priv *priv = info->priv; 78 void __iomem *isr0 = info->mem[3].internal_addr + ISR0_OFFSET; 79 void __iomem *ier0 = info->mem[3].internal_addr + IER0_OFFSET; 80 81 if (!(ioread32(isr0) & ioread32(ier0))) 82 return IRQ_NONE; 83 84 spin_lock(&priv->ier0_cache_lock); 85 sercos3_disable_interrupts(info, priv); 86 spin_unlock(&priv->ier0_cache_lock); 87 88 return IRQ_HANDLED; 89} 90 91static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) 92{ 93 struct sercos3_priv *priv = info->priv; 94 95 spin_lock_irq(&priv->ier0_cache_lock); 96 if (irq_on) 97 sercos3_enable_interrupts(info, priv); 98 else 99 sercos3_disable_interrupts(info, priv); 100 spin_unlock_irq(&priv->ier0_cache_lock); 101 102 return 0; 103} 104 105static int sercos3_setup_iomem(struct pci_dev *dev, struct uio_info *info, 106 int n, int pci_bar) 107{ 108 info->mem[n].addr = pci_resource_start(dev, pci_bar); 109 if (!info->mem[n].addr) 110 return -1; 111 info->mem[n].internal_addr = ioremap(pci_resource_start(dev, pci_bar), 112 pci_resource_len(dev, pci_bar)); 113 if (!info->mem[n].internal_addr) 114 return -1; 115 info->mem[n].size = pci_resource_len(dev, pci_bar); 116 info->mem[n].memtype = UIO_MEM_PHYS; 117 return 0; 118} 119 120static int sercos3_pci_probe(struct pci_dev *dev, 121 const struct pci_device_id *id) 122{ 123 struct uio_info *info; 124 struct sercos3_priv *priv; 125 int i; 126 127 info = kzalloc(sizeof(struct uio_info), GFP_KERNEL); 128 if (!info) 129 return -ENOMEM; 130 131 priv = kzalloc(sizeof(struct sercos3_priv), GFP_KERNEL); 132 if (!priv) 133 goto out_free; 134 135 if (pci_enable_device(dev)) 136 goto out_free_priv; 137 138 if (pci_request_regions(dev, "sercos3")) 139 goto out_disable; 140 141 /* we only need PCI BAR's 0, 2, 3, 4, 5 */ 142 if (sercos3_setup_iomem(dev, info, 0, 0)) 143 goto out_unmap; 144 if (sercos3_setup_iomem(dev, info, 1, 2)) 145 goto out_unmap; 146 if (sercos3_setup_iomem(dev, info, 2, 3)) 147 goto out_unmap; 148 if (sercos3_setup_iomem(dev, info, 3, 4)) 149 goto out_unmap; 150 if (sercos3_setup_iomem(dev, info, 4, 5)) 151 goto out_unmap; 152 153 spin_lock_init(&priv->ier0_cache_lock); 154 info->priv = priv; 155 info->name = "Sercos_III_PCI"; 156 info->version = "0.0.1"; 157 info->irq = dev->irq; 158 info->irq_flags = IRQF_SHARED; 159 info->handler = sercos3_handler; 160 info->irqcontrol = sercos3_irqcontrol; 161 162 pci_set_drvdata(dev, info); 163 164 if (uio_register_device(&dev->dev, info)) 165 goto out_unmap; 166 167 return 0; 168 169out_unmap: 170 for (i = 0; i < 5; i++) { 171 if (info->mem[i].internal_addr) 172 iounmap(info->mem[i].internal_addr); 173 } 174 pci_release_regions(dev); 175out_disable: 176 pci_disable_device(dev); 177out_free_priv: 178 kfree(priv); 179out_free: 180 kfree(info); 181 return -ENODEV; 182} 183 184static void sercos3_pci_remove(struct pci_dev *dev) 185{ 186 struct uio_info *info = pci_get_drvdata(dev); 187 int i; 188 189 uio_unregister_device(info); 190 pci_release_regions(dev); 191 pci_disable_device(dev); 192 for (i = 0; i < 5; i++) { 193 if (info->mem[i].internal_addr) 194 iounmap(info->mem[i].internal_addr); 195 } 196 kfree(info->priv); 197 kfree(info); 198} 199 200static struct pci_device_id sercos3_pci_ids[] = { 201 { 202 .vendor = PCI_VENDOR_ID_PLX, 203 .device = PCI_DEVICE_ID_PLX_9030, 204 .subvendor = SERCOS_SUB_VENDOR_ID, 205 .subdevice = SERCOS_SUB_SYSID_3530, 206 }, 207 { 208 .vendor = PCI_VENDOR_ID_PLX, 209 .device = PCI_DEVICE_ID_PLX_9030, 210 .subvendor = SERCOS_SUB_VENDOR_ID, 211 .subdevice = SERCOS_SUB_SYSID_3535, 212 }, 213 { 214 .vendor = PCI_VENDOR_ID_PLX, 215 .device = PCI_DEVICE_ID_PLX_9030, 216 .subvendor = SERCOS_SUB_VENDOR_ID, 217 .subdevice = SERCOS_SUB_SYSID_3780, 218 }, 219 { 0, } 220}; 221 222static struct pci_driver sercos3_pci_driver = { 223 .name = "sercos3", 224 .id_table = sercos3_pci_ids, 225 .probe = sercos3_pci_probe, 226 .remove = sercos3_pci_remove, 227}; 228 229module_pci_driver(sercos3_pci_driver); 230MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card"); 231MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>"); 232MODULE_LICENSE("GPL v2"); 233