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 | |
46 | struct sercos3_priv { |
47 | u32 ier0_cache; |
48 | spinlock_t ier0_cache_lock; |
49 | }; |
50 | |
51 | /* this function assumes ier0_cache_lock is locked! */ |
52 | static 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! */ |
65 | static 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 | |
75 | static 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(lock: &priv->ier0_cache_lock); |
85 | sercos3_disable_interrupts(info, priv); |
86 | spin_unlock(lock: &priv->ier0_cache_lock); |
87 | |
88 | return IRQ_HANDLED; |
89 | } |
90 | |
91 | static int sercos3_irqcontrol(struct uio_info *info, s32 irq_on) |
92 | { |
93 | struct sercos3_priv *priv = info->priv; |
94 | |
95 | spin_lock_irq(lock: &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(lock: &priv->ier0_cache_lock); |
101 | |
102 | return 0; |
103 | } |
104 | |
105 | static 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 | |
120 | static 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 = devm_kzalloc(dev: &dev->dev, size: sizeof(struct uio_info), GFP_KERNEL); |
128 | if (!info) |
129 | return -ENOMEM; |
130 | |
131 | priv = devm_kzalloc(dev: &dev->dev, size: sizeof(struct sercos3_priv), GFP_KERNEL); |
132 | if (!priv) |
133 | return -ENOMEM; |
134 | |
135 | if (pci_enable_device(dev)) |
136 | return -ENODEV; |
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, n: 0, pci_bar: 0)) |
143 | goto out_unmap; |
144 | if (sercos3_setup_iomem(dev, info, n: 1, pci_bar: 2)) |
145 | goto out_unmap; |
146 | if (sercos3_setup_iomem(dev, info, n: 2, pci_bar: 3)) |
147 | goto out_unmap; |
148 | if (sercos3_setup_iomem(dev, info, n: 3, pci_bar: 4)) |
149 | goto out_unmap; |
150 | if (sercos3_setup_iomem(dev, info, n: 4, pci_bar: 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(pdev: dev, data: info); |
163 | |
164 | if (uio_register_device(&dev->dev, info)) |
165 | goto out_unmap; |
166 | |
167 | return 0; |
168 | |
169 | out_unmap: |
170 | for (i = 0; i < 5; i++) { |
171 | if (info->mem[i].internal_addr) |
172 | iounmap(addr: info->mem[i].internal_addr); |
173 | } |
174 | pci_release_regions(dev); |
175 | out_disable: |
176 | pci_disable_device(dev); |
177 | return -ENODEV; |
178 | } |
179 | |
180 | static void sercos3_pci_remove(struct pci_dev *dev) |
181 | { |
182 | struct uio_info *info = pci_get_drvdata(pdev: dev); |
183 | int i; |
184 | |
185 | uio_unregister_device(info); |
186 | pci_release_regions(dev); |
187 | pci_disable_device(dev); |
188 | for (i = 0; i < 5; i++) { |
189 | if (info->mem[i].internal_addr) |
190 | iounmap(addr: info->mem[i].internal_addr); |
191 | } |
192 | } |
193 | |
194 | static struct pci_device_id sercos3_pci_ids[] = { |
195 | { |
196 | .vendor = PCI_VENDOR_ID_PLX, |
197 | .device = PCI_DEVICE_ID_PLX_9030, |
198 | .subvendor = SERCOS_SUB_VENDOR_ID, |
199 | .subdevice = SERCOS_SUB_SYSID_3530, |
200 | }, |
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_3535, |
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_3780, |
212 | }, |
213 | { 0, } |
214 | }; |
215 | |
216 | static struct pci_driver sercos3_pci_driver = { |
217 | .name = "sercos3" , |
218 | .id_table = sercos3_pci_ids, |
219 | .probe = sercos3_pci_probe, |
220 | .remove = sercos3_pci_remove, |
221 | }; |
222 | |
223 | module_pci_driver(sercos3_pci_driver); |
224 | MODULE_DESCRIPTION("UIO driver for the Automata Sercos III PCI card" ); |
225 | MODULE_AUTHOR("John Ogness <john.ogness@linutronix.de>" ); |
226 | MODULE_LICENSE("GPL v2" ); |
227 | |