drivers/platform/goldfish/pdev_bus.c

   1 /*
   2  * Copyright (C) 2007 Google, Inc.
   3  * Copyright (C) 2011 Intel, Inc.
   4  * Copyright (C) 2013 Intel, Inc.
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/init.h>
  19 #include <linux/interrupt.h>
  20 #include <linux/irq.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/slab.h>
  23 #include <linux/io.h>
  24
  25 #define PDEV_BUS_OP_DONE        (0x00)
  26 #define PDEV_BUS_OP_REMOVE_DEV  (0x04)
  27 #define PDEV_BUS_OP_ADD_DEV     (0x08)
  28
  29 #define PDEV_BUS_OP_INIT        (0x00)
  30
  31 #define PDEV_BUS_OP             (0x00)
  32 #define PDEV_BUS_GET_NAME       (0x04)
  33 #define PDEV_BUS_NAME_LEN       (0x08)
  34 #define PDEV_BUS_ID             (0x0c)
  35 #define PDEV_BUS_IO_BASE        (0x10)
  36 #define PDEV_BUS_IO_SIZE        (0x14)
  37 #define PDEV_BUS_IRQ            (0x18)
  38 #define PDEV_BUS_IRQ_COUNT      (0x1c)
  39
  40 struct pdev_bus_dev {
  41         struct list_head list;
  42         struct platform_device pdev;
  43         struct resource resources[0];
  44 };
  45
  46 static void goldfish_pdev_worker(struct work_struct *work);
  47
  48 static void __iomem *pdev_bus_base;
  49 static unsigned long pdev_bus_addr;
  50 static unsigned long pdev_bus_len;
  51 static u32 pdev_bus_irq;
  52 static LIST_HEAD(pdev_bus_new_devices);
  53 static LIST_HEAD(pdev_bus_registered_devices);
  54 static LIST_HEAD(pdev_bus_removed_devices);
  55 static DECLARE_WORK(pdev_bus_worker, goldfish_pdev_worker);
  56
  57
  58 static void goldfish_pdev_worker(struct work_struct *work)
  59 {
  60         int ret;
  61         struct pdev_bus_dev *pos, *n;
  62
  63         list_for_each_entry_safe(pos, n, &pdev_bus_removed_devices, list) {
  64                 list_del(&pos->list);
  65                 platform_device_unregister(&pos->pdev);
  66                 kfree(pos);
  67         }
  68         list_for_each_entry_safe(pos, n, &pdev_bus_new_devices, list) {
  69                 list_del(&pos->list);
  70                 ret = platform_device_register(&pos->pdev);
  71                 if (ret)
  72                         pr_err("goldfish_pdev_worker failed to register device, %s\n",
  73                                                                 pos->pdev.name);
  74                 list_add_tail(&pos->list, &pdev_bus_registered_devices);
  75         }
  76 }
  77
  78 static void goldfish_pdev_remove(void)
  79 {
  80         struct pdev_bus_dev *pos, *n;
  81         u32 base;
  82
  83         base = readl(pdev_bus_base + PDEV_BUS_IO_BASE);
  84
  85         list_for_each_entry_safe(pos, n, &pdev_bus_new_devices, list) {
  86                 if (pos->resources[0].start == base) {
  87                         list_del(&pos->list);
  88                         kfree(pos);
  89                         return;
  90                 }
  91         }
  92         list_for_each_entry_safe(pos, n, &pdev_bus_registered_devices, list) {
  93                 if (pos->resources[0].start == base) {
  94                         list_del(&pos->list);
  95                         list_add_tail(&pos->list, &pdev_bus_removed_devices);
  96                         schedule_work(&pdev_bus_worker);
  97                         return;
  98                 }
  99         };
 100         pr_err("goldfish_pdev_remove could not find device at %x\n", base);
 101 }
 102
 103 static int goldfish_new_pdev(void)
 104 {
 105         struct pdev_bus_dev *dev;
 106         u32 name_len;
 107         u32 irq = -1, irq_count;
 108         int resource_count = 2;
 109         u32 base;
 110         char *name;
 111
 112         base = readl(pdev_bus_base + PDEV_BUS_IO_BASE);
 113
 114         irq_count = readl(pdev_bus_base + PDEV_BUS_IRQ_COUNT);
 115         name_len = readl(pdev_bus_base + PDEV_BUS_NAME_LEN);
 116         if (irq_count)
 117                 resource_count++;
 118
 119         dev = kzalloc(sizeof(*dev) +
 120                 sizeof(struct resource) * resource_count +
 121                 name_len + 1 + sizeof(*dev->pdev.dev.dma_mask), GFP_ATOMIC);
 122         if (dev == NULL)
 123                 return -ENOMEM;
 124
 125         dev->pdev.num_resources = resource_count;
 126         dev->pdev.resource = (struct resource *)(dev + 1);
 127         dev->pdev.name = name = (char *)(dev->pdev.resource + resource_count);
 128         dev->pdev.dev.coherent_dma_mask = ~0;
 129         dev->pdev.dev.dma_mask = (void *)(dev->pdev.name + name_len + 1);
 130         *dev->pdev.dev.dma_mask = ~0;
 131
 132         writel((unsigned long)name, pdev_bus_base + PDEV_BUS_GET_NAME);
 133         name[name_len] = '\0';
 134         dev->pdev.id = readl(pdev_bus_base + PDEV_BUS_ID);
 135         dev->pdev.resource[0].start = base;
 136         dev->pdev.resource[0].end = base +
 137                                 readl(pdev_bus_base + PDEV_BUS_IO_SIZE) - 1;
 138         dev->pdev.resource[0].flags = IORESOURCE_MEM;
 139         if (irq_count) {
 140                 irq = readl(pdev_bus_base + PDEV_BUS_IRQ);
 141                 dev->pdev.resource[1].start = irq;
 142                 dev->pdev.resource[1].end = irq + irq_count - 1;
 143                 dev->pdev.resource[1].flags = IORESOURCE_IRQ;
 144         }
 145
 146         pr_debug("goldfish_new_pdev %s at %x irq %d\n", name, base, irq);
 147         list_add_tail(&dev->list, &pdev_bus_new_devices);
 148         schedule_work(&pdev_bus_worker);
 149
 150         return 0;
 151 }
 152
 153 static irqreturn_t goldfish_pdev_bus_interrupt(int irq, void *dev_id)
 154 {
 155         irqreturn_t ret = IRQ_NONE;
 156         while (1) {
 157                 u32 op = readl(pdev_bus_base + PDEV_BUS_OP);
 158                 switch (op) {
 159                 case PDEV_BUS_OP_DONE:
 160                         return IRQ_NONE;
 161
 162                 case PDEV_BUS_OP_REMOVE_DEV:
 163                         goldfish_pdev_remove();
 164                         break;
 165
 166                 case PDEV_BUS_OP_ADD_DEV:
 167                         goldfish_new_pdev();
 168                         break;
 169                 }
 170                 ret = IRQ_HANDLED;
 171         }
 172         return ret;
 173 }
 174
 175 static int goldfish_pdev_bus_probe(struct platform_device *pdev)
 176 {
 177         int ret;
 178         struct resource *r;
 179
 180         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 181         if (r == NULL)
 182                 return -EINVAL;
 183
 184         pdev_bus_addr = r->start;
 185         pdev_bus_len = resource_size(r);
 186
 187         if (request_mem_region(pdev_bus_addr, pdev_bus_len, "goldfish")) {
 188                 dev_err(&pdev->dev, "unable to reserve Goldfish MMIO.\n");
 189                 return -EBUSY;
 190         }
 191
 192         pdev_bus_base = ioremap(pdev_bus_addr, pdev_bus_len);
 193         if (pdev_bus_base == NULL) {
 194                 ret = -ENOMEM;
 195                 dev_err(&pdev->dev, "unable to map Goldfish MMIO.\n");
 196                 goto free_resources;
 197         }
 198
 199         r = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 200         if (r == NULL) {
 201                 ret = -ENOENT;
 202                 goto free_map;
 203         }
 204
 205         pdev_bus_irq = r->start;
 206
 207         ret = request_irq(pdev_bus_irq, goldfish_pdev_bus_interrupt,
 208                                 IRQF_SHARED, "goldfish_pdev_bus", pdev);
 209         if (ret) {
 210                 dev_err(&pdev->dev, "unable to request Goldfish IRQ\n");
 211                 goto free_map;
 212         }
 213
 214         writel(PDEV_BUS_OP_INIT, pdev_bus_base + PDEV_BUS_OP);
 215         return 0;
 216
 217 free_map:
 218         iounmap(pdev_bus_base);
 219 free_resources:
 220         release_mem_region(pdev_bus_addr, pdev_bus_len);
 221         return ret;
 222 }
 223
 224 static int goldfish_pdev_bus_remove(struct platform_device *pdev)
 225 {
 226         iounmap(pdev_bus_base);
 227         free_irq(pdev_bus_irq, pdev);
 228         release_mem_region(pdev_bus_addr, pdev_bus_len);
 229         return 0;
 230 }
 231
 232 static struct platform_driver goldfish_pdev_bus_driver = {
 233         .probe = goldfish_pdev_bus_probe,
 234         .remove = goldfish_pdev_bus_remove,
 235         .driver = {
 236                 .name = "goldfish_pdev_bus"
 237         }
 238 };
 239
 240 module_platform_driver(goldfish_pdev_bus_driver);