linux/drivers/platform/goldfish/pdev_bus.c
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   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
  40struct pdev_bus_dev {
  41        struct list_head list;
  42        struct platform_device pdev;
  43        struct resource resources[0];
  44};
  45
  46static void goldfish_pdev_worker(struct work_struct *work);
  47
  48static void __iomem *pdev_bus_base;
  49static unsigned long pdev_bus_addr;
  50static unsigned long pdev_bus_len;
  51static u32 pdev_bus_irq;
  52static LIST_HEAD(pdev_bus_new_devices);
  53static LIST_HEAD(pdev_bus_registered_devices);
  54static LIST_HEAD(pdev_bus_removed_devices);
  55static DECLARE_WORK(pdev_bus_worker, goldfish_pdev_worker);
  56
  57
  58static 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
  78static 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
 103static 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
 153static 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
 175static 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
 217free_map:
 218        iounmap(pdev_bus_base);
 219free_resources:
 220        release_mem_region(pdev_bus_addr, pdev_bus_len);
 221        return ret;
 222}
 223
 224static 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
 232static 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
 240module_platform_driver(goldfish_pdev_bus_driver);
 241
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