| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * drivers/uio/uio_dmem_genirq.c |
| * |
| * Userspace I/O platform driver with generic IRQ handling code. |
| * |
| * Copyright (C) 2012 Damian Hobson-Garcia |
| * |
| * Based on uio_pdrv_genirq.c by Magnus Damm |
| */ |
| |
| #include <linux/platform_device.h> |
| #include <linux/uio_driver.h> |
| #include <linux/spinlock.h> |
| #include <linux/bitops.h> |
| #include <linux/module.h> |
| #include <linux/interrupt.h> |
| #include <linux/platform_data/uio_dmem_genirq.h> |
| #include <linux/stringify.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/slab.h> |
| #include <linux/irq.h> |
| |
| #include <linux/of.h> |
| #include <linux/of_platform.h> |
| #include <linux/of_address.h> |
| |
| #define DRIVER_NAME "uio_dmem_genirq" |
| #define DMEM_MAP_ERROR (~0) |
| |
| struct uio_dmem_genirq_platdata { |
| struct uio_info *uioinfo; |
| spinlock_t lock; |
| unsigned long flags; |
| struct platform_device *pdev; |
| unsigned int dmem_region_start; |
| unsigned int num_dmem_regions; |
| void *dmem_region_vaddr[MAX_UIO_MAPS]; |
| struct mutex alloc_lock; |
| unsigned int refcnt; |
| }; |
| |
| static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode) |
| { |
| struct uio_dmem_genirq_platdata *priv = info->priv; |
| struct uio_mem *uiomem; |
| int dmem_region = priv->dmem_region_start; |
| |
| uiomem = &priv->uioinfo->mem[priv->dmem_region_start]; |
| |
| mutex_lock(&priv->alloc_lock); |
| while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) { |
| void *addr; |
| if (!uiomem->size) |
| break; |
| |
| addr = dma_alloc_coherent(&priv->pdev->dev, uiomem->size, |
| (dma_addr_t *)&uiomem->addr, GFP_KERNEL); |
| if (!addr) { |
| uiomem->addr = DMEM_MAP_ERROR; |
| } |
| priv->dmem_region_vaddr[dmem_region++] = addr; |
| ++uiomem; |
| } |
| priv->refcnt++; |
| |
| mutex_unlock(&priv->alloc_lock); |
| /* Wait until the Runtime PM code has woken up the device */ |
| pm_runtime_get_sync(&priv->pdev->dev); |
| return 0; |
| } |
| |
| static int uio_dmem_genirq_release(struct uio_info *info, struct inode *inode) |
| { |
| struct uio_dmem_genirq_platdata *priv = info->priv; |
| struct uio_mem *uiomem; |
| int dmem_region = priv->dmem_region_start; |
| |
| /* Tell the Runtime PM code that the device has become idle */ |
| pm_runtime_put_sync(&priv->pdev->dev); |
| |
| uiomem = &priv->uioinfo->mem[priv->dmem_region_start]; |
| |
| mutex_lock(&priv->alloc_lock); |
| |
| priv->refcnt--; |
| while (!priv->refcnt && uiomem < &priv->uioinfo->mem[MAX_UIO_MAPS]) { |
| if (!uiomem->size) |
| break; |
| if (priv->dmem_region_vaddr[dmem_region]) { |
| dma_free_coherent(&priv->pdev->dev, uiomem->size, |
| priv->dmem_region_vaddr[dmem_region], |
| uiomem->addr); |
| } |
| uiomem->addr = DMEM_MAP_ERROR; |
| ++dmem_region; |
| ++uiomem; |
| } |
| |
| mutex_unlock(&priv->alloc_lock); |
| return 0; |
| } |
| |
| static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info) |
| { |
| struct uio_dmem_genirq_platdata *priv = dev_info->priv; |
| |
| /* Just disable the interrupt in the interrupt controller, and |
| * remember the state so we can allow user space to enable it later. |
| */ |
| |
| spin_lock(&priv->lock); |
| if (!test_and_set_bit(0, &priv->flags)) |
| disable_irq_nosync(irq); |
| spin_unlock(&priv->lock); |
| |
| return IRQ_HANDLED; |
| } |
| |
| static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on) |
| { |
| struct uio_dmem_genirq_platdata *priv = dev_info->priv; |
| unsigned long flags; |
| |
| /* Allow user space to enable and disable the interrupt |
| * in the interrupt controller, but keep track of the |
| * state to prevent per-irq depth damage. |
| * |
| * Serialize this operation to support multiple tasks and concurrency |
| * with irq handler on SMP systems. |
| */ |
| |
| spin_lock_irqsave(&priv->lock, flags); |
| if (irq_on) { |
| if (test_and_clear_bit(0, &priv->flags)) |
| enable_irq(dev_info->irq); |
| } else { |
| if (!test_and_set_bit(0, &priv->flags)) |
| disable_irq_nosync(dev_info->irq); |
| } |
| spin_unlock_irqrestore(&priv->lock, flags); |
| |
| return 0; |
| } |
| |
| static void uio_dmem_genirq_pm_disable(void *data) |
| { |
| struct device *dev = data; |
| |
| pm_runtime_disable(dev); |
| } |
| |
| static int uio_dmem_genirq_probe(struct platform_device *pdev) |
| { |
| struct uio_dmem_genirq_pdata *pdata = dev_get_platdata(&pdev->dev); |
| struct uio_info *uioinfo = &pdata->uioinfo; |
| struct uio_dmem_genirq_platdata *priv; |
| struct uio_mem *uiomem; |
| int ret = -EINVAL; |
| int i; |
| |
| if (pdev->dev.of_node) { |
| /* alloc uioinfo for one device */ |
| uioinfo = devm_kzalloc(&pdev->dev, sizeof(*uioinfo), GFP_KERNEL); |
| if (!uioinfo) { |
| dev_err(&pdev->dev, "unable to kmalloc\n"); |
| return -ENOMEM; |
| } |
| uioinfo->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", |
| pdev->dev.of_node); |
| uioinfo->version = "devicetree"; |
| } |
| |
| if (!uioinfo || !uioinfo->name || !uioinfo->version) { |
| dev_err(&pdev->dev, "missing platform_data\n"); |
| return -EINVAL; |
| } |
| |
| if (uioinfo->handler || uioinfo->irqcontrol || |
| uioinfo->irq_flags & IRQF_SHARED) { |
| dev_err(&pdev->dev, "interrupt configuration error\n"); |
| return -EINVAL; |
| } |
| |
| priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
| if (!priv) { |
| dev_err(&pdev->dev, "unable to kmalloc\n"); |
| return -ENOMEM; |
| } |
| |
| ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32)); |
| if (ret) { |
| dev_err(&pdev->dev, "DMA enable failed\n"); |
| return ret; |
| } |
| |
| priv->uioinfo = uioinfo; |
| spin_lock_init(&priv->lock); |
| priv->flags = 0; /* interrupt is enabled to begin with */ |
| priv->pdev = pdev; |
| mutex_init(&priv->alloc_lock); |
| |
| if (!uioinfo->irq) { |
| /* Multiple IRQs are not supported */ |
| ret = platform_get_irq(pdev, 0); |
| if (ret == -ENXIO && pdev->dev.of_node) |
| ret = UIO_IRQ_NONE; |
| else if (ret < 0) |
| return ret; |
| uioinfo->irq = ret; |
| } |
| |
| if (uioinfo->irq) { |
| struct irq_data *irq_data = irq_get_irq_data(uioinfo->irq); |
| |
| /* |
| * If a level interrupt, dont do lazy disable. Otherwise the |
| * irq will fire again since clearing of the actual cause, on |
| * device level, is done in userspace |
| * irqd_is_level_type() isn't used since isn't valid until |
| * irq is configured. |
| */ |
| if (irq_data && |
| irqd_get_trigger_type(irq_data) & IRQ_TYPE_LEVEL_MASK) { |
| dev_dbg(&pdev->dev, "disable lazy unmask\n"); |
| irq_set_status_flags(uioinfo->irq, IRQ_DISABLE_UNLAZY); |
| } |
| } |
| |
| uiomem = &uioinfo->mem[0]; |
| |
| for (i = 0; i < pdev->num_resources; ++i) { |
| struct resource *r = &pdev->resource[i]; |
| |
| if (r->flags != IORESOURCE_MEM) |
| continue; |
| |
| if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { |
| dev_warn(&pdev->dev, "device has more than " |
| __stringify(MAX_UIO_MAPS) |
| " I/O memory resources.\n"); |
| break; |
| } |
| |
| uiomem->memtype = UIO_MEM_PHYS; |
| uiomem->addr = r->start; |
| uiomem->size = resource_size(r); |
| ++uiomem; |
| } |
| |
| priv->dmem_region_start = uiomem - &uioinfo->mem[0]; |
| priv->num_dmem_regions = pdata->num_dynamic_regions; |
| |
| for (i = 0; i < pdata->num_dynamic_regions; ++i) { |
| if (uiomem >= &uioinfo->mem[MAX_UIO_MAPS]) { |
| dev_warn(&pdev->dev, "device has more than " |
| __stringify(MAX_UIO_MAPS) |
| " dynamic and fixed memory regions.\n"); |
| break; |
| } |
| uiomem->memtype = UIO_MEM_PHYS; |
| uiomem->addr = DMEM_MAP_ERROR; |
| uiomem->size = pdata->dynamic_region_sizes[i]; |
| ++uiomem; |
| } |
| |
| while (uiomem < &uioinfo->mem[MAX_UIO_MAPS]) { |
| uiomem->size = 0; |
| ++uiomem; |
| } |
| |
| /* This driver requires no hardware specific kernel code to handle |
| * interrupts. Instead, the interrupt handler simply disables the |
| * interrupt in the interrupt controller. User space is responsible |
| * for performing hardware specific acknowledge and re-enabling of |
| * the interrupt in the interrupt controller. |
| * |
| * Interrupt sharing is not supported. |
| */ |
| |
| uioinfo->handler = uio_dmem_genirq_handler; |
| uioinfo->irqcontrol = uio_dmem_genirq_irqcontrol; |
| uioinfo->open = uio_dmem_genirq_open; |
| uioinfo->release = uio_dmem_genirq_release; |
| uioinfo->priv = priv; |
| |
| /* Enable Runtime PM for this device: |
| * The device starts in suspended state to allow the hardware to be |
| * turned off by default. The Runtime PM bus code should power on the |
| * hardware and enable clocks at open(). |
| */ |
| pm_runtime_enable(&pdev->dev); |
| |
| ret = devm_add_action_or_reset(&pdev->dev, uio_dmem_genirq_pm_disable, &pdev->dev); |
| if (ret) |
| return ret; |
| |
| return devm_uio_register_device(&pdev->dev, priv->uioinfo); |
| } |
| |
| static int uio_dmem_genirq_runtime_nop(struct device *dev) |
| { |
| /* Runtime PM callback shared between ->runtime_suspend() |
| * and ->runtime_resume(). Simply returns success. |
| * |
| * In this driver pm_runtime_get_sync() and pm_runtime_put_sync() |
| * are used at open() and release() time. This allows the |
| * Runtime PM code to turn off power to the device while the |
| * device is unused, ie before open() and after release(). |
| * |
| * This Runtime PM callback does not need to save or restore |
| * any registers since user space is responsbile for hardware |
| * register reinitialization after open(). |
| */ |
| return 0; |
| } |
| |
| static const struct dev_pm_ops uio_dmem_genirq_dev_pm_ops = { |
| .runtime_suspend = uio_dmem_genirq_runtime_nop, |
| .runtime_resume = uio_dmem_genirq_runtime_nop, |
| }; |
| |
| #ifdef CONFIG_OF |
| static const struct of_device_id uio_of_genirq_match[] = { |
| { /* empty for now */ }, |
| }; |
| MODULE_DEVICE_TABLE(of, uio_of_genirq_match); |
| #endif |
| |
| static struct platform_driver uio_dmem_genirq = { |
| .probe = uio_dmem_genirq_probe, |
| .driver = { |
| .name = DRIVER_NAME, |
| .pm = &uio_dmem_genirq_dev_pm_ops, |
| .of_match_table = of_match_ptr(uio_of_genirq_match), |
| }, |
| }; |
| |
| module_platform_driver(uio_dmem_genirq); |
| |
| MODULE_AUTHOR("Damian Hobson-Garcia"); |
| MODULE_DESCRIPTION("Userspace I/O platform driver with dynamic memory."); |
| MODULE_LICENSE("GPL v2"); |
| MODULE_ALIAS("platform:" DRIVER_NAME); |