cregit-Linux how code gets into the kernel

Release 4.14 drivers/amba/bus.c

Directory: drivers/amba
/*
 *  linux/arch/arm/common/amba.c
 *
 *  Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/io.h>
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/amba/bus.h>
#include <linux/sizes.h>
#include <linux/limits.h>
#include <linux/clk/clk-conf.h>

#include <asm/irq.h>


#define to_amba_driver(d)	container_of(d, struct amba_driver, drv)


static const struct amba_id * amba_lookup(const struct amba_id *table, struct amba_device *dev) { int ret = 0; while (table->mask) { ret = (dev->periphid & table->mask) == table->id; if (ret) break; table++; } return ret ? table : NULL; }

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static int amba_match(struct device *dev, struct device_driver *drv) { struct amba_device *pcdev = to_amba_device(dev); struct amba_driver *pcdrv = to_amba_driver(drv); /* When driver_override is set, only bind to the matching driver */ if (pcdev->driver_override) return !strcmp(pcdev->driver_override, drv->name); return amba_lookup(pcdrv->id_table, pcdev) != NULL; }

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static int amba_uevent(struct device *dev, struct kobj_uevent_env *env) { struct amba_device *pcdev = to_amba_device(dev); int retval = 0; retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid); if (retval) return retval; retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid); return retval; }

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static ssize_t driver_override_show(struct device *_dev, struct device_attribute *attr, char *buf) { struct amba_device *dev = to_amba_device(_dev); if (!dev->driver_override) return 0; return sprintf(buf, "%s\n", dev->driver_override); }

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static ssize_t driver_override_store(struct device *_dev, struct device_attribute *attr, const char *buf, size_t count) { struct amba_device *dev = to_amba_device(_dev); char *driver_override, *old = dev->driver_override, *cp; if (count > PATH_MAX) return -EINVAL; driver_override = kstrndup(buf, count, GFP_KERNEL); if (!driver_override) return -ENOMEM; cp = strchr(driver_override, '\n'); if (cp) *cp = '\0'; if (strlen(driver_override)) { dev->driver_override = driver_override; } else { kfree(driver_override); dev->driver_override = NULL; } kfree(old); return count; }

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static DEVICE_ATTR_RW(driver_override); #define amba_attr_func(name,fmt,arg...) \ static ssize_t name##_show(struct device *_dev, \ struct device_attribute *attr, char *buf) \ { \ struct amba_device *dev = to_amba_device(_dev); \ return sprintf(buf, fmt, arg); \ } \ static DEVICE_ATTR_RO(name) amba_attr_func(id, "%08x\n", dev->periphid); amba_attr_func(irq0, "%u\n", dev->irq[0]); amba_attr_func(irq1, "%u\n", dev->irq[1]); amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n", (unsigned long long)dev->res.start, (unsigned long long)dev->res.end, dev->res.flags); static struct attribute *amba_dev_attrs[] = { &dev_attr_id.attr, &dev_attr_resource.attr, &dev_attr_driver_override.attr, NULL, }; ATTRIBUTE_GROUPS(amba_dev); #ifdef CONFIG_PM /* * Hooks to provide runtime PM of the pclk (bus clock). It is safe to * enable/disable the bus clock at runtime PM suspend/resume as this * does not result in loss of context. */
static int amba_pm_runtime_suspend(struct device *dev) { struct amba_device *pcdev = to_amba_device(dev); int ret = pm_generic_runtime_suspend(dev); if (ret == 0 && dev->driver) { if (pm_runtime_is_irq_safe(dev)) clk_disable(pcdev->pclk); else clk_disable_unprepare(pcdev->pclk); } return ret; }

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static int amba_pm_runtime_resume(struct device *dev) { struct amba_device *pcdev = to_amba_device(dev); int ret; if (dev->driver) { if (pm_runtime_is_irq_safe(dev)) ret = clk_enable(pcdev->pclk); else ret = clk_prepare_enable(pcdev->pclk); /* Failure is probably fatal to the system, but... */ if (ret) return ret; } return pm_generic_runtime_resume(dev); }

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#endif /* CONFIG_PM */ static const struct dev_pm_ops amba_pm = { .suspend = pm_generic_suspend, .resume = pm_generic_resume, .freeze = pm_generic_freeze, .thaw = pm_generic_thaw, .poweroff = pm_generic_poweroff, .restore = pm_generic_restore, SET_RUNTIME_PM_OPS( amba_pm_runtime_suspend, amba_pm_runtime_resume, NULL ) }; /* * Primecells are part of the Advanced Microcontroller Bus Architecture, * so we call the bus "amba". */ struct bus_type amba_bustype = { .name = "amba", .dev_groups = amba_dev_groups, .match = amba_match, .uevent = amba_uevent, .pm = &amba_pm, };
static int __init amba_init(void) { return bus_register(&amba_bustype); }

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postcore_initcall(amba_init);
static int amba_get_enable_pclk(struct amba_device *pcdev) { int ret; pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk"); if (IS_ERR(pcdev->pclk)) return PTR_ERR(pcdev->pclk); ret = clk_prepare_enable(pcdev->pclk); if (ret) clk_put(pcdev->pclk); return ret; }

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static void amba_put_disable_pclk(struct amba_device *pcdev) { clk_disable_unprepare(pcdev->pclk); clk_put(pcdev->pclk); }

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/* * These are the device model conversion veneers; they convert the * device model structures to our more specific structures. */
static int amba_probe(struct device *dev) { struct amba_device *pcdev = to_amba_device(dev); struct amba_driver *pcdrv = to_amba_driver(dev->driver); const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev); int ret; do { ret = of_clk_set_defaults(dev->of_node, false); if (ret < 0) break; ret = dev_pm_domain_attach(dev, true); if (ret == -EPROBE_DEFER) break; ret = amba_get_enable_pclk(pcdev); if (ret) { dev_pm_domain_detach(dev, true); break; } pm_runtime_get_noresume(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); ret = pcdrv->probe(pcdev, id); if (ret == 0) break; pm_runtime_disable(dev); pm_runtime_set_suspended(dev); pm_runtime_put_noidle(dev); amba_put_disable_pclk(pcdev); dev_pm_domain_detach(dev, true); } while (0); return ret; }

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static int amba_remove(struct device *dev) { struct amba_device *pcdev = to_amba_device(dev); struct amba_driver *drv = to_amba_driver(dev->driver); int ret; pm_runtime_get_sync(dev); ret = drv->remove(pcdev); pm_runtime_put_noidle(dev); /* Undo the runtime PM settings in amba_probe() */ pm_runtime_disable(dev); pm_runtime_set_suspended(dev); pm_runtime_put_noidle(dev); amba_put_disable_pclk(pcdev); dev_pm_domain_detach(dev, true); return ret; }

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static void amba_shutdown(struct device *dev) { struct amba_driver *drv = to_amba_driver(dev->driver); drv->shutdown(to_amba_device(dev)); }

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/** * amba_driver_register - register an AMBA device driver * @drv: amba device driver structure * * Register an AMBA device driver with the Linux device model * core. If devices pre-exist, the drivers probe function will * be called. */
int amba_driver_register(struct amba_driver *drv) { drv->drv.bus = &amba_bustype; #define SETFN(fn) if (drv->fn) drv->drv.fn = amba_##fn SETFN(probe); SETFN(remove); SETFN(shutdown); return driver_register(&drv->drv); }

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/** * amba_driver_unregister - remove an AMBA device driver * @drv: AMBA device driver structure to remove * * Unregister an AMBA device driver from the Linux device * model. The device model will call the drivers remove function * for each device the device driver is currently handling. */
void amba_driver_unregister(struct amba_driver *drv) { driver_unregister(&drv->drv); }

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static void amba_device_release(struct device *dev) { struct amba_device *d = to_amba_device(dev); if (d->res.parent) release_resource(&d->res); kfree(d); }

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static int amba_device_try_add(struct amba_device *dev, struct resource *parent) { u32 size; void __iomem *tmp; int i, ret; WARN_ON(dev->irq[0] == (unsigned int)-1); WARN_ON(dev->irq[1] == (unsigned int)-1); ret = request_resource(parent, &dev->res); if (ret) goto err_out; /* Hard-coded primecell ID instead of plug-n-play */ if (dev->periphid != 0) goto skip_probe; /* * Dynamically calculate the size of the resource * and use this for iomap */ size = resource_size(&dev->res); tmp = ioremap(dev->res.start, size); if (!tmp) { ret = -ENOMEM; goto err_release; } ret = dev_pm_domain_attach(&dev->dev, true); if (ret == -EPROBE_DEFER) { iounmap(tmp); goto err_release; } ret = amba_get_enable_pclk(dev); if (ret == 0) { u32 pid, cid; /* * Read pid and cid based on size of resource * they are located at end of region */ for (pid = 0, i = 0; i < 4; i++) pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) << (i * 8); for (cid = 0, i = 0; i < 4; i++) cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << (i * 8); amba_put_disable_pclk(dev); if (cid == AMBA_CID || cid == CORESIGHT_CID) dev->periphid = pid; if (!dev->periphid) ret = -ENODEV; } iounmap(tmp); dev_pm_domain_detach(&dev->dev, true); if (ret) goto err_release; skip_probe: ret = device_add(&dev->dev); if (ret) goto err_release; if (dev->irq[0]) ret = device_create_file(&dev->dev, &dev_attr_irq0); if (ret == 0 && dev->irq[1]) ret = device_create_file(&dev->dev, &dev_attr_irq1); if (ret == 0) return ret; device_unregister(&dev->dev); err_release: release_resource(&dev->res); err_out: return ret; }

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/* * Registration of AMBA device require reading its pid and cid registers. * To do this, the device must be turned on (if it is a part of power domain) * and have clocks enabled. However in some cases those resources might not be * yet available. Returning EPROBE_DEFER is not a solution in such case, * because callers don't handle this special error code. Instead such devices * are added to the special list and their registration is retried from * periodic worker, until all resources are available and registration succeeds. */ struct deferred_device { struct amba_device *dev; struct resource *parent; struct list_head node; }; static LIST_HEAD(deferred_devices); static DEFINE_MUTEX(deferred_devices_lock); static void amba_deferred_retry_func(struct work_struct *dummy); static DECLARE_DELAYED_WORK(deferred_retry_work, amba_deferred_retry_func); #define DEFERRED_DEVICE_TIMEOUT (msecs_to_jiffies(5 * 1000))
static void amba_deferred_retry_func(struct work_struct *dummy) { struct deferred_device *ddev, *tmp; mutex_lock(&deferred_devices_lock); list_for_each_entry_safe(ddev, tmp, &deferred_devices, node) { int ret = amba_device_try_add(ddev->dev, ddev->parent); if (ret == -EPROBE_DEFER) continue; list_del_init(&ddev->node); kfree(ddev); } if (!list_empty(&deferred_devices)) schedule_delayed_work(&deferred_retry_work, DEFERRED_DEVICE_TIMEOUT); mutex_unlock(&deferred_devices_lock); }

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/** * amba_device_add - add a previously allocated AMBA device structure * @dev: AMBA device allocated by amba_device_alloc * @parent: resource parent for this devices resources * * Claim the resource, and read the device cell ID if not already * initialized. Register the AMBA device with the Linux device * manager. */
int amba_device_add(struct amba_device *dev, struct resource *parent) { int ret = amba_device_try_add(dev, parent); if (ret == -EPROBE_DEFER) { struct deferred_device *ddev; ddev = kmalloc(sizeof(*ddev), GFP_KERNEL); if (!ddev) return -ENOMEM; ddev->dev = dev; ddev->parent = parent; ret = 0; mutex_lock(&deferred_devices_lock); if (list_empty(&deferred_devices)) schedule_delayed_work(&deferred_retry_work, DEFERRED_DEVICE_TIMEOUT); list_add_tail(&ddev->node, &deferred_devices); mutex_unlock(&deferred_devices_lock); } return ret; }

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EXPORT_SYMBOL_GPL(amba_device_add);
static struct amba_device * amba_aphb_device_add(struct device *parent, const char *name, resource_size_t base, size_t size, int irq1, int irq2, void *pdata, unsigned int periphid, u64 dma_mask, struct resource *resbase) { struct amba_device *dev; int ret; dev = amba_device_alloc(name, base, size); if (!dev) return ERR_PTR(-ENOMEM); dev->dev.coherent_dma_mask = dma_mask; dev->irq[0] = irq1; dev->irq[1] = irq2; dev->periphid = periphid; dev->dev.platform_data = pdata; dev->dev.parent = parent; ret = amba_device_add(dev, resbase); if (ret) { amba_device_put(dev); return ERR_PTR(ret); } return dev; }

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struct amba_device * amba_apb_device_add(struct device *parent, const char *name, resource_size_t base, size_t size, int irq1, int irq2, void *pdata, unsigned int periphid) { return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata, periphid, 0, &iomem_resource); }

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EXPORT_SYMBOL_GPL(amba_apb_device_add);
struct amba_device * amba_ahb_device_add(struct device *parent, const char *name, resource_size_t base, size_t size, int irq1, int irq2, void *pdata, unsigned int periphid) { return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata, periphid, ~0ULL, &iomem_resource); }

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EXPORT_SYMBOL_GPL(amba_ahb_device_add);
struct amba_device * amba_apb_device_add_res(struct device *parent, const char *name, resource_size_t base, size_t size, int irq1, int irq2, void *pdata, unsigned int periphid, struct resource *resbase) { return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata, periphid, 0, resbase); }

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EXPORT_SYMBOL_GPL(amba_apb_device_add_res);
struct amba_device * amba_ahb_device_add_res(struct device *parent, const char *name, resource_size_t base, size_t size, int irq1, int irq2, void *pdata, unsigned int periphid, struct resource *resbase) { return amba_aphb_device_add(parent, name, base, size, irq1, irq2, pdata, periphid, ~0ULL, resbase); }

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EXPORT_SYMBOL_GPL(amba_ahb_device_add_res);
static void amba_device_initialize(struct amba_device *dev, const char *name) { device_initialize(&dev->dev); if (name) dev_set_name(&dev->dev, "%s", name); dev->dev.release = amba_device_release; dev->dev.bus = &amba_bustype; dev->dev.dma_mask = &dev->dev.coherent_dma_mask; dev->res.name = dev_name(&dev->dev); }

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/** * amba_device_alloc - allocate an AMBA device * @name: sysfs name of the AMBA device * @base: base of AMBA device * @size: size of AMBA device * * Allocate and initialize an AMBA device structure. Returns %NULL * on failure. */
struct amba_device *amba_device_alloc(const char *name, resource_size_t base, size_t size) { struct amba_device *dev; dev = kzalloc(sizeof(*dev), GFP_KERNEL); if (dev) { amba_device_initialize(dev, name); dev->res.start = base; dev->res.end = base + size - 1; dev->res.flags = IORESOURCE_MEM; } return dev; }

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EXPORT_SYMBOL_GPL(amba_device_alloc); /** * amba_device_register - register an AMBA device * @dev: AMBA device to register * @parent: parent memory resource * * Setup the AMBA device, reading the cell ID if present. * Claim the resource, and register the AMBA device with * the Linux device manager. */
int amba_device_register(struct amba_device *dev, struct resource *parent) { amba_device_initialize(dev, dev->dev.init_name); dev->dev.init_name = NULL; return amba_device_add(dev, parent); }

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/** * amba_device_put - put an AMBA device * @dev: AMBA device to put */
void amba_device_put(struct amba_device *dev) { put_device(&dev->dev); }

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EXPORT_SYMBOL_GPL(amba_device_put); /** * amba_device_unregister - unregister an AMBA device * @dev: AMBA device to remove * * Remove the specified AMBA device from the Linux device * manager. All files associated with this object will be * destroyed, and device drivers notified that the device has * been removed. The AMBA device's resources including * the amba_device structure will be freed once all * references to it have been dropped. */
void amba_device_unregister(struct amba_device *dev) { device_unregister(&dev->dev); }

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struct find_data { struct amba_device *dev; struct device *parent; const char *busid; unsigned int id; unsigned int mask; };
static int amba_find_match(struct device *dev, void *data) { struct find_data *d = data; struct amba_device *pcdev = to_amba_device(dev); int r; r = (pcdev->periphid & d->mask) == d->id; if (d->parent) r &= d->parent == dev->parent; if (d->busid) r &= strcmp(dev_name(dev), d->busid) == 0; if (r) { get_device(dev); d->dev = pcdev; } return r; }

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/** * amba_find_device - locate an AMBA device given a bus id * @busid: bus id for device (or NULL) * @parent: parent device (or NULL) * @id: peripheral ID (or 0) * @mask: peripheral ID mask (or 0) * * Return the AMBA device corresponding to the supplied parameters. * If no device matches, returns NULL. * * NOTE: When a valid device is found, its refcount is * incremented, and must be decremented before the returned * reference. */
struct amba_device * amba_find_device(const char *busid, struct device *parent, unsigned int id, unsigned int mask) { struct find_data data; data.dev = NULL; data.parent = parent; data.busid = busid; data.id = id; data.mask =