https://github.com/torvalds/linux
Tip revision: 4d856f72c10ecb060868ed10ff1b1453943fc6c8 authored by Linus Torvalds on 15 September 2019, 21:19:32 UTC
Linux 5.3
Linux 5.3
Tip revision: 4d856f7
bus.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/arch/arm/common/amba.c
*
* Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
*/
#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 <linux/platform_device.h>
#include <asm/irq.h>
#define to_amba_driver(d) container_of(d, struct amba_driver, drv)
/* called on periphid match and class 0x9 coresight device. */
static int
amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
{
int ret = 0;
struct amba_cs_uci_id *uci;
uci = table->data;
/* no table data or zero mask - return match on periphid */
if (!uci || (uci->devarch_mask == 0))
return 1;
/* test against read devtype and masked devarch value */
ret = (dev->uci.devtype == uci->devtype) &&
((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
return ret;
}
static const struct amba_id *
amba_lookup(const struct amba_id *table, struct amba_device *dev)
{
while (table->mask) {
if (((dev->periphid & table->mask) == table->id) &&
((dev->cid != CORESIGHT_CID) ||
(amba_cs_uci_id_match(table, dev))))
return table;
table++;
}
return NULL;
}
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;
}
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;
}
static ssize_t driver_override_show(struct device *_dev,
struct device_attribute *attr, char *buf)
{
struct amba_device *dev = to_amba_device(_dev);
ssize_t len;
device_lock(_dev);
len = sprintf(buf, "%s\n", dev->driver_override);
device_unlock(_dev);
return len;
}
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, *cp;
/* We need to keep extra room for a newline */
if (count >= (PAGE_SIZE - 1))
return -EINVAL;
driver_override = kstrndup(buf, count, GFP_KERNEL);
if (!driver_override)
return -ENOMEM;
cp = strchr(driver_override, '\n');
if (cp)
*cp = '\0';
device_lock(_dev);
old = dev->driver_override;
if (strlen(driver_override)) {
dev->driver_override = driver_override;
} else {
kfree(driver_override);
dev->driver_override = NULL;
}
device_unlock(_dev);
kfree(old);
return count;
}
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;
}
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);
}
#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".
* DMA configuration for platform and AMBA bus is same. So here we reuse
* platform's DMA config routine.
*/
struct bus_type amba_bustype = {
.name = "amba",
.dev_groups = amba_dev_groups,
.match = amba_match,
.uevent = amba_uevent,
.dma_configure = platform_dma_configure,
.pm = &amba_pm,
};
EXPORT_SYMBOL_GPL(amba_bustype);
static int __init amba_init(void)
{
return bus_register(&amba_bustype);
}
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;
}
static void amba_put_disable_pclk(struct amba_device *pcdev)
{
clk_disable_unprepare(pcdev->pclk);
clk_put(pcdev->pclk);
}
/*
* 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)
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;
}
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;
}
static void amba_shutdown(struct device *dev)
{
struct amba_driver *drv = to_amba_driver(dev->driver);
drv->shutdown(to_amba_device(dev));
}
/**
* 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);
}
/**
* 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);
}
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);
}
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) {
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);
if (cid == CORESIGHT_CID) {
/* set the base to the start of the last 4k block */
void __iomem *csbase = tmp + size - 4096;
dev->uci.devarch =
readl(csbase + UCI_REG_DEVARCH_OFFSET);
dev->uci.devtype =
readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
}
amba_put_disable_pclk(dev);
if (cid == AMBA_CID || cid == CORESIGHT_CID) {
dev->periphid = pid;
dev->cid = cid;
}
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;
}
/*
* 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);
}
/**
* 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;
}
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;
}
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);
}
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);
}
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);
}
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);
}
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);
}
/**
* 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;
}
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);
}
/**
* amba_device_put - put an AMBA device
* @dev: AMBA device to put
*/
void amba_device_put(struct amba_device *dev)
{
put_device(&dev->dev);
}
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);
}
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;
}
/**
* 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 = mask;
bus_for_each_dev(&amba_bustype, NULL, &data, amba_find_match);
return data.dev;
}
/**
* amba_request_regions - request all mem regions associated with device
* @dev: amba_device structure for device
* @name: name, or NULL to use driver name
*/
int amba_request_regions(struct amba_device *dev, const char *name)
{
int ret = 0;
u32 size;
if (!name)
name = dev->dev.driver->name;
size = resource_size(&dev->res);
if (!request_mem_region(dev->res.start, size, name))
ret = -EBUSY;
return ret;
}
/**
* amba_release_regions - release mem regions associated with device
* @dev: amba_device structure for device
*
* Release regions claimed by a successful call to amba_request_regions.
*/
void amba_release_regions(struct amba_device *dev)
{
u32 size;
size = resource_size(&dev->res);
release_mem_region(dev->res.start, size);
}
EXPORT_SYMBOL(amba_driver_register);
EXPORT_SYMBOL(amba_driver_unregister);
EXPORT_SYMBOL(amba_device_register);
EXPORT_SYMBOL(amba_device_unregister);
EXPORT_SYMBOL(amba_find_device);
EXPORT_SYMBOL(amba_request_regions);
EXPORT_SYMBOL(amba_release_regions);