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![Isaac Manjarres](/assets/img/avatar_default.png)
After commitf2d3b9a46e
("ARM: 9220/1: amba: Remove deferred device addition"), it became possible for amba_read_periphid() to be invoked concurrently from two threads for a particular AMBA device. Consider the case where a thread (T0) is registering an AMBA driver, and searching for all of the devices it can match with on the AMBA bus. Suppose that another thread (T1) is executing the deferred probe work, and is searching through all of the AMBA drivers on the bus for a driver that matches a particular AMBA device. Assume that both threads begin operating on the same AMBA device and the device's peripheral ID is still unknown. In this scenario, the amba_match() function will be invoked for the same AMBA device by both threads, which means amba_read_periphid() can also be invoked by both threads, and both threads will be able to manipulate the AMBA device's pclk pointer without any synchronization. It's possible that one thread will initialize the pclk pointer, then the other thread will re-initialize it, overwriting the previous value, and both will race to free the same pclk, resulting in a use-after-free for whichever thread frees the pclk last. Add a lock per AMBA device to synchronize the handling with detecting the peripheral ID to avoid the use-after-free scenario. The following KFENCE bug report helped detect this problem: ================================================================== BUG: KFENCE: use-after-free read in clk_disable+0x14/0x34 Use-after-free read at 0x(ptrval) (in kfence-#19): clk_disable+0x14/0x34 amba_read_periphid+0xdc/0x134 amba_match+0x3c/0x84 __driver_attach+0x20/0x158 bus_for_each_dev+0x74/0xc0 bus_add_driver+0x154/0x1e8 driver_register+0x88/0x11c do_one_initcall+0x8c/0x2fc kernel_init_freeable+0x190/0x220 kernel_init+0x10/0x108 ret_from_fork+0x14/0x3c 0x0 kfence-#19: 0x(ptrval)-0x(ptrval), size=36, cache=kmalloc-64 allocated by task 8 on cpu 0 at 11.629931s: clk_hw_create_clk+0x38/0x134 amba_get_enable_pclk+0x10/0x68 amba_read_periphid+0x28/0x134 amba_match+0x3c/0x84 __device_attach_driver+0x2c/0xc4 bus_for_each_drv+0x80/0xd0 __device_attach+0xb0/0x1f0 bus_probe_device+0x88/0x90 deferred_probe_work_func+0x8c/0xc0 process_one_work+0x23c/0x690 worker_thread+0x34/0x488 kthread+0xd4/0xfc ret_from_fork+0x14/0x3c 0x0 freed by task 8 on cpu 0 at 11.630095s: amba_read_periphid+0xec/0x134 amba_match+0x3c/0x84 __device_attach_driver+0x2c/0xc4 bus_for_each_drv+0x80/0xd0 __device_attach+0xb0/0x1f0 bus_probe_device+0x88/0x90 deferred_probe_work_func+0x8c/0xc0 process_one_work+0x23c/0x690 worker_thread+0x34/0x488 kthread+0xd4/0xfc ret_from_fork+0x14/0x3c 0x0 Cc: Saravana Kannan <saravanak@google.com> Cc: patches@armlinux.org.uk Fixes:f2d3b9a46e
("ARM: 9220/1: amba: Remove deferred device addition") Reported-by: Guenter Roeck <linux@roeck-us.net> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Isaac J. Manjarres <isaacmanjarres@google.com> Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
701 lines
17 KiB
C
701 lines
17 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/arch/arm/common/amba.c
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*
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* Copyright (C) 2003 Deep Blue Solutions Ltd, All Rights Reserved.
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/string.h>
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#include <linux/slab.h>
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#include <linux/io.h>
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#include <linux/pm.h>
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#include <linux/pm_runtime.h>
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#include <linux/pm_domain.h>
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#include <linux/amba/bus.h>
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#include <linux/sizes.h>
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#include <linux/limits.h>
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#include <linux/clk/clk-conf.h>
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#include <linux/platform_device.h>
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#include <linux/reset.h>
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#include <linux/of_irq.h>
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#include <linux/of_device.h>
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#include <linux/acpi.h>
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#include <linux/iommu.h>
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#include <linux/dma-map-ops.h>
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#define to_amba_driver(d) container_of(d, struct amba_driver, drv)
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/* called on periphid match and class 0x9 coresight device. */
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static int
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amba_cs_uci_id_match(const struct amba_id *table, struct amba_device *dev)
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{
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int ret = 0;
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struct amba_cs_uci_id *uci;
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uci = table->data;
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/* no table data or zero mask - return match on periphid */
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if (!uci || (uci->devarch_mask == 0))
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return 1;
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/* test against read devtype and masked devarch value */
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ret = (dev->uci.devtype == uci->devtype) &&
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((dev->uci.devarch & uci->devarch_mask) == uci->devarch);
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return ret;
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}
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static const struct amba_id *
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amba_lookup(const struct amba_id *table, struct amba_device *dev)
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{
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while (table->mask) {
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if (((dev->periphid & table->mask) == table->id) &&
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((dev->cid != CORESIGHT_CID) ||
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(amba_cs_uci_id_match(table, dev))))
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return table;
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table++;
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}
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return NULL;
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}
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static int amba_get_enable_pclk(struct amba_device *pcdev)
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{
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int ret;
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pcdev->pclk = clk_get(&pcdev->dev, "apb_pclk");
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if (IS_ERR(pcdev->pclk))
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return PTR_ERR(pcdev->pclk);
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ret = clk_prepare_enable(pcdev->pclk);
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if (ret)
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clk_put(pcdev->pclk);
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return ret;
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}
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static void amba_put_disable_pclk(struct amba_device *pcdev)
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{
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clk_disable_unprepare(pcdev->pclk);
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clk_put(pcdev->pclk);
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}
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static ssize_t driver_override_show(struct device *_dev,
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struct device_attribute *attr, char *buf)
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{
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struct amba_device *dev = to_amba_device(_dev);
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ssize_t len;
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device_lock(_dev);
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len = sprintf(buf, "%s\n", dev->driver_override);
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device_unlock(_dev);
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return len;
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}
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static ssize_t driver_override_store(struct device *_dev,
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struct device_attribute *attr,
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const char *buf, size_t count)
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{
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struct amba_device *dev = to_amba_device(_dev);
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int ret;
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ret = driver_set_override(_dev, &dev->driver_override, buf, count);
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if (ret)
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return ret;
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return count;
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}
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static DEVICE_ATTR_RW(driver_override);
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#define amba_attr_func(name,fmt,arg...) \
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static ssize_t name##_show(struct device *_dev, \
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struct device_attribute *attr, char *buf) \
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{ \
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struct amba_device *dev = to_amba_device(_dev); \
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return sprintf(buf, fmt, arg); \
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} \
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static DEVICE_ATTR_RO(name)
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amba_attr_func(id, "%08x\n", dev->periphid);
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amba_attr_func(resource, "\t%016llx\t%016llx\t%016lx\n",
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(unsigned long long)dev->res.start, (unsigned long long)dev->res.end,
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dev->res.flags);
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static struct attribute *amba_dev_attrs[] = {
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&dev_attr_id.attr,
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&dev_attr_resource.attr,
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&dev_attr_driver_override.attr,
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NULL,
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};
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ATTRIBUTE_GROUPS(amba_dev);
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static int amba_read_periphid(struct amba_device *dev)
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{
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struct reset_control *rstc;
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u32 size, pid, cid;
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void __iomem *tmp;
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int i, ret;
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ret = dev_pm_domain_attach(&dev->dev, true);
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if (ret) {
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dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
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goto err_out;
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}
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ret = amba_get_enable_pclk(dev);
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if (ret) {
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dev_dbg(&dev->dev, "can't get pclk: %d\n", ret);
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goto err_pm;
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}
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/*
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* Find reset control(s) of the amba bus and de-assert them.
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*/
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rstc = of_reset_control_array_get_optional_shared(dev->dev.of_node);
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if (IS_ERR(rstc)) {
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ret = PTR_ERR(rstc);
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if (ret != -EPROBE_DEFER)
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dev_err(&dev->dev, "can't get reset: %d\n", ret);
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goto err_clk;
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}
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reset_control_deassert(rstc);
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reset_control_put(rstc);
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size = resource_size(&dev->res);
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tmp = ioremap(dev->res.start, size);
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if (!tmp) {
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ret = -ENOMEM;
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goto err_clk;
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}
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/*
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* Read pid and cid based on size of resource
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* they are located at end of region
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*/
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for (pid = 0, i = 0; i < 4; i++)
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pid |= (readl(tmp + size - 0x20 + 4 * i) & 255) << (i * 8);
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for (cid = 0, i = 0; i < 4; i++)
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cid |= (readl(tmp + size - 0x10 + 4 * i) & 255) << (i * 8);
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if (cid == CORESIGHT_CID) {
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/* set the base to the start of the last 4k block */
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void __iomem *csbase = tmp + size - 4096;
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dev->uci.devarch = readl(csbase + UCI_REG_DEVARCH_OFFSET);
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dev->uci.devtype = readl(csbase + UCI_REG_DEVTYPE_OFFSET) & 0xff;
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}
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if (cid == AMBA_CID || cid == CORESIGHT_CID) {
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dev->periphid = pid;
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dev->cid = cid;
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}
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if (!dev->periphid)
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ret = -ENODEV;
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iounmap(tmp);
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err_clk:
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amba_put_disable_pclk(dev);
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err_pm:
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dev_pm_domain_detach(&dev->dev, true);
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err_out:
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return ret;
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}
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static int amba_match(struct device *dev, struct device_driver *drv)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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struct amba_driver *pcdrv = to_amba_driver(drv);
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mutex_lock(&pcdev->periphid_lock);
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if (!pcdev->periphid) {
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int ret = amba_read_periphid(pcdev);
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/*
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* Returning any error other than -EPROBE_DEFER from bus match
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* can cause driver registration failure. So, if there's a
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* permanent failure in reading pid and cid, simply map it to
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* -EPROBE_DEFER.
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*/
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if (ret) {
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mutex_unlock(&pcdev->periphid_lock);
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return -EPROBE_DEFER;
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}
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dev_set_uevent_suppress(dev, false);
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kobject_uevent(&dev->kobj, KOBJ_ADD);
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}
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mutex_unlock(&pcdev->periphid_lock);
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/* When driver_override is set, only bind to the matching driver */
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if (pcdev->driver_override)
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return !strcmp(pcdev->driver_override, drv->name);
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return amba_lookup(pcdrv->id_table, pcdev) != NULL;
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}
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static int amba_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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int retval = 0;
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retval = add_uevent_var(env, "AMBA_ID=%08x", pcdev->periphid);
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if (retval)
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return retval;
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retval = add_uevent_var(env, "MODALIAS=amba:d%08X", pcdev->periphid);
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return retval;
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}
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static int of_amba_device_decode_irq(struct amba_device *dev)
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{
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struct device_node *node = dev->dev.of_node;
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int i, irq = 0;
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if (IS_ENABLED(CONFIG_OF_IRQ) && node) {
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/* Decode the IRQs and address ranges */
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for (i = 0; i < AMBA_NR_IRQS; i++) {
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irq = of_irq_get(node, i);
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if (irq < 0) {
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if (irq == -EPROBE_DEFER)
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return irq;
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irq = 0;
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}
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dev->irq[i] = irq;
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}
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}
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return 0;
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}
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/*
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* These are the device model conversion veneers; they convert the
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* device model structures to our more specific structures.
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*/
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static int amba_probe(struct device *dev)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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struct amba_driver *pcdrv = to_amba_driver(dev->driver);
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const struct amba_id *id = amba_lookup(pcdrv->id_table, pcdev);
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int ret;
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do {
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ret = of_amba_device_decode_irq(pcdev);
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if (ret)
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break;
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ret = of_clk_set_defaults(dev->of_node, false);
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if (ret < 0)
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break;
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ret = dev_pm_domain_attach(dev, true);
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if (ret)
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break;
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ret = amba_get_enable_pclk(pcdev);
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if (ret) {
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dev_pm_domain_detach(dev, true);
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break;
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}
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pm_runtime_get_noresume(dev);
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pm_runtime_set_active(dev);
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pm_runtime_enable(dev);
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ret = pcdrv->probe(pcdev, id);
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if (ret == 0)
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break;
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pm_runtime_disable(dev);
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pm_runtime_set_suspended(dev);
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pm_runtime_put_noidle(dev);
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amba_put_disable_pclk(pcdev);
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dev_pm_domain_detach(dev, true);
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} while (0);
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return ret;
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}
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static void amba_remove(struct device *dev)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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struct amba_driver *drv = to_amba_driver(dev->driver);
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pm_runtime_get_sync(dev);
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if (drv->remove)
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drv->remove(pcdev);
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pm_runtime_put_noidle(dev);
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/* Undo the runtime PM settings in amba_probe() */
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pm_runtime_disable(dev);
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pm_runtime_set_suspended(dev);
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pm_runtime_put_noidle(dev);
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amba_put_disable_pclk(pcdev);
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dev_pm_domain_detach(dev, true);
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}
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static void amba_shutdown(struct device *dev)
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{
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struct amba_driver *drv;
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if (!dev->driver)
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return;
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drv = to_amba_driver(dev->driver);
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if (drv->shutdown)
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drv->shutdown(to_amba_device(dev));
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}
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static int amba_dma_configure(struct device *dev)
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{
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struct amba_driver *drv = to_amba_driver(dev->driver);
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enum dev_dma_attr attr;
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int ret = 0;
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if (dev->of_node) {
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ret = of_dma_configure(dev, dev->of_node, true);
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} else if (has_acpi_companion(dev)) {
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attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
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ret = acpi_dma_configure(dev, attr);
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}
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if (!ret && !drv->driver_managed_dma) {
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ret = iommu_device_use_default_domain(dev);
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if (ret)
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arch_teardown_dma_ops(dev);
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}
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return ret;
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}
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static void amba_dma_cleanup(struct device *dev)
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{
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struct amba_driver *drv = to_amba_driver(dev->driver);
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if (!drv->driver_managed_dma)
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iommu_device_unuse_default_domain(dev);
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}
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#ifdef CONFIG_PM
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/*
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* Hooks to provide runtime PM of the pclk (bus clock). It is safe to
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* enable/disable the bus clock at runtime PM suspend/resume as this
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* does not result in loss of context.
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*/
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static int amba_pm_runtime_suspend(struct device *dev)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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int ret = pm_generic_runtime_suspend(dev);
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if (ret == 0 && dev->driver) {
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if (pm_runtime_is_irq_safe(dev))
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clk_disable(pcdev->pclk);
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else
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clk_disable_unprepare(pcdev->pclk);
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}
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return ret;
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}
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static int amba_pm_runtime_resume(struct device *dev)
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{
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struct amba_device *pcdev = to_amba_device(dev);
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int ret;
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if (dev->driver) {
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if (pm_runtime_is_irq_safe(dev))
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ret = clk_enable(pcdev->pclk);
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else
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ret = clk_prepare_enable(pcdev->pclk);
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/* Failure is probably fatal to the system, but... */
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if (ret)
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return ret;
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}
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return pm_generic_runtime_resume(dev);
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}
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#endif /* CONFIG_PM */
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static const struct dev_pm_ops amba_pm = {
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.suspend = pm_generic_suspend,
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.resume = pm_generic_resume,
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.freeze = pm_generic_freeze,
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.thaw = pm_generic_thaw,
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.poweroff = pm_generic_poweroff,
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.restore = pm_generic_restore,
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SET_RUNTIME_PM_OPS(
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amba_pm_runtime_suspend,
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amba_pm_runtime_resume,
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NULL
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)
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};
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/*
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* Primecells are part of the Advanced Microcontroller Bus Architecture,
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* so we call the bus "amba".
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* DMA configuration for platform and AMBA bus is same. So here we reuse
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* platform's DMA config routine.
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*/
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struct bus_type amba_bustype = {
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.name = "amba",
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.dev_groups = amba_dev_groups,
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.match = amba_match,
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.uevent = amba_uevent,
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.probe = amba_probe,
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.remove = amba_remove,
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.shutdown = amba_shutdown,
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.dma_configure = amba_dma_configure,
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.dma_cleanup = amba_dma_cleanup,
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.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_proxy_probe(struct amba_device *adev,
|
|
const struct amba_id *id)
|
|
{
|
|
WARN(1, "Stub driver should never match any device.\n");
|
|
return -ENODEV;
|
|
}
|
|
|
|
static const struct amba_id amba_stub_drv_ids[] = {
|
|
{ 0, 0 },
|
|
};
|
|
|
|
static struct amba_driver amba_proxy_drv = {
|
|
.drv = {
|
|
.name = "amba-proxy",
|
|
},
|
|
.probe = amba_proxy_probe,
|
|
.id_table = amba_stub_drv_ids,
|
|
};
|
|
|
|
static int __init amba_stub_drv_init(void)
|
|
{
|
|
if (!IS_ENABLED(CONFIG_MODULES))
|
|
return 0;
|
|
|
|
/*
|
|
* The amba_match() function will get called only if there is at least
|
|
* one amba driver registered. If all amba drivers are modules and are
|
|
* only loaded based on uevents, then we'll hit a chicken-and-egg
|
|
* situation where amba_match() is waiting on drivers and drivers are
|
|
* waiting on amba_match(). So, register a stub driver to make sure
|
|
* amba_match() is called even if no amba driver has been registered.
|
|
*/
|
|
return amba_driver_register(&amba_proxy_drv);
|
|
}
|
|
late_initcall_sync(amba_stub_drv_init);
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
if (!drv->probe)
|
|
return -EINVAL;
|
|
|
|
drv->drv.bus = &amba_bustype;
|
|
|
|
return driver_register(&drv->drv);
|
|
}
|
|
EXPORT_SYMBOL(amba_driver_register);
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
EXPORT_SYMBOL(amba_driver_unregister);
|
|
|
|
static void amba_device_release(struct device *dev)
|
|
{
|
|
struct amba_device *d = to_amba_device(dev);
|
|
|
|
if (d->res.parent)
|
|
release_resource(&d->res);
|
|
mutex_destroy(&d->periphid_lock);
|
|
kfree(d);
|
|
}
|
|
|
|
/**
|
|
* 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;
|
|
|
|
ret = request_resource(parent, &dev->res);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* If primecell ID isn't hard-coded, figure it out */
|
|
if (!dev->periphid) {
|
|
/*
|
|
* AMBA device uevents require reading its pid and cid
|
|
* registers. To do this, the device must be on, clocked and
|
|
* out of reset. However in some cases those resources might
|
|
* not yet be available. If that's the case, we suppress the
|
|
* generation of uevents until we can read the pid and cid
|
|
* registers. See also amba_match().
|
|
*/
|
|
if (amba_read_periphid(dev))
|
|
dev_set_uevent_suppress(&dev->dev, true);
|
|
}
|
|
|
|
ret = device_add(&dev->dev);
|
|
if (ret)
|
|
release_resource(&dev->res);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(amba_device_add);
|
|
|
|
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->dev.dma_parms = &dev->dma_parms;
|
|
dev->res.name = dev_name(&dev->dev);
|
|
mutex_init(&dev->periphid_lock);
|
|
}
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
EXPORT_SYMBOL(amba_device_register);
|
|
|
|
/**
|
|
* 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);
|
|
}
|
|
EXPORT_SYMBOL(amba_device_unregister);
|
|
|
|
/**
|
|
* 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;
|
|
}
|
|
EXPORT_SYMBOL(amba_request_regions);
|
|
|
|
/**
|
|
* 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_release_regions);
|