linux/drivers/of/device.c
Rob Herring 9b22c17a3c of: Check 'of_node_reused' flag on of_match_device()
Commit 0f153a1b81 ("usb: chipidea: Set the DT node on the child
device") caused the child device to match on the parent driver
instead of the child's driver since the child's DT node pointer matched.
The worst case result is a loop of the parent driver probing another
instance and creating yet another child device eventually exhausting the
stack. If the child driver happens to match first, then everything works
fine.

A device sharing the DT node should never do DT based driver matching,
so let's simply check of_node_reused in of_match_device() to prevent
that.

Fixes: 0f153a1b81 ("usb: chipidea: Set the DT node on the child device")
Link: https://lore.kernel.org/all/20220114105620.GK18506@ediswmail.ad.cirrus.com/
Reported-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Cc: Frank Rowand <frowand.list@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Chen <peter.chen@nxp.com>
Tested-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220118173404.1891800-1-robh@kernel.org
2022-01-20 12:55:26 -06:00

385 lines
9.8 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_address.h>
#include <linux/of_iommu.h>
#include <linux/of_reserved_mem.h>
#include <linux/dma-direct.h> /* for bus_dma_region */
#include <linux/dma-map-ops.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <asm/errno.h>
#include "of_private.h"
/**
* of_match_device - Tell if a struct device matches an of_device_id list
* @matches: array of of device match structures to search in
* @dev: the of device structure to match against
*
* Used by a driver to check whether an platform_device present in the
* system is in its list of supported devices.
*/
const struct of_device_id *of_match_device(const struct of_device_id *matches,
const struct device *dev)
{
if (!matches || !dev->of_node || dev->of_node_reused)
return NULL;
return of_match_node(matches, dev->of_node);
}
EXPORT_SYMBOL(of_match_device);
int of_device_add(struct platform_device *ofdev)
{
BUG_ON(ofdev->dev.of_node == NULL);
/* name and id have to be set so that the platform bus doesn't get
* confused on matching */
ofdev->name = dev_name(&ofdev->dev);
ofdev->id = PLATFORM_DEVID_NONE;
/*
* If this device has not binding numa node in devicetree, that is
* of_node_to_nid returns NUMA_NO_NODE. device_add will assume that this
* device is on the same node as the parent.
*/
set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));
return device_add(&ofdev->dev);
}
static void
of_dma_set_restricted_buffer(struct device *dev, struct device_node *np)
{
struct device_node *node, *of_node = dev->of_node;
int count, i;
if (!IS_ENABLED(CONFIG_DMA_RESTRICTED_POOL))
return;
count = of_property_count_elems_of_size(of_node, "memory-region",
sizeof(u32));
/*
* If dev->of_node doesn't exist or doesn't contain memory-region, try
* the OF node having DMA configuration.
*/
if (count <= 0) {
of_node = np;
count = of_property_count_elems_of_size(
of_node, "memory-region", sizeof(u32));
}
for (i = 0; i < count; i++) {
node = of_parse_phandle(of_node, "memory-region", i);
/*
* There might be multiple memory regions, but only one
* restricted-dma-pool region is allowed.
*/
if (of_device_is_compatible(node, "restricted-dma-pool") &&
of_device_is_available(node))
break;
}
/*
* Attempt to initialize a restricted-dma-pool region if one was found.
* Note that count can hold a negative error code.
*/
if (i < count && of_reserved_mem_device_init_by_idx(dev, of_node, i))
dev_warn(dev, "failed to initialise \"restricted-dma-pool\" memory node\n");
}
/**
* of_dma_configure_id - Setup DMA configuration
* @dev: Device to apply DMA configuration
* @np: Pointer to OF node having DMA configuration
* @force_dma: Whether device is to be set up by of_dma_configure() even if
* DMA capability is not explicitly described by firmware.
* @id: Optional const pointer value input id
*
* Try to get devices's DMA configuration from DT and update it
* accordingly.
*
* If platform code needs to use its own special DMA configuration, it
* can use a platform bus notifier and handle BUS_NOTIFY_ADD_DEVICE events
* to fix up DMA configuration.
*/
int of_dma_configure_id(struct device *dev, struct device_node *np,
bool force_dma, const u32 *id)
{
const struct iommu_ops *iommu;
const struct bus_dma_region *map = NULL;
u64 dma_start = 0;
u64 mask, end, size = 0;
bool coherent;
int ret;
ret = of_dma_get_range(np, &map);
if (ret < 0) {
/*
* For legacy reasons, we have to assume some devices need
* DMA configuration regardless of whether "dma-ranges" is
* correctly specified or not.
*/
if (!force_dma)
return ret == -ENODEV ? 0 : ret;
} else {
const struct bus_dma_region *r = map;
u64 dma_end = 0;
/* Determine the overall bounds of all DMA regions */
for (dma_start = ~0; r->size; r++) {
/* Take lower and upper limits */
if (r->dma_start < dma_start)
dma_start = r->dma_start;
if (r->dma_start + r->size > dma_end)
dma_end = r->dma_start + r->size;
}
size = dma_end - dma_start;
/*
* Add a work around to treat the size as mask + 1 in case
* it is defined in DT as a mask.
*/
if (size & 1) {
dev_warn(dev, "Invalid size 0x%llx for dma-range(s)\n",
size);
size = size + 1;
}
if (!size) {
dev_err(dev, "Adjusted size 0x%llx invalid\n", size);
kfree(map);
return -EINVAL;
}
}
/*
* If @dev is expected to be DMA-capable then the bus code that created
* it should have initialised its dma_mask pointer by this point. For
* now, we'll continue the legacy behaviour of coercing it to the
* coherent mask if not, but we'll no longer do so quietly.
*/
if (!dev->dma_mask) {
dev_warn(dev, "DMA mask not set\n");
dev->dma_mask = &dev->coherent_dma_mask;
}
if (!size && dev->coherent_dma_mask)
size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1);
else if (!size)
size = 1ULL << 32;
/*
* Limit coherent and dma mask based on size and default mask
* set by the driver.
*/
end = dma_start + size - 1;
mask = DMA_BIT_MASK(ilog2(end) + 1);
dev->coherent_dma_mask &= mask;
*dev->dma_mask &= mask;
/* ...but only set bus limit and range map if we found valid dma-ranges earlier */
if (!ret) {
dev->bus_dma_limit = end;
dev->dma_range_map = map;
}
coherent = of_dma_is_coherent(np);
dev_dbg(dev, "device is%sdma coherent\n",
coherent ? " " : " not ");
iommu = of_iommu_configure(dev, np, id);
if (PTR_ERR(iommu) == -EPROBE_DEFER) {
/* Don't touch range map if it wasn't set from a valid dma-ranges */
if (!ret)
dev->dma_range_map = NULL;
kfree(map);
return -EPROBE_DEFER;
}
dev_dbg(dev, "device is%sbehind an iommu\n",
iommu ? " " : " not ");
arch_setup_dma_ops(dev, dma_start, size, iommu, coherent);
if (!iommu)
of_dma_set_restricted_buffer(dev, np);
return 0;
}
EXPORT_SYMBOL_GPL(of_dma_configure_id);
int of_device_register(struct platform_device *pdev)
{
device_initialize(&pdev->dev);
return of_device_add(pdev);
}
EXPORT_SYMBOL(of_device_register);
void of_device_unregister(struct platform_device *ofdev)
{
device_unregister(&ofdev->dev);
}
EXPORT_SYMBOL(of_device_unregister);
const void *of_device_get_match_data(const struct device *dev)
{
const struct of_device_id *match;
match = of_match_device(dev->driver->of_match_table, dev);
if (!match)
return NULL;
return match->data;
}
EXPORT_SYMBOL(of_device_get_match_data);
static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len)
{
const char *compat;
char *c;
struct property *p;
ssize_t csize;
ssize_t tsize;
if ((!dev) || (!dev->of_node))
return -ENODEV;
/* Name & Type */
/* %p eats all alphanum characters, so %c must be used here */
csize = snprintf(str, len, "of:N%pOFn%c%s", dev->of_node, 'T',
of_node_get_device_type(dev->of_node));
tsize = csize;
len -= csize;
if (str)
str += csize;
of_property_for_each_string(dev->of_node, "compatible", p, compat) {
csize = strlen(compat) + 1;
tsize += csize;
if (csize > len)
continue;
csize = snprintf(str, len, "C%s", compat);
for (c = str; c; ) {
c = strchr(c, ' ');
if (c)
*c++ = '_';
}
len -= csize;
str += csize;
}
return tsize;
}
int of_device_request_module(struct device *dev)
{
char *str;
ssize_t size;
int ret;
size = of_device_get_modalias(dev, NULL, 0);
if (size < 0)
return size;
str = kmalloc(size + 1, GFP_KERNEL);
if (!str)
return -ENOMEM;
of_device_get_modalias(dev, str, size);
str[size] = '\0';
ret = request_module(str);
kfree(str);
return ret;
}
EXPORT_SYMBOL_GPL(of_device_request_module);
/**
* of_device_modalias - Fill buffer with newline terminated modalias string
* @dev: Calling device
* @str: Modalias string
* @len: Size of @str
*/
ssize_t of_device_modalias(struct device *dev, char *str, ssize_t len)
{
ssize_t sl = of_device_get_modalias(dev, str, len - 2);
if (sl < 0)
return sl;
if (sl > len - 2)
return -ENOMEM;
str[sl++] = '\n';
str[sl] = 0;
return sl;
}
EXPORT_SYMBOL_GPL(of_device_modalias);
/**
* of_device_uevent - Display OF related uevent information
* @dev: Device to apply DMA configuration
* @env: Kernel object's userspace event reference
*/
void of_device_uevent(struct device *dev, struct kobj_uevent_env *env)
{
const char *compat, *type;
struct alias_prop *app;
struct property *p;
int seen = 0;
if ((!dev) || (!dev->of_node))
return;
add_uevent_var(env, "OF_NAME=%pOFn", dev->of_node);
add_uevent_var(env, "OF_FULLNAME=%pOF", dev->of_node);
type = of_node_get_device_type(dev->of_node);
if (type)
add_uevent_var(env, "OF_TYPE=%s", type);
/* Since the compatible field can contain pretty much anything
* it's not really legal to split it out with commas. We split it
* up using a number of environment variables instead. */
of_property_for_each_string(dev->of_node, "compatible", p, compat) {
add_uevent_var(env, "OF_COMPATIBLE_%d=%s", seen, compat);
seen++;
}
add_uevent_var(env, "OF_COMPATIBLE_N=%d", seen);
seen = 0;
mutex_lock(&of_mutex);
list_for_each_entry(app, &aliases_lookup, link) {
if (dev->of_node == app->np) {
add_uevent_var(env, "OF_ALIAS_%d=%s", seen,
app->alias);
seen++;
}
}
mutex_unlock(&of_mutex);
}
int of_device_uevent_modalias(struct device *dev, struct kobj_uevent_env *env)
{
int sl;
if ((!dev) || (!dev->of_node))
return -ENODEV;
/* Devicetree modalias is tricky, we add it in 2 steps */
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
sl = of_device_get_modalias(dev, &env->buf[env->buflen-1],
sizeof(env->buf) - env->buflen);
if (sl >= (sizeof(env->buf) - env->buflen))
return -ENOMEM;
env->buflen += sl;
return 0;
}
EXPORT_SYMBOL_GPL(of_device_uevent_modalias);