linux/drivers/clk/clkdev.c
Stephen Boyd 73e0e496af clkdev: Always allocate a struct clk and call __clk_get() w/ CCF
of_clk_get_by_clkspec() returns a struct clk pointer but it
doesn't create a new handle for the consumers when we're using
the common clock framework. Instead it just returns whatever the
clk provider hands out. When the consumers go to call clk_put()
we get an Oops.

Unable to handle kernel paging request at virtual address 00200200
pgd = c0004000
[00200200] *pgd=00000000
Internal error: Oops: 805 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc1-00104-ga251361a-dirty #992
Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
task: ee00b000 ti: ee088000 task.ti: ee088000
PC is at __clk_put+0x24/0xd0
LR is at clk_prepare_lock+0xc/0xec
pc : [<c03eef38>]    lr : [<c03ec1f4>]    psr: 20000153
sp : ee089de8  ip : 00000000  fp : 00000000
r10: ee02f480  r9 : 00000001  r8 : 00000000
r7 : ee031cc0  r6 : ee089e08  r5 : 00000000  r4 : ee02f480
r3 : 00100100  r2 : 00200200  r1 : 0000091e  r0 : 00000001
Flags: nzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
Control: 10c5387d  Table: 4000404a  DAC: 00000015
Process swapper/0 (pid: 1, stack limit = 0xee088238)
Stack: (0xee089de8 to 0xee08a000)
9de0:                   ee7c8f14 c03f0ec8 ee089e08 00000000 c0718dc8 00000001
9e00: 00000000 c04ee0f0 ee7e0844 00000001 00000181 c04edb58 ee2bd320 00000000
9e20: 00000000 c011dc5c ee16a1e0 00000000 00000000 c0718dc8 ee16a1e0 ee2bd1e0
9e40: c0641740 ee16a1e0 00000000 ee2bd320 c0718dc8 ee1d3e10 ee1d3e10 00000000
9e60: c0769a88 00000000 c0718dc8 00000000 00000000 c02c3124 c02c310c ee1d3e10
9e80: c07b4eec 00000000 c0769a88 c02c1d0c ee1d3e10 c0769a88 ee1d3e44 00000000
9ea0: c07091dc c02c1eb8 00000000 c0769a88 c02c1e2c c02c0544 ee005478 ee1676c0
9ec0: c0769a88 ee3a4e80 c0760ce8 c02c150c c0669b90 c0769a88 c0746cd8 c0769a88
9ee0: c0746cd8 ee2bc4c0 c0778c00 c02c24e0 00000000 c0746cd8 c0746cd8 c07091f0
9f00: 00000000 c0008944 c04f405c 00000025 ee00b000 60000153 c074ab00 00000000
9f20: 00000000 c074ab90 60000153 00000000 ef7fca5d c050860c 000000b6 c0036b88
9f40: c065ecc4 c06bc728 00000006 00000006 c074ab30 ef7fca40 c0739bdc 00000006
9f60: c0718dbc c0778c00 000000b6 c0718dc8 c06ed598 c06edd64 00000006 00000006
9f80: c06ed598 c003b438 00000000 c04e64f4 00000000 00000000 00000000 00000000
9fa0: 00000000 c04e64fc 00000000 c000e838 00000000 00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 c0c0c0c0 c0c0c0c0
[<c03eef38>] (__clk_put) from [<c03f0ec8>] (of_clk_set_defaults+0xe0/0x2c0)
[<c03f0ec8>] (of_clk_set_defaults) from [<c02c3124>] (platform_drv_probe+0x18/0xa4)
[<c02c3124>] (platform_drv_probe) from [<c02c1d0c>] (driver_probe_device+0x10c/0x22c)
[<c02c1d0c>] (driver_probe_device) from [<c02c1eb8>] (__driver_attach+0x8c/0x90)
[<c02c1eb8>] (__driver_attach) from [<c02c0544>] (bus_for_each_dev+0x54/0x88)
[<c02c0544>] (bus_for_each_dev) from [<c02c150c>] (bus_add_driver+0xd4/0x1d0)
[<c02c150c>] (bus_add_driver) from [<c02c24e0>] (driver_register+0x78/0xf4)
[<c02c24e0>] (driver_register) from [<c07091f0>] (fimc_md_init+0x14/0x30)
[<c07091f0>] (fimc_md_init) from [<c0008944>] (do_one_initcall+0x80/0x1d0)
[<c0008944>] (do_one_initcall) from [<c06edd64>] (kernel_init_freeable+0x108/0x1d4)
[<c06edd64>] (kernel_init_freeable) from [<c04e64fc>] (kernel_init+0x8/0xec)
[<c04e64fc>] (kernel_init) from [<c000e838>] (ret_from_fork+0x14/0x3c)
Code: ebfff4ae e5943014 e5942018 e3530000 (e5823000)

Let's create a per-user handle here so that clk_put() can
properly unlink it and free the handle. Now that we allocate a
clk structure here we need to free it if __clk_get() fails so
bury the __clk_get() call in __of_clk_get_from_provider(). We
need to handle the same problem in clk_get_sys() so export
__clk_free_clk() to clkdev.c and do the same thing, except let's
use a union to make this code #ifdef free.

This fixes the above crash, properly calls __clk_get() when
of_clk_get_from_provider() is called, and cleans up the clk
structure on the error path of clk_get_sys().

Fixes: 035a61c314 "clk: Make clk API return per-user struct clk instances"
Reported-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Reported-by: Alban Browaeys <alban.browaeys@gmail.com>
Tested-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Tested-by: Alban Browaeys <prahal@yahoo.com>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Michael Turquette <mturquette@linaro.org>
2015-02-06 17:53:20 -08:00

403 lines
9.1 KiB
C

/*
* drivers/clk/clkdev.c
*
* Copyright (C) 2008 Russell King.
*
* 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.
*
* Helper for the clk API to assist looking up a struct clk.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/string.h>
#include <linux/mutex.h>
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/clk-provider.h>
#include <linux/of.h>
#include "clk.h"
static LIST_HEAD(clocks);
static DEFINE_MUTEX(clocks_mutex);
#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
static struct clk *__of_clk_get_by_clkspec(struct of_phandle_args *clkspec,
const char *dev_id, const char *con_id)
{
struct clk *clk;
if (!clkspec)
return ERR_PTR(-EINVAL);
of_clk_lock();
clk = __of_clk_get_from_provider(clkspec, dev_id, con_id);
of_clk_unlock();
return clk;
}
/**
* of_clk_get_by_clkspec() - Lookup a clock form a clock provider
* @clkspec: pointer to a clock specifier data structure
*
* This function looks up a struct clk from the registered list of clock
* providers, an input is a clock specifier data structure as returned
* from the of_parse_phandle_with_args() function call.
*/
struct clk *of_clk_get_by_clkspec(struct of_phandle_args *clkspec)
{
return __of_clk_get_by_clkspec(clkspec, NULL, __func__);
}
static struct clk *__of_clk_get(struct device_node *np, int index,
const char *dev_id, const char *con_id)
{
struct of_phandle_args clkspec;
struct clk *clk;
int rc;
if (index < 0)
return ERR_PTR(-EINVAL);
rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
&clkspec);
if (rc)
return ERR_PTR(rc);
clk = __of_clk_get_by_clkspec(&clkspec, dev_id, con_id);
of_node_put(clkspec.np);
return clk;
}
struct clk *of_clk_get(struct device_node *np, int index)
{
return __of_clk_get(np, index, np->full_name, NULL);
}
EXPORT_SYMBOL(of_clk_get);
static struct clk *__of_clk_get_by_name(struct device_node *np,
const char *dev_id,
const char *name)
{
struct clk *clk = ERR_PTR(-ENOENT);
/* Walk up the tree of devices looking for a clock that matches */
while (np) {
int index = 0;
/*
* For named clocks, first look up the name in the
* "clock-names" property. If it cannot be found, then
* index will be an error code, and of_clk_get() will fail.
*/
if (name)
index = of_property_match_string(np, "clock-names", name);
clk = __of_clk_get(np, index, dev_id, name);
if (!IS_ERR(clk)) {
break;
} else if (name && index >= 0) {
if (PTR_ERR(clk) != -EPROBE_DEFER)
pr_err("ERROR: could not get clock %s:%s(%i)\n",
np->full_name, name ? name : "", index);
return clk;
}
/*
* No matching clock found on this node. If the parent node
* has a "clock-ranges" property, then we can try one of its
* clocks.
*/
np = np->parent;
if (np && !of_get_property(np, "clock-ranges", NULL))
break;
}
return clk;
}
/**
* of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
* @np: pointer to clock consumer node
* @name: name of consumer's clock input, or NULL for the first clock reference
*
* This function parses the clocks and clock-names properties,
* and uses them to look up the struct clk from the registered list of clock
* providers.
*/
struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
{
if (!np)
return ERR_PTR(-ENOENT);
return __of_clk_get_by_name(np, np->full_name, name);
}
EXPORT_SYMBOL(of_clk_get_by_name);
#else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
static struct clk *__of_clk_get_by_name(struct device_node *np,
const char *dev_id,
const char *name)
{
return ERR_PTR(-ENOENT);
}
#endif
/*
* Find the correct struct clk for the device and connection ID.
* We do slightly fuzzy matching here:
* An entry with a NULL ID is assumed to be a wildcard.
* If an entry has a device ID, it must match
* If an entry has a connection ID, it must match
* Then we take the most specific entry - with the following
* order of precedence: dev+con > dev only > con only.
*/
static struct clk_lookup *clk_find(const char *dev_id, const char *con_id)
{
struct clk_lookup *p, *cl = NULL;
int match, best_found = 0, best_possible = 0;
if (dev_id)
best_possible += 2;
if (con_id)
best_possible += 1;
list_for_each_entry(p, &clocks, node) {
match = 0;
if (p->dev_id) {
if (!dev_id || strcmp(p->dev_id, dev_id))
continue;
match += 2;
}
if (p->con_id) {
if (!con_id || strcmp(p->con_id, con_id))
continue;
match += 1;
}
if (match > best_found) {
cl = p;
if (match != best_possible)
best_found = match;
else
break;
}
}
return cl;
}
struct clk *clk_get_sys(const char *dev_id, const char *con_id)
{
struct clk_lookup *cl;
struct clk *clk = NULL;
mutex_lock(&clocks_mutex);
cl = clk_find(dev_id, con_id);
if (!cl)
goto out;
clk = __clk_create_clk(__clk_get_hw(cl->clk), dev_id, con_id);
if (IS_ERR(clk))
goto out;
if (!__clk_get(clk)) {
__clk_free_clk(clk);
cl = NULL;
goto out;
}
out:
mutex_unlock(&clocks_mutex);
return cl ? clk : ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL(clk_get_sys);
struct clk *clk_get(struct device *dev, const char *con_id)
{
const char *dev_id = dev ? dev_name(dev) : NULL;
struct clk *clk;
if (dev) {
clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
return clk;
}
return clk_get_sys(dev_id, con_id);
}
EXPORT_SYMBOL(clk_get);
void clk_put(struct clk *clk)
{
__clk_put(clk);
}
EXPORT_SYMBOL(clk_put);
void clkdev_add(struct clk_lookup *cl)
{
mutex_lock(&clocks_mutex);
list_add_tail(&cl->node, &clocks);
mutex_unlock(&clocks_mutex);
}
EXPORT_SYMBOL(clkdev_add);
void __init clkdev_add_table(struct clk_lookup *cl, size_t num)
{
mutex_lock(&clocks_mutex);
while (num--) {
list_add_tail(&cl->node, &clocks);
cl++;
}
mutex_unlock(&clocks_mutex);
}
#define MAX_DEV_ID 20
#define MAX_CON_ID 16
struct clk_lookup_alloc {
struct clk_lookup cl;
char dev_id[MAX_DEV_ID];
char con_id[MAX_CON_ID];
};
static struct clk_lookup * __init_refok
vclkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt,
va_list ap)
{
struct clk_lookup_alloc *cla;
cla = __clkdev_alloc(sizeof(*cla));
if (!cla)
return NULL;
cla->cl.clk = clk;
if (con_id) {
strlcpy(cla->con_id, con_id, sizeof(cla->con_id));
cla->cl.con_id = cla->con_id;
}
if (dev_fmt) {
vscnprintf(cla->dev_id, sizeof(cla->dev_id), dev_fmt, ap);
cla->cl.dev_id = cla->dev_id;
}
return &cla->cl;
}
struct clk_lookup * __init_refok
clkdev_alloc(struct clk *clk, const char *con_id, const char *dev_fmt, ...)
{
struct clk_lookup *cl;
va_list ap;
va_start(ap, dev_fmt);
cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
va_end(ap);
return cl;
}
EXPORT_SYMBOL(clkdev_alloc);
int clk_add_alias(const char *alias, const char *alias_dev_name, char *id,
struct device *dev)
{
struct clk *r = clk_get(dev, id);
struct clk_lookup *l;
if (IS_ERR(r))
return PTR_ERR(r);
l = clkdev_alloc(r, alias, alias_dev_name);
clk_put(r);
if (!l)
return -ENODEV;
clkdev_add(l);
return 0;
}
EXPORT_SYMBOL(clk_add_alias);
/*
* clkdev_drop - remove a clock dynamically allocated
*/
void clkdev_drop(struct clk_lookup *cl)
{
mutex_lock(&clocks_mutex);
list_del(&cl->node);
mutex_unlock(&clocks_mutex);
kfree(cl);
}
EXPORT_SYMBOL(clkdev_drop);
/**
* clk_register_clkdev - register one clock lookup for a struct clk
* @clk: struct clk to associate with all clk_lookups
* @con_id: connection ID string on device
* @dev_id: format string describing device name
*
* con_id or dev_id may be NULL as a wildcard, just as in the rest of
* clkdev.
*
* To make things easier for mass registration, we detect error clks
* from a previous clk_register() call, and return the error code for
* those. This is to permit this function to be called immediately
* after clk_register().
*/
int clk_register_clkdev(struct clk *clk, const char *con_id,
const char *dev_fmt, ...)
{
struct clk_lookup *cl;
va_list ap;
if (IS_ERR(clk))
return PTR_ERR(clk);
va_start(ap, dev_fmt);
cl = vclkdev_alloc(clk, con_id, dev_fmt, ap);
va_end(ap);
if (!cl)
return -ENOMEM;
clkdev_add(cl);
return 0;
}
EXPORT_SYMBOL(clk_register_clkdev);
/**
* clk_register_clkdevs - register a set of clk_lookup for a struct clk
* @clk: struct clk to associate with all clk_lookups
* @cl: array of clk_lookup structures with con_id and dev_id pre-initialized
* @num: number of clk_lookup structures to register
*
* To make things easier for mass registration, we detect error clks
* from a previous clk_register() call, and return the error code for
* those. This is to permit this function to be called immediately
* after clk_register().
*/
int clk_register_clkdevs(struct clk *clk, struct clk_lookup *cl, size_t num)
{
unsigned i;
if (IS_ERR(clk))
return PTR_ERR(clk);
for (i = 0; i < num; i++, cl++) {
cl->clk = clk;
clkdev_add(cl);
}
return 0;
}
EXPORT_SYMBOL(clk_register_clkdevs);