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![Gustavo A. R. Silva](/assets/img/avatar_default.png)
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertenly introduced[3] to the codebase from now on.
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293
("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200211211010.GA32239@embeddedor
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
280 lines
6.6 KiB
C
280 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2014 ARM Limited
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*/
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/platform_device.h>
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#include <linux/sched/signal.h>
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#include <linux/slab.h>
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#include <linux/syscore_ops.h>
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#include <linux/vexpress.h>
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#define SYS_CFGDATA 0x0
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#define SYS_CFGCTRL 0x4
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#define SYS_CFGCTRL_START (1 << 31)
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#define SYS_CFGCTRL_WRITE (1 << 30)
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#define SYS_CFGCTRL_DCC(n) (((n) & 0xf) << 26)
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#define SYS_CFGCTRL_FUNC(n) (((n) & 0x3f) << 20)
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#define SYS_CFGCTRL_SITE(n) (((n) & 0x3) << 16)
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#define SYS_CFGCTRL_POSITION(n) (((n) & 0xf) << 12)
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#define SYS_CFGCTRL_DEVICE(n) (((n) & 0xfff) << 0)
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#define SYS_CFGSTAT 0x8
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#define SYS_CFGSTAT_ERR (1 << 1)
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#define SYS_CFGSTAT_COMPLETE (1 << 0)
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struct vexpress_syscfg {
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struct device *dev;
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void __iomem *base;
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struct list_head funcs;
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};
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struct vexpress_syscfg_func {
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struct list_head list;
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struct vexpress_syscfg *syscfg;
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struct regmap *regmap;
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int num_templates;
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u32 template[]; /* Keep it last! */
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};
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static int vexpress_syscfg_exec(struct vexpress_syscfg_func *func,
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int index, bool write, u32 *data)
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{
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struct vexpress_syscfg *syscfg = func->syscfg;
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u32 command, status;
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int tries;
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long timeout;
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if (WARN_ON(index >= func->num_templates))
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return -EINVAL;
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command = readl(syscfg->base + SYS_CFGCTRL);
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if (WARN_ON(command & SYS_CFGCTRL_START))
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return -EBUSY;
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command = func->template[index];
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command |= SYS_CFGCTRL_START;
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command |= write ? SYS_CFGCTRL_WRITE : 0;
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/* Use a canary for reads */
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if (!write)
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*data = 0xdeadbeef;
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dev_dbg(syscfg->dev, "func %p, command %x, data %x\n",
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func, command, *data);
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writel(*data, syscfg->base + SYS_CFGDATA);
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writel(0, syscfg->base + SYS_CFGSTAT);
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writel(command, syscfg->base + SYS_CFGCTRL);
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mb();
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/* The operation can take ages... Go to sleep, 100us initially */
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tries = 100;
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timeout = 100;
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do {
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if (!irqs_disabled()) {
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set_current_state(TASK_INTERRUPTIBLE);
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schedule_timeout(usecs_to_jiffies(timeout));
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if (signal_pending(current))
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return -EINTR;
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} else {
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udelay(timeout);
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}
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status = readl(syscfg->base + SYS_CFGSTAT);
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if (status & SYS_CFGSTAT_ERR)
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return -EFAULT;
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if (timeout > 20)
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timeout -= 20;
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} while (--tries && !(status & SYS_CFGSTAT_COMPLETE));
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if (WARN_ON_ONCE(!tries))
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return -ETIMEDOUT;
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if (!write) {
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*data = readl(syscfg->base + SYS_CFGDATA);
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dev_dbg(syscfg->dev, "func %p, read data %x\n", func, *data);
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}
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return 0;
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}
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static int vexpress_syscfg_read(void *context, unsigned int index,
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unsigned int *val)
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{
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struct vexpress_syscfg_func *func = context;
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return vexpress_syscfg_exec(func, index, false, val);
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}
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static int vexpress_syscfg_write(void *context, unsigned int index,
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unsigned int val)
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{
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struct vexpress_syscfg_func *func = context;
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return vexpress_syscfg_exec(func, index, true, &val);
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}
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static struct regmap_config vexpress_syscfg_regmap_config = {
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.lock = vexpress_config_lock,
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.unlock = vexpress_config_unlock,
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.reg_bits = 32,
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.val_bits = 32,
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.reg_read = vexpress_syscfg_read,
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.reg_write = vexpress_syscfg_write,
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.reg_format_endian = REGMAP_ENDIAN_LITTLE,
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.val_format_endian = REGMAP_ENDIAN_LITTLE,
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};
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static struct regmap *vexpress_syscfg_regmap_init(struct device *dev,
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void *context)
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{
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int err;
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struct vexpress_syscfg *syscfg = context;
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struct vexpress_syscfg_func *func;
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struct property *prop;
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const __be32 *val = NULL;
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__be32 energy_quirk[4];
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int num;
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u32 site, position, dcc;
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int i;
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err = vexpress_config_get_topo(dev->of_node, &site,
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&position, &dcc);
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if (err)
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return ERR_PTR(err);
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prop = of_find_property(dev->of_node,
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"arm,vexpress-sysreg,func", NULL);
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if (!prop)
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return ERR_PTR(-EINVAL);
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num = prop->length / sizeof(u32) / 2;
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val = prop->value;
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/*
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* "arm,vexpress-energy" function used to be described
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* by its first device only, now it requires both
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*/
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if (num == 1 && of_device_is_compatible(dev->of_node,
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"arm,vexpress-energy")) {
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num = 2;
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energy_quirk[0] = *val;
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energy_quirk[2] = *val++;
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energy_quirk[1] = *val;
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energy_quirk[3] = cpu_to_be32(be32_to_cpup(val) + 1);
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val = energy_quirk;
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}
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func = kzalloc(struct_size(func, template, num), GFP_KERNEL);
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if (!func)
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return ERR_PTR(-ENOMEM);
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func->syscfg = syscfg;
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func->num_templates = num;
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for (i = 0; i < num; i++) {
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u32 function, device;
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function = be32_to_cpup(val++);
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device = be32_to_cpup(val++);
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dev_dbg(dev, "func %p: %u/%u/%u/%u/%u\n",
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func, site, position, dcc,
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function, device);
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func->template[i] = SYS_CFGCTRL_DCC(dcc);
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func->template[i] |= SYS_CFGCTRL_SITE(site);
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func->template[i] |= SYS_CFGCTRL_POSITION(position);
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func->template[i] |= SYS_CFGCTRL_FUNC(function);
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func->template[i] |= SYS_CFGCTRL_DEVICE(device);
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}
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vexpress_syscfg_regmap_config.max_register = num - 1;
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func->regmap = regmap_init(dev, NULL, func,
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&vexpress_syscfg_regmap_config);
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if (IS_ERR(func->regmap)) {
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void *err = func->regmap;
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kfree(func);
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return err;
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}
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list_add(&func->list, &syscfg->funcs);
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return func->regmap;
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}
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static void vexpress_syscfg_regmap_exit(struct regmap *regmap, void *context)
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{
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struct vexpress_syscfg *syscfg = context;
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struct vexpress_syscfg_func *func, *tmp;
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regmap_exit(regmap);
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list_for_each_entry_safe(func, tmp, &syscfg->funcs, list) {
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if (func->regmap == regmap) {
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list_del(&syscfg->funcs);
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kfree(func);
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break;
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}
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}
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}
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static struct vexpress_config_bridge_ops vexpress_syscfg_bridge_ops = {
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.regmap_init = vexpress_syscfg_regmap_init,
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.regmap_exit = vexpress_syscfg_regmap_exit,
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};
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static int vexpress_syscfg_probe(struct platform_device *pdev)
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{
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struct vexpress_syscfg *syscfg;
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struct resource *res;
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struct device *bridge;
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syscfg = devm_kzalloc(&pdev->dev, sizeof(*syscfg), GFP_KERNEL);
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if (!syscfg)
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return -ENOMEM;
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syscfg->dev = &pdev->dev;
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INIT_LIST_HEAD(&syscfg->funcs);
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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syscfg->base = devm_ioremap_resource(&pdev->dev, res);
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if (IS_ERR(syscfg->base))
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return PTR_ERR(syscfg->base);
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/* Must use dev.parent (MFD), as that's where DT phandle points at... */
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bridge = vexpress_config_bridge_register(pdev->dev.parent,
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&vexpress_syscfg_bridge_ops, syscfg);
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return PTR_ERR_OR_ZERO(bridge);
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}
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static const struct platform_device_id vexpress_syscfg_id_table[] = {
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{ "vexpress-syscfg", },
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{},
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};
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static struct platform_driver vexpress_syscfg_driver = {
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.driver.name = "vexpress-syscfg",
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.id_table = vexpress_syscfg_id_table,
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.probe = vexpress_syscfg_probe,
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};
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static int __init vexpress_syscfg_init(void)
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{
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return platform_driver_register(&vexpress_syscfg_driver);
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}
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core_initcall(vexpress_syscfg_init);
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