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linux/drivers/irqchip/irq-bcm7038-l1.c
Gustavo A. R. Silva b2e1cbfd2d irqchip/irq-bcm7038-l1: Replace zero-length array with flexible-array member 
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
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

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>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20200319214438.GA21123@embeddedor.com
2020-03-22 11:52:52 +00:00

479 lines
12 KiB
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Broadcom BCM7038 style Level 1 interrupt controller driver
*
* Copyright (C) 2014 Broadcom Corporation
* Author: Kevin Cernekee
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/bitops.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/ioport.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_address.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/types.h>
#include <linux/irqchip.h>
#include <linux/irqchip/chained_irq.h>
#include <linux/syscore_ops.h>
#define IRQS_PER_WORD 32
#define REG_BYTES_PER_IRQ_WORD (sizeof(u32) * 4)
#define MAX_WORDS 8
struct bcm7038_l1_cpu;
struct bcm7038_l1_chip {
raw_spinlock_t lock;
unsigned int n_words;
struct irq_domain *domain;
struct bcm7038_l1_cpu *cpus[NR_CPUS];
#ifdef CONFIG_PM_SLEEP
struct list_head list;
u32 wake_mask[MAX_WORDS];
#endif
u32 irq_fwd_mask[MAX_WORDS];
u8 affinity[MAX_WORDS * IRQS_PER_WORD];
};
struct bcm7038_l1_cpu {
void __iomem *map_base;
u32 mask_cache[];
};
/*
* STATUS/MASK_STATUS/MASK_SET/MASK_CLEAR are packed one right after another:
*
* 7038:
* 0x1000_1400: W0_STATUS
* 0x1000_1404: W1_STATUS
* 0x1000_1408: W0_MASK_STATUS
* 0x1000_140c: W1_MASK_STATUS
* 0x1000_1410: W0_MASK_SET
* 0x1000_1414: W1_MASK_SET
* 0x1000_1418: W0_MASK_CLEAR
* 0x1000_141c: W1_MASK_CLEAR
*
* 7445:
* 0xf03e_1500: W0_STATUS
* 0xf03e_1504: W1_STATUS
* 0xf03e_1508: W2_STATUS
* 0xf03e_150c: W3_STATUS
* 0xf03e_1510: W4_STATUS
* 0xf03e_1514: W0_MASK_STATUS
* 0xf03e_1518: W1_MASK_STATUS
* [...]
*/
static inline unsigned int reg_status(struct bcm7038_l1_chip *intc,
unsigned int word)
{
return (0 * intc->n_words + word) * sizeof(u32);
}
static inline unsigned int reg_mask_status(struct bcm7038_l1_chip *intc,
unsigned int word)
{
return (1 * intc->n_words + word) * sizeof(u32);
}
static inline unsigned int reg_mask_set(struct bcm7038_l1_chip *intc,
unsigned int word)
{
return (2 * intc->n_words + word) * sizeof(u32);
}
static inline unsigned int reg_mask_clr(struct bcm7038_l1_chip *intc,
unsigned int word)
{
return (3 * intc->n_words + word) * sizeof(u32);
}
static inline u32 l1_readl(void __iomem *reg)
{
if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
return ioread32be(reg);
else
return readl(reg);
}
static inline void l1_writel(u32 val, void __iomem *reg)
{
if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
iowrite32be(val, reg);
else
writel(val, reg);
}
static void bcm7038_l1_irq_handle(struct irq_desc *desc)
{
struct bcm7038_l1_chip *intc = irq_desc_get_handler_data(desc);
struct bcm7038_l1_cpu *cpu;
struct irq_chip *chip = irq_desc_get_chip(desc);
unsigned int idx;
#ifdef CONFIG_SMP
cpu = intc->cpus[cpu_logical_map(smp_processor_id())];
#else
cpu = intc->cpus[0];
#endif
chained_irq_enter(chip, desc);
for (idx = 0; idx < intc->n_words; idx++) {
int base = idx * IRQS_PER_WORD;
unsigned long pending, flags;
int hwirq;
raw_spin_lock_irqsave(&intc->lock, flags);
pending = l1_readl(cpu->map_base + reg_status(intc, idx)) &
~cpu->mask_cache[idx];
raw_spin_unlock_irqrestore(&intc->lock, flags);
for_each_set_bit(hwirq, &pending, IRQS_PER_WORD) {
generic_handle_irq(irq_find_mapping(intc->domain,
base + hwirq));
}
}
chained_irq_exit(chip, desc);
}
static void __bcm7038_l1_unmask(struct irq_data *d, unsigned int cpu_idx)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
u32 word = d->hwirq / IRQS_PER_WORD;
u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
intc->cpus[cpu_idx]->mask_cache[word] &= ~mask;
l1_writel(mask, intc->cpus[cpu_idx]->map_base +
reg_mask_clr(intc, word));
}
static void __bcm7038_l1_mask(struct irq_data *d, unsigned int cpu_idx)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
u32 word = d->hwirq / IRQS_PER_WORD;
u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
intc->cpus[cpu_idx]->mask_cache[word] |= mask;
l1_writel(mask, intc->cpus[cpu_idx]->map_base +
reg_mask_set(intc, word));
}
static void bcm7038_l1_unmask(struct irq_data *d)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
unsigned long flags;
raw_spin_lock_irqsave(&intc->lock, flags);
__bcm7038_l1_unmask(d, intc->affinity[d->hwirq]);
raw_spin_unlock_irqrestore(&intc->lock, flags);
}
static void bcm7038_l1_mask(struct irq_data *d)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
unsigned long flags;
raw_spin_lock_irqsave(&intc->lock, flags);
__bcm7038_l1_mask(d, intc->affinity[d->hwirq]);
raw_spin_unlock_irqrestore(&intc->lock, flags);
}
static int bcm7038_l1_set_affinity(struct irq_data *d,
const struct cpumask *dest,
bool force)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
unsigned long flags;
irq_hw_number_t hw = d->hwirq;
u32 word = hw / IRQS_PER_WORD;
u32 mask = BIT(hw % IRQS_PER_WORD);
unsigned int first_cpu = cpumask_any_and(dest, cpu_online_mask);
bool was_disabled;
raw_spin_lock_irqsave(&intc->lock, flags);
was_disabled = !!(intc->cpus[intc->affinity[hw]]->mask_cache[word] &
mask);
__bcm7038_l1_mask(d, intc->affinity[hw]);
intc->affinity[hw] = first_cpu;
if (!was_disabled)
__bcm7038_l1_unmask(d, first_cpu);
raw_spin_unlock_irqrestore(&intc->lock, flags);
irq_data_update_effective_affinity(d, cpumask_of(first_cpu));
return 0;
}
#ifdef CONFIG_SMP
static void bcm7038_l1_cpu_offline(struct irq_data *d)
{
struct cpumask *mask = irq_data_get_affinity_mask(d);
int cpu = smp_processor_id();
cpumask_t new_affinity;
/* This CPU was not on the affinity mask */
if (!cpumask_test_cpu(cpu, mask))
return;
if (cpumask_weight(mask) > 1) {
/*
* Multiple CPU affinity, remove this CPU from the affinity
* mask
*/
cpumask_copy(&new_affinity, mask);
cpumask_clear_cpu(cpu, &new_affinity);
} else {
/* Only CPU, put on the lowest online CPU */
cpumask_clear(&new_affinity);
cpumask_set_cpu(cpumask_first(cpu_online_mask), &new_affinity);
}
irq_set_affinity_locked(d, &new_affinity, false);
}
#endif
static int __init bcm7038_l1_init_one(struct device_node *dn,
unsigned int idx,
struct bcm7038_l1_chip *intc)
{
struct resource res;
resource_size_t sz;
struct bcm7038_l1_cpu *cpu;
unsigned int i, n_words, parent_irq;
int ret;
if (of_address_to_resource(dn, idx, &res))
return -EINVAL;
sz = resource_size(&res);
n_words = sz / REG_BYTES_PER_IRQ_WORD;
if (n_words > MAX_WORDS)
return -EINVAL;
else if (!intc->n_words)
intc->n_words = n_words;
else if (intc->n_words != n_words)
return -EINVAL;
ret = of_property_read_u32_array(dn , "brcm,int-fwd-mask",
intc->irq_fwd_mask, n_words);
if (ret != 0 && ret != -EINVAL) {
/* property exists but has the wrong number of words */
pr_err("invalid brcm,int-fwd-mask property\n");
return -EINVAL;
}
cpu = intc->cpus[idx] = kzalloc(sizeof(*cpu) + n_words * sizeof(u32),
GFP_KERNEL);
if (!cpu)
return -ENOMEM;
cpu->map_base = ioremap(res.start, sz);
if (!cpu->map_base)
return -ENOMEM;
for (i = 0; i < n_words; i++) {
l1_writel(~intc->irq_fwd_mask[i],
cpu->map_base + reg_mask_set(intc, i));
l1_writel(intc->irq_fwd_mask[i],
cpu->map_base + reg_mask_clr(intc, i));
cpu->mask_cache[i] = ~intc->irq_fwd_mask[i];
}
parent_irq = irq_of_parse_and_map(dn, idx);
if (!parent_irq) {
pr_err("failed to map parent interrupt %d\n", parent_irq);
return -EINVAL;
}
if (of_property_read_bool(dn, "brcm,irq-can-wake"))
enable_irq_wake(parent_irq);
irq_set_chained_handler_and_data(parent_irq, bcm7038_l1_irq_handle,
intc);
return 0;
}
#ifdef CONFIG_PM_SLEEP
/*
* We keep a list of bcm7038_l1_chip used for suspend/resume. This hack is
* used because the struct chip_type suspend/resume hooks are not called
* unless chip_type is hooked onto a generic_chip. Since this driver does
* not use generic_chip, we need to manually hook our resume/suspend to
* syscore_ops.
*/
static LIST_HEAD(bcm7038_l1_intcs_list);
static DEFINE_RAW_SPINLOCK(bcm7038_l1_intcs_lock);
static int bcm7038_l1_suspend(void)
{
struct bcm7038_l1_chip *intc;
int boot_cpu, word;
u32 val;
/* Wakeup interrupt should only come from the boot cpu */
boot_cpu = cpu_logical_map(0);
list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
for (word = 0; word < intc->n_words; word++) {
val = intc->wake_mask[word] | intc->irq_fwd_mask[word];
l1_writel(~val,
intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
l1_writel(val,
intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
}
}
return 0;
}
static void bcm7038_l1_resume(void)
{
struct bcm7038_l1_chip *intc;
int boot_cpu, word;
boot_cpu = cpu_logical_map(0);
list_for_each_entry(intc, &bcm7038_l1_intcs_list, list) {
for (word = 0; word < intc->n_words; word++) {
l1_writel(intc->cpus[boot_cpu]->mask_cache[word],
intc->cpus[boot_cpu]->map_base + reg_mask_set(intc, word));
l1_writel(~intc->cpus[boot_cpu]->mask_cache[word],
intc->cpus[boot_cpu]->map_base + reg_mask_clr(intc, word));
}
}
}
static struct syscore_ops bcm7038_l1_syscore_ops = {
.suspend = bcm7038_l1_suspend,
.resume = bcm7038_l1_resume,
};
static int bcm7038_l1_set_wake(struct irq_data *d, unsigned int on)
{
struct bcm7038_l1_chip *intc = irq_data_get_irq_chip_data(d);
unsigned long flags;
u32 word = d->hwirq / IRQS_PER_WORD;
u32 mask = BIT(d->hwirq % IRQS_PER_WORD);
raw_spin_lock_irqsave(&intc->lock, flags);
if (on)
intc->wake_mask[word] |= mask;
else
intc->wake_mask[word] &= ~mask;
raw_spin_unlock_irqrestore(&intc->lock, flags);
return 0;
}
#endif
static struct irq_chip bcm7038_l1_irq_chip = {
.name = "bcm7038-l1",
.irq_mask = bcm7038_l1_mask,
.irq_unmask = bcm7038_l1_unmask,
.irq_set_affinity = bcm7038_l1_set_affinity,
#ifdef CONFIG_SMP
.irq_cpu_offline = bcm7038_l1_cpu_offline,
#endif
#ifdef CONFIG_PM_SLEEP
.irq_set_wake = bcm7038_l1_set_wake,
#endif
};
static int bcm7038_l1_map(struct irq_domain *d, unsigned int virq,
irq_hw_number_t hw_irq)
{
struct bcm7038_l1_chip *intc = d->host_data;
u32 mask = BIT(hw_irq % IRQS_PER_WORD);
u32 word = hw_irq / IRQS_PER_WORD;
if (intc->irq_fwd_mask[word] & mask)
return -EPERM;
irq_set_chip_and_handler(virq, &bcm7038_l1_irq_chip, handle_level_irq);
irq_set_chip_data(virq, d->host_data);
irqd_set_single_target(irq_desc_get_irq_data(irq_to_desc(virq)));
return 0;
}
static const struct irq_domain_ops bcm7038_l1_domain_ops = {
.xlate = irq_domain_xlate_onecell,
.map = bcm7038_l1_map,
};
int __init bcm7038_l1_of_init(struct device_node *dn,
struct device_node *parent)
{
struct bcm7038_l1_chip *intc;
int idx, ret;
intc = kzalloc(sizeof(*intc), GFP_KERNEL);
if (!intc)
return -ENOMEM;
raw_spin_lock_init(&intc->lock);
for_each_possible_cpu(idx) {
ret = bcm7038_l1_init_one(dn, idx, intc);
if (ret < 0) {
if (idx)
break;
pr_err("failed to remap intc L1 registers\n");
goto out_free;
}
}
intc->domain = irq_domain_add_linear(dn, IRQS_PER_WORD * intc->n_words,
&bcm7038_l1_domain_ops,
intc);
if (!intc->domain) {
ret = -ENOMEM;
goto out_unmap;
}
#ifdef CONFIG_PM_SLEEP
/* Add bcm7038_l1_chip into a list */
raw_spin_lock(&bcm7038_l1_intcs_lock);
list_add_tail(&intc->list, &bcm7038_l1_intcs_list);
raw_spin_unlock(&bcm7038_l1_intcs_lock);
if (list_is_singular(&bcm7038_l1_intcs_list))
register_syscore_ops(&bcm7038_l1_syscore_ops);
#endif
pr_info("registered BCM7038 L1 intc (%pOF, IRQs: %d)\n",
dn, IRQS_PER_WORD * intc->n_words);
return 0;
out_unmap:
for_each_possible_cpu(idx) {
struct bcm7038_l1_cpu *cpu = intc->cpus[idx];
if (cpu) {
if (cpu->map_base)
iounmap(cpu->map_base);
kfree(cpu);
}
}
out_free:
kfree(intc);
return ret;
}
IRQCHIP_DECLARE(bcm7038_l1, "brcm,bcm7038-l1-intc", bcm7038_l1_of_init);
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