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linux/drivers/gpio/gpio-uniphier.c
Gustavo A. R. Silva ec18d7e7d2 gpio: uniphier: 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
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>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
2020-03-02 08:52:55 +01:00

496 lines
13 KiB
C
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// SPDX-License-Identifier: GPL-2.0
//
// Copyright (C) 2017 Socionext Inc.
// Author: Masahiro Yamada <yamada.masahiro@socionext.com>
#include <linux/bits.h>
#include <linux/gpio/driver.h>
#include <linux/irq.h>
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <dt-bindings/gpio/uniphier-gpio.h>
#define UNIPHIER_GPIO_IRQ_MAX_NUM 24
#define UNIPHIER_GPIO_PORT_DATA 0x0 /* data */
#define UNIPHIER_GPIO_PORT_DIR 0x4 /* direction (1:in, 0:out) */
#define UNIPHIER_GPIO_IRQ_EN 0x90 /* irq enable */
#define UNIPHIER_GPIO_IRQ_MODE 0x94 /* irq mode (1: both edge) */
#define UNIPHIER_GPIO_IRQ_FLT_EN 0x98 /* noise filter enable */
#define UNIPHIER_GPIO_IRQ_FLT_CYC 0x9c /* noise filter clock cycle */
struct uniphier_gpio_priv {
struct gpio_chip chip;
struct irq_chip irq_chip;
struct irq_domain *domain;
void __iomem *regs;
spinlock_t lock;
u32 saved_vals[];
};
static unsigned int uniphier_gpio_bank_to_reg(unsigned int bank)
{
unsigned int reg;
reg = (bank + 1) * 8;
/*
* Unfortunately, the GPIO port registers are not contiguous because
* offset 0x90-0x9f is used for IRQ. Add 0x10 when crossing the region.
*/
if (reg >= UNIPHIER_GPIO_IRQ_EN)
reg += 0x10;
return reg;
}
static void uniphier_gpio_get_bank_and_mask(unsigned int offset,
unsigned int *bank, u32 *mask)
{
*bank = offset / UNIPHIER_GPIO_LINES_PER_BANK;
*mask = BIT(offset % UNIPHIER_GPIO_LINES_PER_BANK);
}
static void uniphier_gpio_reg_update(struct uniphier_gpio_priv *priv,
unsigned int reg, u32 mask, u32 val)
{
unsigned long flags;
u32 tmp;
spin_lock_irqsave(&priv->lock, flags);
tmp = readl(priv->regs + reg);
tmp &= ~mask;
tmp |= mask & val;
writel(tmp, priv->regs + reg);
spin_unlock_irqrestore(&priv->lock, flags);
}
static void uniphier_gpio_bank_write(struct gpio_chip *chip, unsigned int bank,
unsigned int reg, u32 mask, u32 val)
{
struct uniphier_gpio_priv *priv = gpiochip_get_data(chip);
if (!mask)
return;
uniphier_gpio_reg_update(priv, uniphier_gpio_bank_to_reg(bank) + reg,
mask, val);
}
static void uniphier_gpio_offset_write(struct gpio_chip *chip,
unsigned int offset, unsigned int reg,
int val)
{
unsigned int bank;
u32 mask;
uniphier_gpio_get_bank_and_mask(offset, &bank, &mask);
uniphier_gpio_bank_write(chip, bank, reg, mask, val ? mask : 0);
}
static int uniphier_gpio_offset_read(struct gpio_chip *chip,
unsigned int offset, unsigned int reg)
{
struct uniphier_gpio_priv *priv = gpiochip_get_data(chip);
unsigned int bank, reg_offset;
u32 mask;
uniphier_gpio_get_bank_and_mask(offset, &bank, &mask);
reg_offset = uniphier_gpio_bank_to_reg(bank) + reg;
return !!(readl(priv->regs + reg_offset) & mask);
}
static int uniphier_gpio_get_direction(struct gpio_chip *chip,
unsigned int offset)
{
if (uniphier_gpio_offset_read(chip, offset, UNIPHIER_GPIO_PORT_DIR))
return GPIO_LINE_DIRECTION_IN;
return GPIO_LINE_DIRECTION_OUT;
}
static int uniphier_gpio_direction_input(struct gpio_chip *chip,
unsigned int offset)
{
uniphier_gpio_offset_write(chip, offset, UNIPHIER_GPIO_PORT_DIR, 1);
return 0;
}
static int uniphier_gpio_direction_output(struct gpio_chip *chip,
unsigned int offset, int val)
{
uniphier_gpio_offset_write(chip, offset, UNIPHIER_GPIO_PORT_DATA, val);
uniphier_gpio_offset_write(chip, offset, UNIPHIER_GPIO_PORT_DIR, 0);
return 0;
}
static int uniphier_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
return uniphier_gpio_offset_read(chip, offset, UNIPHIER_GPIO_PORT_DATA);
}
static void uniphier_gpio_set(struct gpio_chip *chip,
unsigned int offset, int val)
{
uniphier_gpio_offset_write(chip, offset, UNIPHIER_GPIO_PORT_DATA, val);
}
static void uniphier_gpio_set_multiple(struct gpio_chip *chip,
unsigned long *mask, unsigned long *bits)
{
unsigned long i, bank, bank_mask, bank_bits;
for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
bank = i / UNIPHIER_GPIO_LINES_PER_BANK;
bank_bits = bitmap_get_value8(bits, i);
uniphier_gpio_bank_write(chip, bank, UNIPHIER_GPIO_PORT_DATA,
bank_mask, bank_bits);
}
}
static int uniphier_gpio_to_irq(struct gpio_chip *chip, unsigned int offset)
{
struct irq_fwspec fwspec;
if (offset < UNIPHIER_GPIO_IRQ_OFFSET)
return -ENXIO;
fwspec.fwnode = of_node_to_fwnode(chip->parent->of_node);
fwspec.param_count = 2;
fwspec.param[0] = offset - UNIPHIER_GPIO_IRQ_OFFSET;
/*
* IRQ_TYPE_NONE is rejected by the parent irq domain. Set LEVEL_HIGH
* temporarily. Anyway, ->irq_set_type() will override it later.
*/
fwspec.param[1] = IRQ_TYPE_LEVEL_HIGH;
return irq_create_fwspec_mapping(&fwspec);
}
static void uniphier_gpio_irq_mask(struct irq_data *data)
{
struct uniphier_gpio_priv *priv = data->chip_data;
u32 mask = BIT(data->hwirq);
uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_EN, mask, 0);
return irq_chip_mask_parent(data);
}
static void uniphier_gpio_irq_unmask(struct irq_data *data)
{
struct uniphier_gpio_priv *priv = data->chip_data;
u32 mask = BIT(data->hwirq);
uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_EN, mask, mask);
return irq_chip_unmask_parent(data);
}
static int uniphier_gpio_irq_set_type(struct irq_data *data, unsigned int type)
{
struct uniphier_gpio_priv *priv = data->chip_data;
u32 mask = BIT(data->hwirq);
u32 val = 0;
if (type == IRQ_TYPE_EDGE_BOTH) {
val = mask;
type = IRQ_TYPE_EDGE_FALLING;
}
uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_MODE, mask, val);
/* To enable both edge detection, the noise filter must be enabled. */
uniphier_gpio_reg_update(priv, UNIPHIER_GPIO_IRQ_FLT_EN, mask, val);
return irq_chip_set_type_parent(data, type);
}
static int uniphier_gpio_irq_get_parent_hwirq(struct uniphier_gpio_priv *priv,
unsigned int hwirq)
{
struct device_node *np = priv->chip.parent->of_node;
const __be32 *range;
u32 base, parent_base, size;
int len;
range = of_get_property(np, "socionext,interrupt-ranges", &len);
if (!range)
return -EINVAL;
len /= sizeof(*range);
for (; len >= 3; len -= 3) {
base = be32_to_cpu(*range++);
parent_base = be32_to_cpu(*range++);
size = be32_to_cpu(*range++);
if (base <= hwirq && hwirq < base + size)
return hwirq - base + parent_base;
}
return -ENOENT;
}
static int uniphier_gpio_irq_domain_translate(struct irq_domain *domain,
struct irq_fwspec *fwspec,
unsigned long *out_hwirq,
unsigned int *out_type)
{
if (WARN_ON(fwspec->param_count < 2))
return -EINVAL;
*out_hwirq = fwspec->param[0];
*out_type = fwspec->param[1] & IRQ_TYPE_SENSE_MASK;
return 0;
}
static int uniphier_gpio_irq_domain_alloc(struct irq_domain *domain,
unsigned int virq,
unsigned int nr_irqs, void *arg)
{
struct uniphier_gpio_priv *priv = domain->host_data;
struct irq_fwspec parent_fwspec;
irq_hw_number_t hwirq;
unsigned int type;
int ret;
if (WARN_ON(nr_irqs != 1))
return -EINVAL;
ret = uniphier_gpio_irq_domain_translate(domain, arg, &hwirq, &type);
if (ret)
return ret;
ret = uniphier_gpio_irq_get_parent_hwirq(priv, hwirq);
if (ret < 0)
return ret;
/* parent is UniPhier AIDET */
parent_fwspec.fwnode = domain->parent->fwnode;
parent_fwspec.param_count = 2;
parent_fwspec.param[0] = ret;
parent_fwspec.param[1] = (type == IRQ_TYPE_EDGE_BOTH) ?
IRQ_TYPE_EDGE_FALLING : type;
ret = irq_domain_set_hwirq_and_chip(domain, virq, hwirq,
&priv->irq_chip, priv);
if (ret)
return ret;
return irq_domain_alloc_irqs_parent(domain, virq, 1, &parent_fwspec);
}
static int uniphier_gpio_irq_domain_activate(struct irq_domain *domain,
struct irq_data *data, bool early)
{
struct uniphier_gpio_priv *priv = domain->host_data;
struct gpio_chip *chip = &priv->chip;
return gpiochip_lock_as_irq(chip, data->hwirq + UNIPHIER_GPIO_IRQ_OFFSET);
}
static void uniphier_gpio_irq_domain_deactivate(struct irq_domain *domain,
struct irq_data *data)
{
struct uniphier_gpio_priv *priv = domain->host_data;
struct gpio_chip *chip = &priv->chip;
gpiochip_unlock_as_irq(chip, data->hwirq + UNIPHIER_GPIO_IRQ_OFFSET);
}
static const struct irq_domain_ops uniphier_gpio_irq_domain_ops = {
.alloc = uniphier_gpio_irq_domain_alloc,
.free = irq_domain_free_irqs_common,
.activate = uniphier_gpio_irq_domain_activate,
.deactivate = uniphier_gpio_irq_domain_deactivate,
.translate = uniphier_gpio_irq_domain_translate,
};
static void uniphier_gpio_hw_init(struct uniphier_gpio_priv *priv)
{
/*
* Due to the hardware design, the noise filter must be enabled to
* detect both edge interrupts. This filter is intended to remove the
* noise from the irq lines. It does not work for GPIO input, so GPIO
* debounce is not supported. Unfortunately, the filter period is
* shared among all irq lines. Just choose a sensible period here.
*/
writel(0xff, priv->regs + UNIPHIER_GPIO_IRQ_FLT_CYC);
}
static unsigned int uniphier_gpio_get_nbanks(unsigned int ngpio)
{
return DIV_ROUND_UP(ngpio, UNIPHIER_GPIO_LINES_PER_BANK);
}
static int uniphier_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct device_node *parent_np;
struct irq_domain *parent_domain;
struct uniphier_gpio_priv *priv;
struct gpio_chip *chip;
struct irq_chip *irq_chip;
unsigned int nregs;
u32 ngpios;
int ret;
parent_np = of_irq_find_parent(dev->of_node);
if (!parent_np)
return -ENXIO;
parent_domain = irq_find_host(parent_np);
of_node_put(parent_np);
if (!parent_domain)
return -EPROBE_DEFER;
ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios);
if (ret)
return ret;
nregs = uniphier_gpio_get_nbanks(ngpios) * 2 + 3;
priv = devm_kzalloc(dev, struct_size(priv, saved_vals, nregs),
GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(priv->regs))
return PTR_ERR(priv->regs);
spin_lock_init(&priv->lock);
chip = &priv->chip;
chip->label = dev_name(dev);
chip->parent = dev;
chip->request = gpiochip_generic_request;
chip->free = gpiochip_generic_free;
chip->get_direction = uniphier_gpio_get_direction;
chip->direction_input = uniphier_gpio_direction_input;
chip->direction_output = uniphier_gpio_direction_output;
chip->get = uniphier_gpio_get;
chip->set = uniphier_gpio_set;
chip->set_multiple = uniphier_gpio_set_multiple;
chip->to_irq = uniphier_gpio_to_irq;
chip->base = -1;
chip->ngpio = ngpios;
irq_chip = &priv->irq_chip;
irq_chip->name = dev_name(dev);
irq_chip->irq_mask = uniphier_gpio_irq_mask;
irq_chip->irq_unmask = uniphier_gpio_irq_unmask;
irq_chip->irq_eoi = irq_chip_eoi_parent;
irq_chip->irq_set_affinity = irq_chip_set_affinity_parent;
irq_chip->irq_set_type = uniphier_gpio_irq_set_type;
uniphier_gpio_hw_init(priv);
ret = devm_gpiochip_add_data(dev, chip, priv);
if (ret)
return ret;
priv->domain = irq_domain_create_hierarchy(
parent_domain, 0,
UNIPHIER_GPIO_IRQ_MAX_NUM,
of_node_to_fwnode(dev->of_node),
&uniphier_gpio_irq_domain_ops, priv);
if (!priv->domain)
return -ENOMEM;
platform_set_drvdata(pdev, priv);
return 0;
}
static int uniphier_gpio_remove(struct platform_device *pdev)
{
struct uniphier_gpio_priv *priv = platform_get_drvdata(pdev);
irq_domain_remove(priv->domain);
return 0;
}
static int __maybe_unused uniphier_gpio_suspend(struct device *dev)
{
struct uniphier_gpio_priv *priv = dev_get_drvdata(dev);
unsigned int nbanks = uniphier_gpio_get_nbanks(priv->chip.ngpio);
u32 *val = priv->saved_vals;
unsigned int reg;
int i;
for (i = 0; i < nbanks; i++) {
reg = uniphier_gpio_bank_to_reg(i);
*val++ = readl(priv->regs + reg + UNIPHIER_GPIO_PORT_DATA);
*val++ = readl(priv->regs + reg + UNIPHIER_GPIO_PORT_DIR);
}
*val++ = readl(priv->regs + UNIPHIER_GPIO_IRQ_EN);
*val++ = readl(priv->regs + UNIPHIER_GPIO_IRQ_MODE);
*val++ = readl(priv->regs + UNIPHIER_GPIO_IRQ_FLT_EN);
return 0;
}
static int __maybe_unused uniphier_gpio_resume(struct device *dev)
{
struct uniphier_gpio_priv *priv = dev_get_drvdata(dev);
unsigned int nbanks = uniphier_gpio_get_nbanks(priv->chip.ngpio);
const u32 *val = priv->saved_vals;
unsigned int reg;
int i;
for (i = 0; i < nbanks; i++) {
reg = uniphier_gpio_bank_to_reg(i);
writel(*val++, priv->regs + reg + UNIPHIER_GPIO_PORT_DATA);
writel(*val++, priv->regs + reg + UNIPHIER_GPIO_PORT_DIR);
}
writel(*val++, priv->regs + UNIPHIER_GPIO_IRQ_EN);
writel(*val++, priv->regs + UNIPHIER_GPIO_IRQ_MODE);
writel(*val++, priv->regs + UNIPHIER_GPIO_IRQ_FLT_EN);
uniphier_gpio_hw_init(priv);
return 0;
}
static const struct dev_pm_ops uniphier_gpio_pm_ops = {
SET_LATE_SYSTEM_SLEEP_PM_OPS(uniphier_gpio_suspend,
uniphier_gpio_resume)
};
static const struct of_device_id uniphier_gpio_match[] = {
{ .compatible = "socionext,uniphier-gpio" },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, uniphier_gpio_match);
static struct platform_driver uniphier_gpio_driver = {
.probe = uniphier_gpio_probe,
.remove = uniphier_gpio_remove,
.driver = {
.name = "uniphier-gpio",
.of_match_table = uniphier_gpio_match,
.pm = &uniphier_gpio_pm_ops,
},
};
module_platform_driver(uniphier_gpio_driver);
MODULE_AUTHOR("Masahiro Yamada <yamada.masahiro@socionext.com>");
MODULE_DESCRIPTION("UniPhier GPIO driver");
MODULE_LICENSE("GPL v2");
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