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HID: cp2112: make transfer buffers DMA capable
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Kernel v4.9 strictly enforces DMA capable buffers, so we need to remove
buffers allocated on the stack.

Use a spinlock to prevent concurrent accesses to the buffer.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Benjamin Tissoires authored and Jiri Kosina committed Nov 23, 2016
1 parent 4c4480a commit 1ffb3c4
Showing 1 changed file with 79 additions and 36 deletions.
115 changes: 79 additions & 36 deletions drivers/hid/hid-cp2112.c
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Original file line number Diff line number Diff line change
Expand Up @@ -32,6 +32,11 @@
#include <linux/usb/ch9.h>
#include "hid-ids.h"

#define CP2112_REPORT_MAX_LENGTH 64
#define CP2112_GPIO_CONFIG_LENGTH 5
#define CP2112_GPIO_GET_LENGTH 2
#define CP2112_GPIO_SET_LENGTH 3

enum {
CP2112_GPIO_CONFIG = 0x02,
CP2112_GPIO_GET = 0x03,
Expand Down Expand Up @@ -161,6 +166,8 @@ struct cp2112_device {
atomic_t read_avail;
atomic_t xfer_avail;
struct gpio_chip gc;
u8 *in_out_buffer;
spinlock_t lock;
};

static int gpio_push_pull = 0xFF;
Expand All @@ -171,97 +178,131 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
{
struct cp2112_device *dev = gpiochip_get_data(chip);
struct hid_device *hdev = dev->hdev;
u8 buf[5];
u8 *buf = dev->in_out_buffer;
unsigned long flags;
int ret;

spin_lock_irqsave(&dev->lock, flags);

ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
sizeof(buf), HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret != sizeof(buf)) {
CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret != CP2112_GPIO_CONFIG_LENGTH) {
hid_err(hdev, "error requesting GPIO config: %d\n", ret);
return ret;
goto exit;
}

buf[1] &= ~(1 << offset);
buf[2] = gpio_push_pull;

ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
HID_REQ_SET_REPORT);
if (ret < 0) {
hid_err(hdev, "error setting GPIO config: %d\n", ret);
return ret;
goto exit;
}

return 0;
ret = 0;

exit:
spin_unlock_irqrestore(&dev->lock, flags);
return ret <= 0 ? ret : -EIO;
}

static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
{
struct cp2112_device *dev = gpiochip_get_data(chip);
struct hid_device *hdev = dev->hdev;
u8 buf[3];
u8 *buf = dev->in_out_buffer;
unsigned long flags;
int ret;

spin_lock_irqsave(&dev->lock, flags);

buf[0] = CP2112_GPIO_SET;
buf[1] = value ? 0xff : 0;
buf[2] = 1 << offset;

ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf, sizeof(buf),
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
ret = hid_hw_raw_request(hdev, CP2112_GPIO_SET, buf,
CP2112_GPIO_SET_LENGTH, HID_FEATURE_REPORT,
HID_REQ_SET_REPORT);
if (ret < 0)
hid_err(hdev, "error setting GPIO values: %d\n", ret);

spin_unlock_irqrestore(&dev->lock, flags);
}

static int cp2112_gpio_get(struct gpio_chip *chip, unsigned offset)
{
struct cp2112_device *dev = gpiochip_get_data(chip);
struct hid_device *hdev = dev->hdev;
u8 buf[2];
u8 *buf = dev->in_out_buffer;
unsigned long flags;
int ret;

ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf, sizeof(buf),
HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
if (ret != sizeof(buf)) {
spin_lock_irqsave(&dev->lock, flags);

ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf,
CP2112_GPIO_GET_LENGTH, HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret != CP2112_GPIO_GET_LENGTH) {
hid_err(hdev, "error requesting GPIO values: %d\n", ret);
return ret;
ret = ret < 0 ? ret : -EIO;
goto exit;
}

return (buf[1] >> offset) & 1;
ret = (buf[1] >> offset) & 1;

exit:
spin_unlock_irqrestore(&dev->lock, flags);

return ret;
}

static int cp2112_gpio_direction_output(struct gpio_chip *chip,
unsigned offset, int value)
{
struct cp2112_device *dev = gpiochip_get_data(chip);
struct hid_device *hdev = dev->hdev;
u8 buf[5];
u8 *buf = dev->in_out_buffer;
unsigned long flags;
int ret;

spin_lock_irqsave(&dev->lock, flags);

ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
sizeof(buf), HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret != sizeof(buf)) {
CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
HID_REQ_GET_REPORT);
if (ret != CP2112_GPIO_CONFIG_LENGTH) {
hid_err(hdev, "error requesting GPIO config: %d\n", ret);
return ret;
goto fail;
}

buf[1] |= 1 << offset;
buf[2] = gpio_push_pull;

ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf, sizeof(buf),
HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
HID_REQ_SET_REPORT);
if (ret < 0) {
hid_err(hdev, "error setting GPIO config: %d\n", ret);
return ret;
goto fail;
}

spin_unlock_irqrestore(&dev->lock, flags);

/*
* Set gpio value when output direction is already set,
* as specified in AN495, Rev. 0.2, cpt. 4.4
*/
cp2112_gpio_set(chip, offset, value);

return 0;

fail:
spin_unlock_irqrestore(&dev->lock, flags);
return ret < 0 ? ret : -EIO;
}

static int cp2112_hid_get(struct hid_device *hdev, unsigned char report_number,
Expand Down Expand Up @@ -1007,6 +1048,17 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
struct cp2112_smbus_config_report config;
int ret;

dev = devm_kzalloc(&hdev->dev, sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;

dev->in_out_buffer = devm_kzalloc(&hdev->dev, CP2112_REPORT_MAX_LENGTH,
GFP_KERNEL);
if (!dev->in_out_buffer)
return -ENOMEM;

spin_lock_init(&dev->lock);

ret = hid_parse(hdev);
if (ret) {
hid_err(hdev, "parse failed\n");
Expand Down Expand Up @@ -1063,12 +1115,6 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
goto err_power_normal;
}

dev = kzalloc(sizeof(*dev), GFP_KERNEL);
if (!dev) {
ret = -ENOMEM;
goto err_power_normal;
}

hid_set_drvdata(hdev, (void *)dev);
dev->hdev = hdev;
dev->adap.owner = THIS_MODULE;
Expand All @@ -1087,7 +1133,7 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)

if (ret) {
hid_err(hdev, "error registering i2c adapter\n");
goto err_free_dev;
goto err_power_normal;
}

hid_dbg(hdev, "adapter registered\n");
Expand Down Expand Up @@ -1123,8 +1169,6 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
gpiochip_remove(&dev->gc);
err_free_i2c:
i2c_del_adapter(&dev->adap);
err_free_dev:
kfree(dev);
err_power_normal:
hid_hw_power(hdev, PM_HINT_NORMAL);
err_hid_close:
Expand All @@ -1149,7 +1193,6 @@ static void cp2112_remove(struct hid_device *hdev)
*/
hid_hw_close(hdev);
hid_hw_stop(hdev);
kfree(dev);
}

static int cp2112_raw_event(struct hid_device *hdev, struct hid_report *report,
Expand Down

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