[PATCH 1/4] HID: cp2112: make transfer buffers DMA capable

From: Benjamin Tissoires
Date: Mon Nov 21 2016 - 05:49:46 EST

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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@xxxxxxxxxx>
---
drivers/hid/hid-cp2112.c | 115 ++++++++++++++++++++++++++++++++---------------
1 file changed, 79 insertions(+), 36 deletions(-)

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index 086d8a5..60d3020 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -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,
@@ -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;
@@ -171,62 +178,86 @@ 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,
@@ -234,27 +265,33 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
{
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
@@ -262,6 +299,10 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
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,
@@ -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");
@@ -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;
@@ -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");
@@ -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:
@@ -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,
--
2.7.4

Next message: Sekhar Nori: "Re: [PATCH v3 10/10] ARM: dts: da850: add usb device node"
Previous message: Benjamin Tissoires: "[PATCH 0/4] HID: fix few non-DMA capable HID transfers"
In reply to: Benjamin Tissoires: "[PATCH 3/4] HID: magicmouse: make transfer buffers DMA capable"
Next in thread: Jiri Kosina: "Re: [PATCH 0/4] HID: fix few non-DMA capable HID transfers"
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