On Wed, Feb 28, 2018 at 8:43 PM, Rodrigo Rivas Costa
<rodrigorivascosta@xxxxxxxxx> wrote:
> This device has a feature report to send and receive commands.
> Use it to get the serial number and set the device's uniq value.
> #include <linux/module.h>
> #include <linux/workqueue.h>
> #include <linux/rcupdate.h>
> +#include <linux/delay.h>
Better to keep it somehow sorted (yes, I see it's not originally, but
better to squeeze new header to the most ordered part).
> @@ -41,8 +42,99 @@ struct steam_device {
> unsigned long quirks;
> struct work_struct work_connect;
> bool connected;
> + char serial_no[11];
11 is a magic.
> };
>
> +static int steam_recv_report(struct steam_device *steam,
> + u8 *data, int size)
> +{
> + struct hid_report *r;
> + u8 *buf;
> + int ret;
> +
> + r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
> + if (hid_report_len(r) < 64)
> + return -EINVAL;
+ empty line.
> + buf = hid_alloc_report_buf(r, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + /*
> + * The report ID is always 0, so strip the first byte from the output.
> + * hid_report_len() is not counting the report ID, so +1 to the length
> + * or else we get a EOVERFLOW. We are safe from a buffer overflow
> + * because hid_alloc_report_buf() allocates +7 bytes.
> + */
> + ret = hid_hw_raw_request(steam->hdev, 0x00,
> + buf, hid_report_len(r) + 1,
> + HID_FEATURE_REPORT, HID_REQ_GET_REPORT);
> + if (ret > 0)
> + memcpy(data, buf + 1, min(size, ret - 1));
> + kfree(buf);
> + return ret;
> +}
> +
> +static int steam_send_report(struct steam_device *steam,
> + u8 *cmd, int size)
> +{
> + struct hid_report *r;
> + u8 *buf;
> + int retry;
> + int ret;
> +
> + r = steam->hdev->report_enum[HID_FEATURE_REPORT].report_id_hash[0];
> + if (hid_report_len(r) < 64)
> + return -EINVAL;
+empty line.
> + buf = hid_alloc_report_buf(r, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + /* The report ID is always 0 */
> + memcpy(buf + 1, cmd, size);
> +
> + /*
> + * Sometimes the wireless controller fails with EPIPE
> + * when sending a feature report.
> + * Doing a HID_REQ_GET_REPORT and waiting for a while
> + * seems to fix that.
> + */
> + for (retry = 0; retry < 10; ++retry) {
> + ret = hid_hw_raw_request(steam->hdev, 0,
> + buf, size + 1,
> + HID_FEATURE_REPORT, HID_REQ_SET_REPORT);
> + if (ret != -EPIPE)
> + break;
> + steam_recv_report(steam, NULL, 0);
> + msleep(50);
> + }
Personally I consider do{}while in case of "timeout loops" much easier to parse.
unsigned int retry = 10;
...
do {
...
} while (--retry);
> + kfree(buf);
> + if (ret < 0)
> + hid_err(steam->hdev, "%s: error %d (%*ph)\n", __func__,
> + ret, size, cmd);
> + return ret;
> +}
> +
> +static int steam_get_serial(struct steam_device *steam)
> +{
> + /*
> + * Send: 0xae 0x15 0x01
> + * Recv: 0xae 0x15 0x01 serialnumber (10 chars)
> + */
> + int ret;
> + u8 cmd[] = {0xae, 0x15, 0x01};
> + u8 reply[14];
> +
> + ret = steam_send_report(steam, cmd, sizeof(cmd));
> + if (ret < 0)
> + return ret;
> + ret = steam_recv_report(steam, reply, sizeof(reply));
> + if (ret < 0)
> + return ret;
> + reply[13] = 0;
> + strcpy(steam->serial_no, reply + 3);
strlcpy()
> + return 0;
> +}
--
With Best Regards,
Andy Shevchenko
--
To unsubscribe from this list: send the line "unsubscribe linux-input" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
