[PATCH 2/2] fsi: sbefifo: implement FSI_SBEFIFO_READ_TIMEOUT ioctl

[Joel Stanley]

On Wed, 15 Dec 2021 at 00:58, Amitay Isaacs <amitay at ozlabs.org> wrote:
>
> FSI_SBEFIFO_READ_TIMEOUT ioctl sets the read timeout (in seconds) for
> the response to *the next* chip-op sent to sbe.  The timeout value is
> reset to default after the chip-op.  The timeout affects only the read()
> operation on sbefifo device fd.

Makes sense to me.

Lets see if Greg or Andrew will review the icotl interface for us.

Reviewed-by: Joel Stanley <joel at jms.id.au>

>
> Signed-off-by: Amitay Isaacs <amitay at ozlabs.org>
> ---
>  drivers/fsi/fsi-sbefifo.c | 42 +++++++++++++++++++++++++++++++++++++++
>  include/uapi/linux/fsi.h  |  6 ++++++
>  2 files changed, 48 insertions(+)
>
> diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
> index 9188161f440c..b2654b143b85 100644
> --- a/drivers/fsi/fsi-sbefifo.c
> +++ b/drivers/fsi/fsi-sbefifo.c
> @@ -32,6 +32,8 @@
>  #include <linux/vmalloc.h>
>  #include <linux/mm.h>
>
> +#include <uapi/linux/fsi.h>
> +
>  /*
>   * The SBEFIFO is a pipe-like FSI device for communicating with
>   * the self boot engine on POWER processors.
> @@ -134,6 +136,7 @@ struct sbefifo_user {
>         void                    *cmd_page;
>         void                    *pending_cmd;
>         size_t                  pending_len;
> +       uint32_t                read_timeout_ms;
>  };
>
>  static DEFINE_MUTEX(sbefifo_ffdc_mutex);
> @@ -796,6 +799,7 @@ static int sbefifo_user_open(struct inode *inode, struct file *file)
>                 return -ENOMEM;
>         }
>         mutex_init(&user->file_lock);
> +       user->read_timeout_ms = SBEFIFO_TIMEOUT_START_RSP;
>
>         return 0;
>  }
> @@ -838,7 +842,11 @@ static ssize_t sbefifo_user_read(struct file *file, char __user *buf,
>         rc = mutex_lock_interruptible(&sbefifo->lock);
>         if (rc)
>                 goto bail;
> +       sbefifo->timeout_start_rsp_ms = user->read_timeout_ms;
>         rc = __sbefifo_submit(sbefifo, user->pending_cmd, cmd_len, &resp_iter);
> +       /* Reset the read timeout after a single chip-op */
> +       sbefifo->timeout_start_rsp_ms = SBEFIFO_TIMEOUT_START_RSP;
> +       user->read_timeout_ms = SBEFIFO_TIMEOUT_START_RSP;
>         mutex_unlock(&sbefifo->lock);
>         if (rc < 0)
>                 goto bail;
> @@ -847,6 +855,7 @@ static ssize_t sbefifo_user_read(struct file *file, char __user *buf,
>         rc = len - iov_iter_count(&resp_iter);
>   bail:
>         sbefifo_release_command(user);
> +       user->read_timeout_ms = 0;
>         mutex_unlock(&user->file_lock);
>         return rc;
>  }
> @@ -928,12 +937,45 @@ static int sbefifo_user_release(struct inode *inode, struct file *file)
>         return 0;
>  }
>
> +static int sbefifo_read_timeout(struct sbefifo_user *user, void __user **argp)
> +{
> +       uint32_t timeout;
> +
> +       if (get_user(timeout, (__u32 __user *)argp))
> +               return -EFAULT;
> +       if (timeout < 10 || timeout > 120)
> +               return -EINVAL;
> +
> +       user->read_timeout_ms = timeout * 1000; /* user timeout is in sec */
> +       return 0;
> +}
> +
> +static long sbefifo_user_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> +       struct sbefifo_user *user = file->private_data;
> +       void __user **argp = (void __user *)arg;
> +       int rc = -ENOTTY;
> +
> +       if (!user)
> +               return -EINVAL;
> +
> +       mutex_lock(&user->file_lock);
> +       switch (cmd) {
> +       case FSI_SBEFIFO_READ_TIMEOUT:
> +               rc = sbefifo_read_timeout(user, argp);
> +               break;
> +       }
> +       mutex_unlock(&user->file_lock);
> +       return rc;
> +}
> +
>  static const struct file_operations sbefifo_fops = {
>         .owner          = THIS_MODULE,
>         .open           = sbefifo_user_open,
>         .read           = sbefifo_user_read,
>         .write          = sbefifo_user_write,
>         .release        = sbefifo_user_release,
> +       .unlocked_ioctl = sbefifo_user_ioctl,
>  };
>
>  static void sbefifo_free(struct device *dev)
> diff --git a/include/uapi/linux/fsi.h b/include/uapi/linux/fsi.h
> index da577ecd90e7..3e00874ace22 100644
> --- a/include/uapi/linux/fsi.h
> +++ b/include/uapi/linux/fsi.h
> @@ -55,4 +55,10 @@ struct scom_access {
>  #define FSI_SCOM_WRITE _IOWR('s', 0x02, struct scom_access)
>  #define FSI_SCOM_RESET _IOW('s', 0x03, __u32)
>
> +/*
> + * /dev/sbefifo* ioctl interface
> + */
> +
> +#define FSI_SBEFIFO_READ_TIMEOUT       _IOW('s', 0x00, __u32)
> +
>  #endif /* _UAPI_LINUX_FSI_H */
> --
> 2.33.1
>