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SubjectRe: [PATCH v3 2/2] fsi: sbefifo: Implement FSI_SBEFIFO_READ_TIMEOUT_SECONDS ioctl
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On 1/20/22 23:38, Joel Stanley wrote:
> From: Amitay Isaacs <amitay@ozlabs.org>
>
> FSI_SBEFIFO_READ_TIMEOUT_SECONDS ioctl sets the read timeout (in
> seconds) for the response received by sbefifo device from sbe. The
> timeout affects only the read operation on current sbefifo device fd.
>
> Certain SBE operations can take long time to complete and the default
> timeout of 10 seconds might not be sufficient to start receiving
> response from SBE. In such cases, allow the timeout to be set to the
> maximum of 120 seconds.
>
> The kernel does not contain the definition of the various SBE
> operations, so we must expose an interface to userspace to set the
> timeout for the given operation.


Reviewed-by: Eddie James <eajames@linux.ibm.com>


>
> Signed-off-by: Amitay Isaacs <amitay@ozlabs.org>
> Signed-off-by: Joel Stanley <joel@jms.id.au>
> ---
> v3:
> - Clarify why this is an ioctl and not hardcoded in the kernel
> - Add seconds to the name
> ---
> drivers/fsi/fsi-sbefifo.c | 49 +++++++++++++++++++++++++++++++++++++++
> include/uapi/linux/fsi.h | 14 +++++++++++
> 2 files changed, 63 insertions(+)
>
> diff --git a/drivers/fsi/fsi-sbefifo.c b/drivers/fsi/fsi-sbefifo.c
> index 1e9b326e8f67..f52a912cdf16 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;
> + u32 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 +842,9 @@ 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);
> + sbefifo->timeout_start_rsp_ms = SBEFIFO_TIMEOUT_START_RSP;
> mutex_unlock(&sbefifo->lock);
> if (rc < 0)
> goto bail;
> @@ -928,12 +934,55 @@ 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)
> +{
> + struct device *dev = &user->sbefifo->dev;
> + u32 timeout;
> +
> + if (get_user(timeout, (__u32 __user *)argp))
> + return -EFAULT;
> +
> + if (timeout == 0) {
> + user->read_timeout_ms = SBEFIFO_TIMEOUT_START_RSP;
> + dev_dbg(dev, "Timeout reset to %d\n", user->read_timeout_ms);
> + return 0;
> + }
> +
> + if (timeout < 10 || timeout > 120)
> + return -EINVAL;
> +
> + user->read_timeout_ms = timeout * 1000; /* user timeout is in sec */
> +
> + dev_dbg(dev, "Timeout set to %d\n", user->read_timeout_ms);
> +
> + return 0;
> +}
> +
> +static long sbefifo_user_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> +{
> + struct sbefifo_user *user = file->private_data;
> + int rc = -ENOTTY;
> +
> + if (!user)
> + return -EINVAL;
> +
> + mutex_lock(&user->file_lock);
> + switch (cmd) {
> + case FSI_SBEFIFO_READ_TIMEOUT_SECONDS:
> + rc = sbefifo_read_timeout(user, (void __user *)arg);
> + 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..b2f1977378c7 100644
> --- a/include/uapi/linux/fsi.h
> +++ b/include/uapi/linux/fsi.h
> @@ -55,4 +55,18 @@ 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
> + */
> +
> +/**
> + * FSI_SBEFIFO_READ_TIMEOUT sets the read timeout for response from SBE.
> + *
> + * The read timeout is specified in seconds. The minimum value of read
> + * timeout is 10 seconds (default) and the maximum value of read timeout is
> + * 120 seconds. A read timeout of 0 will reset the value to the default of
> + * (10 seconds).
> + */
> +#define FSI_SBEFIFO_READ_TIMEOUT_SECONDS _IOW('s', 0x00, __u32)
> +
> #endif /* _UAPI_LINUX_FSI_H */

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