> -----Original Message-----
> From: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Sent: mardi 24 mars 2020 22:46
> To: bjorn.andersson@xxxxxxxxxx
> Cc: ohad@xxxxxxxxxx; Loic PALLARDY <loic.pallardy@xxxxxx>; s-
> anna@xxxxxx; peng.fan@xxxxxxx; Arnaud POULIQUEN
> <arnaud.pouliquen@xxxxxx>; Fabien DESSENNE
> <fabien.dessenne@xxxxxx>; linux-remoteproc@xxxxxxxxxxxxxxx
> Subject: [PATCH v2 15/17] remoteproc: Correctly deal with MCU
> synchronisation when changing FW image
>
> This patch prevents the firmware image from being displayed or changed
> when
> the remoteproc core is synchronising with an MCU. This is needed since
> there is no guarantee about the nature of the firmware image that is loaded
> by the external entity.
>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> ---
> drivers/remoteproc/remoteproc_sysfs.c | 25
> ++++++++++++++++++++++++-
> 1 file changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/remoteproc/remoteproc_sysfs.c
> b/drivers/remoteproc/remoteproc_sysfs.c
> index 7f8536b73295..4956577ad4b4 100644
> --- a/drivers/remoteproc/remoteproc_sysfs.c
> +++ b/drivers/remoteproc/remoteproc_sysfs.c
> @@ -13,9 +13,20 @@
> static ssize_t firmware_show(struct device *dev, struct device_attribute
> *attr,
> char *buf)
> {
> + ssize_t ret;
> struct rproc *rproc = to_rproc(dev);
>
> - return sprintf(buf, "%s\n", rproc->firmware);
> + /*
> + * In most instances there is no guarantee about the firmware
> + * that was loaded by the external entity. As such simply don't
> + * print anything.
> + */
> + if (rproc_sync_with_mcu(rproc))
> + ret = sprintf(buf, "\n");
Is it enough to provide empty name, or should we add a message to indicate that's name is unkown/undefined ?
Regards,
Loic
> + else
> + ret = sprintf(buf, "%s\n", rproc->firmware);
> +
> + return ret;
> }
>
> /* Change firmware name via sysfs */
> @@ -33,6 +44,18 @@ static ssize_t firmware_store(struct device *dev,
> return -EINVAL;
> }
>
> + /*
> + * There is no point in trying to change the firmware if the MCU
> + * is currently running or if loading of the image is done by
> + * another entity.
> + */
> + if (rproc_sync_with_mcu(rproc)) {
> + dev_err(dev,
> + "can't change firmware while synchronising with
> MCU\n");
> + err = -EBUSY;
> + goto out;
> + }
> +
> if (rproc->state != RPROC_OFFLINE) {
> dev_err(dev, "can't change firmware while running\n");
> err = -EBUSY;
> --
> 2.20.1
