Re: [PATCH v3 1/2] nvme: Enable FUA

[Bin Meng <bmeng.cn@gmail.com>]

Hi Jon,

On Tue, Oct 19, 2021 at 10:41 AM Jon Lin <jon.lin@rock-chips.com> wrote:
>
> Most NVME devcies maintain data in internal cache for an uncertain
> times, and u-boot has no method to force NVME to flush cache.
> So this patch adds FUA to avoid data loss caused by power off after data
> programming.
>
> Signed-off-by: Jon Lin <jon.lin@rock-chips.com>
> Reviewed-by: Stefan Agner <stefan@agner.ch>
> ---
>
> Changes in v3:
>   Only enable FUA when vwc is enabled
>
>  drivers/nvme/nvme.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/nvme/nvme.c b/drivers/nvme/nvme.c
> index 3c529a2fce..9623c896a1 100644
> --- a/drivers/nvme/nvme.c
> +++ b/drivers/nvme/nvme.c
> @@ -762,6 +762,10 @@ static ulong nvme_blk_rw(struct udevice *udev, lbaint_t blknr,
>         c.rw.appmask = 0;
>         c.rw.metadata = 0;
>
> +       /* Enable FUA for data integrity if vwc is enabled */
> +       if (dev->vwc)

Still this does not look correct to me.

The dev->vwc field only indicates the presence of the Volatile Write
Cache, but not the enable status of it.

> +               c.rw.control |= NVME_RW_FUA;
> +
>         while (total_lbas) {
>                 if (total_lbas < lbas) {
>                         lbas = (u16)total_lbas;

Regards,
Bin