Re: [PATCH 3/4] HID: intel-ish-hid: move doorbell writing before flush

[Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>]

On Tue, 2019-02-12 at 20:05 +0800, Hong Liu wrote:
> Reading of IPC_REG_ISH_HOST_FWSTS will flush both message register
> and doorbell. So move the doorbell write before reading of
> IPC_REG_ISH_HOST_FWSTS.
> 
> Signed-off-by: Hong Liu <hong.liu@xxxxxxxxx>
> Tested-by: Hongyan Song <hongyan.song@xxxxxxxxx>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>

> ---
>  drivers/hid/intel-ish-hid/ipc/ipc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hid/intel-ish-hid/ipc/ipc.c b/drivers/hid/intel-
> ish-hid/ipc/ipc.c
> index ff8eca11ff73..30d8a639a5bb 100644
> --- a/drivers/hid/intel-ish-hid/ipc/ipc.c
> +++ b/drivers/hid/intel-ish-hid/ipc/ipc.c
> @@ -314,6 +314,8 @@ static int write_ipc_from_queue(struct
> ishtp_device *dev)
>  		memcpy(&reg, &r_buf[length >> 2], rem);
>  		ish_reg_write(dev, reg_addr, reg);
>  	}
> +	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, doorbell_val);
> +
>  	/* Flush writes to msg registers and doorbell */
>  	ish_reg_read(dev, IPC_REG_ISH_HOST_FWSTS);
>  
> @@ -321,8 +323,6 @@ static int write_ipc_from_queue(struct
> ishtp_device *dev)
>  	++dev->ipc_tx_cnt;
>  	dev->ipc_tx_bytes_cnt += IPC_HEADER_GET_LENGTH(doorbell_val);
>  
> -	ish_reg_write(dev, IPC_REG_HOST2ISH_DRBL, doorbell_val);
> -
>  	ipc_send_compl = ipc_link->ipc_send_compl;
>  	ipc_send_compl_prm = ipc_link->ipc_send_compl_prm;
>  	list_del_init(&ipc_link->link);