[PATCH u-boot-marvell 2/5] tools: kwboot: Do not call tcdrain() after each sent packet

[Stefan Roese]

On 27.10.21 20:56, Marek Behún wrote:
> From: Pali Rohár <pali at kernel.org>
> 
> Kwboot puts each xmodem packet to kernel queue, then waits until all bytes
> of that packet are transmitted over UART and then waits for xmodem reply
> until it is received into kernel queue.
> 
> If some reply is received during the time we are waiting until all bytes
> are transmitted, then kernel puts them into the queue and returns it to
> kwboot in next read() call.
> 
> So there is no need to wait (with tcdrain() function) until all bytes from
> xmodem packet are transmitted over UART, since any reply received either
> during that time or after is returned to kwboot with the next read().
> 
> Therefore do not call tcdrain() after each xmodem packet sent. Instead
> directly wait for any reply after putting xmodem packet into write kernel
> queue.
> 
> This change could speed up xmodem transfer in case tcdrain() function waits
> for a longer time.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> Reviewed-by: Marek Behún <marek.behun at nic.cz>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
>   tools/kwboot.c | 13 ++++++++-----
>   1 file changed, 8 insertions(+), 5 deletions(-)
> 
> diff --git a/tools/kwboot.c b/tools/kwboot.c
> index b2c48812c3..a6bfd3d4ce 100644
> --- a/tools/kwboot.c
> +++ b/tools/kwboot.c
> @@ -404,7 +404,7 @@ out:
>   }
>   
>   static int
> -kwboot_tty_send(int fd, const void *buf, size_t len)
> +kwboot_tty_send(int fd, const void *buf, size_t len, int nodrain)
>   {
>   	if (!buf)
>   		return 0;
> @@ -412,13 +412,16 @@ kwboot_tty_send(int fd, const void *buf, size_t len)
>   	if (kwboot_write(fd, buf, len) < 0)
>   		return -1;
>   
> +	if (nodrain)
> +		return 0;
> +
>   	return tcdrain(fd);
>   }
>   
>   static int
>   kwboot_tty_send_char(int fd, unsigned char c)
>   {
> -	return kwboot_tty_send(fd, &c, 1);
> +	return kwboot_tty_send(fd, &c, 1, 0);
>   }
>   
>   static speed_t
> @@ -705,7 +708,7 @@ kwboot_bootmsg(int tty, void *msg)
>   			break;
>   
>   		for (count = 0; count < 128; count++) {
> -			rc = kwboot_tty_send(tty, msg, 8);
> +			rc = kwboot_tty_send(tty, msg, 8, 0);
>   			if (rc) {
>   				usleep(msg_req_delay * 1000);
>   				continue;
> @@ -737,7 +740,7 @@ kwboot_debugmsg(int tty, void *msg)
>   		if (rc)
>   			break;
>   
> -		rc = kwboot_tty_send(tty, msg, 8);
> +		rc = kwboot_tty_send(tty, msg, 8, 0);
>   		if (rc) {
>   			usleep(msg_req_delay * 1000);
>   			continue;
> @@ -929,7 +932,7 @@ kwboot_xm_sendblock(int fd, struct kwboot_block *block, int allow_non_xm,
>   
>   	retries = 0;
>   	do {
> -		rc = kwboot_tty_send(fd, block, sizeof(*block));
> +		rc = kwboot_tty_send(fd, block, sizeof(*block), 1);
>   		if (rc)
>   			return rc;
>   
> 


Viele Grüße,
Stefan

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