From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751513AbbIKGex (ORCPT ); Fri, 11 Sep 2015 02:34:53 -0400 Received: from mailout2.w1.samsung.com ([210.118.77.12]:12378 "EHLO mailout2.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751036AbbIKGev (ORCPT ); Fri, 11 Sep 2015 02:34:51 -0400 X-AuditID: cbfec7f5-f794b6d000001495-45-55f276098b23 Subject: Re: [PATCH v2 4/4] serial: samsung: Fix UART status handling in DMA mode To: Robert Baldyga , gregkh@linuxfoundation.org References: <1441892476-14273-1-git-send-email-r.baldyga@samsung.com> <1441892476-14273-5-git-send-email-r.baldyga@samsung.com> <55F26FBE.3060500@samsung.com> <55F27595.1080609@samsung.com> Cc: jslaby@suse.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, m.szyprowski@samsung.com From: Krzysztof Kozlowski Message-id: <55F2760B.2000600@samsung.com> Date: Fri, 11 Sep 2015 15:34:51 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-version: 1.0 In-reply-to: <55F27595.1080609@samsung.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrMLMWRmVeSWpSXmKPExsVy+t/xq7qcZZ9CDf5dF7RoXryezWLKhg9M Fq9fGFpc3jWHzeLM4l52i7VH7rJbPDi8k92B3WP/3DXsHn1bVjF6rN9ylcXj8ya5AJYoLpuU 1JzMstQifbsEroylB84yFiyVqtjRvJi5gfG0aBcjJ4eEgIlEy9ftzBC2mMSFe+vZuhi5OIQE ljJK3Jn1gBXC+cIoceH9f6YuRg4OYYFgie9rk0EaRATcJBb9uwvVcJBRoqnjIjtIglkgW+Jj 8zIWEJtNwFhi8/IlbCC9vAJaEj9f54GEWQRUJT49+QdWLioQIXHq7Fs2EJtXQFDix+R7YK2c AtoSe1bPBWtlFtCTuH9RC2K6vMTmNW+ZJzAKzELSMQuhahaSqgWMzKsYRVNLkwuKk9JzjfSK E3OLS/PS9ZLzczcxQoL66w7GpcesDjEKcDAq8fBaqH4KFWJNLCuuzD3EKMHBrCTCayAHFOJN SaysSi3Kjy8qzUktPsQozcGiJM47c9f7ECGB9MSS1OzU1ILUIpgsEwenVAPjlT3L3q9fK76n l29ldtc1q12cy6zOrP/wVf+cP3/JnmeZCxZX7b7gqcaZw58s+XSxZda36u8RG7r2H9Px3Xqw 7YxCv9QG15Z0wXnODzat/yKr6dByU0VvqdvaH37qvS5sf8y3tX4vWr1R06Usn+XjyzMvo8KX T6kW0Y1Y35ZoqrjxzqT0mxHXlViKMxINtZiLihMBejHbgmYCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11.09.2015 15:32, Robert Baldyga wrote: > On 09/11/2015 08:07 AM, Krzysztof Kozlowski wrote: >> On 10.09.2015 22:41, Robert Baldyga wrote: >>> This patch fixes UART status handling in DMA mode. >> >> I don't see any changes here. You did not respond to my comment neither. >> >> Code looks itself good... except a locking issue but I don't know what's >> the cause. It may be not related to the patchset and maybe just not all >> of issues are fixed yet. Anyway I'll describe it in 3/4. >> >> Best regards, >> Krzysztof >> >>> For this purpose we >>> use s3c24xx_serial_rx_drain_fifo() instead of uart_rx_drain_fifo(), which >>> does the same thing plus checks for special conditions (such as 'break'). >>> >>> Thanks to this we have, for example, Magic SysRq handling, which was >>> missing in DMA mode so far. Since we can use UART in DMA mode as serial >>> console, this is a quite important improvement. >>> >>> This change additionally simplifies RX handling code, as we no longer >>> need uart_rx_drain_fifo() function, so we can remove it. >>> >>> Reported-by: Marek Szyprowski >>> Signed-off-by: Robert Baldyga >>> --- >>> drivers/tty/serial/samsung.c | 30 +++--------------------------- >>> 1 file changed, 3 insertions(+), 27 deletions(-) >>> >>> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c >>> index 1d7dd86..d72cd73 100644 >>> --- a/drivers/tty/serial/samsung.c >>> +++ b/drivers/tty/serial/samsung.c >>> @@ -385,32 +385,6 @@ static void s3c24xx_uart_copy_rx_to_tty(struct s3c24xx_uart_port *ourport, >>> } >>> } >>> >>> -static int s3c24xx_serial_rx_fifocnt(struct s3c24xx_uart_port *ourport, >>> - unsigned long ufstat); >>> - >>> -static void uart_rx_drain_fifo(struct s3c24xx_uart_port *ourport) >>> -{ >>> - struct uart_port *port = &ourport->port; >>> - struct tty_port *tty = &port->state->port; >>> - unsigned int ch, ufstat; >>> - unsigned int count; >>> - >>> - ufstat = rd_regl(port, S3C2410_UFSTAT); >>> - count = s3c24xx_serial_rx_fifocnt(ourport, ufstat); >>> - >>> - if (!count) >>> - return; >>> - >>> - while (count-- > 0) { >>> - ch = rd_regb(port, S3C2410_URXH); >>> - >>> - ourport->port.icount.rx++; >>> - tty_insert_flip_char(tty, ch, TTY_NORMAL); >>> - } >>> - >>> - tty_flip_buffer_push(tty); >>> -} >>> - >>> static void s3c24xx_serial_stop_rx(struct uart_port *port) >>> { >>> struct s3c24xx_uart_port *ourport = to_ourport(port); >>> @@ -573,6 +547,8 @@ static void enable_rx_pio(struct s3c24xx_uart_port *ourport) >>> ourport->rx_mode = S3C24XX_RX_PIO; >>> } >>> >>> +static void s3c24xx_serial_rx_drain_fifo(struct s3c24xx_uart_port *ourport); >>> + >>> static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id) >>> { >>> unsigned int utrstat, ufstat, received; >>> @@ -606,7 +582,7 @@ static irqreturn_t s3c24xx_serial_rx_chars_dma(void *dev_id) >>> enable_rx_pio(ourport); >>> } >>> > > The essence of change is here. We use another method for draining FIFO. > Instead of just putting them into tty buffer, we additionally check for > special conditions, and that's the improvement. Hm? I was referring to my comment - I did not see any changes around "fixes" in commit message. Best regards, Krzysztof