From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751440AbbIKGc7 (ORCPT ); Fri, 11 Sep 2015 02:32:59 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:21716 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751036AbbIKGc4 (ORCPT ); Fri, 11 Sep 2015 02:32:56 -0400 X-AuditID: cbfec7f4-f79c56d0000012ee-db-55f27596e894 Message-id: <55F27595.1080609@samsung.com> Date: Fri, 11 Sep 2015 08:32:53 +0200 From: Robert Baldyga User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-version: 1.0 To: Krzysztof Kozlowski , gregkh@linuxfoundation.org Cc: jslaby@suse.com, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, m.szyprowski@samsung.com Subject: Re: [PATCH v2 4/4] serial: samsung: Fix UART status handling in DMA mode 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> In-reply-to: <55F26FBE.3060500@samsung.com> Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrHLMWRmVeSWpSXmKPExsVy+t/xK7rTSj+FGqzqYbNoXryezWLKhg9M Fq9fGFpc3jWHzeLM4l52i7VH7rI7sHnsn7uG3aNvyypGj/VbrrJ4fN4kF8ASxWWTkpqTWZZa pG+XwJWxdHYPa8FuyYq+yZ1sDYyPRLoYOTkkBEwkfm5ewQJhi0lcuLeerYuRi0NIYCmjxPrW fUwQzjNGiQuXb7GDVPEKaEk0fVrMBGKzCKhKzNkyhxHEZhPQkdjyfQKYLSoQIbF89UlGiHpB iR+T74FtEBHwlbg54S6YzSyQLfGxeRmQzcEhLBAs8X1tMsSuRYwS32Y2MoHEOQW0Jc5/UwEx mQX0JO5f1ILolJfYvOYt8wRGgVlIFsxCqJqFpGoBI/MqRtHU0uSC4qT0XEO94sTc4tK8dL3k /NxNjJBQ/rKDcfExq0OMAhyMSjy8FqqfQoVYE8uKK3MPMUpwMCuJ8BrIAYV4UxIrq1KL8uOL SnNSiw8xSnOwKInzzt31PkRIID2xJDU7NbUgtQgmy8TBKdXA2HR2XYzGPaEzv58cZFh2Zvbb L28EHCtPnVOfu+/1DwmR2RfWZC+vlnRyKz0tt3vpHNHqAwG8K3xjFHQF/sxvqXfR+1Y+e2l2 xbXTnWqmn645my9s3y6dd8ssTXdp23XvCFcV2R/b4kV2v1xedOSA+t3VB0pkeqZ39u9z/G/z /4LY0+OOGlE2nkosxRmJhlrMRcWJAMp4nUZhAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. >> - uart_rx_drain_fifo(ourport); >> + s3c24xx_serial_rx_drain_fifo(ourport); >> >> if (tty) { >> tty_flip_buffer_push(t); >> > >