linux-kernel - Re: [PATCH 3/4] tty: serial: samsung: Increase maximum baudrate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20181221103433.GJ13248@dell>
Date:   Fri, 21 Dec 2018 10:34:33 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>
Cc:     linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Beomho Seo <beomho.seo@...sung.com>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        Sylwester Nawrocki <s.nawrocki@...sung.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH 3/4] tty: serial: samsung: Increase maximum baudrate

On Fri, 21 Dec 2018, Marek Szyprowski wrote:
> On 2018-12-21 11:15, Lee Jones wrote:
> > On Fri, 14 Dec 2018, Marek Szyprowski wrote:
> >> From: Seung-Woo Kim <sw0312.kim@...sung.com>
> >>
> >> This driver can be used to communicate with Bluetooth chip in high-speed
> >> UART mode, so increase the maximum baudrate to 3Mbps.
> >>
> >> Signed-off-by: Seung-Woo Kim <sw0312.kim@...sung.com>
> >> [mszyprow: rephrased commit message]
> >> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
> >> ---
> >>  drivers/tty/serial/samsung.c | 2 +-
> >>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
> >> index 2a49b6d876b8..9fc3559f80d9 100644
> >> --- a/drivers/tty/serial/samsung.c
> >> +++ b/drivers/tty/serial/samsung.c
> >> @@ -1287,7 +1287,7 @@ static void s3c24xx_serial_set_termios(struct uart_port *port,
> >>  	 * Ask the core to calculate the divisor for us.
> >>  	 */
> >>  
> >> -	baud = uart_get_baud_rate(port, termios, old, 0, 115200*8);
> >> +	baud = uart_get_baud_rate(port, termios, old, 0, 3000000);
> > Does that mean the low speed devices will stop working?  It looks like
> > this should be dynamically configurable based on what device is
> > connected to it, no?
> 
> The changed parameter is maximum supported rate, so this change doesn't
> affect any low speed device.

Understood.  Thanks for the explanation.

> >>  	quot = s3c24xx_serial_getclk(ourport, baud, &clk, &clk_sel);
> >>  	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
> >>  		quot = port->custom_divisor;
> 
> Best regards

-- 
Lee Jones [李琼斯]
Linaro Services Technical Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog