From: "Pali Rohár" <pali@kernel.org> To: Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Andrew Lunn" <andrew@lunn.ch>, "Gregory Clement" <gregory.clement@bootlin.com>, "Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>, "Vladimir Vid" <vladimir.vid@sartura.hr>, "Marek Behún" <kabel@kernel.org>, linux-clk@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 03/10] serial: mvebu-uart: correctly calculate minimal possible baudrate Date: Fri, 25 Jun 2021 00:49:02 +0200 [thread overview] Message-ID: <20210624224909.6350-4-pali@kernel.org> (raw) In-Reply-To: <20210624224909.6350-1-pali@kernel.org> For default (x16) scheme which is currently used by mvebu-uart.c driver, maximal divisor of UART base clock is 1023*16. Therefore there is limit for minimal supported baudrate. This change calculate it correctly and prevents setting invalid divisor 0 into hardware registers. Signed-off-by: Pali Rohár <pali@kernel.org> Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") --- drivers/tty/serial/mvebu-uart.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index dc0c26824ddb..f8b0016db847 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -481,7 +481,7 @@ static void mvebu_uart_set_termios(struct uart_port *port, struct ktermios *old) { unsigned long flags; - unsigned int baud; + unsigned int baud, min_baud, max_baud; spin_lock_irqsave(&port->lock, flags); @@ -500,16 +500,21 @@ static void mvebu_uart_set_termios(struct uart_port *port, port->ignore_status_mask |= STAT_RX_RDY(port) | STAT_BRK_ERR; /* + * Maximal divisor is 1023 * 16 when using default (x16) scheme. * Maximum achievable frequency with simple baudrate divisor is 230400. * Since the error per bit frame would be of more than 15%, achieving * higher frequencies would require to implement the fractional divisor * feature. */ - baud = uart_get_baud_rate(port, termios, old, 0, 230400); + min_baud = DIV_ROUND_UP(port->uartclk, 1023 * 16); + max_baud = 230400; + + baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud); if (mvebu_uart_baud_rate_set(port, baud)) { /* No clock available, baudrate cannot be changed */ if (old) - baud = uart_get_baud_rate(port, old, NULL, 0, 230400); + baud = uart_get_baud_rate(port, old, NULL, + min_baud, max_baud); } else { tty_termios_encode_baud_rate(termios, baud, baud); uart_update_timeout(port, termios->c_cflag, baud); -- 2.20.1
WARNING: multiple messages have this Message-ID (diff)
From: "Pali Rohár" <pali@kernel.org> To: Michael Turquette <mturquette@baylibre.com>, Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Andrew Lunn" <andrew@lunn.ch>, "Gregory Clement" <gregory.clement@bootlin.com>, "Sebastian Hesselbarth" <sebastian.hesselbarth@gmail.com>, "Vladimir Vid" <vladimir.vid@sartura.hr>, "Marek Behún" <kabel@kernel.org>, linux-clk@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 03/10] serial: mvebu-uart: correctly calculate minimal possible baudrate Date: Fri, 25 Jun 2021 00:49:02 +0200 [thread overview] Message-ID: <20210624224909.6350-4-pali@kernel.org> (raw) In-Reply-To: <20210624224909.6350-1-pali@kernel.org> For default (x16) scheme which is currently used by mvebu-uart.c driver, maximal divisor of UART base clock is 1023*16. Therefore there is limit for minimal supported baudrate. This change calculate it correctly and prevents setting invalid divisor 0 into hardware registers. Signed-off-by: Pali Rohár <pali@kernel.org> Fixes: 68a0db1d7da2 ("serial: mvebu-uart: add function to change baudrate") --- drivers/tty/serial/mvebu-uart.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/tty/serial/mvebu-uart.c b/drivers/tty/serial/mvebu-uart.c index dc0c26824ddb..f8b0016db847 100644 --- a/drivers/tty/serial/mvebu-uart.c +++ b/drivers/tty/serial/mvebu-uart.c @@ -481,7 +481,7 @@ static void mvebu_uart_set_termios(struct uart_port *port, struct ktermios *old) { unsigned long flags; - unsigned int baud; + unsigned int baud, min_baud, max_baud; spin_lock_irqsave(&port->lock, flags); @@ -500,16 +500,21 @@ static void mvebu_uart_set_termios(struct uart_port *port, port->ignore_status_mask |= STAT_RX_RDY(port) | STAT_BRK_ERR; /* + * Maximal divisor is 1023 * 16 when using default (x16) scheme. * Maximum achievable frequency with simple baudrate divisor is 230400. * Since the error per bit frame would be of more than 15%, achieving * higher frequencies would require to implement the fractional divisor * feature. */ - baud = uart_get_baud_rate(port, termios, old, 0, 230400); + min_baud = DIV_ROUND_UP(port->uartclk, 1023 * 16); + max_baud = 230400; + + baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud); if (mvebu_uart_baud_rate_set(port, baud)) { /* No clock available, baudrate cannot be changed */ if (old) - baud = uart_get_baud_rate(port, old, NULL, 0, 230400); + baud = uart_get_baud_rate(port, old, NULL, + min_baud, max_baud); } else { tty_termios_encode_baud_rate(termios, baud, baud); uart_update_timeout(port, termios->c_cflag, baud); -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-24 22:50 UTC|newest] Thread overview: 152+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-24 22:48 [PATCH 00/10] serial: mvebu-uart: Fixes and new support for higher baudrates Pali Rohár 2021-06-24 22:48 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 01/10] serial: mvebu-uart: fix calculation of clock divisor Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 02/10] serial: mvebu-uart: do not allow changing baudrate when uartclk is not available Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` Pali Rohár [this message] 2021-06-24 22:49 ` [PATCH 03/10] serial: mvebu-uart: correctly calculate minimal possible baudrate Pali Rohár 2021-06-24 22:49 ` [PATCH 04/10] dt-bindings: mvebu-uart: fix documentation Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 05/10] arm64: dts: marvell: armada-37xx: Fix reg for standard variant of UART Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 06/10] serial: mvebu-uart: remove unused member nb from struct mvebu_uart Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 07/10] serial: mvebu-uart: implement UART clock driver for configuring UART base clock Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-25 5:36 ` kernel test robot 2021-06-25 5:36 ` kernel test robot 2021-06-25 8:15 ` kernel test robot 2021-06-25 8:15 ` kernel test robot 2021-06-25 9:31 ` Pali Rohár 2021-06-25 9:31 ` Pali Rohár 2021-06-25 11:05 ` Geert Uytterhoeven 2021-06-25 11:05 ` Geert Uytterhoeven 2021-06-25 11:29 ` Pali Rohár 2021-06-25 11:29 ` Pali Rohár 2021-06-25 12:44 ` Geert Uytterhoeven 2021-06-25 12:44 ` Geert Uytterhoeven 2021-06-25 13:22 ` Pali Rohár 2021-06-25 13:22 ` Pali Rohár 2021-06-25 13:35 ` Geert Uytterhoeven 2021-06-25 13:35 ` Geert Uytterhoeven 2021-06-25 14:09 ` Pali Rohár 2021-06-25 14:09 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 08/10] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-06-24 22:49 ` [PATCH 08/10] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Pali Rohár 2021-06-24 22:49 ` [PATCH 09/10] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-24 22:49 ` [PATCH 10/10] serial: mvebu-uart: implement support for baudrates higher than 230400 Pali Rohár 2021-06-24 22:49 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 00/11] serial: mvebu-uart: Fixes and new support for higher baudrates Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 01/11] serial: mvebu-uart: fix calculation of clock divisor Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 02/11] serial: mvebu-uart: do not allow changing baudrate when uartclk is not available Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 03/11] serial: mvebu-uart: correctly calculate minimal possible baudrate Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 04/11] dt-bindings: mvebu-uart: fix documentation Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 05/11] arm64: dts: marvell: armada-37xx: Fix reg for standard variant of UART Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 06/11] serial: mvebu-uart: remove unused member nb from struct mvebu_uart Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 07/11] math64: New DIV_U64_ROUND_CLOSEST helper Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 15:22 ` Geert Uytterhoeven 2021-06-25 15:22 ` Geert Uytterhoeven 2021-06-25 15:38 ` Pali Rohár 2021-06-25 15:38 ` Pali Rohár 2021-06-25 15:50 ` Willy Tarreau 2021-06-25 15:50 ` Willy Tarreau 2021-06-25 17:39 ` Geert Uytterhoeven 2021-06-25 17:39 ` Geert Uytterhoeven 2021-06-25 17:44 ` Pali Rohár 2021-06-25 17:44 ` Pali Rohár 2021-06-25 18:11 ` Geert Uytterhoeven 2021-06-25 18:11 ` Geert Uytterhoeven 2021-07-19 12:45 ` Andy Shevchenko 2021-07-19 12:45 ` Andy Shevchenko 2021-06-25 14:36 ` [PATCH v2 08/11] serial: mvebu-uart: implement UART clock driver for configuring UART base clock Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 09/11] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-06-25 14:36 ` [PATCH v2 09/11] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Pali Rohár 2021-06-25 14:36 ` [PATCH v2 10/11] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-06-25 14:36 ` [PATCH v2 11/11] serial: mvebu-uart: implement support for baudrates higher than 230400 Pali Rohár 2021-06-25 14:36 ` Pali Rohár 2021-07-17 12:38 ` [PATCH v3 0/5] serial: mvebu-uart: Support for higher baudrates Pali Rohár 2021-07-17 12:38 ` Pali Rohár 2021-07-17 12:38 ` [PATCH v3 1/5] math64: New DIV_U64_ROUND_CLOSEST helper Pali Rohár 2021-07-17 12:38 ` Pali Rohár 2021-07-19 12:47 ` Andy Shevchenko 2021-07-19 12:47 ` Andy Shevchenko 2021-07-22 21:57 ` Pali Rohár 2021-07-22 21:57 ` Pali Rohár 2021-07-24 11:38 ` David Laight 2021-07-24 11:38 ` David Laight 2021-07-17 12:38 ` [PATCH v3 2/5] serial: mvebu-uart: implement UART clock driver for configuring UART base clock Pali Rohár 2021-07-17 12:38 ` Pali Rohár 2021-07-17 17:26 ` Andrew Lunn 2021-07-17 17:26 ` Andrew Lunn 2021-07-17 18:05 ` Pali Rohár 2021-07-17 18:05 ` Pali Rohár 2021-07-24 9:48 ` Pali Rohár 2021-07-24 9:48 ` Pali Rohár 2021-07-24 16:33 ` Andrew Lunn 2021-07-24 16:33 ` Andrew Lunn 2021-07-25 12:14 ` Pali Rohár 2021-07-25 12:14 ` Pali Rohár 2021-07-17 12:38 ` [PATCH v3 3/5] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-07-17 12:38 ` [PATCH v3 3/5] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Pali Rohár 2021-07-17 17:30 ` Andrew Lunn 2021-07-17 17:30 ` Andrew Lunn 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-07-17 12:38 ` [PATCH v3 4/5] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it Pali Rohár 2021-07-17 12:38 ` Pali Rohár 2021-07-17 12:38 ` [PATCH v3 5/5] serial: mvebu-uart: implement support for baudrates higher than 230400 Pali Rohár 2021-07-17 12:38 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 0/6] serial: mvebu-uart: Support for higher baudrates Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 1/6] math64: New DIV_U64_ROUND_CLOSEST helper Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 2/6] serial: mvebu-uart: implement UART clock driver for configuring UART base clock Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-08-02 14:45 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Pali Rohár 2021-08-06 0:30 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Stephen Boyd 2021-08-06 0:30 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Stephen Boyd 2021-08-06 8:28 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-08-06 8:28 ` Pali Rohár 2021-08-12 19:33 ` Stephen Boyd 2021-08-12 19:33 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Stephen Boyd 2021-08-12 20:08 ` [PATCH v4 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-08-12 20:08 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 4/6] dt-bindings: mvebu-uart: update information about UART clock Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 5/6] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-02 14:45 ` [PATCH v4 6/6] serial: mvebu-uart: implement support for baudrates higher than 230400 Pali Rohár 2021-08-02 14:45 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 0/6] serial: mvebu-uart: Support for higher baudrates Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 1/6] math64: New DIV_U64_ROUND_CLOSEST helper Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 2/6] serial: mvebu-uart: implement UART clock driver for configuring UART base clock Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell,armada-3700-uart-clock Pali Rohár 2021-08-09 14:53 ` [PATCH v5 3/6] dt-bindings: mvebu-uart: document DT bindings for marvell, armada-3700-uart-clock Pali Rohár 2021-08-09 14:53 ` [PATCH v5 4/6] dt-bindings: mvebu-uart: update information about UART clock Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 5/6] arm64: dts: marvell: armada-37xx: add device node for UART clock and use it Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-09 14:53 ` [PATCH v5 6/6] serial: mvebu-uart: implement support for baudrates higher than 230400 Pali Rohár 2021-08-09 14:53 ` Pali Rohár 2021-08-20 17:22 ` [PATCH v5 0/6] serial: mvebu-uart: Support for higher baudrates Pali Rohár 2021-08-20 17:22 ` Pali Rohár 2021-08-31 8:35 ` Pali Rohár 2021-08-31 8:35 ` Pali Rohár 2021-09-21 7:41 ` Greg Kroah-Hartman 2021-09-21 7:41 ` Greg Kroah-Hartman
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