From: Timur Tabi <timur@codeaurora.org> To: linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Andrew.Jackson@arm.com, andre.przywara@arm.com, jun.nie@linaro.org, peter@hurleysoftware.com, Linus Walleij <linus.walleij@linaro.org>, Greg Kroah-Hartman <greg@kroah.com>, jslaby@suse.com, rmk+kernel@arm.linux.org.uk Subject: [PATCH] tty: amba-pl011: add support for 32-bit register access for earlycon Date: Fri, 6 Nov 2015 18:18:23 -0600 [thread overview] Message-ID: <1446855503-25881-1-git-send-email-timur@codeaurora.org> (raw) Add support the "mmio32" earlycon option for the pl011 device. If specified in the earlycon parameter, all reads/writes to pl011 registers during early console will use 32-bit accessors. Normally the function uses 8-bit writes. Normal console uses the "access_32b" field of the vendor data structure to determine whether the registers needs 32-bit accessors. Early console is used before the vendor data is available, so we need a different mechanism to choose the accessor. Example: earlycon=pl011,mmio32,0x3ced1000 Signed-off-by: Timur Tabi <timur@codeaurora.org> --- This patch applies on top of Russell's 12-part amba-pl011.c patchset. Documentation/kernel-parameters.txt | 5 ++++- drivers/tty/serial/amba-pl011.c | 9 ++++++--- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 22a4b68..2436f62 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -992,10 +992,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. unspecified, the h/w is not initialized. pl011,<addr> + pl011,mmio32,<addr> Start an early, polled-mode console on a pl011 serial port at the specified address. The pl011 serial port must already be setup and configured. Options are not - yet supported. + yet supported. If 'mmio32' is specified, then only + the driver will use only 32-bit accessors to read/write + the device registers. msm_serial,<addr> Start an early, polled-mode console on an msm serial diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 373b152..6643ed9 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2301,10 +2301,13 @@ static struct console amba_console = { static void pl011_putc(struct uart_port *port, int c) { - while (readl(port->membase + REG_FR) & UART01x_FR_TXFF) + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) ; - writeb(c, port->membase + REG_DR); - while (readl(port->membase + REG_FR) & UART01x_FR_BUSY) + if (port->iotype == UPIO_MEM32) + writel(c, port->membase + UART01x_DR); + else + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) ; } -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
WARNING: multiple messages have this Message-ID (diff)
From: timur@codeaurora.org (Timur Tabi) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH] tty: amba-pl011: add support for 32-bit register access for earlycon Date: Fri, 6 Nov 2015 18:18:23 -0600 [thread overview] Message-ID: <1446855503-25881-1-git-send-email-timur@codeaurora.org> (raw) Add support the "mmio32" earlycon option for the pl011 device. If specified in the earlycon parameter, all reads/writes to pl011 registers during early console will use 32-bit accessors. Normally the function uses 8-bit writes. Normal console uses the "access_32b" field of the vendor data structure to determine whether the registers needs 32-bit accessors. Early console is used before the vendor data is available, so we need a different mechanism to choose the accessor. Example: earlycon=pl011,mmio32,0x3ced1000 Signed-off-by: Timur Tabi <timur@codeaurora.org> --- This patch applies on top of Russell's 12-part amba-pl011.c patchset. Documentation/kernel-parameters.txt | 5 ++++- drivers/tty/serial/amba-pl011.c | 9 ++++++--- 2 files changed, 10 insertions(+), 4 deletions(-) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 22a4b68..2436f62 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -992,10 +992,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted. unspecified, the h/w is not initialized. pl011,<addr> + pl011,mmio32,<addr> Start an early, polled-mode console on a pl011 serial port at the specified address. The pl011 serial port must already be setup and configured. Options are not - yet supported. + yet supported. If 'mmio32' is specified, then only + the driver will use only 32-bit accessors to read/write + the device registers. msm_serial,<addr> Start an early, polled-mode console on an msm serial diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 373b152..6643ed9 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2301,10 +2301,13 @@ static struct console amba_console = { static void pl011_putc(struct uart_port *port, int c) { - while (readl(port->membase + REG_FR) & UART01x_FR_TXFF) + while (readl(port->membase + UART01x_FR) & UART01x_FR_TXFF) ; - writeb(c, port->membase + REG_DR); - while (readl(port->membase + REG_FR) & UART01x_FR_BUSY) + if (port->iotype == UPIO_MEM32) + writel(c, port->membase + UART01x_DR); + else + writeb(c, port->membase + UART01x_DR); + while (readl(port->membase + UART01x_FR) & UART01x_FR_BUSY) ; } -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
next reply other threads:[~2015-11-07 0:18 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2015-11-07 0:18 Timur Tabi [this message] 2015-11-07 0:18 ` [PATCH] tty: amba-pl011: add support for 32-bit register access for earlycon Timur Tabi 2015-12-13 6:06 ` Greg Kroah-Hartman 2015-12-13 6:06 ` Greg Kroah-Hartman 2015-12-13 15:34 ` Timur Tabi 2015-12-13 15:34 ` Timur Tabi 2015-12-17 15:55 ` Timur Tabi 2015-12-17 15:55 ` Timur Tabi 2015-12-17 16:27 ` Greg Kroah-Hartman 2015-12-17 16:27 ` Greg Kroah-Hartman 2015-12-17 16:47 ` Timur Tabi 2015-12-17 16:47 ` Timur Tabi 2015-12-17 17:06 ` Peter Hurley 2015-12-17 17:06 ` Peter Hurley
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