Re: [PATCH 3/5] ARM: zynq: add driver for Zynq uarts

[Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>]

On 18:48 Sat 02 Mar     , Josh Cartwright wrote:
> 
> Simple UART driver for Zynq SoCs, based loosely on the u-boot driver.
> 
> Signed-off-by: Josh Cartwright <joshc@eso.teric.us>
> ---
>  drivers/serial/Kconfig       |   6 ++
>  drivers/serial/Makefile      |   1 +
>  drivers/serial/serial_zynq.c | 144 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 151 insertions(+)
>  create mode 100644 drivers/serial/serial_zynq.c
> 
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index f61d670..608b616 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -113,4 +113,10 @@ config DRIVER_SERIAL_OMAP4_USBBOOT
>  	help
>  	  Enable this to get console support over the usb bus used to boot an OMAP4
>  
> +config DRIVER_SERIAL_ZYNQ
> +	bool "driver for Zynq uarts"
> +	default n
> +	help
> +	  Say Y here to get console out support with the Zynq uarts
> +
>  endmenu
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 893e282..883394f 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -21,3 +21,4 @@ obj-$(CONFIG_DRIVER_SERIAL_ALTERA)		+= serial_altera.o
>  obj-$(CONFIG_DRIVER_SERIAL_ALTERA_JTAG)		+= serial_altera_jtag.o
>  obj-$(CONFIG_DRIVER_SERIAL_PXA)			+= serial_pxa.o
>  obj-$(CONFIG_DRIVER_SERIAL_OMAP4_USBBOOT)	+= serial_omap4_usbboot.o
> +obj-$(CONFIG_DRIVER_SERIAL_ZYNQ)		+= serial_zynq.o
> diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
> new file mode 100644
> index 0000000..ec93b58
> --- /dev/null
> +++ b/drivers/serial/serial_zynq.c
> @@ -0,0 +1,144 @@
> +/*
> + * (C) Copyright 2013 Josh Cartwright
> + *
> + * Based very loosely on u-boot drivers/serial/serial_zynq.c.
> + *
> + * Copyright (C) 2012 Michal Simek <monstr@monstr.eu>
> + * Copyright (C) 2011-2012 Xilinx, Inc. All rights reserved.
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU General Public License as
> + * published by the Free Software Foundation; either version 2 of
> + * the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
> + * MA 02111-1307 USA
> + */
> +#include <common.h>
> +#include <io.h>
> +#include <init.h>
> +#include <driver.h>
> +#include <xfuncs.h>
> +#include <console.h>
> +#include <malloc.h>
> +
> +#include <linux/clk.h>
> +
> +#define UART_CR		0x00000000
> +#define UART_CR_TXEN	(1<<4)
> +#define UART_CR_RXEN	(1<<2)
> +#define UART_CR_TXRST	(1<<1)
> +#define UART_CR_RXRST	(1<<0)
> +
> +#define UART_SR		0x0000002C
> +#define UART_SR_TXFULL	(1<<4)
> +#define UART_SR_TXEMPTY	(1<<3)
> +#define UART_SR_RXFULL	(1<<2)
> +#define UART_SR_RXEMPTY	(1<<1)
> +
> +#define UART_FIFO	0x00000030
> +
> +struct zynq_serial_device {
> +	struct console_device cdev;
> +	struct clk *clk;
> +	void __iomem *regs;
> +};
> +
> +#define to_zynq_device(p) container_of(p, struct zynq_serial_device, cdev)
> +
> +static void zynq_serial_init_device(struct zynq_serial_device *dev)
> +{
> +	writel(UART_CR_TXEN | UART_CR_RXEN | UART_CR_TXEN | UART_CR_RXEN,
> +	       dev->regs + UART_CR);
> +}
> +
> +static int zynq_serial_tstc(struct console_device *cdev)
> +{
> +	struct zynq_serial_device *zynq = to_zynq_device(cdev);
> +
> +	return !(readl(zynq->regs + UART_SR) & UART_SR_RXEMPTY);
> +}
> +
> +static void zynq_serial_putc(struct console_device *cdev, char c)
> +{
> +	struct zynq_serial_device *zynq = to_zynq_device(cdev);
> +
> +	while (readl(zynq->regs + UART_SR) & UART_SR_TXFULL);
> +
> +	writel(c, zynq->regs + UART_FIFO);
> +}
> +
> +static int zynq_serial_getc(struct console_device *cdev)
> +{
> +	struct zynq_serial_device *zynq = to_zynq_device(cdev);
> +
> +	return readl(zynq->regs + UART_FIFO);
> +}
> +
> +static void zynq_serial_flush(struct console_device *cdev)
> +{
> +	struct zynq_serial_device *zynq = to_zynq_device(cdev);
> +
> +	while (!(readl(zynq->regs + UART_SR) & UART_SR_TXEMPTY));
> +}
> +
> +static int zynq_serial_probe(struct device_d *dev)
> +{
> +	struct zynq_serial_device *priv;
> +	struct console_device *cdev;
> +	int err;
> +
> +	priv = xzalloc(sizeof(*priv));
> +	cdev = &priv->cdev;
> +
> +	priv->regs	= dev_request_mem_region(dev, 0);
> +	cdev->dev	= dev;
> +	cdev->f_caps	= CONSOLE_STDIN | CONSOLE_STDOUT | CONSOLE_STDERR;
> +	cdev->tstc	= zynq_serial_tstc;
> +	cdev->putc	= zynq_serial_putc;
> +	cdev->getc	= zynq_serial_getc;
> +	cdev->flush	= zynq_serial_flush;
> +
> +	priv->clk = clk_get(dev, NULL);
you need to check here too
> +
> +	err = clk_enable(priv->clk);
> +	if (err) {
> +		free(priv);
> +		return err;
> +	}
> +
> +	zynq_serial_init_device(priv);
> +
> +	dev->priv = priv;
> +
> +	return console_register(cdev);
> +}
> +
> +static void zynq_serial_remove(struct device_d *dev)
> +{
> +	struct zynq_serial_device *zynq = dev->priv;
> +	clk_disable(zynq->clk);
> +	free(zynq);
> +}
> +
> +static struct driver_d zynq_serial_driver = {
> +	.name	= "zynq_serial",
> +	.probe	= zynq_serial_probe,
> +	.remove = zynq_serial_remove,
> +};
> +
> +static int zynq_serial_init(void)
> +{
> +	return platform_driver_register(&zynq_serial_driver);
> +}
> +console_initcall(zynq_serial_init);
> -- 
> 1.8.1.2
> 
> 
> 
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