[RFCv2 1/2] serial: add driver for SiFive UART

[Sascha Hauer]

On Mon, Nov 14, 2016 at 12:50:14AM +0300, Antony Pavlov wrote:
> Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> ---
> 
> TODO:
> 
>   * add speed setup support.
> 
>  drivers/serial/Kconfig         |   3 ++
>  drivers/serial/Makefile        |   1 +
>  drivers/serial/serial_sifive.c | 109 +++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 113 insertions(+)
> 
> diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
> index b112d7e..70509b9 100644
> --- a/drivers/serial/Kconfig
> +++ b/drivers/serial/Kconfig
> @@ -117,6 +117,9 @@ config DRIVER_SERIAL_S3C_AUTOSYNC
>  	  Say Y here if you want to use the auto flow feature of this
>  	  UART. RTS and CTS will be handled by the hardware when enabled.
>  
> +config DRIVER_SERIAL_SIFIVE
> +	bool "SiFive serial driver"
> +
>  config DRIVER_SERIAL_PXA
>  	bool "PXA serial driver"
>  	depends on ARCH_PXA
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index 189e777..368e992 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -20,3 +20,4 @@ obj-$(CONFIG_DRIVER_SERIAL_AUART)		+= serial_auart.o
>  obj-$(CONFIG_DRIVER_SERIAL_CADENCE)		+= serial_cadence.o
>  obj-$(CONFIG_DRIVER_SERIAL_EFI_STDIO)		+= efi-stdio.o
>  obj-$(CONFIG_DRIVER_SERIAL_DIGIC)		+= serial_digic.o
> +obj-$(CONFIG_DRIVER_SERIAL_SIFIVE)		+= serial_sifive.o
> diff --git a/drivers/serial/serial_sifive.c b/drivers/serial/serial_sifive.c
> new file mode 100644
> index 0000000..06e3521
> --- /dev/null
> +++ b/drivers/serial/serial_sifive.c
> @@ -0,0 +1,109 @@
> +/*
> + * Copyright (C) 2016 Antony Pavlov <antonynpavlov at gmail.com>
> + *
> + * This file is part of barebox.
> + * 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 version 2
> + * as published by the Free Software Foundation.
> + *
> + * 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.
> + *
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <malloc.h>
> +#include <io.h>
> +
> +#define UART_RX_OFFSET 0
> +#define UART_TX_OFFSET 0
> +#define UART_TX_COUNT_OFFSET 0x4
> +#define UART_RX_COUNT_OFFSET 0x8
> +#define UART_DIVIDER_OFFSET  0xC
> +
> +static inline uint32_t sifive_serial_readl(struct console_device *cdev,
> +						uint32_t offset)
> +{
> +	void __iomem *base = cdev->dev->priv;
> +
> +	return readl(base + offset);
> +}
> +
> +static inline void sifive_serial_writel(struct console_device *cdev,
> +					uint32_t value, uint32_t offset)
> +{
> +	void __iomem *base = cdev->dev->priv;
> +
> +	writel(value, base + offset);
> +}
> +
> +static int sifive_serial_setbaudrate(struct console_device *cdev, int baudrate)
> +{
> +	/* FIXME: no baudrate setup at the momement :( */
> +
> +	return 0;
> +}
> +
> +static void sifive_serial_putc(struct console_device *cdev, char c)
> +{
> +	sifive_serial_writel(cdev, c, UART_TX_OFFSET);
> +}

This doesn't test if there is space in the FIFO. This is necessary, no?

Sascha

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