Re: [Xen-devel] [RFC 25/29] xen/arm: Add exynos 4210 UART support

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-04-29 at 00:02 +0100, Julien Grall wrote:
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>

WIthout a datasheet there isn't much review to be done, 
> ---
>  config/arm32.mk                 |    1 +
>  xen/drivers/char/Makefile       |    1 +
>  xen/drivers/char/exynos5-uart.c |  346 
> +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 348 insertions(+)
>  create mode 100644 xen/drivers/char/exynos5-uart.c
> 
> diff --git a/config/arm32.mk b/config/arm32.mk
> index 83a7767..593a1d1 100644
> --- a/config/arm32.mk
> +++ b/config/arm32.mk
> @@ -19,6 +19,7 @@ CFLAGS += -marm
>  #   - pl011: printk with PL011 UART
>  CONFIG_EARLY_PRINTK := none
>  HAS_PL011 := y
> +HAS_EXYNOS5 := y
> 
>  # Use only if calling $(LD) directly.
>  #LDFLAGS_DIRECT_OpenBSD = _obsd
> diff --git a/xen/drivers/char/Makefile b/xen/drivers/char/Makefile
> index e68a54a..12a4b49 100644
> --- a/xen/drivers/char/Makefile
> +++ b/xen/drivers/char/Makefile
> @@ -1,6 +1,7 @@
>  obj-y += console.o
>  obj-$(HAS_NS16550) += ns16550.o
>  obj-$(HAS_PL011) += pl011.o
> +obj-$(HAS_EXYNOS5) += exynos5-uart.o
>  obj-$(HAS_EHCI) += ehci-dbgp.o
>  obj-$(CONFIG_ARM) += arm-uart.o
>  obj-y += serial.o
> diff --git a/xen/drivers/char/exynos5-uart.c b/xen/drivers/char/exynos5-uart.c
> new file mode 100644
> index 0000000..1bae153
> --- /dev/null
> +++ b/xen/drivers/char/exynos5-uart.c
> @@ -0,0 +1,346 @@
> +/*
> + * xen/drivers/char/exynos5-uart.c
> + *
> + * Driver for Exynos 4210 UART.
> + *
> + * Anthony PERARD <anthony.perard@xxxxxxxxxx>
> + * Copyright (c) 2012 Citrix Systems.
> + *
> + * 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.
> + */
> +
> +#include <xen/config.h>
> +#include <xen/console.h>
> +#include <xen/errno.h>
> +#include <xen/serial.h>
> +#include <xen/init.h>
> +#include <xen/irq.h>
> +#include <asm/early_printk.h>
> +#include <asm/device.h>
> +
> +static struct exynos5_uart {
> +    unsigned int baud, clock_hz, data_bits, parity, stop_bits;
> +    struct dt_irq irq;
> +    volatile uint32_t *regs;
> +    struct irqaction irqaction;
> +} exynos5_com[2] = {{0}};
> +
> +/* register addresses */
> +#define ULCON     (0x00/4)
> +#define UCON      (0x04/4)
> +#define UFCON     (0x08/4)
> +#define UMCON     (0x0c/4)
> +#define UTRSTAT   (0x10/4)
> +#define UERSTAT   (0x14/4)
> +#define UFSTAT    (0x18/4)
> +#define UMSTAT    (0x1c/4)
> +#define UTXH      (0x20/4)
> +#define URXH      (0x24/4)
> +#define UBRDIV    (0x28/4)
> +#define UFRACVAL  (0x2c/4)
> +#define UINTP     (0x30/4)
> +#define UINTS     (0x34/4)
> +#define UINTM     (0x38/4)
> +
> +/* ULCON */
> +#define RXIRQ (0x1<<0)
> +#define RXDMA (0x2<<0)
> +#define TXIRQ (0x1<<2)
> +#define TXDMA (0x2<<2)
> +
> +/* UFCON */
> +#define FIFO_TX_RESET (1<<2)
> +#define FIFO_RX_RESET (1<<1)
> +#define FIFO_EN   (1<<0)
> +
> +/* UMCON */
> +#define INT_EN (1<<3)
> +
> +/* UTRSTAT */
> +#define TXE     (1<<2)
> +#define TXFE    (1<<1)
> +#define RXDR    (1<<0)
> +
> +/* Interrupt bits (UINTP, UINTS, UINTM) */
> +#define MODEM   (1<<3)
> +#define TXD     (1<<2)
> +#define ERROR   (1<<1)
> +#define RXD     (1<<0)
> +#define ALLI    (MODEM|TXD|ERROR|RXD)
> +
> +/* These parity settings can be ORed directly into the ULCON. */
> +#define PARITY_NONE  (0)
> +#define PARITY_ODD   (0x4)
> +#define PARITY_EVEN  (0x5)
> +#define FORCED_CHECKED_AS_ONE (0x6)
> +#define FORCED_CHECKED_AS_ZERO (0x7)
> +
> +static void exynos5_uart_interrupt(int irq, void *data, struct cpu_user_regs 
> *regs)
> +{
> +    struct serial_port *port = data;
> +    struct exynos5_uart *uart = port->uart;
> +    unsigned int status = uart->regs[UINTP];
> +
> +    if ( status )
> +    {
> +        do
> +        {
> +            // clear all pending interrept
> +            // but should take care of ERROR and MODEM

Xen comments are always /* */ I think. A bunch of instance of this in
this patch.

> +
> +            if ( status & ERROR )
> +            {
> +                int error_bit = uart->regs[UERSTAT] & 0xf;
> +                if ( error_bit & (1 << 0) )
> +                    printk(XENLOG_ERR "uart: overrun error\n");
> +                if ( error_bit & (1 << 1) )
> +                    printk(XENLOG_ERR "uart: parity error\n");
> +                if ( error_bit & (1 << 2) )
> +                    printk(XENLOG_ERR "uart: frame error\n");
> +                if ( error_bit & (1 << 3) )

Can you #define these bits?

[...]
> +    // reset FIFO_TX_RESET | FIFO_RX_RESET |
> +    uart->regs[UFCON] = (0x6 << 8) | FIFO_EN;

#define
> +
> +    /* Enable the UART for RX and TX */
> +    // level tx/rx interrupt,only rx
> +    // enable rx timeout interrupt
> +    uart->regs[UCON] = (0 << 9) | (0 << 8) | RXIRQ | TXIRQ | ( 1 << 7);

More #defines, I expect there's a bunch more too ;-)

> +}
> +
> +static void __init exynos5_uart_init_postirq(struct serial_port *port)
> +{
> +    struct exynos5_uart *uart = port->uart;
> +    int rc;
> +
> +    if ( uart->irq.irq > 0 )
> +    {
> +        uart->irqaction.handler = exynos5_uart_interrupt;
> +        uart->irqaction.name    = "exynos5_uart";
> +        uart->irqaction.dev_id  = port;
> +        if ( (rc = setup_irq(uart->irq.irq, &uart->irqaction)) != 0 )
> +            printk("ERROR: Failed to allocate exynos5_uart IRQ %d\n",
> +                   uart->irq.irq);
> +
> +        /* Unmask interrupts */
> +        uart->regs[UINTM] = 0; //MODEM|TXD|ERROR; // only have rx interrupt

Left over debug?

Ian.



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