Re: [Xen-devel] [PATCH 18/38] arm: implement vpl011 (UART) emulator.

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Fri, 1 Jun 2012, Ian Campbell wrote:
> This is not interended to provide a full emulation, but rather just enough to
> satisfy the use made by Linux' boot time decompressor code (which is too early
> for DT etc)
> 
> Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> ---
>  xen/arch/arm/Makefile        |    1 +
>  xen/arch/arm/domain.c        |    4 +
>  xen/arch/arm/io.c            |    1 +
>  xen/arch/arm/io.h            |    1 +
>  xen/arch/arm/vpl011.c        |  155 
> ++++++++++++++++++++++++++++++++++++++++++
>  xen/arch/arm/vpl011.h        |   34 +++++++++
>  xen/include/asm-arm/domain.h |    8 ++
>  7 files changed, 204 insertions(+), 0 deletions(-)
>  create mode 100644 xen/arch/arm/vpl011.c
>  create mode 100644 xen/arch/arm/vpl011.h
> 
> diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
> index 9440a21..5a87ba6 100644
> --- a/xen/arch/arm/Makefile
> +++ b/xen/arch/arm/Makefile
> @@ -25,6 +25,7 @@ obj-y += shutdown.o
>  obj-y += traps.o
>  obj-y += vgic.o
>  obj-y += vtimer.o
> +obj-y += vpl011.o
>  
>  #obj-bin-y += ....o
>  
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index e867cb2..d830980 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -13,6 +13,7 @@
>  
>  #include "gic.h"
>  #include "vtimer.h"
> +#include "vpl011.h"
>  
>  DEFINE_PER_CPU(struct vcpu *, curr_vcpu);
>  
> @@ -201,6 +202,9 @@ int arch_domain_create(struct domain *d, unsigned int 
> domcr_flags)
>      if ( (rc = domain_vgic_init(d)) != 0 )
>          goto fail;
>  
> +    if ( (rc = domain_uart0_init(d)) != 0 )
> +        goto fail;
> +
>      if ( !is_idle_domain(d) )
>      {
>          rc = -ENOMEM;
> diff --git a/xen/arch/arm/io.c b/xen/arch/arm/io.c
> index 4461225..18f6164 100644
> --- a/xen/arch/arm/io.c
> +++ b/xen/arch/arm/io.c
> @@ -25,6 +25,7 @@
>  static const struct mmio_handler *const mmio_handlers[] =
>  {
>      &vgic_distr_mmio_handler,
> +    &uart0_mmio_handler,
>  };
>  #define MMIO_HANDLER_NR ARRAY_SIZE(mmio_handlers)
>  
> diff --git a/xen/arch/arm/io.h b/xen/arch/arm/io.h
> index 8cc5ca7..9a507f5 100644
> --- a/xen/arch/arm/io.h
> +++ b/xen/arch/arm/io.h
> @@ -40,6 +40,7 @@ struct mmio_handler {
>  };
>  
>  extern const struct mmio_handler vgic_distr_mmio_handler;
> +extern const struct mmio_handler uart0_mmio_handler;
>  
>  extern int handle_mmio(mmio_info_t *info);
>  
> diff --git a/xen/arch/arm/vpl011.c b/xen/arch/arm/vpl011.c
> new file mode 100644
> index 0000000..1491dcc
> --- /dev/null
> +++ b/xen/arch/arm/vpl011.c
> @@ -0,0 +1,155 @@
> +/*
> + * xen/arch/arm/vpl011.c
> + *
> + * ARM PL011 UART Emulator (DEBUG)
> + *
> + * Ian Campbell <ian.campbell@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.
> + */
> +
> +/*
> + * This is not intended to be a full emulation of a PL011
> + * device. Rather it is intended to provide a sufficient veneer of one
> + * that early code (such as Linux's boot time decompressor) which
> + * hardcodes output directly to such a device are able to make progress.
> + *
> + * This device is not intended to be enumerable or exposed to the OS
> + * (e.g. via Device Tree).
> + */
> +
> +#include <xen/config.h>
> +#include <xen/lib.h>
> +#include <xen/sched.h>
> +#include <xen/errno.h>
> +#include <xen/ctype.h>
> +
> +#include "io.h"
> +
> +#define UART0_BASE_ADDRESS 0x1c090000
> +
> +#define UARTDR 0x000
> +#define UARTFR 0x018
> +
> +int domain_uart0_init(struct domain *d)
> +{
> +    int rc;
> +    if ( d->domain_id == 0 )
> +        return 0;
> +
> +    spin_lock_init(&d->arch.uart0.lock);
> +    d->arch.uart0.idx = 0;
> +
> +    rc = -ENOMEM;
> +    d->arch.uart0.buf = xzalloc_array(char, VPL011_BUF_SIZE);
> +    if ( !d->arch.uart0.buf )
> +        goto out;
> +
> +    rc = 0;
> +out:
> +    return rc;
> +}
> +
> +static void uart0_print_char(char c)
> +{
> +    struct vpl011 *uart = &current->domain->arch.uart0;
> +
> +    /* Accept only printable characters, newline, and horizontal tab. */
> +    if ( !isprint(c) && (c != '\n') && (c != '\t') )
> +        return ;
> +
> +    spin_lock(&uart->lock);
> +    uart->buf[uart->idx++] = c;
> +    if ( (uart->idx == (VPL011_BUF_SIZE - 2)) || (c == '\n') )
> +    {
> +        if ( c != '\n' )
> +            uart->buf[uart->idx++] = '\n';
> +        uart->buf[uart->idx] = '\0';
> +        printk(XENLOG_G_DEBUG "DOM%u: %s",
> +               current->domain->domain_id, uart->buf);
> +        uart->idx = 0;
> +    }
> +    spin_unlock(&uart->lock);
> +}
> +
> +static int uart0_mmio_check(struct vcpu *v, paddr_t addr)
> +{
> +    return v->domain->domain_id && addr >= UART0_BASE_ADDRESS && addr < 
> (UART0_BASE_ADDRESS+65536);
> +}

maybe we need UART0_BASE_ADDRESS_START and UART0_BASE_ADDRESS_END
instead of having an arbitrary +65536


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