On Wed, 25 Nov 2020, Rahul Singh wrote:
> The NS16550 driver is assuming that NS16550 PCI card are usable if the
> architecture supports PCI (i.e. CONFIG_HAS_PCI=y). However, the code is
> very x86 focus and will fail to build on Arm (/!\ it is not all the
> errors):
> 
> ns16550.c: In function ‘ns16550_init_irq’:
> ns16550.c:726:21: error: implicit declaration of function ‘create_irq’;
> did you mean ‘release_irq’? [-Werror=implicit-function-declaration]
>           uart->irq = create_irq(0, false);
>                       ^~~~~~~~~~
>                       release_irq
> ns16550.c:726:21: error: nested extern declaration of ‘create_irq’
> [-Werror=nested-externs]
> ns16550.c: In function ‘ns16550_init_postirq’:
> ns16550.c:768:33: error: ‘mmio_ro_ranges’ undeclared (first use in this
> function); did you mean ‘mmio_handler’?
>                rangeset_add_range(mmio_ro_ranges, uart->io_base,
>                                   ^~~~~~~~~~~~~~
>                                   mmio_handler
> ns16550.c:768:33: note: each undeclared identifier is reported only once
> for each function it appears in
> ns16550.c:780:20: error: variable ‘msi’ has initializer but incomplete
> type
>               struct msi_info msi = {
>                      ^~~~~~~~
> 
> Enabling support for NS16550 PCI card on Arm would require more plumbing
> in addition to fixing the compilation error.
> 
> Arm systems tend to have platform UART available such as NS16550, PL011.
> So there are limited reasons to get NS16550 PCI support for now on Arm.
> 
> Guard all remaining PCI code that is not under x86 flag with CONFIG_X86.
> 
> No functional change intended.
> 
> Signed-off-by: Rahul Singh <rahul.singh@arm.com>

Acked-by: Stefano Stabellini <sstabellini@kernel.org>


> ---
> 
> Changes in v4:
> - As per the discussion guard all remaining PCI code with CONFIG_X86
> 
> ---
>  xen/drivers/char/ns16550.c | 16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/xen/drivers/char/ns16550.c b/xen/drivers/char/ns16550.c
> index 9235d854fe..26e601857a 100644
> --- a/xen/drivers/char/ns16550.c
> +++ b/xen/drivers/char/ns16550.c
> @@ -16,7 +16,7 @@
>  #include <xen/timer.h>
>  #include <xen/serial.h>
>  #include <xen/iocap.h>
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>  #include <xen/pci.h>
>  #include <xen/pci_regs.h>
>  #include <xen/pci_ids.h>
> @@ -51,7 +51,7 @@ static struct ns16550 {
>      unsigned int timeout_ms;
>      bool_t intr_works;
>      bool_t dw_usr_bsy;
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      /* PCI card parameters. */
>      bool_t pb_bdf_enable;   /* if =1, pb-bdf effective, port behind bridge */
>      bool_t ps_bdf_enable;   /* if =1, ps_bdf effective, port on pci card */
> @@ -66,7 +66,7 @@ static struct ns16550 {
>  #endif
>  } ns16550_com[2] = { { 0 } };
>  
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>  struct ns16550_config {
>      u16 vendor_id;
>      u16 dev_id;
> @@ -256,7 +256,7 @@ static int ns16550_getc(struct serial_port *port, char *pc)
>  
>  static void pci_serial_early_init(struct ns16550 *uart)
>  {
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      if ( !uart->ps_bdf_enable || uart->io_base >= 0x10000 )
>          return;
>  
> @@ -355,7 +355,7 @@ static void __init ns16550_init_preirq(struct serial_port *port)
>  
>  static void __init ns16550_init_irq(struct serial_port *port)
>  {
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      struct ns16550 *uart = port->uart;
>  
>      if ( uart->msi )
> @@ -397,7 +397,7 @@ static void __init ns16550_init_postirq(struct serial_port *port)
>      uart->timeout_ms = max_t(
>          unsigned int, 1, (bits * uart->fifo_size * 1000) / uart->baud);
>  
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      if ( uart->bar || uart->ps_bdf_enable )
>      {
>          if ( uart->param && uart->param->mmio &&
> @@ -477,7 +477,7 @@ static void ns16550_suspend(struct serial_port *port)
>  
>      stop_timer(&uart->timer);
>  
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      if ( uart->bar )
>         uart->cr = pci_conf_read16(PCI_SBDF(0, uart->ps_bdf[0], uart->ps_bdf[1],
>                                    uart->ps_bdf[2]), PCI_COMMAND);
> @@ -486,7 +486,7 @@ static void ns16550_suspend(struct serial_port *port)
>  
>  static void _ns16550_resume(struct serial_port *port)
>  {
> -#ifdef CONFIG_HAS_PCI
> +#if defined(CONFIG_X86) && defined(CONFIG_HAS_PCI)
>      struct ns16550 *uart = port->uart;
>  
>      if ( uart->bar )
> -- 
> 2.17.1
>