[PATCH] ns16550: adjust suspend/resume logic

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[PATCH] ns16550: adjust suspend/resume logic

Jan Beulich-2
- no need to read BAR during suspend
- command register is 16-bits rather than 32
- BAR and command register must be restored before trying to access
  the device
- use ps_bdf[] for storing the device coordinates (pb_bdf[] is used to
  store the bridge's ones)

--- a/xen/drivers/char/ns16550.c
+++ b/xen/drivers/char/ns16550.c
@@ -49,7 +49,9 @@ static struct ns16550 {
     unsigned int ps_bdf[3]; /* pci serial port BDF */
     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 */
-    int bar, cr, bar_idx;
+    u32 bar;
+    u16 cr;
+    u8 bar_idx;
 } ns16550_com[2] = { { 0 } };
 
 /* Register offsets */
@@ -324,30 +326,24 @@ static void ns16550_suspend(struct seria
     stop_timer(&uart->timer);
 
     if ( uart->bar )
-    {
-       uart->bar = pci_conf_read32(
-           0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
-           PCI_BASE_ADDRESS_0 + uart->bar_idx*4);
-       uart->cr = pci_conf_read32(
-           0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
-           PCI_COMMAND);
-    }
+       uart->cr = pci_conf_read16(0, uart->ps_bdf[0], uart->ps_bdf[1],
+                                  uart->ps_bdf[2], PCI_COMMAND);
 }
 
 static void ns16550_resume(struct serial_port *port)
 {
     struct ns16550 *uart = port->uart;
 
-    ns16550_setup_preirq(port->uart);
-    ns16550_setup_postirq(port->uart);
-
     if ( uart->bar )
     {
-       pci_conf_write32(0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
+       pci_conf_write32(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
                         PCI_BASE_ADDRESS_0 + uart->bar_idx*4, uart->bar);
-       pci_conf_write32(0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
+       pci_conf_write16(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
                         PCI_COMMAND, uart->cr);
     }
+
+    ns16550_setup_preirq(port->uart);
+    ns16550_setup_postirq(port->uart);
 }
 
 #ifdef CONFIG_X86
@@ -483,9 +479,9 @@ pci_uart_config (struct ns16550 *uart, i
                 if ( (len & 0xffff) != 0xfff9 )
                     continue;
 
-                uart->pb_bdf[0] = b;
-                uart->pb_bdf[1] = d;
-                uart->pb_bdf[2] = f;
+                uart->ps_bdf[0] = b;
+                uart->ps_bdf[1] = d;
+                uart->ps_bdf[2] = f;
                 uart->bar = bar;
                 uart->bar_idx = bar_idx;
                 uart->io_base = bar & 0xfffe;



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sercon-ns16550-suspend.patch (2K) Download Attachment
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Re: [PATCH] ns16550: adjust suspend/resume logic

Keir Fraser-5
On 07/05/2012 16:29, "Jan Beulich" <[hidden email]> wrote:

> - no need to read BAR during suspend
> - command register is 16-bits rather than 32
> - BAR and command register must be restored before trying to access
>   the device
> - use ps_bdf[] for storing the device coordinates (pb_bdf[] is used to
>   store the bridge's ones)

Looks good to me.

Acked-by: Keir Fraser <[hidden email]>

> --- a/xen/drivers/char/ns16550.c
> +++ b/xen/drivers/char/ns16550.c
> @@ -49,7 +49,9 @@ static struct ns16550 {
>      unsigned int ps_bdf[3]; /* pci serial port BDF */
>      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 */
> -    int bar, cr, bar_idx;
> +    u32 bar;
> +    u16 cr;
> +    u8 bar_idx;
>  } ns16550_com[2] = { { 0 } };
>  
>  /* Register offsets */
> @@ -324,30 +326,24 @@ static void ns16550_suspend(struct seria
>      stop_timer(&uart->timer);
>  
>      if ( uart->bar )
> -    {
> -       uart->bar = pci_conf_read32(
> -           0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
> -           PCI_BASE_ADDRESS_0 + uart->bar_idx*4);
> -       uart->cr = pci_conf_read32(
> -           0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
> -           PCI_COMMAND);
> -    }
> +       uart->cr = pci_conf_read16(0, uart->ps_bdf[0], uart->ps_bdf[1],
> +                                  uart->ps_bdf[2], PCI_COMMAND);
>  }
>  
>  static void ns16550_resume(struct serial_port *port)
>  {
>      struct ns16550 *uart = port->uart;
>  
> -    ns16550_setup_preirq(port->uart);
> -    ns16550_setup_postirq(port->uart);
> -
>      if ( uart->bar )
>      {
> -       pci_conf_write32(0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
> +       pci_conf_write32(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
>                          PCI_BASE_ADDRESS_0 + uart->bar_idx*4, uart->bar);
> -       pci_conf_write32(0, uart->pb_bdf[0], uart->pb_bdf[1], uart->pb_bdf[2],
> +       pci_conf_write16(0, uart->ps_bdf[0], uart->ps_bdf[1], uart->ps_bdf[2],
>                          PCI_COMMAND, uart->cr);
>      }
> +
> +    ns16550_setup_preirq(port->uart);
> +    ns16550_setup_postirq(port->uart);
>  }
>  
>  #ifdef CONFIG_X86
> @@ -483,9 +479,9 @@ pci_uart_config (struct ns16550 *uart, i
>                  if ( (len & 0xffff) != 0xfff9 )
>                      continue;
>  
> -                uart->pb_bdf[0] = b;
> -                uart->pb_bdf[1] = d;
> -                uart->pb_bdf[2] = f;
> +                uart->ps_bdf[0] = b;
> +                uart->ps_bdf[1] = d;
> +                uart->ps_bdf[2] = f;
>                  uart->bar = bar;
>                  uart->bar_idx = bar_idx;
>                  uart->io_base = bar & 0xfffe;
>
>
> _______________________________________________
> Xen-devel mailing list
> [hidden email]
> http://lists.xen.org/xen-devel



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