Re: [PATCH] x86_64 io_apic.c: Memorize at bootup where the i8259 is connected

[yhlu <yhlu.kernel@gmail.com>]

Is that for Nvidia CK804 stuff?

Actually in LinuxBIOS I swap the irq 0 and 2 entries in mptable to
solve the problem. and it could work well with current code.

YH

On 7/29/05, Eric W. Biederman <ebiederm@xmission.com> wrote:
> 
> Currently we attempt to restore virtual wire mode on reboot, which
> only works if we can figure out where the i8259 is connected.  This
> is very useful when we kexec another kernel and likely helpful
> when dealing with a BIOS that make assumptions about how the system is setup.
> 
> Since the acpi MADT table does not provide the location where the i8259
> is connected we have to look at the hardware to figure it out.
> 
> Most systems have the i8259 connected to the local apic of the cpu so
> won't be affected but people running on Opteron and some serverworks chipsets
> should be able to use kexec now.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
> 
>  arch/x86_64/kernel/io_apic.c |   52 ++++++++++++++++++++++++++++++++++++++----
>  1 files changed, 47 insertions(+), 5 deletions(-)
> 
> 96c59dd871b00735ef159ddf0d68f338958387fc
> diff --git a/arch/x86_64/kernel/io_apic.c b/arch/x86_64/kernel/io_apic.c
> --- a/arch/x86_64/kernel/io_apic.c
> +++ b/arch/x86_64/kernel/io_apic.c
> @@ -45,6 +45,9 @@ int sis_apic_bug; /* not actually suppor
> 
>  static int no_timer_check;
> 
> +/* Where if anywhere is the i8259 connect in external int mode */
> +static int ioapic_i8259_pin = -1;
> +
>  static DEFINE_SPINLOCK(ioapic_lock);
> 
>  /*
> @@ -330,7 +333,7 @@ static int find_irq_entry(int apic, int
>  /*
>   * Find the pin to which IRQ[irq] (ISA) is connected
>   */
> -static int find_isa_irq_pin(int irq, int type)
> +static int __init find_isa_irq_pin(int irq, int type)
>  {
>         int i;
> 
> @@ -1096,6 +1099,44 @@ void __apicdebuginit print_PIC(void)
> 
>  #endif  /*  0  */
> 
> +static void __init find_i8259_pin(void)
> +{
> +       struct IO_APIC_route_entry entry;
> +       unsigned long flags;
> +       int pin, pins;
> +
> +       ioapic_i8259_pin = -1;
> +
> +       /* Find the number of pins on the primary ioapic */
> +       spin_lock_irqsave(&ioapic_lock, flags);
> +       pins = ((io_apic_read(0, 0x01) >> 16) & 0xff) + 1;
> +       spin_unlock_irqrestore(&ioapic_lock, flags);
> +
> +       /* See if any of the pins is in ExtINT mode */
> +       for(pin = 0; pin < pins; pin++) {
> +               spin_lock_irqsave(&ioapic_lock, flags);
> +               *(((int *)&entry) + 0) = io_apic_read(0, 0x10 + 2 * pin);
> +               *(((int *)&entry) + 1) = io_apic_read(0, 0x11 + 2 * pin);
> +               spin_unlock_irqrestore(&ioapic_lock, flags);
> +
> +               /* If the interrupt line is enabled and in ExtInt mode
> +                * I have found the pin where the i8259 is connected.
> +                */
> +               if ((entry.mask == 0) && (entry.delivery_mode == dest_ExtINT)) {
> +                       ioapic_i8259_pin = pin;
> +                       break;
> +               }
> +       }
> +
> +       /* If we could not find an appropriate pin by looking at the ioapic
> +        * the i8259 probably isn't connected to the ioapic but give
> +        * the mptable a chance anyway.
> +        */
> +       if (ioapic_i8259_pin == -1) {
> +               ioapic_i8259_pin = find_isa_irq_pin(0, mp_ExtINT);
> +       }
> +}
> +
>  static void __init enable_IO_APIC(void)
>  {
>         union IO_APIC_reg_01 reg_01;
> @@ -1138,11 +1179,11 @@ void disable_IO_APIC(void)
>         clear_IO_APIC();
> 
>         /*
> -        * If the i82559 is routed through an IOAPIC
> +        * If the i8259 is routed through an IOAPIC
>          * Put that IOAPIC in virtual wire mode
>          * so legacy interrups can be delivered.
>          */
> -       pin = find_isa_irq_pin(0, mp_ExtINT);
> +       pin = ioapic_i8259_pin;
>         if (pin != -1) {
>                 struct IO_APIC_route_entry entry;
>                 unsigned long flags;
> @@ -1154,7 +1195,7 @@ void disable_IO_APIC(void)
>                 entry.polarity        = 0; /* High */
>                 entry.delivery_status = 0;
>                 entry.dest_mode       = 0; /* Physical */
> -               entry.delivery_mode   = 7; /* ExtInt */
> +               entry.delivery_mode   = dest_ExtINT; /* ExtInt */
>                 entry.vector          = 0;
>                 entry.dest.physical.physical_dest = 0;
> 
> @@ -1626,7 +1667,7 @@ static inline void check_timer(void)
>         enable_8259A_irq(0);
> 
>         pin1 = find_isa_irq_pin(0, mp_INT);
> -       pin2 = find_isa_irq_pin(0, mp_ExtINT);
> +       pin2 = ioapic_i8259_pin;
> 
>         apic_printk(APIC_VERBOSE,KERN_INFO "..TIMER: vector=0x%02X pin1=%d pin2=%d\n", vector, pin1, pin2);
> 
> @@ -1723,6 +1764,7 @@ __setup("no_timer_check", notimercheck);
> 
>  void __init setup_IO_APIC(void)
>  {
> +       find_i8259_pin();
>         enable_IO_APIC();
> 
>         if (acpi_ioapic)
> -
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