Re: [PATCH 05/15] x86/dtb: add early parsing of APIC and IO APIC

[Grant Likely]

On Fri, Dec 17, 2010 at 04:33:43PM +0100, Sebastian Andrzej Siewior wrote:
> The apic & ioapic have to be added to system early because
> native_init_IRQ() requires it. In order to obtain the address of the
> ioapic the device tree has to be unflattened because
> of_address_to_resource() has to work.
> The device tree is relocated to ensure it is always covered by the
> kernel and the boot loader does not have to make assumptions about
> kernel's memory layout.
> 
> Cc: devicetree-discuss@xxxxxxxxxxxxxxxx
> Cc: Dirk Brandewie <dirk.brandewie@xxxxxxxxx>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>  arch/x86/include/asm/prom.h |    7 +++
>  arch/x86/kernel/irqinit.c   |    2 +-
>  arch/x86/kernel/prom.c      |  123 +++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 128 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/x86/include/asm/prom.h b/arch/x86/include/asm/prom.h
> index 9076ae4..3bc8ed5 100644
> --- a/arch/x86/include/asm/prom.h
> +++ b/arch/x86/include/asm/prom.h
> @@ -22,10 +22,17 @@
>  #include <asm/irq_controller.h>
>  
>  #ifdef CONFIG_OF
> +extern int of_ioapic;
> +extern u64 initial_dtb;
>  extern void add_dtb(u64 data);
> +void x86_dtb_find_config(void);
> +void x86_dtb_get_config(unsigned int unused);
>  void add_interrupt_host(struct irq_domain *ih);
>  #else
>  static inline void add_dtb(u64 data) { }
> +#define x86_dtb_find_config x86_init_noop
> +#define x86_dtb_get_config x86_init_uint_noop
> +#define of_ioapic 0
>  #endif
>  
>  extern char cmd_line[COMMAND_LINE_SIZE];
> diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
> index 149c87f..4cadf86 100644
> --- a/arch/x86/kernel/irqinit.c
> +++ b/arch/x86/kernel/irqinit.c
> @@ -244,7 +244,7 @@ void __init native_init_IRQ(void)
>  			set_intr_gate(i, interrupt[i-FIRST_EXTERNAL_VECTOR]);
>  	}
>  
> -	if (!acpi_ioapic)
> +	if (!acpi_ioapic && !of_ioapic)
>  		setup_irq(2, &irq2);
>  
>  #ifdef CONFIG_X86_32
> diff --git a/arch/x86/kernel/prom.c b/arch/x86/kernel/prom.c
> index 53948cb..9cbb52b 100644
> --- a/arch/x86/kernel/prom.c
> +++ b/arch/x86/kernel/prom.c
> @@ -6,15 +6,20 @@
>  #include <linux/interrupt.h>
>  #include <linux/list.h>
>  #include <linux/of.h>
> +#include <linux/of_address.h>
>  #include <linux/of_platform.h>
>  #include <linux/slab.h>
>  
>  #include <asm/irq_controller.h>
> +#include <asm/io_apic.h>
>  
> +__initdata u64 initial_dtb;
>  char __initdata cmd_line[COMMAND_LINE_SIZE];
>  static LIST_HEAD(irq_domains);
>  static DEFINE_RAW_SPINLOCK(big_irq_lock);
>  
> +int __initdata of_ioapic;
> +
>  void add_interrupt_host(struct irq_domain *ih)
>  {
>  	unsigned long flags;
> @@ -93,7 +98,119 @@ u64 __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
>  
>  void __init add_dtb(u64 data)
>  {
> -	initial_boot_params = (struct boot_param_header *)
> -		phys_to_virt((u64) (u32) data +
> -				offsetof(struct setup_data, data));
> +	initial_dtb = data + offsetof(struct setup_data, data);
> +}
> +
> +static void __init dtb_lapic_setup(void)
> +{
> +#ifdef CONFIG_X86_LOCAL_APIC
> +	if (apic_force_enable())
> +		return;
> +
> +	smp_found_config = 1;
> +	pic_mode = 1;
> +	/* Required for ioapic registration */
> +	set_fixmap_nocache(FIX_APIC_BASE, mp_lapic_addr);
> +	if (boot_cpu_physical_apicid == -1U)
> +		boot_cpu_physical_apicid = read_apic_id();
> +
> +	generic_processor_info(boot_cpu_physical_apicid,
> +			GET_APIC_VERSION(apic_read(APIC_LVR)));
> +#endif
> +}
> +
> +#ifdef CONFIG_X86_IO_APIC
> +static void __init dtb_add_ioapic(struct device_node *dn)
> +{
> +	unsigned int ioapic_id;
> +	const __be32 *cell;
> +	int len;
> +	struct resource r;
> +	int ret;
> +
> +	cell = of_get_property(dn, "id", &len);
> +	if (!cell) {
> +		printk(KERN_ERR "Node %s is missing id property.\n",
> +				dn->full_name);
> +		return;
> +	}
> +	ioapic_id = of_read_ulong(cell, len / 4);
> +
> +	ret = of_address_to_resource(dn, 0, &r);
> +	if (ret) {
> +		printk(KERN_ERR "Can't obtain address from node %s.\n",
> +				dn->full_name);
> +		return;
> +	}
> +	mp_register_ioapic(ioapic_id, r.start, gsi_top);
> +}
> +
> +static void __init dtb_ioapic_setup(void)
> +{
> +	struct device_node *dn;
> +
> +	if (!smp_found_config)
> +		return;
> +
> +	for_each_compatible_node(dn, NULL, "intel,ioapic")
> +		dtb_add_ioapic(dn);
> +
> +	if (nr_ioapics) {
> +		of_ioapic = 1;
> +		return;
> +	}
> +	printk(KERN_ERR "Error: No information about IO-APIC in OF.\n");
> +	smp_found_config = 0;
> +}
> +#else
> +static void __init dtb_ioapic_setup(void) {}
> +#endif
> +
> +static void __init dtb_apic_setup(void)
> +{
> +	dtb_lapic_setup();
> +	dtb_ioapic_setup();
> +}
> +
> +void __init x86_dtb_find_config(void)
> +{
> +	if (initial_dtb)
> +		smp_found_config = 1;
> +	else
> +		printk(KERN_ERR "Missing device tree!.\n");
> +}
> +
> +void __init x86_dtb_get_config(unsigned int unused)
> +{
> +	u32 size;
> +	u32 map_len;
> +	void *new_dtb;
> +
> +	if (!initial_dtb)
> +		return;
> +
> +	map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK),
> +			(u64)sizeof(struct boot_param_header));
> +
> +	initial_boot_params = early_memremap(initial_dtb, map_len);
> +	size = be32_to_cpu(initial_boot_params->totalsize);
> +	if (map_len < size) {
> +		early_iounmap(initial_boot_params, map_len);
> +		initial_boot_params = early_memremap(initial_dtb, size);

Add "map_len = size;" here eliminate the early_iounmap() dance done below.

> +	}
> +
> +	new_dtb = alloc_bootmem(size);
> +	memcpy(new_dtb, initial_boot_params, size);
> +	if (map_len < size)
> +		early_iounmap(initial_boot_params, size);
> +	else
> +		early_iounmap(initial_boot_params, map_len);
> +
> +	initial_boot_params = new_dtb;
> +
> +	/* root level address cells */
> +	of_scan_flat_dt(early_init_dt_scan_root, NULL);
> +
> +	unflatten_device_tree();
> +	dtb_apic_setup();
>  }
> -- 
> 1.7.3.2
> 
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