Re: [patch 1/4] ia64 UV: provide a LED driver for UV Systems

[Mike Travis <travis@sgi.com>]

Hi Andrew,

Could you revert these patches?  After testing, it was shown that it has much
too high an overhead.  I had planned on proposing the same "SCIR" driver as was
done for x86 but ia64 is lower priority than getting the cpumask_t stuff setup
correctly in 2.6.28.

Thanks again,
Mike

akpm@linux-foundation.org wrote:
> From: Mike Travis <travis@sgi.com>
> 
>   * Add base functionality for writing to the LED's on
>     the ia64 UV architecture.
> 
> Note that this is a RAS feature that allows external monitoring of
> various cpu state indicators, not just providing "pretty blinking
> lights", as the LED state is readable by the system controller.
> 
> Signed-off-by: Mike Travis <travis@sgi.com>
> Cc: Tony Luck <tony.luck@intel.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  arch/ia64/include/asm/uv/uv_hub.h |   61 +++++++++++++++++++++++++++-
>  arch/ia64/uv/kernel/setup.c       |    2 
>  2 files changed, 62 insertions(+), 1 deletion(-)
> 
> diff -puN arch/ia64/include/asm/uv/uv_hub.h~ia64-uv-provide-a-led-driver-for-uv-systems arch/ia64/include/asm/uv/uv_hub.h
> --- a/arch/ia64/include/asm/uv/uv_hub.h~ia64-uv-provide-a-led-driver-for-uv-systems
> +++ a/arch/ia64/include/asm/uv/uv_hub.h
> @@ -99,6 +99,7 @@ struct uv_hub_info_s {
>  	unsigned long	gnode_upper;
>  	unsigned long	lowmem_remap_top;
>  	unsigned long	lowmem_remap_base;
> +	unsigned long	led_offset;
>  	unsigned short	pnode;
>  	unsigned short	pnode_mask;
>  	unsigned short	coherency_domain_number;
> @@ -106,6 +107,7 @@ struct uv_hub_info_s {
>  	unsigned char	blade_processor_id;
>  	unsigned char	m_val;
>  	unsigned char	n_val;
> +	unsigned char	led_state;
>  };
>  DECLARE_PER_CPU(struct uv_hub_info_s, __uv_hub_info);
>  #define uv_hub_info 		(&__get_cpu_var(__uv_hub_info))
> @@ -134,6 +136,20 @@ DECLARE_PER_CPU(struct uv_hub_info_s, __
>  #define UV_GLOBAL_MMR64_PNODE_BITS(p)					\
>  	((unsigned long)(p) << UV_GLOBAL_MMR64_PNODE_SHIFT)
>  
> +/* Local Bus from cpu's perspective */
> +#define LOCAL_BUS_BASE		0x1c00000
> +#define LOCAL_BUS_SIZE		(4 * 1024 * 1024)
> +
> +/* LED windows - located at top of ACPI MMR space */
> +#define LED_WINDOW_COUNT	64
> +#define LED_LOCAL_MMR_BASE	(LOCAL_BUS_BASE + LOCAL_BUS_SIZE - \
> +							LED_WINDOW_COUNT)
> +
> +#define LED_CPU_HEARTBEAT	0x01	/* timer interrupt */
> +#define LED_CPU_ACTIVITY	0x02	/* not idle */
> +#define LED_CPU_BLINK		0xffff	/* blink led */
> +#define LED_CPU_HB_INTERVAL	(HZ/2)	/* blink once per second */
> +
>  /*
>   * Macros for converting between kernel virtual addresses, socket local physical
>   * addresses, and UV global physical addresses.
> @@ -240,6 +256,16 @@ static inline void uv_write_local_mmr(un
>  	*uv_local_mmr_address(offset) = val;
>  }
>  
> +static inline unsigned char uv_read_local_mmr8(unsigned long offset)
> +{
> +	return *((unsigned char *)uv_local_mmr_address(offset));
> +}
> +
> +static inline void uv_write_local_mmr8(unsigned long offset, unsigned char val)
> +{
> +	*((unsigned char *)uv_local_mmr_address(offset)) = val;
> +}
> +
>  /*
>   * Structures and definitions for converting between cpu, node, pnode, and blade
>   * numbers.
> @@ -305,5 +331,38 @@ static inline int uv_num_possible_blades
>  	return 1;
>  }
>  
> -#endif /* __ASM_IA64_UV_HUB__ */
> +/* Light up the leds */
> +static inline void uv_set_led_bits(unsigned short value, unsigned char mask)
> +{
> +	unsigned char state = uv_hub_info->led_state;
> +
> +	if (value = LED_CPU_BLINK)
> +		state ^= mask;
> +	else
> +		state = (state & ~mask) | (value & mask);
>  
> +	if (uv_hub_info->led_state != state) {
> +		uv_hub_info->led_state = state;
> +		uv_write_local_mmr8(uv_hub_info->led_offset, state);
> +	}
> +}
> +
> +/* Light up the leds */
> +static inline void uv_set_led_bits_on(int cpu, unsigned short value,
> +					       unsigned char mask)
> +
> +{
> +	unsigned char state = uv_cpu_hub_info(cpu)->led_state;
> +
> +	if (value = LED_CPU_BLINK)
> +		state ^= mask;
> +	else
> +		state = (state & ~mask) | (value & mask);
> +
> +	if (uv_cpu_hub_info(cpu)->led_state != state) {
> +		uv_cpu_hub_info(cpu)->led_state = state;
> +		uv_write_local_mmr8(uv_cpu_hub_info(cpu)->led_offset, state);
> +	}
> +}
> +
> +#endif /* __ASM_IA64_UV_HUB__ */
> diff -puN arch/ia64/uv/kernel/setup.c~ia64-uv-provide-a-led-driver-for-uv-systems arch/ia64/uv/kernel/setup.c
> --- a/arch/ia64/uv/kernel/setup.c~ia64-uv-provide-a-led-driver-for-uv-systems
> +++ a/arch/ia64/uv/kernel/setup.c
> @@ -104,6 +104,8 @@ void __init uv_setup(char **cmdline_p)
>  		uv_cpu_hub_info(cpu)->gnode_upper = gnode_upper;
>  		uv_cpu_hub_info(cpu)->global_mmr_base = mmr_base;
>  		uv_cpu_hub_info(cpu)->coherency_domain_number = 0;/* ZZZ */
> +		uv_cpu_hub_info(cpu)->led_offset = LED_LOCAL_MMR_BASE + lcpu;
> +		uv_cpu_hub_info(cpu)->led_state = 0;
>  		printk(KERN_DEBUG "UV cpu %d, nid %d\n", cpu, nid);
>  	}
>  }
> _