Subject: Re: [PATCH] PowerPC: const intspec pointers

From: Benjamin Herrenschmidt <[email-masked]>
Date: Wed, 09 Dec 2009 13:45:06 +1100

On Tue, 2009-12-08 at 13:39 +0100, Roman Fietze wrote:
> Hello,
> 
> Writing a driver using SCLPC on the MPC5200B I detected, that the
> intspec arrays to map irqs to Linux virq cannot be const, because the
> mapping and xlate functions only take non const pointers. All those
> functions do not modify the intspec, so a const pointer could be used.
> 
> I tried to compile that patch on different platforms and got no
> compiler errors, so I'd like to ask you to review that patch, and
> check if it's worth using it.

Looks good.

I'll give it a go and if it doesn't break anything, will apply.

Cheers,
Ben.

> Signed-off-by: Roman Fietze <[email-masked]>
> ---
>  arch/powerpc/include/asm/irq.h                  |    4 ++--
>  arch/powerpc/kernel/irq.c                       |    2 +-
>  arch/powerpc/platforms/52xx/media5200.c         |    2 +-
>  arch/powerpc/platforms/52xx/mpc52xx_gpt.c       |    2 +-
>  arch/powerpc/platforms/52xx/mpc52xx_pic.c       |    2 +-
>  arch/powerpc/platforms/85xx/socrates_fpga_pic.c |    2 +-
>  arch/powerpc/platforms/86xx/gef_pic.c           |    2 +-
>  arch/powerpc/platforms/cell/beat_interrupt.c    |    4 ++--
>  arch/powerpc/platforms/cell/interrupt.c         |    2 +-
>  arch/powerpc/platforms/cell/spider-pic.c        |    2 +-
>  arch/powerpc/platforms/powermac/pic.c           |    2 +-
>  arch/powerpc/platforms/pseries/xics.c           |    2 +-
>  arch/powerpc/sysdev/cpm2_pic.c                  |    2 +-
>  arch/powerpc/sysdev/i8259.c                     |    2 +-
>  arch/powerpc/sysdev/ipic.c                      |    2 +-
>  arch/powerpc/sysdev/mpc8xx_pic.c                |    2 +-
>  arch/powerpc/sysdev/mpic.c                      |    2 +-
>  arch/powerpc/sysdev/qe_lib/qe_ic.c              |    2 +-
>  arch/powerpc/sysdev/tsi108_pci.c                |    2 +-
>  arch/powerpc/sysdev/uic.c                       |    2 +-
>  arch/powerpc/sysdev/xilinx_intc.c               |    2 +-
>  21 files changed, 23 insertions(+), 23 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/irq.h b/arch/powerpc/include/asm/irq.h
> index bbcd1aa..a0bcafc 100644
> --- a/arch/powerpc/include/asm/irq.h
> +++ b/arch/powerpc/include/asm/irq.h
> @@ -99,7 +99,7 @@ struct irq_host_ops {
>  	 * interrupt controller has for that line)
>  	 */
>  	int (*xlate)(struct irq_host *h, struct device_node *ctrler,
> -		     u32 *intspec, unsigned int intsize,
> +		     const u32 *intspec, unsigned int intsize,
>  		     irq_hw_number_t *out_hwirq, unsigned int *out_type);
>  };
>  
> @@ -313,7 +313,7 @@ extern void irq_free_virt(unsigned int virq, unsigned int 
> count);
>   * of the of_irq_map_*() functions.
>   */
>  extern unsigned int irq_create_of_mapping(struct device_node *controller,
> -					  u32 *intspec, unsigned int intsize);
> +					  const u32 *intspec, unsigned int intsize);
>  
>  /**
>   * irq_of_parse_and_map - Parse and Map an interrupt into linux virq space
> diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
> index e5d1211..6e294e0 100644
> --- a/arch/powerpc/kernel/irq.c
> +++ b/arch/powerpc/kernel/irq.c
> @@ -699,7 +699,7 @@ unsigned int irq_create_mapping(struct irq_host *host,
>  EXPORT_SYMBOL_GPL(irq_create_mapping);
>  
>  unsigned int irq_create_of_mapping(struct device_node *controller,
> -				   u32 *intspec, unsigned int intsize)
> +				   const u32 *intspec, unsigned int intsize)
>  {
>  	struct irq_host *host;
>  	irq_hw_number_t hwirq;
> diff --git a/arch/powerpc/platforms/52xx/media5200.c 
> b/arch/powerpc/platforms/52xx/media5200.c
> index 68e4f16..b1ec9bb 100644
> --- a/arch/powerpc/platforms/52xx/media5200.c
> +++ b/arch/powerpc/platforms/52xx/media5200.c
> @@ -127,7 +127,7 @@ static int media5200_irq_map(struct irq_host *h, unsigned 
> int virq,
>  }
>  
>  static int media5200_irq_xlate(struct irq_host *h, struct device_node *ct,
> -				 u32 *intspec, unsigned int intsize,
> +				 const u32 *intspec, unsigned int intsize,
>  				 irq_hw_number_t *out_hwirq,
>  				 unsigned int *out_flags)
>  {
> diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c 
> b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
> index bfbcd41..78f0ab6 100644
> --- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
> +++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
> @@ -182,7 +182,7 @@ static int mpc52xx_gpt_irq_map(struct irq_host *h, 
> unsigned int virq,
>  }
>  
>  static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct,
> -				 u32 *intspec, unsigned int intsize,
> +				 const u32 *intspec, unsigned int intsize,
>  				 irq_hw_number_t *out_hwirq,
>  				 unsigned int *out_flags)
>  {
> diff --git a/arch/powerpc/platforms/52xx/mpc52xx_pic.c 
> b/arch/powerpc/platforms/52xx/mpc52xx_pic.c
> index 480f806..53d44f6 100644
> --- a/arch/powerpc/platforms/52xx/mpc52xx_pic.c
> +++ b/arch/powerpc/platforms/52xx/mpc52xx_pic.c
> @@ -355,7 +355,7 @@ static int mpc52xx_is_extirq(int l1, int l2)
>   * mpc52xx_irqhost_xlate - translate virq# from device tree interrupts 
> property
>   */
>  static int mpc52xx_irqhost_xlate(struct irq_host *h, struct device_node *ct,
> -				 u32 *intspec, unsigned int intsize,
> +				 const u32 *intspec, unsigned int intsize,
>  				 irq_hw_number_t *out_hwirq,
>  				 unsigned int *out_flags)
>  {
> diff --git a/arch/powerpc/platforms/85xx/socrates_fpga_pic.c 
> b/arch/powerpc/platforms/85xx/socrates_fpga_pic.c
> index 60edf63..380858a 100644
> --- a/arch/powerpc/platforms/85xx/socrates_fpga_pic.c
> +++ b/arch/powerpc/platforms/85xx/socrates_fpga_pic.c
> @@ -253,7 +253,7 @@ static int socrates_fpga_pic_host_map(struct irq_host *h, 
> unsigned int virq,
>  }
>  
>  static int socrates_fpga_pic_host_xlate(struct irq_host *h,
> -		struct device_node *ct,	u32 *intspec, unsigned int intsize,
> +		struct device_node *ct,	const u32 *intspec, unsigned int intsize,
>  		irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  	struct socrates_fpga_irq_info *fpga_irq = &fpga_irqs[intspec[0]];
> diff --git a/arch/powerpc/platforms/86xx/gef_pic.c 
> b/arch/powerpc/platforms/86xx/gef_pic.c
> index 50d0a2b..8d4479f 100644
> --- a/arch/powerpc/platforms/86xx/gef_pic.c
> +++ b/arch/powerpc/platforms/86xx/gef_pic.c
> @@ -170,7 +170,7 @@ static int gef_pic_host_map(struct irq_host *h, unsigned 
> int virq,
>  }
>  
>  static int gef_pic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 *intspec, unsigned int intsize,
> +			    const u32 *intspec, unsigned int intsize,
>  			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  
> diff --git a/arch/powerpc/platforms/cell/beat_interrupt.c 
> b/arch/powerpc/platforms/cell/beat_interrupt.c
> index 7225484..1f2fd65 100644
> --- a/arch/powerpc/platforms/cell/beat_interrupt.c
> +++ b/arch/powerpc/platforms/cell/beat_interrupt.c
> @@ -166,11 +166,11 @@ static void beatic_pic_host_remap(struct irq_host *h, 
> unsigned int virq,
>   * Note: We have only 1 entry to translate.
>   */
>  static int beatic_pic_host_xlate(struct irq_host *h, struct device_node *ct,
> -				 u32 *intspec, unsigned int intsize,
> +				 const u32 *intspec, unsigned int intsize,
>  				 irq_hw_number_t *out_hwirq,
>  				 unsigned int *out_flags)
>  {
> -	u64 *intspec2 = (u64 *)intspec;
> +	const u64 *intspec2 = (const u64 *)intspec;
>  
>  	*out_hwirq = *intspec2;
>  	*out_flags |= IRQ_TYPE_LEVEL_LOW;
> diff --git a/arch/powerpc/platforms/cell/interrupt.c 
> b/arch/powerpc/platforms/cell/interrupt.c
> index 882e470..d9d33cb 100644
> --- a/arch/powerpc/platforms/cell/interrupt.c
> +++ b/arch/powerpc/platforms/cell/interrupt.c
> @@ -297,7 +297,7 @@ static int iic_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int iic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			   u32 *intspec, unsigned int intsize,
> +			   const u32 *intspec, unsigned int intsize,
>  			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  
>  {
> diff --git a/arch/powerpc/platforms/cell/spider-pic.c 
> b/arch/powerpc/platforms/cell/spider-pic.c
> index 4e56556..37c2e4e 100644
> --- a/arch/powerpc/platforms/cell/spider-pic.c
> +++ b/arch/powerpc/platforms/cell/spider-pic.c
> @@ -187,7 +187,7 @@ static int spider_host_map(struct irq_host *h, unsigned 
> int virq,
>  }
>  
>  static int spider_host_xlate(struct irq_host *h, struct device_node *ct,
> -			   u32 *intspec, unsigned int intsize,
> +			   const u32 *intspec, unsigned int intsize,
>  			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  
>  {
> diff --git a/arch/powerpc/platforms/powermac/pic.c 
> b/arch/powerpc/platforms/powermac/pic.c
> index d212006..da6b4b9 100644
> --- a/arch/powerpc/platforms/powermac/pic.c
> +++ b/arch/powerpc/platforms/powermac/pic.c
> @@ -303,7 +303,7 @@ static int pmac_pic_host_map(struct irq_host *h, unsigned 
> int virq,
>  }
>  
>  static int pmac_pic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			       u32 *intspec, unsigned int intsize,
> +			       const u32 *intspec, unsigned int intsize,
>  			       irq_hw_number_t *out_hwirq,
>  			       unsigned int *out_flags)
>  
> diff --git a/arch/powerpc/platforms/pseries/xics.c 
> b/arch/powerpc/platforms/pseries/xics.c
> index b9bf0ee..1821eae 100644
> --- a/arch/powerpc/platforms/pseries/xics.c
> +++ b/arch/powerpc/platforms/pseries/xics.c
> @@ -434,7 +434,7 @@ static int xics_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int xics_host_xlate(struct irq_host *h, struct device_node *ct,
> -			   u32 *intspec, unsigned int intsize,
> +			   const u32 *intspec, unsigned int intsize,
>  			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  
>  {
> diff --git a/arch/powerpc/sysdev/cpm2_pic.c b/arch/powerpc/sysdev/cpm2_pic.c
> index 78f1f7c..3d2be56 100644
> --- a/arch/powerpc/sysdev/cpm2_pic.c
> +++ b/arch/powerpc/sysdev/cpm2_pic.c
> @@ -216,7 +216,7 @@ static int cpm2_pic_host_map(struct irq_host *h, unsigned 
> int virq,
>  }
>  
>  static int cpm2_pic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 *intspec, unsigned int intsize,
> +			    const u32 *intspec, unsigned int intsize,
>  			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  	*out_hwirq = intspec[0];
> diff --git a/arch/powerpc/sysdev/i8259.c b/arch/powerpc/sysdev/i8259.c
> index a96584a..ccc9a3b 100644
> --- a/arch/powerpc/sysdev/i8259.c
> +++ b/arch/powerpc/sysdev/i8259.c
> @@ -198,7 +198,7 @@ static void i8259_host_unmap(struct irq_host *h, unsigned 
> int virq)
>  }
>  
>  static int i8259_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 *intspec, unsigned int intsize,
> +			    const u32 *intspec, unsigned int intsize,
>  			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  	static unsigned char map_isa_senses[4] = {
> diff --git a/arch/powerpc/sysdev/ipic.c b/arch/powerpc/sysdev/ipic.c
> index cb7689c..27259f4 100644
> --- a/arch/powerpc/sysdev/ipic.c
> +++ b/arch/powerpc/sysdev/ipic.c
> @@ -697,7 +697,7 @@ static int ipic_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int ipic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			   u32 *intspec, unsigned int intsize,
> +			   const u32 *intspec, unsigned int intsize,
>  			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  
>  {
> diff --git a/arch/powerpc/sysdev/mpc8xx_pic.c 
> b/arch/powerpc/sysdev/mpc8xx_pic.c
> index 5d2d552..72544a1 100644
> --- a/arch/powerpc/sysdev/mpc8xx_pic.c
> +++ b/arch/powerpc/sysdev/mpc8xx_pic.c
> @@ -130,7 +130,7 @@ static int mpc8xx_pic_host_map(struct irq_host *h, 
> unsigned int virq,
>  
> 
>  static int mpc8xx_pic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 *intspec, unsigned int intsize,
> +			    const u32 *intspec, unsigned int intsize,
>  			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  	static unsigned char map_pic_senses[4] = {
> diff --git a/arch/powerpc/sysdev/mpic.c b/arch/powerpc/sysdev/mpic.c
> index 30c44e6..1452a4e 100644
> --- a/arch/powerpc/sysdev/mpic.c
> +++ b/arch/powerpc/sysdev/mpic.c
> @@ -994,7 +994,7 @@ static int mpic_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int mpic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			   u32 *intspec, unsigned int intsize,
> +			   const u32 *intspec, unsigned int intsize,
>  			   irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  
>  {
> diff --git a/arch/powerpc/sysdev/qe_lib/qe_ic.c 
> b/arch/powerpc/sysdev/qe_lib/qe_ic.c
> index 3faa42e..8192f58 100644
> --- a/arch/powerpc/sysdev/qe_lib/qe_ic.c
> +++ b/arch/powerpc/sysdev/qe_lib/qe_ic.c
> @@ -271,7 +271,7 @@ static int qe_ic_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int qe_ic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 * intspec, unsigned int intsize,
> +			    const u32 * intspec, unsigned int intsize,
>  			    irq_hw_number_t * out_hwirq,
>  			    unsigned int *out_flags)
>  {
> diff --git a/arch/powerpc/sysdev/tsi108_pci.c 
> b/arch/powerpc/sysdev/tsi108_pci.c
> index cf244a4..a23223d 100644
> --- a/arch/powerpc/sysdev/tsi108_pci.c
> +++ b/arch/powerpc/sysdev/tsi108_pci.c
> @@ -384,7 +384,7 @@ static struct irq_chip tsi108_pci_irq = {
>  };
>  
>  static int pci_irq_host_xlate(struct irq_host *h, struct device_node *ct,
> -			    u32 *intspec, unsigned int intsize,
> +			    const u32 *intspec, unsigned int intsize,
>  			    irq_hw_number_t *out_hwirq, unsigned int *out_flags)
>  {
>  	*out_hwirq = intspec[0];
> diff --git a/arch/powerpc/sysdev/uic.c b/arch/powerpc/sysdev/uic.c
> index 466ce9a..1c315d8 100644
> --- a/arch/powerpc/sysdev/uic.c
> +++ b/arch/powerpc/sysdev/uic.c
> @@ -202,7 +202,7 @@ static int uic_host_map(struct irq_host *h, unsigned int 
> virq,
>  }
>  
>  static int uic_host_xlate(struct irq_host *h, struct device_node *ct,
> -			  u32 *intspec, unsigned int intsize,
> +			  const u32 *intspec, unsigned int intsize,
>  			  irq_hw_number_t *out_hwirq, unsigned int *out_type)
>  
>  {
> diff --git a/arch/powerpc/sysdev/xilinx_intc.c 
> b/arch/powerpc/sysdev/xilinx_intc.c
> index 40edad5..368db32 100644
> --- a/arch/powerpc/sysdev/xilinx_intc.c
> +++ b/arch/powerpc/sysdev/xilinx_intc.c
> @@ -148,7 +148,7 @@ static struct irq_chip xilinx_intc_edge_irqchip = {
>   * xilinx_intc_xlate - translate virq# from device tree interrupts property
>   */
>  static int xilinx_intc_xlate(struct irq_host *h, struct device_node *ct,
> -				u32 *intspec, unsigned int intsize,
> +				const u32 *intspec, unsigned int intsize,
>  				irq_hw_number_t *out_hwirq,
>  				unsigned int *out_flags)
>  {
> -- 
> 1.6.5.3
> 
> 
> Thanks a lot for your help
> 
> 
> Roman
>