linux-kernel - Re: [PATCH 04/12] coresight: Add support for reading 64bit registers

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Message-ID: <20170613174558.GB6392@xps15>
Date:   Tue, 13 Jun 2017 11:45:58 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suzuki K Poulose <suzuki.poulose@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/12] coresight: Add support for reading 64bit registers

On Mon, Jun 12, 2017 at 03:36:43PM +0100, Suzuki K Poulose wrote:
> Add support for reading a lower and upper 32bits of a register
> as a single 64bit register.
> 
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@....com>

Just a few cosmetic details...

> ---
>  drivers/hwtracing/coresight/coresight-priv.h | 27 ++++++++++++++++++++++-----
>  drivers/hwtracing/coresight/coresight-tmc.c  |  6 +++---
>  2 files changed, 25 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/hwtracing/coresight/coresight-priv.h b/drivers/hwtracing/coresight/coresight-priv.h
> index 5f662d8..b62dc6a 100644
> --- a/drivers/hwtracing/coresight/coresight-priv.h
> +++ b/drivers/hwtracing/coresight/coresight-priv.h
> @@ -39,23 +39,29 @@
>  #define ETM_MODE_EXCL_USER	BIT(31)
>  
>  typedef u32 (*coresight_read_fn)(const struct device *, u32 offset);
> -#define coresight_simple_func(type, func, name, offset)			\
> +#define __coresight_simple_func(type, func, name, lo_off, hi_off)	\
>  static ssize_t name##_show(struct device *_dev,				\
>  			   struct device_attribute *attr, char *buf)	\
>  {									\
>  	type *drvdata = dev_get_drvdata(_dev->parent);			\
>  	coresight_read_fn fn = func;					\
> -	u32 val;							\
> +	u64 val;							\
>  	pm_runtime_get_sync(_dev->parent);				\
>  	if (fn)								\
> -		val = fn(_dev->parent, offset);				\
> +		val = (u64)fn(_dev->parent, lo_off);			\
>  	else								\
> -		val = readl_relaxed(drvdata->base + offset);		\
> +		val = coresight_read_reg_pair(drvdata->base,		\
> +						 lo_off, hi_off);	\
>  	pm_runtime_put_sync(_dev->parent);				\
> -	return scnprintf(buf, PAGE_SIZE, "0x%x\n", val);		\
> +	return scnprintf(buf, PAGE_SIZE, "0x%llx\n", val);		\
>  }									\
>  static DEVICE_ATTR_RO(name)
>  
> +#define coresight_simple_func(type, func, name, offset)			\
> +	__coresight_simple_func(type, func, name, offset, -1)
> +#define coresight_simple_reg64(type, name, lo_off, hi_off)		\
> +	__coresight_simple_func(type, NULL, name, lo_off, hi_off)
> +
>  enum etm_addr_type {
>  	ETM_ADDR_TYPE_NONE,
>  	ETM_ADDR_TYPE_SINGLE,
> @@ -106,6 +112,17 @@ static inline void CS_UNLOCK(void __iomem *addr)
>  	} while (0);
>  }
>  
> +static inline u64
> +coresight_read_reg_pair(void __iomem *addr, s32 lo_offset, s32 hi_offset)
> +{
> +	u64 val;
> +
> +	val = readl_relaxed(addr + lo_offset);
> +	val |= (hi_offset < 0) ? 0 :
> +		(u64)readl_relaxed(addr + hi_offset) << 32;

This should probably be aligned with the other '('.

> +	return val;
> +}
> +
>  void coresight_disable_path(struct list_head *path);
>  int coresight_enable_path(struct list_head *path, u32 mode);
>  struct coresight_device *coresight_get_sink(struct list_head *path);
> diff --git a/drivers/hwtracing/coresight/coresight-tmc.c b/drivers/hwtracing/coresight/coresight-tmc.c
> index eb0c7b3..7025982 100644
> --- a/drivers/hwtracing/coresight/coresight-tmc.c
> +++ b/drivers/hwtracing/coresight/coresight-tmc.c
> @@ -219,11 +219,8 @@ static enum tmc_mem_intf_width tmc_get_memwidth(u32 devid)
>  
>  #define coresight_tmc_simple_func(name, offset)			\
>  	coresight_simple_func(struct tmc_drvdata, NULL, name, offset)
> -

Please restore.

>  coresight_tmc_simple_func(rsz, TMC_RSZ);
>  coresight_tmc_simple_func(sts, TMC_STS);
> -coresight_tmc_simple_func(rrp, TMC_RRP);
> -coresight_tmc_simple_func(rwp, TMC_RWP);
>  coresight_tmc_simple_func(trg, TMC_TRG);
>  coresight_tmc_simple_func(ctl, TMC_CTL);
>  coresight_tmc_simple_func(ffsr, TMC_FFSR);
> @@ -232,6 +229,9 @@ coresight_tmc_simple_func(mode, TMC_MODE);
>  coresight_tmc_simple_func(pscr, TMC_PSCR);
>  coresight_tmc_simple_func(devid, CORESIGHT_DEVID);
>  

No need for a new line here.  In fact I would put the following two lines in
place of the ones you've replaced above.

> +coresight_simple_reg64(struct tmc_drvdata, rrp, TMC_RRP, TMC_RRPHI);
> +coresight_simple_reg64(struct tmc_drvdata, rwp, TMC_RWP, TMC_RWPHI);
> +
>  static struct attribute *coresight_tmc_mgmt_attrs[] = {
>  	&dev_attr_rsz.attr,
>  	&dev_attr_sts.attr,
> -- 
> 2.7.4
>