[PATCH v3 2/5] usb: chipidea: add freescale imx28 special write register method

[Hector Palacios]

Dear Peter,

On 10/25/2013 08:02 AM, Peter Chen wrote:
> According to Freescale imx28 Errata, "ENGR119653 USB: ARM to USB
> register error issue", All USB register write operations must
> use the ARM SWP instruction. So, we implement special hw_write
> and hw_test_and_clear for imx28.
>
> Discussion for it at below:
> http://marc.info/?l=linux-usb&m=137996395529294&w=2
>
> Signed-off-by: Peter Chen <peter.chen-KZfg59tc24xl57MIdRCFDg at public.gmane.org>
> ---
> Changes for v2:
> - Rebase to latest usb-next tree
>
>   drivers/usb/chipidea/ci.h    |   23 +++++++++++++++++++++++
>   drivers/usb/chipidea/core.c  |    2 ++
>   drivers/usb/chipidea/host.c  |    1 +
>   include/linux/usb/chipidea.h |    1 +
>   4 files changed, 27 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
> index 1c94fc5..4eb61d0 100644
> --- a/drivers/usb/chipidea/ci.h
> +++ b/drivers/usb/chipidea/ci.h
> @@ -173,6 +173,8 @@ struct ci_hdrc {
>   	struct dentry			*debugfs;
>   	bool				id_event;
>   	bool				b_sess_valid_event;
> +	/* imx28 needs swp instruction for writing */
> +	bool				imx28_write_fix;
>   };
>
>   static inline struct ci_role_driver *ci_role(struct ci_hdrc *ci)
> @@ -253,6 +255,13 @@ static inline u32 hw_read(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask)
>   	return ioread32(ci->hw_bank.regmap[reg]) & mask;
>   }
>
> +#ifdef CONFIG_SOC_IMX28
> +static inline void imx28_ci_writel(u32 val32, volatile u32 *addr)
> +{
> +	__asm__ ("swp %0, %0, [%1]" : : "r"(val32), "r"(addr));
> +}
> +#endif
> +
>   /**
>    * hw_write: writes to a hw register
>    * @reg:  register index
> @@ -266,7 +275,14 @@ static inline void hw_write(struct ci_hdrc *ci, enum ci_hw_regs reg,
>   		data = (ioread32(ci->hw_bank.regmap[reg]) & ~mask)
>   			| (data & mask);
>
> +#ifdef CONFIG_SOC_IMX28
> +	if (ci->imx28_write_fix)
> +		imx28_ci_writel(data, ci->hw_bank.regmap[reg]);
> +	else
> +		iowrite32(data, ci->hw_bank.regmap[reg]);
> +#else
>   	iowrite32(data, ci->hw_bank.regmap[reg]);
> +#endif
>   }
>
>   /**
> @@ -281,7 +297,14 @@ static inline u32 hw_test_and_clear(struct ci_hdrc *ci, enum ci_hw_regs reg,
>   {
>   	u32 val = ioread32(ci->hw_bank.regmap[reg]) & mask;
>
> +#ifdef CONFIG_SOC_IMX28
> +	if (ci->imx28_write_fix)
> +		imx28_ci_writel(val, ci->hw_bank.regmap[reg]);
> +	else
> +		iowrite32(val, ci->hw_bank.regmap[reg]);
> +#else
>   	iowrite32(val, ci->hw_bank.regmap[reg]);
> +#endif
>   	return val;
>   }

Can't we remove the #ifdefs CONFIG_SOC_IMX28 all around?
The check is done on the new flag ci->imx28_write_fix which exists for all platforms, 
isn't it?.

Best regards,
-- 
Héctor Palacios