Re: [PATCH 7/8] x86/mrst: add vrtc driver which serves as a wall clock device

Thomas Gleixner
2010-05-11T14:58:23Z

On Fri, 7 May 2010, Jacob Pan wrote:
> --- /dev/null
> +++ b/arch/x86/include/asm/vrtc.h
> @@ -0,0 +1,27 @@
> +#ifndef _MRST_VRTC_H
> +#define _MRST_VRTC_H
> +
> +#ifdef CONFIG_X86_MRST
> +extern unsigned char vrtc_cmos_read(unsigned char reg);
> +extern void vrtc_cmos_write(unsigned char val, unsigned char reg);
> +extern unsigned long vrtc_get_time(void);
> +extern int vrtc_set_mmss(unsigned long nowtime);
> +extern void vrtc_set_base(void __iomem *base);
> +
> +#define MRST_VRTC_PGOFFSET (0xc00)
> +
> +#else

Errm. That's a MRST specific header and nothing outside of MRST is
using it. So why the #ifdef CONFIG_X86_MRST and the inline functions
in the #else path ?

> +static inline unsigned char vrtc_cmos_read(unsigned char reg)
> +{
> + return 0xff;
> +}
> +

> /**
> * the clockevent devices on Moorestown/Medfield can be APBT or LAPIC clock,
> @@ -268,7 +269,24 @@ void __init mrst_time_init(void)
>
> void __init mrst_rtc_init(void)
> {
> + unsigned long rtc_paddr;
> + void __iomem *virt_base;
> +
> sfi_table_parse(SFI_SIG_MRTC, NULL, NULL, sfi_parse_mrtc);
> + if (!sfi_mrtc_num)
> + return;
> +
> + rtc_paddr = sfi_mrtc_array[0].phys_addr;
> +
> + /* vRTC's register address may not be page aligned */
> + set_fixmap_nocache(FIX_LNW_VRTC, rtc_paddr);

Why do we need a fixmap for that ? There is no need to setup RTC that
early. The first call is from timekeeping_init()

Also this RTC init code should be in vrtc.c

> +
> +static unsigned char __iomem *vrtc_virt_base;
> +
> +void vrtc_set_base(void __iomem *base)
> +{
> + vrtc_virt_base = base;
> +}
> +
> +unsigned char vrtc_cmos_read(unsigned char reg)
> +{
> + unsigned char retval;
> +
> + /* vRTC's registers range from 0x0 to 0xD */
> + if (reg > 0xd || !vrtc_virt_base)
> + return 0xff;
> +
> + lock_cmos_prefix(reg);

This lock_cmos magic should just die. I have no idea why something
wants or wanted to access the RTC from an NMI.

> + retval = __raw_readb(vrtc_virt_base + (reg << 2));
> + lock_cmos_suffix(reg);
> + return retval;
> +}
> +EXPORT_SYMBOL(vrtc_cmos_read);
> +
> +void vrtc_cmos_write(unsigned char val, unsigned char reg)
> +{
> + if (reg > 0xd || !vrtc_virt_base)
> + return;
> +
> + lock_cmos_prefix(reg);
> + __raw_writeb(val, vrtc_virt_base + (reg << 2));
> + lock_cmos_suffix(reg);
> +}
> +EXPORT_SYMBOL(vrtc_cmos_write);
> +
> +unsigned long vrtc_get_time(void)
> +{
> + u8 sec, min, hour, mday, mon;
> + u32 year;
> +
> + while ((vrtc_cmos_read(RTC_FREQ_SELECT) & RTC_UIP))
> + cpu_relax();
> +
> + sec = vrtc_cmos_read(RTC_SECONDS);
> + min = vrtc_cmos_read(RTC_MINUTES);
> + hour = vrtc_cmos_read(RTC_HOURS);
> + mday = vrtc_cmos_read(RTC_DAY_OF_MONTH);
> + mon = vrtc_cmos_read(RTC_MONTH);
> + year = vrtc_cmos_read(RTC_YEAR);
> +
> + /* vRTC YEAR reg contains the offset to 1960 */
> + year += 1960;
> +
> + printk(KERN_INFO "vRTC: sec: %d min: %d hour: %d day: %d "
> + "mon: %d year: %d\n", sec, min, hour, mday, mon, year);

Please remove the debug noise

Thanks,

tglx