Messages in this thread | | | Date | Fri, 11 Sep 2009 15:01:16 +0900 | Subject | Re: [PATCH] Add memory mapped RTC driver for UV | From | Minchan Kim <> |
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On Fri, Sep 11, 2009 at 2:52 PM, Andrew Morton <akpm@linux-foundation.org> wrote: > On Thu, 10 Sep 2009 20:30:54 -0500 Dimitri Sivanich <sivanich@sgi.com> wrote: > >> This driver memory maps the UV Hub RTC. >> >> ... >> >> +/** >> + * uv_mmtimer_ioctl - ioctl interface for /dev/uv_mmtimer >> + * @file: file structure for the device >> + * @cmd: command to execute >> + * @arg: optional argument to command >> + * >> + * Executes the command specified by @cmd. Returns 0 for success, < 0 for >> + * failure. >> + * >> + * Valid commands: >> + * >> + * %MMTIMER_GETOFFSET - Should return the offset (relative to the start >> + * of the page where the registers are mapped) for the counter in question. >> + * >> + * %MMTIMER_GETRES - Returns the resolution of the clock in femto (10^-15) >> + * seconds >> + * >> + * %MMTIMER_GETFREQ - Copies the frequency of the clock in Hz to the address >> + * specified by @arg >> + * >> + * %MMTIMER_GETBITS - Returns the number of bits in the clock's counter >> + * >> + * %MMTIMER_MMAPAVAIL - Returns 1 if registers can be mmap'd into userspace >> + * >> + * %MMTIMER_GETCOUNTER - Gets the current value in the counter and places it >> + * in the address specified by @arg. > > Are these % thingies part of kerneldoc? > >> + */ >> +static long uv_mmtimer_ioctl(struct file *file, unsigned int cmd, >> + unsigned long arg) >> +{ >> + int ret = 0; >> + >> + switch (cmd) { >> + case MMTIMER_GETOFFSET: /* offset of the counter */ >> + /* >> + * UV RTC register is on it's own page > > "its" ;) > >> + */ >> + if (PAGE_SIZE <= (1 << 16)) >> + ret = ((UV_LOCAL_MMR_BASE | UVH_RTC) & (PAGE_SIZE-1)) >> + / 8; >> + else >> + ret = -ENOSYS; >> + break; >> + >> + case MMTIMER_GETRES: /* resolution of the clock in 10^-15 s */ >> + if (copy_to_user((unsigned long __user *)arg, >> + &uv_mmtimer_femtoperiod, sizeof(unsigned long))) >> + ret = -EFAULT; >> + break; >> + >> + case MMTIMER_GETFREQ: /* frequency in Hz */ >> + if (copy_to_user((unsigned long __user *)arg, >> + &sn_rtc_cycles_per_second, >> + sizeof(unsigned long))) >> + ret = -EFAULT; >> + break; >> + >> + case MMTIMER_GETBITS: /* number of bits in the clock */ >> + ret = hweight64(UVH_RTC_REAL_TIME_CLOCK_MASK); >> + break; >> + >> + case MMTIMER_MMAPAVAIL: /* can we mmap the clock into userspace? */ >> + ret = (PAGE_SIZE <= (1 << 16)) ? 1 : 0; >> + break; >> + >> + case MMTIMER_GETCOUNTER: >> + if (copy_to_user((unsigned long __user *)arg, >> + (unsigned long *)uv_local_mmr_address(UVH_RTC), >> + sizeof(unsigned long))) >> + ret = -EFAULT; >> + break; >> + default: >> + ret = -ENOTTY; >> + break; >> + } >> + return ret; >> +} >> + >> +/** >> + * uv_mmtimer_mmap - maps the clock's registers into userspace >> + * @file: file structure for the device >> + * @vma: VMA to map the registers into >> + * >> + * Calls remap_pfn_range() to map the clock's registers into >> + * the calling process' address space. >> + */ >> +static int uv_mmtimer_mmap(struct file *file, struct vm_area_struct *vma) >> +{ >> + unsigned long uv_mmtimer_addr; >> + >> + if (vma->vm_end - vma->vm_start != PAGE_SIZE) >> + return -EINVAL; >> + >> + if (vma->vm_flags & VM_WRITE) >> + return -EPERM; >> + >> + if (PAGE_SIZE > (1 << 16)) >> + return -ENOSYS; >> + >> + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); >> + >> + uv_mmtimer_addr = UV_LOCAL_MMR_BASE | UVH_RTC; >> + uv_mmtimer_addr &= ~(PAGE_SIZE - 1); >> + uv_mmtimer_addr &= 0xfffffffffffffffUL; >> + >> + if (remap_pfn_range(vma, vma->vm_start, uv_mmtimer_addr >> PAGE_SHIFT, >> + PAGE_SIZE, vma->vm_page_prot)) { >> + printk(KERN_ERR "remap_pfn_range failed in uv_mmtimer_mmap\n"); >> + return -EAGAIN; >> + } >> + >> + return 0; >> +} > > Methinks we should be setting vma->vm_flags's VM_IO here and perhaps > also VM_RESERVED.
remap_pfn_range already does it. :)
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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