From: robin.murphy@arm•com (Robin Murphy)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 4/7] io-64-nonatomic: Add relaxed accessor variants
Date: Mon, 25 Apr 2016 16:28:01 +0100 [thread overview]
Message-ID: <571E3781.3070609@arm.com> (raw)
In-Reply-To: <5485134.l18Z1dlVmn@wuerfel>
Hi Arnd,
On 25/04/16 16:21, Arnd Bergmann wrote:
> On Monday 25 April 2016 14:32:42 Will Deacon wrote:
>>>>>
>>>>> +static inline __u64 hi_lo_readq_relaxed(const volatile void __iomem *addr)
>>>>> +{
>>>>> + const volatile u32 __iomem *p = addr;
>>>>> + u32 low, high;
>>>>> +
>>>>> + high = readl_relaxed(p + 1);
>>>>> + low = readl_relaxed(p);
>>>>> +
>>>>> + return low + ((u64)high << 32);
>>>>> +}
>>>>> +
>>>>> +static inline void hi_lo_writeq_relaxed(__u64 val, volatile void __iomem *addr)
>>>>> +{
>>>>> + writel_relaxed(val >> 32, addr + 4);
>>>>> + writel_relaxed(val, addr);
>>>>> +}
>>>>
>>>> Could we not generate the _relaxed variants with some macro magic?
>>>
>>> We _could_ - indeed I started doing that, but then decided that the
>>> obfuscation of horrible macro-templated functions wasn't worth saving a
>>> couple of hundred bytes in some code that isn't exactly difficult to
>>> maintain and has needed touching once in 4 years.
>>>
>>> If you did want to go down the macro route, I may as well also generate both
>>> lo-hi and hi-lo headers all from a single template, it'd be really clever...
>>> <alarm bells>
>>
>> I certainly wasn't suggesting any more than the obvious macroisation,
>> but I'll leave it up to Arnd, as I think this falls on his lap.
>
> I'd prefer the open-coded variant as well.
By that, do you mean sticking with the smmu_writeq() implementation in
the driver and dropping this patch, or merging this patch as-is without
further macro-magic?
Thanks,
Robin.
>
> Arnd
>
next prev parent reply other threads:[~2016-04-25 15:28 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-13 17:12 [PATCH 0/7] arm-smmu: Implementation and context format differentiation Robin Murphy
2016-04-13 17:12 ` [PATCH 1/7] iommu/arm-smmu: Differentiate specific implementations Robin Murphy
2016-04-13 21:15 ` Chalamarla, Tirumalesh
2016-04-13 17:12 ` [PATCH 2/7] iommu/arm-smmu: Convert ThunderX workaround to new method Robin Murphy
2016-04-13 21:16 ` Chalamarla, Tirumalesh
2016-04-13 17:12 ` [PATCH 3/7] iommu/arm-smmu: Work around MMU-500 prefetch errata Robin Murphy
2016-04-21 16:15 ` Will Deacon
2016-04-21 16:16 ` Will Deacon
2016-04-13 17:13 ` [PATCH 4/7] io-64-nonatomic: Add relaxed accessor variants Robin Murphy
2016-04-21 16:18 ` Will Deacon
2016-04-22 17:08 ` Robin Murphy
2016-04-25 13:32 ` Will Deacon
2016-04-25 15:21 ` Arnd Bergmann
2016-04-25 15:28 ` Robin Murphy [this message]
2016-04-25 15:41 ` Arnd Bergmann
2016-04-25 16:11 ` Will Deacon
2016-04-25 16:11 ` Arnd Bergmann
2016-04-26 10:38 ` [PATCH v2] " Robin Murphy
2016-04-13 17:13 ` [PATCH 5/7] iommu/arm-smmu: Tidy up 64-bit/atomic I/O accesses Robin Murphy
2016-04-13 17:13 ` [PATCH 6/7] iommu/arm-smmu: Decouple context format from kernel config Robin Murphy
2016-04-21 16:30 ` Will Deacon
2016-04-22 17:38 ` Robin Murphy
2016-04-25 11:02 ` Will Deacon
2016-04-25 13:14 ` Robin Murphy
2016-04-25 13:41 ` Will Deacon
2016-04-25 16:21 ` Robin Murphy
2016-04-28 16:12 ` [PATCH v2] " Robin Murphy
2016-04-13 17:13 ` [PATCH 7/7] iommu/arm-smmu: Support SMMUv1 64KB supplement Robin Murphy
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