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From: Robin Murphy <robin.murphy@arm.com>
To: Will Deacon <will@kernel.org>
Cc: bjorn.andersson@linaro.org, iommu@lists.linux-foundation.org,
	gregory.clement@bootlin.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 04/15] iommu/arm-smmu: Rework cb_base handling
Date: Thu, 15 Aug 2019 12:14:14 +0100
Message-ID: <6acaf8b3-c425-99ed-a90d-11d2501e6305@arm.com> (raw)
In-Reply-To: <20190814180556.5asp5qflrxxjipal@willie-the-truck>

On 14/08/2019 19:05, Will Deacon wrote:
> On Fri, Aug 09, 2019 at 06:07:41PM +0100, Robin Murphy wrote:
>> To keep register-access quirks manageable, we want to structure things
>> to avoid needing too many individual overrides. It seems fairly clean to
>> have a single interface which handles both global and context registers
>> in terms of the architectural pages, so the first preparatory step is to
>> rework cb_base into a page number rather than an absolute address.
>>
>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
>> ---
>>   drivers/iommu/arm-smmu.c | 22 ++++++++++++----------
>>   1 file changed, 12 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
>> index d9a93e5f422f..463bc8d98adb 100644
>> --- a/drivers/iommu/arm-smmu.c
>> +++ b/drivers/iommu/arm-smmu.c
>> @@ -95,7 +95,7 @@
>>   #endif
>>   
>>   /* Translation context bank */
>> -#define ARM_SMMU_CB(smmu, n)	((smmu)->cb_base + ((n) << (smmu)->pgshift))
>> +#define ARM_SMMU_CB(smmu, n)	((smmu)->base + (((smmu)->cb_base + (n)) << (smmu)->pgshift))
>>   
>>   #define MSI_IOVA_BASE			0x8000000
>>   #define MSI_IOVA_LENGTH			0x100000
>> @@ -168,8 +168,8 @@ struct arm_smmu_device {
>>   	struct device			*dev;
>>   
>>   	void __iomem			*base;
>> -	void __iomem			*cb_base;
>> -	unsigned long			pgshift;
>> +	unsigned int			cb_base;
> 
> I think this is now a misnomer. Would you be able to rename it cb_pfn or
> something, please?

Good point; in the architectural terms (section 8.1 of the spec), 
SMMU_CB_BASE is strictly a byte offset from SMMU_BASE, and the quantity 
we now have here is actually NUMPAGE. I've renamed it as such and 
tweaked the comments to be a bit more useful too.

Robin.
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Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-09 17:07 [PATCH 00/15] Arm SMMU refactoring Robin Murphy
2019-08-09 17:07 ` [PATCH 01/15] iommu/arm-smmu: Convert GR0 registers to bitfields Robin Murphy
2019-08-14 17:20   ` Will Deacon
2019-08-14 17:35     ` Robin Murphy
2019-08-09 17:07 ` [PATCH 02/15] iommu/arm-smmu: Convert GR1 " Robin Murphy
2019-08-09 17:07 ` [PATCH 03/15] iommu/arm-smmu: Convert context bank " Robin Murphy
2019-08-09 17:07 ` [PATCH 04/15] iommu/arm-smmu: Rework cb_base handling Robin Murphy
2019-08-14 18:05   ` Will Deacon
2019-08-15 11:14     ` Robin Murphy [this message]
2019-08-09 17:07 ` [PATCH 05/15] iommu/arm-smmu: Split arm_smmu_tlb_inv_range_nosync() Robin Murphy
2019-08-15 10:56   ` Will Deacon
2019-08-15 11:22     ` Robin Murphy
2019-08-09 17:07 ` [PATCH 06/15] iommu/arm-smmu: Get rid of weird "atomic" write Robin Murphy
2019-08-09 17:07 ` [PATCH 07/15] iommu/arm-smmu: Abstract GR1 accesses Robin Murphy
2019-08-09 17:07 ` [PATCH 08/15] iommu/arm-smmu: Abstract context bank accesses Robin Murphy
2019-08-15 10:56   ` Will Deacon
2019-08-15 11:41     ` Robin Murphy
2019-08-09 17:07 ` [PATCH 09/15] iommu/arm-smmu: Abstract GR0 accesses Robin Murphy
2019-08-09 17:07 ` [PATCH 10/15] iommu/arm-smmu: Rename arm-smmu-regs.h Robin Murphy
2019-08-09 17:07 ` [PATCH 11/15] iommu/arm-smmu: Add implementation infrastructure Robin Murphy
2019-08-09 17:07 ` [PATCH 12/15] iommu/arm-smmu: Move Secure access quirk to implementation Robin Murphy
2019-08-09 17:07 ` [PATCH 13/15] iommu/arm-smmu: Add configuration implementation hook Robin Murphy
2019-08-09 17:07 ` [PATCH 14/15] iommu/arm-smmu: Add reset " Robin Murphy
2019-08-09 17:07 ` [PATCH 15/15] iommu/arm-smmu: Add context init " Robin Murphy
2019-08-13 19:11   ` Krishna Reddy
2019-08-15 10:56   ` Will Deacon
2019-08-15 12:09     ` Robin Murphy
2019-08-15 15:09       ` Jordan Crouse
2019-08-09 17:11 ` [PATCH 00/15] Arm SMMU refactoring Robin Murphy
2019-08-15 10:55 ` Will Deacon

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