| Message ID | 20180814105528.20592-5-vivek.gautam@codeaurora.org (mailing list archive) |
|---|---|
| State | Deferred, archived |
| Delegated to: | Andy Gross |
| Headers | show |
| Series | Qcom smmu-500 TLB invalidation errata for sdm845 | expand |
On Tue, Aug 14, 2018 at 04:25:27PM +0530, Vivek Gautam wrote:
> Cleanup to re-use some of the stuff
Maybe we should factor a few of the other bits whilst we're here.
Or just write a proper commit message ;)
Will
On 8/14/2018 5:10 PM, Will Deacon wrote: > On Tue, Aug 14, 2018 at 04:25:27PM +0530, Vivek Gautam wrote: >> Cleanup to re-use some of the stuff > Maybe we should factor a few of the other bits whilst we're here. Sure, do you want me to refactor anything besides this change? > > Or just write a proper commit message ;) My bad. I should have written a more descriptive commit message. :| Will change this. Best regards Vivek > > Will
On 14/08/18 11:55, Vivek Gautam wrote: > Cleanup to re-use some of the stuff > > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > --- > drivers/iommu/arm-smmu.c | 32 +++++++++++++++++++++++++------- > 1 file changed, 25 insertions(+), 7 deletions(-) I think the overall diffstat would be an awful lot smaller if the erratum workaround just has its own readl_poll_timeout() as it does in the vendor kernel. The burst-polling loop is for minimising latency in high-throughput situations, and if you're in a workaround which has to lock *every* register write and issue two firmware calls around each sync I think you're already well out of that game. > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c > index 32e86df80428..75c146751c87 100644 > --- a/drivers/iommu/arm-smmu.c > +++ b/drivers/iommu/arm-smmu.c > @@ -391,21 +391,31 @@ static void __arm_smmu_free_bitmap(unsigned long *map, int idx) > clear_bit(idx, map); > } > > -/* Wait for any pending TLB invalidations to complete */ > -static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, > - void __iomem *sync, void __iomem *status) > +static int __arm_smmu_tlb_sync_wait(void __iomem *status) > { > unsigned int spin_cnt, delay; > > - writel_relaxed(0, sync); > for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) { > for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) { > if (!(readl_relaxed(status) & sTLBGSTATUS_GSACTIVE)) > - return; > + return 0; > cpu_relax(); > } > udelay(delay); > } > + > + return -EBUSY; > +} > + > +/* Wait for any pending TLB invalidations to complete */ > +static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, > + void __iomem *sync, void __iomem *status) > +{ > + writel_relaxed(0, sync); > + > + if (!__arm_smmu_tlb_sync_wait(status)) > + return; > + > dev_err_ratelimited(smmu->dev, > "TLB sync timed out -- SMMU may be deadlocked\n"); > } > @@ -461,8 +471,9 @@ static void arm_smmu_tlb_inv_context_s2(void *cookie) > arm_smmu_tlb_sync_global(smmu); > } > > -static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, > - size_t granule, bool leaf, void *cookie) > +static void __arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, > + size_t granule, bool leaf, > + void *cookie) > { > struct arm_smmu_domain *smmu_domain = cookie; > struct arm_smmu_cfg *cfg = &smmu_domain->cfg; > @@ -498,6 +509,13 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, > } > } > > +static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, > + size_t granule, bool leaf, > + void *cookie) > +{ > + __arm_smmu_tlb_inv_range_nosync(iova, size, granule, leaf, cookie); > +} > + AFAICS even after patch #5 this does absolutely nothing except make the code needlessly harder to read :( Robin. > /* > * On MMU-401 at least, the cost of firing off multiple TLBIVMIDs appears > * almost negligible, but the benefit of getting the first one in as far ahead >
Hi Robin, On 8/14/2018 10:29 PM, Robin Murphy wrote: > On 14/08/18 11:55, Vivek Gautam wrote: >> Cleanup to re-use some of the stuff >> >> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >> --- >> drivers/iommu/arm-smmu.c | 32 +++++++++++++++++++++++++------- >> 1 file changed, 25 insertions(+), 7 deletions(-) > > I think the overall diffstat would be an awful lot smaller if the > erratum workaround just has its own readl_poll_timeout() as it does in > the vendor kernel. The burst-polling loop is for minimising latency in > high-throughput situations, and if you're in a workaround which has to > lock *every* register write and issue two firmware calls around each > sync I think you're already well out of that game. Sorry for the delayed response. I was on vacation. I will fix this in my next version by adding the separate read_poll_timeout() for the erratum WA. > >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 32e86df80428..75c146751c87 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -391,21 +391,31 @@ static void __arm_smmu_free_bitmap(unsigned >> long *map, int idx) >> clear_bit(idx, map); >> } >> -/* Wait for any pending TLB invalidations to complete */ >> -static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, >> - void __iomem *sync, void __iomem *status) >> +static int __arm_smmu_tlb_sync_wait(void __iomem *status) >> { >> unsigned int spin_cnt, delay; >> - writel_relaxed(0, sync); >> for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) { >> for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) { >> if (!(readl_relaxed(status) & sTLBGSTATUS_GSACTIVE)) >> - return; >> + return 0; >> cpu_relax(); >> } >> udelay(delay); >> } >> + >> + return -EBUSY; >> +} >> + >> +/* Wait for any pending TLB invalidations to complete */ >> +static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, >> + void __iomem *sync, void __iomem *status) >> +{ >> + writel_relaxed(0, sync); >> + >> + if (!__arm_smmu_tlb_sync_wait(status)) >> + return; >> + >> dev_err_ratelimited(smmu->dev, >> "TLB sync timed out -- SMMU may be deadlocked\n"); >> } >> @@ -461,8 +471,9 @@ static void arm_smmu_tlb_inv_context_s2(void >> *cookie) >> arm_smmu_tlb_sync_global(smmu); >> } >> -static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, >> size_t size, >> - size_t granule, bool leaf, void *cookie) >> +static void __arm_smmu_tlb_inv_range_nosync(unsigned long iova, >> size_t size, >> + size_t granule, bool leaf, >> + void *cookie) >> { >> struct arm_smmu_domain *smmu_domain = cookie; >> struct arm_smmu_cfg *cfg = &smmu_domain->cfg; >> @@ -498,6 +509,13 @@ static void >> arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, >> } >> } >> +static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, >> size_t size, >> + size_t granule, bool leaf, >> + void *cookie) >> +{ >> + __arm_smmu_tlb_inv_range_nosync(iova, size, granule, leaf, cookie); >> +} >> + > > AFAICS even after patch #5 this does absolutely nothing except make > the code needlessly harder to read :( Sure, I will rather call arm_smmu_tlb_inv_range_nosync() from qcom_errata_tlb_inv_range_nosync() then make this change. Thanks for the review. Best regards Vivek > > Robin. > >> /* >> * On MMU-401 at least, the cost of firing off multiple TLBIVMIDs >> appears >> * almost negligible, but the benefit of getting the first one in >> as far ahead >>
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index 32e86df80428..75c146751c87 100644 --- a/drivers/iommu/arm-smmu.c +++ b/drivers/iommu/arm-smmu.c @@ -391,21 +391,31 @@ static void __arm_smmu_free_bitmap(unsigned long *map, int idx) clear_bit(idx, map); } -/* Wait for any pending TLB invalidations to complete */ -static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, - void __iomem *sync, void __iomem *status) +static int __arm_smmu_tlb_sync_wait(void __iomem *status) { unsigned int spin_cnt, delay; - writel_relaxed(0, sync); for (delay = 1; delay < TLB_LOOP_TIMEOUT; delay *= 2) { for (spin_cnt = TLB_SPIN_COUNT; spin_cnt > 0; spin_cnt--) { if (!(readl_relaxed(status) & sTLBGSTATUS_GSACTIVE)) - return; + return 0; cpu_relax(); } udelay(delay); } + + return -EBUSY; +} + +/* Wait for any pending TLB invalidations to complete */ +static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu, + void __iomem *sync, void __iomem *status) +{ + writel_relaxed(0, sync); + + if (!__arm_smmu_tlb_sync_wait(status)) + return; + dev_err_ratelimited(smmu->dev, "TLB sync timed out -- SMMU may be deadlocked\n"); } @@ -461,8 +471,9 @@ static void arm_smmu_tlb_inv_context_s2(void *cookie) arm_smmu_tlb_sync_global(smmu); } -static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, - size_t granule, bool leaf, void *cookie) +static void __arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, + size_t granule, bool leaf, + void *cookie) { struct arm_smmu_domain *smmu_domain = cookie; struct arm_smmu_cfg *cfg = &smmu_domain->cfg; @@ -498,6 +509,13 @@ static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, } } +static void arm_smmu_tlb_inv_range_nosync(unsigned long iova, size_t size, + size_t granule, bool leaf, + void *cookie) +{ + __arm_smmu_tlb_inv_range_nosync(iova, size, granule, leaf, cookie); +} + /* * On MMU-401 at least, the cost of firing off multiple TLBIVMIDs appears * almost negligible, but the benefit of getting the first one in as far ahead
Cleanup to re-use some of the stuff Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> --- drivers/iommu/arm-smmu.c | 32 +++++++++++++++++++++++++------- 1 file changed, 25 insertions(+), 7 deletions(-)