[PATCH v3 1/7] iommu/arm-smmu-v3: Introduce SMMU option PAGE0_REGS_ONLY for ThunderX2 errata #74
Robin Murphy
robin.murphy at arm.com
Mon May 8 02:59:46 PDT 2017
On 08/05/17 10:17, Linu Cherian wrote:
> On Sat May 06, 2017 at 01:03:28AM +0200, Robert Richter wrote:
>> On 05.05.17 17:38:05, Geetha sowjanya wrote:
>>> From: Linu Cherian <linu.cherian at cavium.com>
>>>
>>> Cavium ThunderX2 SMMU implementation doesn't support page 1 register space
>>> and PAGE0_REGS_ONLY option will be enabled as an errata workaround.
>>>
>>> This option when turned on, replaces all page 1 offsets used for
>>> EVTQ_PROD/CONS, PRIQ_PROD/CONS register access with page 0 offsets.
>>>
>>> Signed-off-by: Linu Cherian <linu.cherian at cavium.com>
>>> Signed-off-by: Geetha Sowjanya <geethasowjanya.akula at cavium.com>
>>> ---
>>> .../devicetree/bindings/iommu/arm,smmu-v3.txt | 6 +++
>>> drivers/iommu/arm-smmu-v3.c | 44 ++++++++++++++++------
>>> 2 files changed, 38 insertions(+), 12 deletions(-)
>>
>>> @@ -1995,8 +2011,10 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
>>> if (!(smmu->features & ARM_SMMU_FEAT_PRI))
>>> return 0;
>>>
>>> - return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD,
>>> - ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS);
>>> + return arm_smmu_init_one_queue(smmu, &smmu->priq.q,
>>> + ARM_SMMU_PRIQ_PROD(smmu),
>>> + ARM_SMMU_PRIQ_CONS(smmu),
>>> + PRIQ_ENT_DWORDS);
>>
>> I would also suggest Robin's idea from the v1 review here. This works
>> if we rework arm_smmu_init_one_queue() to pass addresses instead of
>> offsets.
>>
>> This would make these widespread offset calculations obsolete.
>>
>
> Have pasted here the relevant changes for doing fixups on smmu base instead
> of offset to get feedback.
>
> This actually results in more lines of changes. If you think the below
> approach is still better, will post a V4 of this series with this change.
Why not just do this?:
static inline unsigned long page1_offset_adjust(
unsigned long off, struct arm_smmu_device *smmu)
{
if (off > SZ_64K && ARM_SMMU_PAGE0_REGS_ONLY(smmu))
return (off - SZ_64K);
return off;
}
AFAICS that should be the least disruptive way to go about it.
Robin.
>
>
> +static inline unsigned long arm_smmu_page1_base(
> + struct arm_smmu_device *smmu)
> +{
> + if (ARM_SMMU_PAGE0_REGS_ONLY(smmu))
> + return smmu->base;
> + else
> + return smmu->base + SZ_64K;
> +}
> +
>
> @@ -1948,8 +1962,8 @@ static void arm_smmu_put_resv_regions(struct device *dev,
> /* Probing and initialisation functions */
> static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
> struct arm_smmu_queue *q,
> - unsigned long prod_off,
> - unsigned long cons_off,
> + unsigned long prod_addr,
> + unsigned long cons_addr,
> size_t dwords)
> {
> size_t qsz = ((1 << q->max_n_shift) * dwords) << 3;
> @@ -1961,8 +1975,8 @@ static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
> return -ENOMEM;
> }
>
> - q->prod_reg = smmu->base + prod_off;
> - q->cons_reg = smmu->base + cons_off;
> + q->prod_reg = prod_addr;
> + q->cons_reg = cons_addr;
> q->ent_dwords = dwords;
>
> q->q_base = Q_BASE_RWA;
> @@ -1977,17 +1991,25 @@ static int arm_smmu_init_one_queue(struct arm_smmu_device *smmu,
> static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
> {
> int ret;
> + unsigned long page1_base, page0_base;
> +
> + page0_base = smmu->base;
> + page1_base = arm_smmu_page1_base(smmu);
>
> /* cmdq */
> spin_lock_init(&smmu->cmdq.lock);
> - ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q, ARM_SMMU_CMDQ_PROD,
> - ARM_SMMU_CMDQ_CONS, CMDQ_ENT_DWORDS);
> + ret = arm_smmu_init_one_queue(smmu, &smmu->cmdq.q,
> + page0_base + ARM_SMMU_CMDQ_PROD,
> + page0_base + ARM_SMMU_CMDQ_CONS,
> + CMDQ_ENT_DWORDS);
> if (ret)
> return ret;
>
> /* evtq */
> - ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q, ARM_SMMU_EVTQ_PROD,
> - ARM_SMMU_EVTQ_CONS, EVTQ_ENT_DWORDS);
> + ret = arm_smmu_init_one_queue(smmu, &smmu->evtq.q,
> + page1_base + ARM_SMMU_EVTQ_PROD,
> + page1_base + ARM_SMMU_EVTQ_CONS,
> + EVTQ_ENT_DWORDS);
> if (ret)
> return ret;
>
> @@ -1995,8 +2017,10 @@ static int arm_smmu_init_queues(struct arm_smmu_device *smmu)
> if (!(smmu->features & ARM_SMMU_FEAT_PRI))
> return 0;
>
> - return arm_smmu_init_one_queue(smmu, &smmu->priq.q, ARM_SMMU_PRIQ_PROD,
> - ARM_SMMU_PRIQ_CONS, PRIQ_ENT_DWORDS);
> + return arm_smmu_init_one_queue(smmu, &smmu->priq.q,
> + page1_base + ARM_SMMU_PRIQ_PROD,
> + page1_base + ARM_SMMU_PRIQ_CONS,
> + PRIQ_ENT_DWORDS);
> }
>
>
>
> @@ -2301,8 +2349,11 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
> {
> int ret;
> u32 reg, enables;
> + unsigned long page1_base;
> struct arm_smmu_cmdq_ent cmd;
>
> + page1_base = arm_smmu_page1_base(smmu);
> +
> /* Clear CR0 and sync (disables SMMU and queue processing) */
> reg = readl_relaxed(smmu->base + ARM_SMMU_CR0);
> if (reg & CR0_SMMUEN)
> @@ -2363,8 +2414,8 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
>
> /* Event queue */
> writeq_relaxed(smmu->evtq.q.q_base, smmu->base + ARM_SMMU_EVTQ_BASE);
> - writel_relaxed(smmu->evtq.q.prod, smmu->base + ARM_SMMU_EVTQ_PROD);
> - writel_relaxed(smmu->evtq.q.cons, smmu->base + ARM_SMMU_EVTQ_CONS);
> + writel_relaxed(smmu->evtq.q.prod, page1_base + ARM_SMMU_EVTQ_PROD);
> + writel_relaxed(smmu->evtq.q.cons, page1_base + ARM_SMMU_EVTQ_CONS);
>
> enables |= CR0_EVTQEN;
> ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
> @@ -2379,9 +2430,9 @@ static int arm_smmu_device_reset(struct arm_smmu_device *smmu, bool bypass)
> writeq_relaxed(smmu->priq.q.q_base,
> smmu->base + ARM_SMMU_PRIQ_BASE);
> writel_relaxed(smmu->priq.q.prod,
> - smmu->base + ARM_SMMU_PRIQ_PROD);
> + page1_base + ARM_SMMU_PRIQ_PROD);
> writel_relaxed(smmu->priq.q.cons,
> - smmu->base + ARM_SMMU_PRIQ_CONS);
> + page1_base + ARM_SMMU_PRIQ_CONS);
>
> enables |= CR0_PRIQEN;
> ret = arm_smmu_write_reg_sync(smmu, enables, ARM_SMMU_CR0,
>
>
>
> Thanks.
>
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