On 8/30/2024 6:01 PM, Robin Murphy wrote:
On 30/08/2024 11:00 am, Bibek Kumar Patro wrote:On 8/27/2024 6:17 PM, Will Deacon wrote:On Mon, Aug 26, 2024 at 04:33:24PM +0530, Bibek Kumar Patro wrote:On 8/23/2024 9:29 PM, Will Deacon wrote:On Fri, Aug 16, 2024 at 11:12:58PM +0530, Bibek Kumar Patro wrote:Add ACTLR data table for SC7280 along with support for same including SC7280 specific implementation operations. Signed-off-by: Bibek Kumar Patro <quic_bibekkum@xxxxxxxxxxx> ---drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 58 +++++++++++++++++++++-1 file changed, 57 insertions(+), 1 deletion(-)diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.cindex dc143b250704..a776c7906c76 100644 --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c @@ -31,6 +31,55 @@ #define PREFETCH_MODERATE (2 << PREFETCH_SHIFT) #define PREFETCH_DEEP (3 << PREFETCH_SHIFT) +static const struct actlr_config sc7280_apps_actlr_cfg[] = { + { 0x0800, 0x04e0, PREFETCH_DEFAULT | CMTLB }, + { 0x0900, 0x0402, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x0901, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x0d01, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x1181, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1182, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1183, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1184, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1185, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1186, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1187, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1188, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x1189, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x118b, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x118c, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x118d, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x118e, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x118f, 0x0420, PREFETCH_DEEP | CPRE | CMTLB }, + { 0x2000, 0x0020, PREFETCH_DEFAULT | CMTLB }, + { 0x2040, 0x0000, PREFETCH_DEFAULT | CMTLB }, + { 0x2062, 0x0000, PREFETCH_DEFAULT | CMTLB }, + { 0x2080, 0x0020, PREFETCH_DEFAULT | CMTLB }, + { 0x20c0, 0x0020, PREFETCH_DEFAULT | CMTLB }, + { 0x2100, 0x0020, PREFETCH_DEFAULT | CMTLB }, + { 0x2140, 0x0000, PREFETCH_DEFAULT | CMTLB }, + { 0x2180, 0x0020, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x2181, 0x0004, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x2183, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x2184, 0x0020, PREFETCH_SHALLOW | CPRE | CMTLB }, + { 0x2187, 0x0000, PREFETCH_SHALLOW | CPRE | CMTLB }, +}; + +static const struct actlr_config sc7280_gfx_actlr_cfg[] = { + { 0x0000, 0x07ff, PREFETCH_DEEP | CPRE | CMTLB }, +};It's Will "stuck record" Deacon here again to say that I don't think this data belongs in the driver.Hi Will,It will be difficult to reach a consensus here, with Robin and the DT folks okay to keep it in the driver, while you believe it doesn't belong there.Robin, Rob, could you please share your thoughts on concluding the placementof this prefetch data?As discussed earlier [1], the prefetch value for each client doesn’t define the hardware topology and is implementation-defined register writes used bythe software driver.It does reflect the hardware topology though, doesn't it? Those magic hex masks above refer to stream ids, so the table is hard-coding the prefetchvalues for particular matches.That is correct in the sense that stream id is mapped to context bank where these configurations are applied. However the other part of it is implementation-defined register/values for which community opinion was register/value kind of data, should not belong to device tree and are not generally approved of. Would also like to point out that the prefetch values are recommended settings and doesn’t mean these are the only configuration which would work for the soc. So the SID-to-prefetch isn't strictly SoC defined but is a software configuration, IMO.What's particularly confusing is that most of the IDs encoded here don't actually seem to line up with what's in the respective SoC DTSIs...However by this point I'm wary of whether we've lost sight of *why* we're doing this, and that we're deep into begging the question of whether identifying devices by StreamID is the right thing to do in the first place. For example, as best I can tell from a quick skim, we have over 2 dozen lines of data here which all serve the exact same purpose of applying PREFETCH_DEEP | CPRE | CMTLB to instances of "qcom,fastrpc-compute-cb". In general it seems unlikely that the same device would want wildly different prefetch settings across different SoCs, or even between different instances in the same SoC, so I'm really coming round to the conclusion that this data would probably be best handled as an extension of the existing qcom_smmu_client_of_match mechanism.
As per your design idea,do you mean to use qcom_smmu_client_of_match to identify the device using compatible string and apply the device specific settings for all the SoCs (instead of StreamID based device identification) ?
something like this rough snippet(?):
qcom_smmu_find_actlr_client(struct device *dev)
{
if (of_match_device(qcom_smmu_client_of_match, dev) ==
qcom,fastrpc-compute-cb )
qcom_smmu_set_actlr_value(dev, (PREFETCH_DEEP | CPRE | CMTLB));
/*where (PREFETCH_DEEP | CPRE | CMTLB) is used for compute-cb client.*/
else if (of_match_device(qcom_smmu_client_of_match, dev) == qcom,adreno )qcom_smmu_set_actlr_value(dev, (PREFETCH_SHALLOW | CPRE | CMTLB)); /*Where (PREFETCH_SHALLOW | CPRE | CMTLB) is for adreno client. */
} Let me know if my understanding is incorrect.Then in this case if different SoC would have a different settings for same device, then everytime a new compatible would be necessary for same device on different SoC?
On similar lines there is another TBU based approach which I can think of. Identify the TBU -> Identify clients from TopoID derived from SID range specified in qcom,stream-id-range -> Apply the client
specific settings ? Both approaches would be driver-based, as they are now.Also I'd like to point out that in the current design, since we fixed the smr_is_subset arguments to make the stream IDs a subset of entries in the actlr_cfg table, we can reduce the number of entries in the table. This way, fewer SID-mask pairs can accommodate several stream IDs.
Thanks & regards, Bibek
Thanks, Robin.If I run on a different SoC configuration > with the same table, then the prefetch settings will be applied to thewrong devices. How is that not hardware topology?The configuration table is tied to SoC compatible string however as I mentioned above, its basically a s/w recommended setting.(using prefetch settings other than the recommended values e.g PREFECH_DEFAULT instead of PREFETCH_DEEP would not render the device unusable unlike changing stream-ids which can make it unusable).Since it is implementation specific we cannot have a generic DT binding, tying stream ids to these recommended settings. Even with qcom specific binding due to dependency on implementation, not sure if we would be able to maintain consistency. So from maintenance perspective carrying these in driver appear to be simpler/flexible. And if it doesn’t violate existing precedence, we would prefer to carry it that way.This parallels how _"QoS settings"_ are handled within the driver (similar to this example [1]).[1]. https://lore.kernel.org/linux-arm-msm/20231030-sc8280xp-dpu-safe-lut-v1-1-6d485d7b428f@xxxxxxxxxxx/#tThanks & regards, BibekWIll
