Re: [PATCH v4 2/4] interconnect: qcom: Add OSM L3 interconnect provider support

[Georgi Djakov]

On 1/22/20 08:45, Sibi Sankar wrote:
> Hey Evan,
> 
> Thanks for the review!
> 
> On 2020-01-22 03:03, Evan Green wrote:
>> On Thu, Jan 9, 2020 at 1:12 PM Sibi Sankar <sibis@xxxxxxxxxxxxxx> wrote:
>>>
>>> On some Qualcomm SoCs, Operating State Manager (OSM) controls the
>>> resources of scaling L3 caches. Add a driver to handle bandwidth
>>> requests to OSM L3 from CPU on SDM845 SoCs.
>>>
>>> Signed-off-by: Sibi Sankar <sibis@xxxxxxxxxxxxxx>
>>> ---
>>> Âdrivers/interconnect/qcom/Kconfig | 7 +
>>> Âdrivers/interconnect/qcom/Makefile |ÂÂ 2 +
>>> Âdrivers/interconnect/qcom/osm-l3.c | 267 +++++++++++++++++++++++++++++
>>> Â3 files changed, 276 insertions(+)
>>> Âcreate mode 100644 drivers/interconnect/qcom/osm-l3.c
>>>
>>> diff --git a/drivers/interconnect/qcom/Kconfig
>>> b/drivers/interconnect/qcom/Kconfig
>>> index a9bbbdf7400f9..b94d28e7bf700 100644
>>> --- a/drivers/interconnect/qcom/Kconfig
>>> +++ b/drivers/interconnect/qcom/Kconfig
>>> @@ -14,6 +14,13 @@ config INTERCONNECT_QCOM_MSM8974
>>> ÂÂÂÂÂÂÂÂ This is a driver for the Qualcomm Network-on-Chip on msm8974-based
>>> ÂÂÂÂÂÂÂÂ platforms.
>>>
>>> +config INTERCONNECT_QCOM_OSM_L3
>>> +ÂÂÂÂÂÂ tristate "Qualcomm OSM L3 interconnect driver"
>>> +ÂÂÂÂÂÂ depends on INTERCONNECT_QCOM || COMPILE_TEST
>>> +ÂÂÂÂÂÂ help
>>> +ÂÂÂÂÂÂÂÂ Say y here to support the Operating State Manager (OSM) interconnect
>>> +ÂÂÂÂÂÂÂÂ driver which controls the scaling of L3 caches on Qualcomm SoCs.
>>> +
>>> Âconfig INTERCONNECT_QCOM_QCS404
>>> ÂÂÂÂÂÂÂ tristate "Qualcomm QCS404 interconnect driver"
>>> ÂÂÂÂÂÂÂ depends on INTERCONNECT_QCOM
>>> diff --git a/drivers/interconnect/qcom/Makefile
>>> b/drivers/interconnect/qcom/Makefile
>>> index 55ec3c5c89dbd..89fecbd1257c7 100644
>>> --- a/drivers/interconnect/qcom/Makefile
>>> +++ b/drivers/interconnect/qcom/Makefile
>>> @@ -1,5 +1,6 @@
>>> Â# SPDX-License-Identifier: GPL-2.0
>>>
>>> +icc-osm-l3-objsÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ := osm-l3.o
>>> Âqnoc-msm8974-objsÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ := msm8974.o
>>> Âqnoc-qcs404-objsÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ := qcs404.o
>>> Âqnoc-sc7180-objsÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ := sc7180.o
>>> @@ -12,6 +13,7 @@ icc-smd-rpm-objsÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ := smd-rpm.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_BCM_VOTER) += icc-bcm-voter.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_MSM8916) += qnoc-msm8916.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_MSM8974) += qnoc-msm8974.o
>>> +obj-$(CONFIG_INTERCONNECT_QCOM_OSM_L3) += icc-osm-l3.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_QCS404) += qnoc-qcs404.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_RPMH) += icc-rpmh.o
>>> Âobj-$(CONFIG_INTERCONNECT_QCOM_SC7180) += qnoc-sc7180.o
>>> diff --git a/drivers/interconnect/qcom/osm-l3.c
>>> b/drivers/interconnect/qcom/osm-l3.c
>>> new file mode 100644
>>> index 0000000000000..7fde53c70081e
>>> --- /dev/null
>>> +++ b/drivers/interconnect/qcom/osm-l3.c
>>> @@ -0,0 +1,267 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/*
>>> + * Copyright (c) 2019, The Linux Foundation. All rights reserved.
>>> + *
>>> + */
>>> +
>>> +#include <dt-bindings/interconnect/qcom,osm-l3.h>
>>> +#include <linux/bitfield.h>
>>> +#include <linux/clk.h>
>>> +#include <linux/interconnect-provider.h>
>>> +#include <linux/io.h>
>>> +#include <linux/kernel.h>
>>> +#include <linux/module.h>
>>> +#include <linux/of_device.h>
>>> +#include <linux/of_platform.h>
>>> +#include <linux/platform_device.h>
>>> +
>>> +#define LUT_MAX_ENTRIESÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 40U
>>> +#define LUT_SRCÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GENMASK(31, 30)
>>> +#define LUT_L_VALÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GENMASK(7, 0)
>>> +#define LUT_ROW_SIZEÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 32
>>> +#define CLK_HW_DIVÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 2
>>> +
>>> +/* Register offsets */
>>> +#define REG_ENABLEÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 0x0
>>> +#define REG_FREQ_LUTÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 0x110
>>> +#define REG_PERF_STATEÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 0x920
>>> +
>>> +#define OSM_L3_MAX_LINKSÂÂÂÂÂÂÂÂÂÂÂÂÂÂ 1
>>> +#define SDM845_MAX_RSC_NODESÂÂÂÂÂÂÂÂÂÂ 130
>>
>> I'm nervous this define is going to fall out of date with
>> qcom,sdm845.h. I'm worried someone will end up adding a few more nodes
>> that were always there but previously hidden from Linux. Can we put
>> this define in include/dt-bindings/interconnect/qcom,sdm845.h, so at
>> least when that happens they'll come face to face with this define?
>> The same comment goes for the SC7180 define in patch 4.
> 
> Yeah both solution require manual
> intervention how about we just go
> with what I proposed below.
> 
>>
>> On second thought, this trick only works once. Are we sure there
>> aren't going to be other drivers that might want to tag on
>> interconnect nodes as well? How about instead we just add the enum
>> values below in qcom,sdm845.h as defines?
> 
> Georgi/Evan,
> Since qcom,sdm845.h is specific to
> bindings shouldn't I just create a
> .h file with all the enums so that
> it can used across all icc providers
> on SDM845?

This sounds good to me, unless Evan has any objections.

Thanks,
Georgi