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Message-ID: <03f83755-bdcc-dc39-0eae-08414751be57@linaro.org>
Date: Wed, 22 Jan 2020 10:19:58 +0200
From: Georgi Djakov <georgi.djakov@...aro.org>
To: Sibi Sankar <sibis@...eaurora.org>,
Evan Green <evgreen@...omium.org>
Cc: Rob Herring <robh+dt@...nel.org>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Andy Gross <agross@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>,
linux-arm-msm <linux-arm-msm@...r.kernel.org>,
Mark Rutland <mark.rutland@....com>,
David Dai <daidavid1@...eaurora.org>,
Saravana Kannan <saravanak@...gle.com>,
Viresh Kumar <viresh.kumar@...aro.org>
Subject: Re: [PATCH v4 2/4] interconnect: qcom: Add OSM L3 interconnect
provider support
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@...eaurora.org> 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@...eaurora.org>
>>> ---
>>> drivers/interconnect/qcom/Kconfig | 7 +
>>> drivers/interconnect/qcom/Makefile | 2 +
>>> drivers/interconnect/qcom/osm-l3.c | 267 +++++++++++++++++++++++++++++
>>> 3 files changed, 276 insertions(+)
>>> create 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
>>> This is a driver for the Qualcomm Network-on-Chip on msm8974-based
>>> platforms.
>>>
>>> +config INTERCONNECT_QCOM_OSM_L3
>>> + tristate "Qualcomm OSM L3 interconnect driver"
>>> + depends on INTERCONNECT_QCOM || COMPILE_TEST
>>> + help
>>> + Say y here to support the Operating State Manager (OSM) interconnect
>>> + driver which controls the scaling of L3 caches on Qualcomm SoCs.
>>> +
>>> config INTERCONNECT_QCOM_QCS404
>>> tristate "Qualcomm QCS404 interconnect driver"
>>> 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 @@
>>> # SPDX-License-Identifier: GPL-2.0
>>>
>>> +icc-osm-l3-objs := osm-l3.o
>>> qnoc-msm8974-objs := msm8974.o
>>> qnoc-qcs404-objs := qcs404.o
>>> qnoc-sc7180-objs := sc7180.o
>>> @@ -12,6 +13,7 @@ icc-smd-rpm-objs := smd-rpm.o
>>> obj-$(CONFIG_INTERCONNECT_QCOM_BCM_VOTER) += icc-bcm-voter.o
>>> obj-$(CONFIG_INTERCONNECT_QCOM_MSM8916) += qnoc-msm8916.o
>>> obj-$(CONFIG_INTERCONNECT_QCOM_MSM8974) += qnoc-msm8974.o
>>> +obj-$(CONFIG_INTERCONNECT_QCOM_OSM_L3) += icc-osm-l3.o
>>> obj-$(CONFIG_INTERCONNECT_QCOM_QCS404) += qnoc-qcs404.o
>>> obj-$(CONFIG_INTERCONNECT_QCOM_RPMH) += icc-rpmh.o
>>> obj-$(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_ENTRIES 40U
>>> +#define LUT_SRC GENMASK(31, 30)
>>> +#define LUT_L_VAL GENMASK(7, 0)
>>> +#define LUT_ROW_SIZE 32
>>> +#define CLK_HW_DIV 2
>>> +
>>> +/* Register offsets */
>>> +#define REG_ENABLE 0x0
>>> +#define REG_FREQ_LUT 0x110
>>> +#define REG_PERF_STATE 0x920
>>> +
>>> +#define OSM_L3_MAX_LINKS 1
>>> +#define SDM845_MAX_RSC_NODES 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
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