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Message-ID: <a16b57be-34cd-d093-ac63-d02aef049e51@linaro.org>
Date: Wed, 28 Jun 2023 16:14:05 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Komal Bajaj <quic_kbajaj@...cinc.com>
Cc: Andy Gross <agross@...nel.org>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
Conor Dooley <conor+dt@...nel.org>,
linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
devicetree@...r.kernel.org
Subject: Re: [PATCH v4 5/6] soc: qcom: Add LLCC support for multi channel DDR
On 28/06/2023 11:45, Komal Bajaj wrote:
No HTML emails on public mailing lists, please.
>
>
> On 6/23/2023 7:56 PM, Dmitry Baryshkov wrote:
>> On Fri, 23 Jun 2023 at 17:19, Komal Bajaj<quic_kbajaj@...cinc.com> wrote:
>>> Add LLCC support for multi channel DDR configuration
>>> based on a feature register. Reading DDR channel
>>> confiuration uses nvmem framework, so select the
>>> dependency in Kconfig. Without this, there will be
>>> errors while building the driver with COMPILE_TEST only.
>>>
>>> Signed-off-by: Komal Bajaj<quic_kbajaj@...cinc.com>
>>> ---
>>> drivers/soc/qcom/Kconfig | 2 ++
>>> drivers/soc/qcom/llcc-qcom.c | 33 ++++++++++++++++++++++++++++++---
>>> 2 files changed, 32 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
>>> index a491718f8064..cc9ad41c63aa 100644
>>> --- a/drivers/soc/qcom/Kconfig
>>> +++ b/drivers/soc/qcom/Kconfig
>>> @@ -64,6 +64,8 @@ config QCOM_LLCC
>>> tristate "Qualcomm Technologies, Inc. LLCC driver"
>>> depends on ARCH_QCOM || COMPILE_TEST
>>> select REGMAP_MMIO
>>> + select NVMEM
>> No need to select NVMEM. The used functions are stubbed if NVMEM is disabled
>
> With the previous patch, where this config was not selected, below error
> was flagged by kernel test robot -
>
> drivers/soc/qcom/llcc-qcom.c: In function 'qcom_llcc_get_cfg_index':
> >> drivers/soc/qcom/llcc-qcom.c:951:15: error: implicit declaration
> of function 'nvmem_cell_read_u8'; did you mean
> 'nvmem_cell_read_u64'? [-Werror=implicit-function-declaration]
> 951 | ret = nvmem_cell_read_u8(&pdev->dev,
> "multi_chan_ddr", cfg_index);
> | ^~~~~~~~~~~~~~~~~~
> | nvmem_cell_read_u64
> cc1: some warnings being treated as errors
Judging from the rest of nvmem-consumer.h, it appears that not having
stubs for this function is an omission. Please fix the header instead.
>
>>> + select QCOM_SCM
>>> help
>>> Qualcomm Technologies, Inc. platform specific
>>> Last Level Cache Controller(LLCC) driver for platforms such as,
>>> diff --git a/drivers/soc/qcom/llcc-qcom.c b/drivers/soc/qcom/llcc-qcom.c
>>> index 6cf373da5df9..3c29612da1c5 100644
>>> --- a/drivers/soc/qcom/llcc-qcom.c
>>> +++ b/drivers/soc/qcom/llcc-qcom.c
>>> @@ -12,6 +12,7 @@
>>> #include <linux/kernel.h>
>>> #include <linux/module.h>
>>> #include <linux/mutex.h>
>>> +#include <linux/nvmem-consumer.h>
>>> #include <linux/of.h>
>>> #include <linux/of_device.h>
>>> #include <linux/regmap.h>
>>> @@ -943,6 +944,19 @@ static int qcom_llcc_cfg_program(struct platform_device *pdev,
>>> return ret;
>>> }
>>>
>>> +static int qcom_llcc_get_cfg_index(struct platform_device *pdev, u8 *cfg_index)
>>> +{
>>> + int ret;
>>> +
>>> + ret = nvmem_cell_read_u8(&pdev->dev, "multi-chan-ddr", cfg_index);
>>> + if (ret == -ENOENT) {
>> || ret == -EOPNOTSUPP ?
>
> Okay
>
>>> + *cfg_index = 0;
>>> + return 0;
>>> + }
>>> +
>>> + return ret;
>>> +}
>>> +
>>> static int qcom_llcc_remove(struct platform_device *pdev)
>>> {
>>> /* Set the global pointer to a error code to avoid referencing it */
>>> @@ -975,11 +989,13 @@ static int qcom_llcc_probe(struct platform_device *pdev)
>>> struct device *dev = &pdev->dev;
>>> int ret, i;
>>> struct platform_device *llcc_edac;
>>> - const struct qcom_llcc_config *cfg;
>>> + const struct qcom_llcc_config *cfg, *entry;
>>> const struct llcc_slice_config *llcc_cfg;
>>> u32 sz;
>>> + u8 cfg_index;
>>> u32 version;
>>> struct regmap *regmap;
>>> + u32 num_entries = 0;
>>>
>>> drv_data = devm_kzalloc(dev, sizeof(*drv_data), GFP_KERNEL);
>>> if (!drv_data) {
>>> @@ -1040,8 +1056,19 @@ static int qcom_llcc_probe(struct platform_device *pdev)
>>>
>>> drv_data->version = version;
>>>
>>> - llcc_cfg = cfg[0]->sct_data;
>>> - sz = cfg[0]->size;
>>> + ret = qcom_llcc_get_cfg_index(pdev, &cfg_index);
>>> + if (ret)
>>> + goto err;
>>> +
>>> + for (entry = cfg; entry->sct_data; entry++, num_entries++)
>>> + ;
>> Please add num_cfgs to the configuration data instead.
>
> Shall I create a new wrapper struct having a field num_cfg and a pointer
> to those cfgs
> because configuration data is itself an instance of "struct
> qcom_llcc_config" and
> we can have multiple instances of it.
A wrapper struct is a better approach in my opinion.
>
>
>>> + if (cfg_index >= num_entries || cfg_index < 0) {
>> cfg_index is unsigned, so it can not be less than 0.
>
> Okay.
>
>>> + ret = -EINVAL;
>>> + goto err;
>>> + }
>>> +
>>> + llcc_cfg = cfg[cfg_index].sct_data;
>>> + sz = cfg[cfg_index].size;
>>>
>>> for (i = 0; i < sz; i++)
>>> if (llcc_cfg[i].slice_id > drv_data->max_slices)
>>> --
>>> 2.40.1
>>>
>
--
With best wishes
Dmitry
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